ams AG

austriamicrosystems AG
is now
ams AG
The technical content of this austriamicrosystems datasheet is still valid.
Contact information:
Headquarters:
ams AG
Tobelbaderstrasse 30
8141 Unterpremstaetten, Austria
Tel: +43 (0) 3136 500 0
e-Mail: [email protected]
Please visit our website at www.ams.com
AS3687/87XM
Datasheet
Datasheet
AS3687/87XM
Flexible Lighting Management (Charge Pump, DCDC Step
Up, Seven Current Sinks, ADC, LED Test, Audio Light)
Internal PWM Generation
− 8 Bit resolution
− Autonomous Logarithmic up/down
dimming

Led Pattern Generator
− Autonomous driving for Fun RGB LEDs
− Support indicator LEDs

10-bit Successive Approximation ADC
− 27µs Conversion Time
− Selectable Inputs: all current sources,
VBAT, CP_OUT, DCDC_FB
− Internal Temp. Measurement

Support for automatic LED testing (open and
shorted LEDs can be identified in-circuit)

Standby LDO always on if serial interface is on
− Regulated 2.5V max. output 10mA
− 3µA Quiescent Current
− Automatic wakeup if serial interface is
enabled (allows ultra low power for device
shutdown)

Audio can be used to drive RGB LED
(AS3687XM only)
− RGB Color and Brightness is dependent
on audio input amplitude
− Can drive one or two RGB LEDs

Wide Battery Supply Range: 3.0 to 5.5V

Two Wire Serial Interface Control

Overcurrent and Thermal Protection

Small Package
WL-CSP 4x5 balls 0.5mm pitch
2 Key Features

High-Efficiency Step Up DC/DC Converter
− Up to 25V/50mA for White LEDs
− Programmable Output Voltage with
External Resistors and Serial Interface
− Overvoltage Protection
High-Efficiency Low Noise Charge Pump
− 1:1, 1:1.5, and 1:2 Mode
− Automatic Up Switching (can be disabled
and 1:2 mode can be blocked)
− Output Current up to 150mA
− Efficiency up to 95%
− Only 4 External Capacitors Required:
2 x 500nF Flying Capacitors, 2 x 1µF
Input/Output Capacitors
− Supports LCD White Backlight or RGB
LEDs
ch
ni
ca

Seven Current Sinks
− All seven current sinks fully Programmable
(8-bit) from: 0.15mA to 38.5mA (CURR1,
CURR2, CURR6, CURR30, CURR31,
CURR32, CURR33)
− Three current sinks are High Voltage
capable (CURR1, CURR2, CURR6)
− Selectively Enable/Disable Current Sinks
3 Application
Te

am
lc s
on A
te G
nt
st
il
The AS3687/87XM is a highly-integrated CMOS
Lighting Management Unit for mobile telephones,
and other 1-cell Li+ or 3-cell NiMH powered
devices.
The AS3687/87XM incorporates one Step Up
DC/DC Converter for white backlight LEDs, one low
noise Charge Pump for indicator- or RGB- LEDs,
LED test circuit (production test of the soldered
LEDs at the customer site), one Analog-to-Digital
Converter, seven current sinks, a two wire serial
interface, and control logic all onto a single device.
Output voltages and output currents are fully
programmable. The AS3687XM has an audio input
to control one or two RGB LEDs.
The AS3687/87XM is a successor to the
austrimicrosystems AS3689 and therefore software
compatible to the AS3689 (software written for the
AS3689 can be easily reused for the
AS3687/87XM).
al
id
1 General Description
www.austriamicrosystems.com/AS3687
(mlg/ptr)
Lighting-management for mobile telephones and
other 1-cell Li+ or 3-cell NiMH powered devices.
1v3-4
1 - 54
AS3687/87XM
Datasheet
4 Block Diagram
Figure 1 – Application Diagram of the AS3687/AS3687XM
Battery
DCDC_GATE
LED
Test
Step Up DC/DC
Converter
Battery
R2
1MΩ
C7
1.5nF
R3
100kΩ
C8
15nF
am
lc s
on A
te G
nt
st
il
VBAT
References
and
Temperature
Supervision
C1
1µF
R1
0.1Ω
DCDC_FB
8Bit PWM
Generator
Automatic Dimming
and LED Pattern
Generator
V2_5
C9
4.7µF
Q1
DCDC_SNS
lv
AS3687/
AS3687
AS3687XM
Lighting
Lighting
Management
Management
Unit
Unit
D1
al
id
C6
1µF
L1
10µH
VBAT
C2_P
Charge Pump
1:1, 1:1.5, 1:2
C3
500nF
C2_N
C2
1µF
C1_P
D6
D9
D12
D7
D10
D13
D8
D11
D14
C4
500nF
150mA
C1_N
CPOUT
Zero Power
Device
Wakeup
DATA
R5
DATA
CLK
D3
D4
D5
C5
1.0µF
CURR31
CURR32
Serial
Interface
CURR33
ca
CLK
D2
CURR30
VDD_I/F
R4
1-10kΩ
Current Sinks
each 0.15-38.25mA
ADC
HV Current Sinks
each 0.15-38.25mA
vtemp
currx
dcdc
ni
CURR2
CURR6
VSS
Te
ch
CURR1
www.austriamicrosystems.com/AS3687
1v3-4
2 - 54
AS3687/87XM
Datasheet
Figure 2 – Application Diagram of the AS3687XM
Alternative:
use DCDC step up
C6 for CURR1,2,6
1µF
L1
10µH
DCDC_GATE
Step Up DC/DC
Converter
References
and
Temperature
Supervision
C1
1µF
C7
1.5nF
C8
15nF
VBAT
Battery
C2_P
Charge Pump
C2_N
C3
500nF
C2
1µF
am
lc s
on A
te G
nt
st
il
V2_5
R2
1MΩ
DCDC_FB
8Bit PWM
Generator
Automatic Dimming
and LED Pattern
Generator
VBAT
R1
0.1Ω
al
id
LED
Test
C9
4.7µF
Q1
DCDC_SNS
lv
AS3687XM
Lighting
Management
Unit
D1
1:1, 1:1.5, 1:2
C1_P
150mA
C1_N
C4
500nF
CPOUT
Zero Power
Device
Wakeup
R4
1-10kΩ
DATA
CLK
Current Sinks
each 0.15-38.25mA
DRGB1
C5
1.0µF
CURR30
VDD_I/F
CURR31
DATA
CLK
CURR32
Serial
Interface
CURR33/AUDIO_IN
C10
100nF
Audio IN
Alternative:
2nd Audio or Backlight
Audio Processing
ADC
HV Current Sinks
each 0.15-38.25mA
D2
D3
D4
CURR6
VSS
Te
ch
DRGB2
CURR1
CURR2
ni
ca
vtemp
currx
dcdc
www.austriamicrosystems.com/AS3687
1v3-4
3 - 54
AS3687/87XM
Datasheet
Table of Contents
General Description ....................................................................................................................................... 1
Key Features.................................................................................................................................................. 1
Application ..................................................................................................................................................... 1
Block Diagram................................................................................................................................................ 2
Characteristics ............................................................................................................................................... 5
5.1
Absolute Maximum Ratings .................................................................................................................... 5
5.2
Operating Conditions .............................................................................................................................. 5
6 Typical Operating Characteristics .................................................................................................................. 6
7 Detailed Functional Description ..................................................................................................................... 8
7.1
Step Up DC/DC Converter...................................................................................................................... 8
7.1.1
Feedback Selection ......................................................................................................................... 9
7.1.2
Overvoltage Protection in Current Feedback Mode ......................................................................... 9
7.1.3
Voltage Feedback.......................................................................................................................... 10
7.1.4
PCB Layout Hints .......................................................................................................................... 11
7.1.5
Step up Registers .......................................................................................................................... 11
7.2
Charge Pump........................................................................................................................................ 13
7.2.1
Charge Pump Mode Switching ...................................................................................................... 15
7.2.2
Soft Start........................................................................................................................................ 16
7.2.3
Charge Pump Registers ................................................................................................................ 16
7.3
Current Sinks ........................................................................................................................................ 18
7.3.1
High Voltage Current Sinks CURR1, CURR2, CURR6.................................................................. 19
7.3.2
Current Sinks CURR30, CURR31, CURR32, CURR33................................................................. 21
7.3.3
LED Pattern Generator .................................................................................................................. 24
7.3.4
PWM Generator............................................................................................................................. 28
7.4
LED Test............................................................................................................................................... 33
7.4.1
Function Testing for single LEDs connected to the Charge Pump ................................................ 33
7.4.2
Function Testing for LEDs connected to the Step Up DCDC Converter ........................................ 34
7.5
Analog-To-Digital Converter ................................................................................................................. 34
7.5.1
ADC Registers ............................................................................................................................... 35
7.6
Audio controlled RGB LEDs (only AS3687XM)..................................................................................... 37
7.6.1
AGC............................................................................................................................................... 39
7.6.2
Audio Control Registers................................................................................................................. 41
7.7
Power-On Reset ................................................................................................................................... 42
7.7.1
Reset control register..................................................................................................................... 43
7.8
Temperature Supervision...................................................................................................................... 43
7.8.1
Temperature Supervision Registers .............................................................................................. 44
7.9
Serial Interface...................................................................................................................................... 44
7.9.1
Serial Interface Features ............................................................................................................... 44
7.9.2
Device Address Selection.............................................................................................................. 45
7.10 Operating Modes .................................................................................................................................. 47
8 Register Map................................................................................................................................................ 48
9 External Components .................................................................................................................................. 50
10 Pinout and Packaging .................................................................................................................................. 51
10.1 Pin Description...................................................................................................................................... 51
10.2 Package Drawings and Markings ......................................................................................................... 52
11 Ordering Information .................................................................................................................................... 53
Te
ch
ni
ca
am
lc s
on A
te G
nt
st
il
lv
al
id
1
2
3
4
5
www.austriamicrosystems.com/AS3687
1v3-4
4 - 54
AS3687/87XM
Datasheet
5 Characteristics
5.1 Absolute Maximum Ratings
Stresses beyond those listed in Table 1 may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated in Section 5
Electrical Characteristics is not implied.
Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Min
Max
Unit
VIN_HV
15V Pins
-0.3
17
V
VIN_MV
5V Pins
-0.3
7.0
V
VIN_LV
3.3V Pins
-0.3
5.0
V
IIN
Input Pin Current
-25
+25
mA
Tstrg
Storage Temperature Range
-55
125
°C
Humidity
5
85
%
Electrostatic Discharge
Norm: MIL 883 E Method 3015
-2000
2000
V
-1000
1000
V
VCDM
Norm: JEDEC JESD 22-A115-A
level A
-500
500
V
Pt
Total Power Dissipation
0.75
W
TBODY
Peak Body Temperature
260
°C
VESD
5.2
Note
Applicable for high-voltage
current sink pins CURR1,CURR2,
CURR6
Applicable for 5V pins
VBAT, CURR30-33,
CURR33/AUDIO_IN, C1_N, C2_N,
C1_P, C2_P, CPOUT, DCDC_FB,
DCDC_GATE, CLK, DATA;
Applicable for 3.3V pins
V2_5; DCDC_SNS
At 25ºC, Norm: JEDEC 17
lv
Parameter
am
lc s
on A
te G
nt
st
il
Symbol
al
id
Table 1 – Absolute Maximum Ratings
Non-condensing
All pins except
CURR33/AUDIO_IN
Pin CURR33/AUDIO_IN
TA = 70 ºC, Tjunc_max = 125ºC
T = 20 to 40s, in accordance with
IPC/JEDEC J-STD 020.
Operating Conditions
Table 2 – Operating Conditions
Battery Voltage
3.0
3.6
5.5
V
Note
Applicable for high-voltage current
sink pins CURR1, CURR2 and
CURR6.
VBAT
Interface Supply Voltage
1.5
1.8 / 2.8
5.5
V
For serial interface pins.
Voltage on Pin V2_5
2.4
2.5
2.6
V
Internally generated
TAMB
Operating Temperature Range
-30
25
85
°C
IACTIVE
Battery current
70
ISTANDBY
Standby Mode Current
5.8
13
µA
ISHUTDOWN
Shutdown Mode Current
0.1
3
µA
VDDI/F
High Voltage
0.0
Te
ch
V2_5
Min
ni
VHV
VBAT
Parameter
ca
Symbol
www.austriamicrosystems.com/AS3687
Typ
1v3-4
Max
Unit
15.0
V
µA
Normal Operating current – see
section ‘Operating Modes’;
interface active (excluding current
of the enabled blocks)
Current consumption in standby
mode. Only 2.5V regulator on,
interface active
interface inactive (CLK and DATA
set to 0V)
5 - 54
AS3687/87XM
Datasheet
6 Typical Operating Characteristics
Note: Typical conditions are measured at 25°C and 3.6V (unless otherwise noted).
Figure 3 – DCDC Step Up Converter: Efficiency of +15V Step Up to 15V
vs. Load Current at VBAT = 3.8V
100
VOUT=14.2V
VOUT=14.2V
fclk=550kHz
80
VOUT=22V
Efficiency of CP [%]
VOUT=17.2V
80
75
70
60
50
ILOAD=80mA
40
ILOAD=40mA
lv
85
Efficiency of DCDC [%]
ILOAD=150mA
90
al
id
90
Figure 4 – Charge Pump: Efficiency vs. VBAT
30
20
70
am
lc s
on A
te G
nt
st
il
10
0
65
0
0.01
0.02
0.03
0.04
0.05
2.8
0.06
3
3.2
3.4
3.6
3.8
4
4.2
VBAT [V]
Load Current [A]
Figure 6 – Current Sink CURR1 vs. V(CURRx)
Figure 5 – Charge Pump: Battery Current vs. VBAT
40.0
250
ICURR1=38.25mA
35.0
200
30.0
150
100
ICURR1 [mA]
IBat[mA]
ILOAD=150mA
ILOAD=80mA
ILOAD=40mA
50
25.0
ICURR1=19.2mAm
20.0
15.0
10.0
5.0
0
0.0
3
3.2
3.4
3.6
VBat[V]
3.8
4
4.2
0.0
ni
1.5
2.0
40.0
curr_prot1_on=1
ICURR30=38.25mA
35.0
ch
2,5
1.0
Figure 8 – Current Sink CURR3x vs. VBAT
Figure 7 – Current Sink CURR1 Protection Current
3,0
0.5
VCURR1 [V]
ca
2.8
30.0
ICURR30 [mA]
2,0
1,5
Te
Current [mA]
ICURR1=2.4mA
1,0
25.0
ICURR30=19.2mAm
20.0
15.0
10.0
4.5uA
0,5
5.0
curr_prot1_on=0
0,0
ICURR30=2.4mA
0.0
0,0
5,0
10,0
15,0
20,0
0.0
0.5
1.0
1.5
2.0
VCURR30 [V]
V(CURR1) [V]
Protection Current vs. Voltage (curr sinks off, curr_protX_on=0/1)
www.austriamicrosystems.com/AS3687
1v3-4
6 - 54
AS3687/87XM
Datasheet
Figure 9 – Charge Pump Input and Output Ripple 1:1.5 Mode, 100mA load
Figure 10 – Charge Pump Input and Output Ripple 1:2 Mode, 100mA load
VBAT,
20mV/div,
AC-coupled
VBAT,
20mV/div,
AC-coupled
V(CPOUT),
100mV/div,
AC-coupled
lv
al
id
V(CPOUT),
20mV/div,
AC-coupled
250ns/div
Measured with battery (3.0V) on demoboard
Te
ch
ni
ca
am
lc s
on A
te G
nt
st
il
250ns/div
Measured with battery (3.8V) on demoboard
www.austriamicrosystems.com/AS3687
1v3-4
7 - 54
AS3687/87XM
Datasheet
7 Detailed Functional Description
7.1
Step Up DC/DC Converter
The Step Up DC/DC Converter is a high-efficiency current mode PWM regulator, providing output voltage up to e.g.
25V/35mA or e.g. 16V/55mA. A constant switching-frequency results in a low noise on the supply and output voltages.
al
id
Figure 11 – Step Up DCDC Converter Block Diagramm Option: Current Feedback with Overvoltage protection
Battery
C6
1µF
L1
10µH
lv
DCDC_GATE
D1
C9
4.7µF
Q1
DCDC_SNS
Step Up DC/DC
Converter
R2
1M
C7
1.5nF
R3
100k
C8
15nF
am
lc s
on A
te G
nt
st
il
R1
DCDC_FB
HV Current Sinks
each 0.156-40mA
D6
D9
D12
D7
D10
D13
D8
D11
D14
CURR1
CURR2
ca
CURR6
Table 3 – Step Up DC/DC Converter Parameters
Parameter
ni
Symbol
Min
TYP
Max
Quiescent Current
VFB1
Feedback Voltage for
External Resistor Divider
1.20
1.25
1.30
V
VFB2
Feedback Voltage for Current
Sink Regulation
0.4
0.5
0.6
V
0
31
µA
-6
6
%
Te
ch
IVDD
IDCDC_FB
Additional Tuning Current at
Pin DCDC_FB and
overvoltage protection
Accuracy of Feedback
Current at full scale
www.austriamicrosystems.com/AS3687
140
Unit
1v3-4
µA
Note
Pulse skipping mode.
For constant voltage control.
step_up_res = 1
on CURR1, CURR2 or CURR6 in
regulation.
step_up_res = 0
Adjustable by software using
Register DCDC control1
1μA step size (0-15µA)
VPROTECT = 1.25V +
IDCDC_FB * R2
8 - 54
AS3687/87XM
Datasheet
Table 3 – Step Up DC/DC Converter Parameters
Vrsense_max
Vrsense_max_st
art
Current Limit Voltage at
RSENSE (R1)
Vrsense_max_lc
RSW
Switch Resistance
Iload
Load Current
fIN
Switching Frequency
L
tMIN_ON
MDC
Vripple
Efficiency
TYP
Max
46
66
85
25
33
43
30
43
57
1
0
55
0
35
0.9
1
1.1
Unit
Note
e.g., 0.66A for 0.1Ω sense
resistor
mV
For fixed startup time of
500us
If stepup_lowcur= 1
Ω
mA
ON-resistance of external
switching transistor.
At 16V output voltage.
At 25V output voltage.
MHz
Internally trimmed.
µF
Ceramic, ±20%. Use nominal
4.7μF capacitors to obtain at least
0.7µF under all conditions
(voltage dependance of
capacitors)
Use inductors with small Cparasitic
(<100pF) to get high efficiency.
Output Capacitor
0.7
4.7
Inductor
7
10
13
µH
Minimum on Time
90
140
190
ns
Maximum Duty Cycle
88
91
am
lc s
on A
te G
nt
st
il
Cout
Min
al
id
Parameter
lv
Symbol
%
Voltage ripple >20kHz
160
mV
Voltage ripple <20kHz
40
mV
Cout=4.7uF,Iout=0..45mA,
Vbat=3.0...4.2V
%
Iout=20mA,Vout=17V,Vbat=3.8V
Efficiency
85
To ensure soft startup of the dcdc converter, the overcurrent limits are reduced for a fixed time after enabling the
dcdc converter. The total startup time for an output voltage of e.g. 25V is less than 2ms.
7.1.1 Feedback Selection
Register 12 (DCDC Control) selects the type of feedback for the Step Up DC/DC Converter.
ca
The feedback for the DC/DC converter can be selected either by current sinks (CURR1, CURR2, CURR6) or by a
voltage feedback at pin DCDC_FB. If the register bit step_up_fb_auto is set, the feedback path is automatically
selected between CURR1, CURR2 and CURR6 (the lowest voltage of these current sinks is used).
ch
ni
Setting step_up_fb enables feedback on the pins CURR1, CURR2 or CURR6. The Step Up DC/DC Converter is
regulated such that the required current at the feedback path can be supported. (Bit step_up_res should be set
to 0 in this configuration)
Te
Note: Always choose the path with the highest voltage drop as feedback to guarantee adequate supply for the
other (unregulated) paths or enable the register bit step_up_fb_auto.
7.1.2 Overvoltage Protection in Current Feedback Mode
The overvoltage protection in current feedback mode (step_up_fb = 01, 10 or 11 or step_up_fb_auto = 1) works
as follows: Only resistor R3 and C10/C11 is soldered and R4 is omitted. An internal current source (sink) is
used to generate a voltage drop across the resistor R3. If then the voltage on DCDC_FB is above 1.25V, the
DCDC is momentarily disabled to avoid too high voltages on the output of the DCDC converter.
The protection voltage can be calculated according to the following formula:
VPROTECT = 1.25V + IDCDC_FB * R2
www.austriamicrosystems.com/AS3687
1v3-4
9 - 54
AS3687/87XM
Datasheet
Notes:
1.
The voltage on the pin DCDC_FB is limited by an internal protection diode to VBAT + one diode
forward voltage (typ. 0.6V).
If the overvoltage protection is not used in current feedback mode, connect DCDC_FB to ground.
2.
Figure 12 –Step Up DC/DC Converter Detail Diagram; Option: Regulated Output Current, Feedback is automatically selected between CURR1,
CURR2, CURR6 (step_up_fb_auto=1); overvoltage protection is enabled (step_up_prot=1); 1MHz clock frequency (step_up_freq=0)
C6
1µF
L1
10µH
clk
PWM
Logic
DCDC_GATE
Gate
Driver
DCDC_SNS
ov_curr
Vrsense_max
R1
step_up_vtuning
R2
1M
C7
1.5nF
am
lc s
on A
te G
nt
st
il
DCDC_FB
R3
100k
step_up_prot
ramp
C9
4.7µF
Q1
lv
step_up_freq
pulse_skip
overshoot
ov_voltage
1MHz
500kHz
D1
al
id
Battery
V
overshoot comp
error ota
1.25V
D6
D9
D12
1.35V
0.8V
D7
D10
D13
1.25V
0.5V
D8
D11
D14
step_up_fb
HV Current Sinks
each 0.156-40mA
step_up_fb_auto
C8
15nF
CURR1
Automatic
feedback select
(CURR1,2,6)
CURR2
CURR6
ca
CURRX on and
currX_on_cp=0
ni
7.1.3 Voltage Feedback
Setting bit step_up_fb = 00 enables voltage feedback at pin DCDC_FB..
Te
ch
The output voltage is regulated to a constant value, given by (Bit step_up_res should be set to 1 in this
configuration)
Ustepup_out = (R2+R3)/R3 x 1.25 + IDCDC_FB x R2
If R3 is not used, the output voltage is by (Bit step_up_res should be set to 0 in this configuration):
Ustepup_out = 1.25 + IDCDC_FB x R2
Where:
Ustepup_out = Step Up DC/DC Converter output voltage.
www.austriamicrosystems.com/AS3687
1v3-4
10 - 54
AS3687/87XM
Datasheet
R2 = Feedback resistor R2.
R3 = Feedback resistor R3.
IDCDC_FB = Tuning current at pin 29 (DCDC_FB); 0 to 31µA.
Ustepup_out
µA
R2 = 1MΩ, R3 not used
R2 = 500kΩ, R3 = 50kΩ
0
-
13.75
1
-
14.25
2
-
14.75
3
-
15.25
4
-
15.75
5
6.25
16.25
6
7.25
16.75
7
8.25
17.25
lv
Ustepup_out
am
lc s
on A
te G
nt
st
il
Ivtuning
al
id
Table 4 – Voltage Feedback Example Values
8
9
10
11
12
13
14
15
…
30
31
9.25
17.75
10.25
18.25
11.25
18.75
12.25
19.25
13.25
19.75
14.25
20.25
15.25
20.75
16.25
21.25
…
…
31.25
28.75
32.25
29.25
Caution: The voltage on CURR1, CURR2 and CURR6 must not exceed 15V – see also section ‘High
Voltage Current Sinks’.
ca
7.1.4 PCB Layout Hints
ni
To ensure good EMC performance of the DCDC converter, keep its external power components C2, R2, L1, Q1,
D1 and C9 close together. Connect the ground of C2, Q1 and C9 locally together and connect this path with a
single via to the main ground plane. This ensures that local high-frequency currents will not flow to the battery.
ch
7.1.5 Step up Registers
Addr: 00
Reg. Control
This register enables/disables the Charge Pump and the Step Up DC/DC Converter
Bit Name
Default
Access
3
step_up_on
0
R/W
Te
Bit
www.austriamicrosystems.com/AS3687
Description
Enable the step up converter
0b = Disable the Step Up DC/DC Converter.
1b = Enable the Step Up DC/DC Converter.
1v3-4
11 - 54
AS3687/87XM
Datasheet
Addr: 21h
Bit Name
0
step_up_frequ
2:1
step_up_fb
7:3
step_up_vtuning
Bit Name
0
step_up_res
1
skip_fast
2
step_up_prot
3
stepup_lowcur
DCDC Control 2
This register controls the Step Up DC/DC Converter and low-voltage current sinks
CURR3x.
Default
Access
Description
Gain selection for Step Up DC/DC Converter.
0 = Select 0 if Step Up DC/DC Converter is used with
current feedback (CURR1, CURR2 , CURR6) or if
0
R/W
DCDC_FB is used with current feedback only – only R1,
C1 connected
1 = Select 1 if DCDC_FB is used with external resistor
divider (2 resistors).
Step Up DC/DC Converter output voltage at low loads,
when pulse skipping is active.
0
R/W
0 = Accurate output voltage, more ripple.
1 = Elevated output voltage, less ripple.
Step Up DC/DC Converter protection.
0 = No overvoltage protection.
1
R/W
1 = Overvoltage protection on pin DCDC_FB enabled
voltage limitation =1.25V on DCDC_FB
Step Up DC/DC Converter coil current limit.
1
R/W
0 = Normal current limit
1 = Current limit reduced by approx. 33%
0 = No overvoltage protection
0
R/W
1 = Pull down current switched on, if voltage exceeds
13.75V, and step_up_on=1
0 = No overvoltage protection
0
R/W
1 = Pull down current switched on, if voltage exceeds
13.75V, and step_up_on=1
0 = No overvoltage protection
0
R/W
1 = Pull down current switched on, if voltage exceeds
13.75V, and step_up_on=1
0 = step_up_fb select the feedback of the DCDC converter
0
R/W
1 = The feedback is automatically chosen within the current
sinks CURR1, CURR2 and CURR6 (never DCDC_FB).
ch
ni
ca
Bit
curr1_prot_on
Te
4
lv
am
lc s
on A
te G
nt
st
il
Addr: 22h
al
id
Bit
DCDC Control 1
This register controls the Step Up DC/DC Converter.
Default
Access
Description
Defines the clock frequency of the Step Up DC/DC
Converter.
0
R/W
0 = 1 MHz
1 = 500 kHz
Controls the feedback source if step_up_fb_auto = 0
00 = DCDC_FB enabled (external resistor divider).
Set step_up_fb=00 (DCDC_FB), if external
PWM is enabled for CURR1, CURR2 or CURR6
00
R/W
01 = CURR1 feedback enabled (feedback via white LEDs.
10 = CURR2 feedback enabled (feedback via white LEDs.
11 = CURR6 feedback enabled (feedback via white LEDs.
Defines the tuning current at pin DCDC_FB.
00000 = 0 μA
00001 = 1 μA
00010 = 2 μA
00000
R/W
…
10000 = 15 μA
…
11111 = 31 μA
5
curr2_prot_on
6
curr6_prot_on
7
step_up_fb_auto
www.austriamicrosystems.com/AS3687
1v3-4
12 - 54
AS3687/87XM
Datasheet
Bit
Bit Name
al
id
DCDC Control 2
This register controls the Step Up DC/DC Converter and low-voltage current sinks
CURR3x.
Default
Access
Description
Only those are used for this selection, which are enabled
(currX_mode must not be 00) and not connected to the
charge pump (currX_on_cp must be 0). Don’t use automatic
feedback selection together with external PWM for the
current sources CURR1, CURR2 or CURR6.
Addr: 22h
7.2 Charge Pump

1:1 Bypass Mode
− Battery input and output are connected by a low-impedance switch
− battery current = output current.
1:1.5 Mode
− The output voltage is up to 1.5 times the battery voltage (without load), but is limited to VCPOUTmax all
the time
− battery current = 1.5 times output current.
1:2 Mode
− The output voltage is up to 2 times the battery voltage (without load), but is limited to VCPOUTmax all
the time
− battery current = 2 times output current
am
lc s
on A
te G
nt
st
il

lv
The Charge Pump uses two external flying capacitors C6, C7 to generate output voltages higher than the battery
voltage. There are three different operating modes of the charge pump itself:
As the battery voltage decreases, the Charge Pump must be switched from 1:1 mode to 1:1.5 mode and
eventually in 1:2 mode in order to provide enough supply for the current sinks. Depending on the actual current
the mode with best overall efficiency can be automatically or manually selected:
Examples:
Battery voltage = 3.7V, LED dropout voltage = 3.5V. The 1:1 mode will be selected and there is 200mV drop
on the current sink and on the Charge Pump switch. Efficiency 95%.

Battery voltage = 3.5V, LED dropout voltage = 3.5V. The 1:1.5 mode will be selected and there is 1.5V drop
on the current sink and 250mV on the Charge Pump. Efficiency 66%.

Battery voltage = 3.8V, LED dropout voltage = 4.5V (Camera Flash). The 1:2 mode can be selected and there
is 600mV drop on the current sink and 2.5V on the Charge Pump. Efficiency 60%.
ca

The efficiency is dependent on the LED forward voltage given by:
ni
Eff=(V_LED*Iout)/(Uin*Iin)
The charge pump mode switching can be done manually or automatically with the following possible software
settings:
Automatic up all modes allowed (1:1, 1:1.5, 1:2)
− Start with 1:1 mode
− Switch up automatically 1:1 to 1:1.5 to 1:2
Automatic up, but only 1:1 and 1:1.5 allowed
− Start with 1:1 mode
− Switch up automatically only from 1:1 to 1:1.5 mode; 1:2 mode is not used
Manual
− Set modes 1:1, 1:1.5, 1:2 by software
ch

www.austriamicrosystems.com/AS3687
1v3-4
13 - 54
AS3687/87XM
Datasheet
Figure 13 – Charge Pump Pin Connections
Battery
VBAT
C2
1µF
C2_P
1:1, 1:1.5, 1:2
C3
500nF
C2_N
al
id
Charge Pump
C1_P
C4
500nF
150mA
C1_N
C5
1.0µF
am
lc s
on A
te G
nt
st
il
The Charge Pump requires the external components listed in the following table:
lv
CPOUT
Table 5 – Charge Pump External Components
Symbol
Parameter
Min
Typ
Max
Unit
Note
µF
Ceramic low-ESR capacitor between
pins VBAT and VSS.
C2
External Decoupling
Capacitor
C3, C4
External Flying
Capacitor (2x)
500
nF
External Storage
Capacitor
1.0
µF
C5
Note:
1.0
Ceramic low-ESR capacitor between
pins C1_P and C1_N, between pins
C2_P and C2_N and between VBAT
and VSS.
Ceramic low-ESR capacitor between
pins CP_OUT and VSS, pins
CP_OUT and VSS. Use nominal 1µF
capacitors (size 0603)
ca
1.) The connections of the external capacitors C2, C3, C4 and C5 should be kept as short as possible.
ni
2.) The maximum voltage on the flying capacitors C3 and C4 is VBAT
Table 6 – Charge Pump Characteristics
Parameter
Output Current
Continuous
ch
Symbol
ICPOUT
Te
VCPOUTmax
Efficiency
ICP1_1.5
Power Consumption
without Load
fclk = 1 MHz
Effective Charge Pump
Output Resistance
Rcp1_1
Rcp1_1.5
Typ
0.0
Output Voltage
η
ICP1_2
Min
www.austriamicrosystems.com/AS3687
60
3.4
3.8
0.57
2.65
1v3-4
Max
Unit
150
mA
5.5
V
90
%
mA
Ω
Ω
Note
Depending on PCB layout
Internally limited, Including output
ripple
Including current sink loss;
ICPOUT < 100mA.
1:1.5 Mode
1:2 Mode
1:1 Mode; VBAT >= 3.5V
1:1.5 Mode; VBAT >= 3.3V
14 - 54
AS3687/87XM
Datasheet
Table 6 – Charge Pump Characteristics
fclk Accuracy
currhv_switch
Vcurr3x_switch
Min
Max
3.25
-10
CURR1, 2, 6
minumum voltage
CURR30-33
minumum voltage
CP automatic upswitching debounce
time
Unit
Ω
10
%
0.45
V
0.2
V
Note
1:1.2 Mode; VBAT >= 3.1V
If the voltage drops below this
threshold, the charge pump will use
the next available mode
(1:1 -> 1:1.5 or 1:1.5 -> 1:2)
240
μsec
cp_start_debounce=0
2000
μsec
After switching on CP (cp_on set to
1), if cp_start_debounce=1
am
lc s
on A
te G
nt
st
il
tdeb
Typ
al
id
Rcp1_2
Parameter
(Open Loop, fclk =
1MHz)
Accuracy of Clock
Frequency
lv
Symbol
7.2.1 Charge Pump Mode Switching
Te
ch
ni
ca
If automatic mode switching is enabled (cp_mode_switching = 00 or cp_mode_switching = 01) the charge pump
monitors the current sinks, which are connected via a led to the output CP_OUT. To identify these current
sources (sinks), the registers cp_mode_switch1 and cp_mode_switch2 (register bits curr30_on_cp …
curr33_on_cp, curr1_on_cp, curr2_on_cp, curr6_on_cp) should be setup before starting the charge pump
(cp_on = 1). If any of the voltage on these current sources drops below the threshold (currlv_switch,
currhv_switch, curr3x_switch), the next higher mode is selected after the debounce time.
To avoid switching into 1:2 mode (battery current = 2 times output current), set cp_mode_switching = 10.
If the currX_on_cp=0 and the according current sink is connected to the chargepump, the current sink will be
functional, but there is no up switching of the chargepump, if the voltage compliance is too low for the current sink
to supply the specified current.
www.austriamicrosystems.com/AS3687
1v3-4
15 - 54
AS3687/87XM
Datasheet
Figure 14 – Automatic Mode Switching
Battery
VBAT
C2
1µF
C2_P
cp_mode<1:0>
1:1 -> 1:1.5
1:1.5 -> 1:2
Charge Pump
1:1, 1:1.5, 1:2
C2_N
C3
500nF
C1_P
C1_N
CPOUT
C4
500nF
al
id
Mode Switching
curr30_on_cp
CURR30
200mV
(curr3x_switch)
CURR31
am
lc s
on A
te G
nt
st
il
curr31_on_cp
lv
C5
1.0µF
Debounce
curr32_on_cp
CURR32
curr33_on_cp
CURR33
curr1_on_cp
CURR1
450mV
(currhv_switch)
curr2_on_cp
curr6_on_cp
CURR2
CURR6
7.2.2 Soft Start
An implemented soft start mechanism reduces the inrush current. Battery current is smoothed when switching the
charge pump on and also at each switching condition. This precaution reduces electromagnetic radiation
significantly.
ca
7.2.3 Charge Pump Registers
Reg. Control
Addr: 00h
ni
Bit Name
ch
Bit
This register enables/disables the Charge Pump and the Step Up DC/DC Converter.
cp_on
Access
0
R/W
Description
0 = Set Charge Pump into 1:1 mode (off state) unless
cp_auto_on is set
1 = Enable manual or automatic mode switching – see
register CP Control for actual settings
Te
2
Default
www.austriamicrosystems.com/AS3687
1v3-4
16 - 54
AS3687/87XM
Datasheet
Bit Name
0
cp_clk
2:1
cp_mode
lv
Bit
CP Control
This register controls the Charge Pump.
Default
Access
Description
Clock frequency selection.
0
R/W
0 = 1 MHz
1 = 500 kHz
Charge Pump mode (in manual mode sets this mode, in
automatic mode reports the actual mode used)
00 = 1:1 mode
01 = 1:1.5 mode
10 = 1:2 mode
00b
R/W
11 = NA
Note: Direct switching from 1:1.5 mode into 1:2 in manual
mode and vice versa is not allowed. Always switch over 1:1
mode.
al
id
Addr: 23h
am
lc s
on A
te G
nt
st
il
4:3 cp_mode_switching
00b
R/W
5
cp_start_debounce
0
R/W
6
cp_auto_on
0
R/W
Note :
1.
Set the mode switching algorithm:
1
00 = Automatic Mode switching; 1:1, 1:1.5 and 1:2 allowed
01 = Automatic Mode switching; only 1:1 and 1:1.5 allowed1
10 = Manual Mode switching; register cp_mode defines the
actual charge pump mode used
11 = reserved
0 = Mode switching debounce timer is always 240us
1 = Upon startup (cp_on set to 1) the mode switching
debounce time is first started with 2ms then reduced to
240us
0 = Charge Pump is switched on/off with cp_on
1 = Charge Pump is automatically switched on if a current
sink, which is connected to the charge pump (defined by
registers CP Mode Switch 1 & 2) is switched on
Don’t use automatic mode switching together with external PWM for the current sources connceted
to the charge pump with less than 500us high time.
CP Mode Switch 1
Setup which current sinks are connected (via leds) to the charge pump; if set to ‘1’ the
correspond current source (sink) is used for automatic mode selection of the charge
pump
Default
Access
Description
0 = current Sink CURR30 is not connected to charge pump
0
R/W
1 = current sink CURR30 is connected to charge pump
ca
Addr: 24h
Bit Name
0
curr30_on_cp
1
curr31_on_cp
ni
Bit
0
R/W
0 = current Sink CURR31 is not connected to charge pump
1 = current sink CURR31 is connected to charge pump
curr32_on_cp
0
R/W
0 = current Sink CURR32 is not connected to charge pump
1 = current sink CURR32 is connected to charge pump
3
curr33_on_cp
0
R/W
0 = current Sink CURR33 is not connected to charge pump
1 = current sink CURR33 is connected to charge pump
Te
ch
2
www.austriamicrosystems.com/AS3687
1v3-4
17 - 54
AS3687/87XM
Datasheet
Addr: 25h
CP Mode Switch 2
Setup which current sinks are connected (via leds) to the charge pump; if set to ‘1’ the
correspond current source (sink) is used for automatic mode selection of the charge
pump
Default
Access
Description
0 = current Sink CURR1 is not connected to charge pump
0
R/W
1 = current sink CURR1 is connected to charge pump
Bit Name
0
curr1_on_cp
1
curr2_on_cp
0
R/W
0 = current Sink CURR2 is not connected to charge pump
1 = current sink CURR2 is connected to charge pump
7
curr6_on_cp
0
R/W
0 = current Sink CURR6 is not connected to charge pump
1 = current sink CURR6 is connected to charge pump
al
id
Bit
Curr low voltage status 1
Indicates the low voltage status of the current sinks. If the currX_low_v bit is set, the
voltage on the current sink is too low, to drive the selected output current
Default
Access
Description
0 = voltage of current Sink CURR30 >curr3x_switch
1
R
1 = voltage of current Sink CURR30 <curr3x_switch
lv
Addr: 2Ah
Bit Name
0
curr30_low_v
1
curr31_low_v
1
R
0 = voltage of current Sink CURR31 >curr3x_switch
1 = voltage of current Sink CURR31 <curr3x_switch
2
curr32_low_v
1
R
0 = voltage of current Sink CURR32 >curr3x_switch
1 = voltage of current Sink CURR32 <curr3x_switch
3
curr33_low_v
1
R
0 = voltage of current Sink CURR33 >curr3x_switch
1 = voltage of current Sink CURR33 <curr3x_switch
7
curr6_low_v
0
R
0 = voltage of current Sink CURR6 >currlv_switch
1 = voltage of current Sink CURR6 <currlv_switch
Addr: 2Bh
am
lc s
on A
te G
nt
st
il
Bit
Bit Name
0
curr1_low_v
1
curr2_low_v
ca
Bit
Curr low voltage status 2
Indicates the low voltage status of the current sinks. If the currX_low_v bit is set, the
voltage on the current sink is too low, to drive the selected output current
Default
Access
Description
0 = voltage of current Sink CURR1 >currhv_switch
0
R
1 = voltage of current Sink CURR1 <currhv_switch
R
0 = voltage of current Sink CURR2 >currhv_switch
1 = voltage of current Sink CURR2 <currhv_switch
ni
7.3
0
Current Sinks
ch
The AS3687/87XM contains general purpose current sinks intended to control backlights, buzzers, and vibrators.
All current sinks have an integrated protection against overvoltage.
Te
CURR1, CURR2 and CURR6 is also used as feedback for the Step Up DC/DC Converter (regulated to 0.5V in
this configuration).

Current sinks CURR1, CURR2 and CURR6 are high-voltage compliant (15V) current sinks, used e.g., for
series of white LEDs

Current sinks CURR3x (CURR30, CURR31, CURR32 and CURR33) are parallel 5V current sinks, used for
backlighting or indicator LEDs.
www.austriamicrosystems.com/AS3687
1v3-4
18 - 54
AS3687/87XM
Datasheet
7.3.1 High Voltage Current Sinks CURR1, CURR2, CURR6
The high voltage current sinks have a resolution of 8 bits. Additionally an internal protection circuit monitors with
a voltage divider (max 3µA @ 15) the voltage on CURR1, CURR2 and CURR6 and increases the current in off
state in case of overvoltage.
Table 8 – HV - Current Sinks Characteristics
Parameter
Max
Unit
Note
IBIT7
Current sink if Bit7 = 1
19.2
IBIT6
Current sink if Bit6 = 1
9.6
IBIT5
Current sink if Bit5 = 1
4.8
IBIT4
Current sink if Bit4 = 1
2.4
IBIT3
Current sink if Bit3 = 1
1.2
mA
For V(CURRx) > 0.45V
IBIT2
Current sink if Bit2 = 1
0.6
IBIT1
Current sink if Bit1 = 1
0.3
IBIT0
Current sink if Bit0 = 1
0.15
Δm
matching Accuracy
-10
+10
%
Δ
absolute Accuracy
-15
+15
%
VCURRx
Voltage compliance
0.45
15
V
Ov_prot_
13V
Overvoltage Protection of
current sink CURR1,2,6
3.0
μA
At 13V, independent of
curr1_prot_on, curr2_prot_on or
curr6_prot_on
Ov_prot_
15V
Overvoltage Protection of
current sink CURR1,2,6
mA
At 15V, step_up_on=1,
curr1_prot_on=1 for CURR1,
curr2_prot_on=1 for CURR2,
curr6_prot_on=1 for CURR6
lv
Typ
am
lc s
on A
te G
nt
st
il
Min
al
id
Symbol
0.8
4.0
CURR1,CURR2,CURR6
7.3.1.1 High Voltage Current Sinks CURR1, CURR2, CURR6 Registers
Addr: 09h
Bit Name
7:0
curr1_current
ch
ni
ca
Bit
Curr1 current
This register controls the High voltage current sink current.
Default
Access
Description
Defines current into Current sink curr1
00h = 0 mA
0
R/W
01h = 0.15 mA
...
FFh = 38.25 mA
Addr: 0Ah
Bit Name
Te
Bit
7:0
curr2_current
Curr2 current
This register controls the High voltage current sink current.
Default
Access
Description
Defines current into Current sink curr2
00h = 0 mA
0
R/W
01h = 0.15 mA
...
FFh = 38.25 mA
www.austriamicrosystems.com/AS3687
1v3-4
19 - 54
AS3687/87XM
Datasheet
Addr: 2Fh
Bit Name
7:0
curr6_current
al
id
Bit
Bit Name
1:0
curr1_mode
3:2
curr2_mode
am
lc s
on A
te G
nt
st
il
Bit
Bit
Bit Name
7:6
curr6_mode
Bit Name
0
step_up_res
ch
skip_fast
Te
2
DCDC Control 2
This register controls the Step Up DC/DC Converter and low-voltage current sinks
CURR3x.
Default
Access
Description
Gain selection for Step Up DC/DC Converter.
Select 0 if Step Up DC/DC Converter is used with current
feedback (CURR1, CURR2) or if DCDC_FB is used with
0
R/W
current feedback only – only R1, C1 connected
Select 1 if DCDC_FB is used with external resistor divider (2
resistors).
Step Up DC/DC Converter output voltage at low loads,
when pulse skipping is active.
0
R/W
0 = Accurate output voltage, more ripple.
1 = Elevated output voltage, less ripple.
Step Up DC/DC Converter protection.
0 = No overvoltage protection.
1
R/W
1 = Overvoltage protection on pin DCDC_FB enabled
voltage limitation =1.25V on DCDC_FB
ni
Bit
1
curr 6 control
This register select the mode of the current sinks CURR6
Default
Access
Description
Select the mode of the current sink CURR6
00b = off
0
R/W
01b = on
10b = PWM controlled
11b = LED pattern controlled
ca
Addr: 22h
curr12 control
This register select the mode of the current sinkscontrols High voltage current sink
current.
Default
Access
Description
Select the mode of the current sink curr1
00b = off
0
R/W
01b = on
10b = PWM controlled
11b = LED pattern controlled
Select the mode of the current sink curr2
00b = off
0
R/W
01b = on
10b = PWM controlled
11b = LED pattern controlled
lv
Addr: 01h
Addr: 02h
Curr6 current
This register controls the High voltage current sink current.
Default
Access
Description
Defines current into Current sink curr6
00h = 0 mA
0
R/W
01h = 0.15 mA
...
FFh = 38.25 mA
stepup_prot
www.austriamicrosystems.com/AS3687
1v3-4
20 - 54
AS3687/87XM
Datasheet
3
stepup_lowcur
4
curr1_prot_on
5
curr2_prot_on
6
curr6_prot_on
7
step_up_fb_auto
al
id
Bit Name
am
lc s
on A
te G
nt
st
il
Bit
DCDC Control 2
This register controls the Step Up DC/DC Converter and low-voltage current sinks
CURR3x.
Default
Access
Description
Step Up DC/DC Converter coil current limit.
1
R/W
0: Normal current limit
1: Current limit reduced by approx. 33%
0 = No overvoltage protection
1 = Pull down current on CURR1 switched on, if voltage on
0
R/W
CURR1 exceeds 13.75V, and step_up_on=1
0 = No overvoltage protection
0
R/W
1 = Pull down current on CURR2 switched on, if voltage
exceeds on CURR2 13.75V, and step_up_on=1
0 = No overvoltage protection
0
R/W
1 = Pull down current on CURR6 switched on, if voltage on
CURR6 exceeds 13.75V, and step_up_on=1
0 = step_up_fb select the feedback of the DCDC converter
1 = The feedback is automatically chosen within the current
sinks CURR1and CURR2 (never DCDC_FB). Only those
0
R/W
are used for this selection, which are enabled (currX_mode
must not be 00) and not connected to the charge pump
(currX_on_cp must be 0).
lv
Addr: 22h
7.3.2 Current Sinks CURR30, CURR31, CURR32, CURR33
These current sinks have a resolution of 8 bits and can sink up to 40mA. The current values can be controlled
individually with curr30_current – curr33_current or common with curr3x_strobe or curr3x_preview.
Table 9 – Current Sinks CURR30,31,32,33 Parameters
Symbol
Parameter
Min
Typ
Max
Unit
Note
mA
For V(CURR3x) > 0.2V
CURR30-33
Current sink if Bit7 = 1
19.2
IBIT6
Current sink if Bit6 = 1
9.6
IBIT5
Current sink if Bit5 = 1
4.8
IBIT4
Current sink if Bit4 = 1
2.4
IBIT3
Current sink if Bit3 = 1
1.2
IBIT2
Current sink if Bit2 = 1
0.6
IBIT1
Current sink if Bit1 = 1
0.3
IBIT0
Current sink if Bit0 = 1
0.15
Δm
matching Accuracy
-10
+10
%
absolute Accuracy
-15
+15
%
Voltage compliance
0.2
CPOUT
V
ch
VCURR3X
ni
Δ
ca
IBIT7
Te
7.3.2.1 Current Sinks CURR3x Registers
Addr: 12h
Bit
Bit Name
0
preview_off_after
strobe
Curr3 control1
This register select the modes of the current sinks30..33 current.
Default Access Description
Select the switch off mode after strobe pulse
0 = normal preview/strobe mode,
0b
R/W
1 = switch off preview after strobe duration has expired. To reinitiate
the torch mode the preview_ctrl has to be set off and on again
www.austriamicrosystems.com/AS3687
1v3-4
21 - 54
AS3687/87XM
Datasheet
Addr: 12h
Bit
Bit Name
2:1
preview_ctrl
Bit Name
1:0
strobe_ctrl
strobe_mode
7:4
strobe_timing
00b
R/W
am
lc s
on A
te G
nt
st
il
3:2
Selects strobe mode
00b = Mode1 (Tstrobe=Ts; strobe trigger signal >= 10μs)
01b = Mode 2 (Tstrobe=max Ts)
10b = Mode 3 (Tstrobe = strobe signal)
11b = not used
Selects strobe time (Ts)
0000b = 100 msec
0001b = 200 msec
0010b = 300 msec
0011b = 400 msec
0100b = 500 msec
0101b = 600 msec
0110b = 700 msec
0111b = 800 msec
1000b = 900 msec
1001b = 1000 msec
1010b = 1100 msec
1011b = 1200 msec
1100b = 1300 msec
1101b = 1400 msec
1110b = 1500 msec
1111b = 1600 msec
lv
Bit
Curr3 strobe control
This register select the modes of the current sinks30..33 current.
Default Access Description
Strobe is triggered by
00b = off
00b
R/W
01b = software trigger (setting this bit automatically triggers strobe)
al
id
Addr: 11h
Curr3 control1
This register select the modes of the current sinks30..33 current.
Default Access Description
Preview is triggered by
00b
R/W 00 = off
01 = software trigger (setting this bit automatically triggers preview)
R/W
ca
0000b
Addr: 0Eh
Bit Name
5:0
curr3x_strobe
ch
ni
Bit
Curr3x strobe
This register select the strobe current of the current sinks30..33
Default Access Description
Defines Strobe current of Current sinks curr30-33
00h = 0 mA
00
R/W
01h = 0.6 mA
...
3Fh = 37.8 mA
Te
Addr: 0Fh
Bit
Bit Name
5:0
curr3x_preview
Curr3x preview
This register select the preview current of the current sinks30..33
Default Access Description
Defines Preview current of Current sinks curr30-33
00h = 0 mA
00
R/W
01h = 0.6 mA
...
3Fh = 37.8 mA
www.austriamicrosystems.com/AS3687
1v3-4
22 - 54
AS3687/87XM
Datasheet
Addr: 10h
Bit Name
5:0
curr3x_other
al
id
Bit
Bit Name
7:0
curr30_current
am
lc s
on A
te G
nt
st
il
Bit
Bit
Bit Name
7:0
curr31_current
Addr: 42h
Bit Name
7:0
curr32_current
Curr32 Current
This register selects the current of the current sink32
Default Access Description
Selects curr32 current, if curr32 is not used for strobe/preview
(curr32_mode=11b)
00h = 0 mA
00
R/W
01h = 0.15 mA
...
FFh = 38.25 mA
ni
ch
Addr: 43h
Bit Name
Te
7:0
Curr31 Current
This register selects the current of the current sink31
Default Access Description
Selects curr30 current, if curr30 is not used for strobe/preview
(curr30_mode=11b)
00h = 0 mA
00
R/W
01h = 0.15 mA
...
FFh = 38.25 mA
ca
Bit
Bit
Curr30 Current
This register selects the current of the current sink30
Default Access Description
Selects curr30 current, if curr30 is not used for strobe/preview
(curr30_mode=11b)
00h = 0 mA
00
R/W
01h = 0.15 mA
...
FFh = 38.25 mA
lv
Addr: 40h
Addr: 41h
Curr3x other
This register selects the current of the current sinks30..33
Default Access Description
Selects curr30 current, if curr30 is not used for strobe/preview
(curr30_mode=11b)
00h = 0 mA
00
R/W
01h = 0.6 mA
...
3Fh = 37.8 mA
curr33_current
Curr33 Current
This register selects the current of the current sink33
Default Access Description
Selects curr33 current, if curr33 is not used for strobe/preview
(curr33_mode=11b)
00h = 0 mA
00
R/W
01h = 0.15 mA
...
FFh = 38.25 mA
www.austriamicrosystems.com/AS3687
1v3-4
23 - 54
AS3687/87XM
Datasheet
Addr: 18h
am
lc s
on A
te G
nt
st
il
lv
curr3 control
This register select the mode of the current sinks30 - 33
Bit
Bit Name
Default
Access
Description
Select the mode of the current sink curr30
00b = off
1:0
curr30_mode
0
R/W
01b = strobe/preview
10b = curr30_other PWM controlled
1)
11b = curr30_current
Select the mode of the current sink curr31
00b = off
3:2
curr31_mode
0
R/W
01b = strobe/preview
10b = curr31_other PWM controlled
1)
11b = curr31_current
Select the mode of the current sink curr32
00b = off
5:4
curr32_mode
0
R/W
01b = strobe/preview
10b = curr32_other PWM controlled
1)
11b = curr32_current
Select the mode of the current sink curr33
00b = off
7:6
curr33_mode
0
R/W
01b = strobe/preview
10b = curr33_other PWM controlled
1)
11b = curr33_current
1)
don’t use this mode (11b) if softdim_pattern=1, use strobe/preview instead
al
id
Addr: 03h
Bit
Bit Name
4
curr30_pattern
5
curr31_pattern
0b
curr33_pattern
0b
R/W
Additional CURR33 LED pattern control bit
0b = CURR31 controlled according curr31_mode register
1b = CURR31 controlled by LED pattern generator
R/W
Additional CURR33 LED pattern control bit
0b = CURR32 controlled according curr32_mode register
1b = CURR32 controlled by LED pattern generator
R/W
Additional CURR33 LED pattern control bit
0b = CURR33 controlled according curr33_mode register
1b = CURR33 controlled by LED pattern generator
ni
7
curr32_pattern
0b
ca
6
Pattern control
This register controls the LED pattern
Default
Access
Description
Additional CURR33 LED pattern control bit
0b = CURR30 controlled according curr30_mode register
0b
R/W
1b = CURR30 controlled by LED pattern generator
7.3.3 LED Pattern Generator
ch
The LED pattern generator is capable of producing a pattern with 32 bits length and 1 second duration (31.25ms
for each bit). The pattern itself can be started every second, every 2nd, 3rd or 4th second.
Te
With this pattern all current sinks can be controlled. The pattern itself switches the configured current sources
between 0 and their programmed current.
If everything else is switched off, the current consumption in this mode is IACTIVE. (excluding current through
switched on current source) and the charge pump, if required. The charge pump can be automatically switched
on/off depending on the pattern (see register cp_auto_on in the charge pump section) to reduce the overall
current consumption.
www.austriamicrosystems.com/AS3687
1v3-4
24 - 54
AS3687/87XM
Datasheet
Figure 15 – LED Pattern Generator AS3687/87XM for pattern_color = 0
Defined by bit in the setup register pattern_data
in this example the code is 101110011...
I
any current sink
1 2 3 4 5 6 7 8 9 ... 32 1 2 3 4 5 6 7 8 9 ...
t
At this time a delay of 0s,1s,2s,...,8s,16s,24s,32s,40s,48s,56s
can be programmed
al
id
31.25ms
(250ms if pattern_slow=1)
To select the different current sinks to be controlled by the LED pattern generator, see the ‘xxxx’_mode registers
(where ‘xxxx’ stands for the to be controlled current sink, e.g. curr1_mode for CURR1 current sink). See also the
descirption of the different current sinks.
lv
To allow the generator of a color patterns set the bit pattern_color to ‘1’. Then the pattern can be connected to
CURR30-32 as follows:
Figure 16 – LED Pattern Generator AS3687/87XM for pattern_color = 1
am
lc s
on A
te G
nt
st
il
Defined by bit in the setup register pattern_data
in this example the code is 111110001011111000110111...
I
CURR1/CURR30
CURR2/CURR31
CURR6/CURR32,33
1 47
... 28 1 4 7
...
2 58
... 29 2 5 8
...
3 69
... 30 3 6 9
...
t
100ms
(800ms if pattern_slow=1)
At this time a delay of 0s,1s,2s,...,8s,16s,24s,32s,40s,48s,56s
can be programmed
Only those current sinks will be controlled, where the ‘xxxx’_mode register is configured for LED pattern.
If the register bit pattern_slow is set, all pattern times are increased by a factor of eigth. (bit duration: 250ms if
pattern_color=0 / 800ms if pattern_color=1, delays between pattern up to 24s).
7.3.3.1 Soft Dimming for Pattern
ca
The internal pattern generator can be combined with the internal pwm dimming modulator to obtain as shown in
the following figure:
Te
ch
Pattern
Generator
ni
Figure 17 – Softdimming Architecture for the AS3687/87XM (softdim_pattern=1 and pattern_color = 1)
set
RS
reset Flip Flop
out
set
RS
reset Flip Flop
out
set
RS
reset Flip Flop
out
Zero
Detect
up down Dimming
Ramp
Gen
8
CURR1/CURR30
CURR2/CURR31
CURR6/CURR32,33
controls current sources (on/off) for
current source where
currX_mode = LED pattern
PWM
Modulator
With the AS3687/87XM smooth fade-in and fade-out effects can be automatically generated.
www.austriamicrosystems.com/AS3687
1v3-4
25 - 54
AS3687/87XM
Datasheet
As there is only one dimming ramp generator and one pwm modulator following constraints have to be
considered when setting up the pattern (applies only if pattern_color=1):
Figure 18 – Softdimming example Waveform for CURR30-32
CURR30
ok
CURR31
ok
CURR32
al
id
A new dimming up (CURR32) can be
started after the dimming
down (CURR30) is finished
A new dimming up (CURR32) cannot be
started after or while one channel (CURR30)
is dimming up
lv
not possible
am
lc s
on A
te G
nt
st
il
However using the identical dimming waveform for two channels is possible as shown in the following figure:
Figure 19 – Softdimming example Waveform for CURR30-32
CURR30
ok
CURR31
ok
CURR32
ok
7.3.3.2 LED Pattern Registers
Addr: 19h,1Ah,1Bh,1Ch Pattern data0, Pattern data1, Pattern data2, Pattern data3
This registers contains the pattern data for the current sinks.
Bit
Bit Name
Default
Access
Description
1
7:0
pattern_data0[7:0]
7:0
pattern_data1[15:8]
7:0
pattern_data2[23:16]
7:0
pattern_data3[31:24]
R/W
Pattern data0
0
R/W
Pattern data1
0
R/W
Pattern data2
R/W
Pattern data3
ca
1
0
ni
1
0
ch
1
Note:
Update any of the pattern register only if none of the current sources is connected to the pattern
generator (‘xxxx’_mode must not be 11b). The pattern generator is automatically started at the
same time when any of the current sources is connected to the pattern generator
Te
1.
www.austriamicrosystems.com/AS3687
1v3-4
26 - 54
AS3687/87XM
Datasheet
Bit Name
0
pattern_color
2:1
pattern_delay
3
softdim_pattern
4
curr30_pattern
al
id
Bit
Pattern control
This register controls the LED pattern
Default
Access
Description
Defines the pattern type for the current sinks
0b = single 32 bit pattern (also set currX_mode = 11)
0
R/W
1b = RGB pattern with each 10 bits (set all currX_mode =
11)
Delay between pattern, details see table LED Pattern timing;
00b
R/W
together with pattern_delay2 sets the delay time between
patterns
Enable the ‘soft’ dimming feature for the pattern generator
0 = Pattern generator directly control current sources
0b
R/W
1 = ‘Soft Dimming’ is performed – see section ’Soft Dimming
for pattern’
Additional CURR33 LED pattern control bit
0b = CURR30 controlled according curr30_mode register
0b
R/W
1b = CURR30 controlled by LED pattern generator
lv
Addr: 18h
curr31_pattern
0b
R/W
6
curr32_pattern
0b
R/W
Additional CURR33 LED pattern control bit
0b = CURR32 controlled according curr32_mode register
1b = CURR32 controlled by LED pattern generator
7
curr33_pattern
0b
R/W
Additional CURR33 LED pattern control bit
0b = CURR33 controlled according curr33_mode register
1b = CURR33 controlled by LED pattern generator
Addr: 2Ch
am
lc s
on A
te G
nt
st
il
5
Additional CURR33 LED pattern control bit
0b = CURR31 controlled according curr31_mode register
1b = CURR31 controlled by LED pattern generator
gpio_current
Bit Name
Default
Access
4
pattern_delay2
0
R/W
6
pattern_slow
0
R/W
Description
Delay between pattern see table LED Pattern timing;
together with pattern_delay sets the delay time between
patterns
Pattern timing control
0b = normal mode
1b = slow mode (all pattern times are increased by a
factor of eight)
ca
Bit
Figure 20 –LED Pattern timing
ni
pattern_slow pattern_delay2 pattern_delay[1..0]
ch
delay between patterns
Te
0
0
0
0
0
0
0
0
1
1
0
0
0
0
1
1
1
1
0
00
01
10
11
00
01
10
11
00
bit duration [ms]
pattern_color=0 pattern_color=1
31
31
31
31
31
31
31
31
250
100
100
100
100
100
100
100
100
800
delay [s]
between
patterns
01
1
2
3
4
5
6
7
0
pattern duration [s]
(total cycle time:
pattern + delay)
1
2
3
4
5
6
7
8
8
Even by setting 000 for pattern delay, there is a small delay before the new patterns starts.
www.austriamicrosystems.com/AS3687
1v3-4
27 - 54
AS3687/87XM
Datasheet
Figure 20 –LED Pattern timing
delay between patterns
0
0
0
1
1
1
1
01
10
11
00
01
10
11
pattern_color=0 pattern_color=1
250
250
250
250
250
250
250
800
800
800
800
800
800
800
delay [s]
between
patterns
8
16
24
32
40
48
56
pattern duration [s]
(total cycle time:
pattern + delay)
16
24
32
40
48
56
64
lv
1
1
1
1
1
1
1
bit duration [ms]
al
id
pattern_slow pattern_delay2 pattern_delay[1..0]
7.3.4 PWM Generator
am
lc s
on A
te G
nt
st
il
The PWM generator can be used for any current sink (CURR1, CURR2, CURR3x, CURR6). The setting applies
for all current sinks, which are controlled by the pwm generator (e.g. CURR1 is pwm controlled if curr1_mode =
10). The pwm modulated signal can switch on/off the current sinks and therefore depending on its duty cycle
change the brightness of an attached LED.
7.3.4.1 Internal PWM Generator
The internal PWM generator uses the 2MHz internal clock as input frequency and its dimming range is 6 bits
digital (2MHz / 2^6 = 31.3kHz pwm frequency) and 2 bits analog. Depending on the actual code in the register
‘pwm_code’ the following algorithm is used:
If pwm_code bit 7 = 1
Then the upper 6 bits (Bits 7:2) of pwm_code are used for the 6 bits PWM generation, which controls the
selected currents sinks directly

If pwm_code bit 7 =0 and bit 6 = 1
Then bits 6:1 of pwm_code are used for the 6 bits PWM generation. This signal controls the selected current
sinks, but the analog current of these sinks is divided by 2

If pwm_code bit 7 and bit 6 = 0
Then bits 5:0 of pwm_code are used for the 6 bits PWM generation. This signal controls the selected current
sinks, but the analog current of these sinks is divided by 4
Figure 21 – PWM Control
0 0
6 bit PWM
ni
0
6 bit PWM
ca

to current sink(s) but analog
currents are divided by 2
to current sink(s)
ch
6 bit PWM
to current sink(s) but analog
currents are divided by 4
7 6 5 4 3 2 1 0
pwm_code
Te
Automatic Up/Down Dimming
If the register pwm_dim_mode is set to 01 (up dimming) or 10 (down dimming) the value within the register
th
th
pwm_code is increased (up dimming) or decreased (down dimming) every time and amount (either 1/4 or 1/8 )
defined by the register pwm_dim_speed. The maximum value of 255 (completely on) and the minimum value of
0 (off) is never exceeded. It is used to smoothly and automatically dim the brightness of the LEDs connceted to
any of the current sinks. The PWM code is readable all the time (Also during up and down dimming)
The waveform for up dimming looks as follows (cycles omitted for simplicity):
www.austriamicrosystems.com/AS3687
1v3-4
28 - 54
AS3687/87XM
Datasheet
Figure 22 – PWM Dimming Waveform for up dimming (pwm_dim_mode = 01); currX_mode = PWM controlled (not all steps shown)
I
currX_current
I/2
I/4
t
next step: I/2 with
50% duty cycle
The internal pwm modulator circuit controls the current sinks as shown in the following figure:
Figure 23 – PWM Control Circuit (currX_mode = 10b (PWM controlled)); X = any current sink
currX_adder
currX_current
8
/2
0
8
From serial
Interface
8
IDAC
CURRX
am
lc s
on A
te G
nt
st
il
/4
8
lv
Adder Logic
al
id
32µs
I/4 with up to
100% duty cycle
pwm_code
2MHz
Dimming
Ramp
Gen
subX_en
PWM
Modulator
8
adder_currentX
if pwm_dim_mode = 01 or 10
The adder logic (available for CURR30-32, CURR1, CURR2 and CURR6) is intended to allow dimming not only
from 0% to 100% (or 100% to 0%) of currX_current, but also e.g. from 10% to 110% (or 110% to 10%) of
currX_current. That means for up dimming the starting current is defined by 0 + currX_adder and the end
current is defined by currX_current + currX_adder.
An overflow of the internal bus (8 Bits wide to the IDAC) has to be avoided by the register settings (currX_current
+ currX_adder must not exceed 255).
ca
If the register subX_en is set, the result from the pwm_modulator is inverted logically. That means for up
dimming the starting current is defined by currX_adder - 1 and the end current is defined by currX_adder currX_current - 1. An overflow of the internal bus (8 Bits wide to the IDAC) has to be avoided by the register
settings (currX_adder - currX_current - 1 must not be below zero).
Its purpose is to dim one channel e.g. CURR30 from e.g. 110% to 10% of curr30_current and at the same time
dim another channel e.g. CURR31 from 20% to 120% of curr31_current.
Note:
ch
2.
The adder logic operates independent of the currX_mode setting, but its main purpose is to work
together with the pwm modulator (improved up/down dimming)
If the adder logic is not used anymore, set the bit currX_adder to 0. (Setting adder_currentX to 0 is
not sufficient)
ni
1.
Figure 24 – PWM Dimming Table
Te
Decrease by 1/4th every Decrease by 1/8th every
step
step
Seconds
Seconds Seconds
Seconds
Step
%Dimming
PWM
%Dimming
PWM
50msec/
Step
25msec/
Step
5msec/
Step
2,5msec/
Step
1
2
3
4
5
100,0
75,3
56,5
42,4
31,8
255
192
144
108
81
100,0
87,8
76,9
67,5
59,2
255
224
196
172
151
0,00s
0,05s
0,10s
0,15s
0,20s
0,00s
0,03s
0,05s
0,08s
0,10s
0,000s
0,005s
0,010s
0,015s
0,020s
0,000s
0,003s
0,005s
0,008s
0,010s
www.austriamicrosystems.com/AS3687
1v3-4
29 - 54
AS3687/87XM
Datasheet
Figure 24 – PWM Dimming Table
Seconds
Seconds Seconds
Seconds
Step
%Dimming
PWM
%Dimming
PWM
50msec/
Step
25msec/
Step
5msec/
Step
2,5msec/
Step
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
23,9
18,0
13,7
10,6
8,2
6,3
4,7
3,5
2,7
2,4
2,0
1,6
1,2
0,8
0,4
61
46
35
27
21
16
12
9
7
6
5
4
3
2
1
52,2
45,9
40,4
35,7
31,4
27,5
24,3
21,6
19,2
16,9
14,9
13,3
11,8
10,6
9,4
133
117
103
91
80
70
62
55
49
43
38
34
30
27
24
0,25s
0,30s
0,35s
0,40s
0,45s
0,50s
0,55s
0,60s
0,65s
0,70s
0,75s
0,80s
0,85s
0,90s
0,95s
0,13s
0,15s
0,18s
0,20s
0,23s
0,25s
0,28s
0,30s
0,33s
0,35s
0,38s
0,40s
0,43s
0,45s
0,48s
0,025s
0,030s
0,035s
0,040s
0,045s
0,050s
0,055s
0,060s
0,065s
0,070s
0,075s
0,080s
0,085s
0,090s
0,095s
0,013s
0,015s
0,018s
0,020s
0,023s
0,025s
0,028s
0,030s
0,033s
0,035s
0,038s
0,040s
0,043s
0,045s
0,048s
21
0,0
0
8,2
21
1,00s
0,50s
0,100s
0,050s
7,5
6,7
5,9
5,5
5,1
4,7
4,3
3,9
3,5
3,1
2,7
2,4
2,0
1,6
1,2
0,8
0,4
19
17
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
1,05s
1,10s
1,15s
1,20s
1,25s
1,30s
1,35s
1,40s
1,45s
1,50s
1,55s
1,60s
1,65s
1,70s
1,75s
1,80s
1,85s
0,53s
0,55s
0,58s
0,60s
0,63s
0,65s
0,68s
0,70s
0,73s
0,75s
0,78s
0,80s
0,83s
0,85s
0,88s
0,90s
0,93s
0,105s
0,110s
0,115s
0,120s
0,125s
0,130s
0,135s
0,140s
0,145s
0,150s
0,155s
0,160s
0,165s
0,170s
0,175s
0,180s
0,185s
0,053s
0,055s
0,058s
0,060s
0,063s
0,065s
0,068s
0,070s
0,073s
0,075s
0,078s
0,080s
0,083s
0,085s
0,088s
0,090s
0,093s
0,0
0
1,90s
0,95s
0,190s
0,095s
ch
39
lv
am
lc s
on A
te G
nt
st
il
ni
ca
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
al
id
Decrease by 1/4th every Decrease by 1/8th every
step
step
7.3.4.2 PWM Generator Registers
Te
Addr: 16h
Bit
Bit Name
2:1
pwm_dim_mode
Pwm control
This register controls PWM generator
Default
Access Description
Selects the dimming mode
00b = no dimming; actual content of register pwm_code is
00b
R/W
used for pwm generator
01b = logarithmic up dimming (codes are increased). Start
value is actual pwm_code
www.austriamicrosystems.com/AS3687
1v3-4
30 - 54
AS3687/87XM
Datasheet
Bit Name
5:3
pwm_dim_speed
Addr: 17h
Bit
Bit Name
7:0
pwm_code
Addr: 30h
am
lc s
on A
te G
nt
st
il
lv
Bit
Pwm control
This register controls PWM generator
Default
Access Description
10b = logarithmic down dimming (codes are decreased)
Start value is actual pwm_code; switch off the dimmed current
source after dimming is finished to avoid unnecessary
quiescent current
11b = NA
Defines dimming speed by increase/descrease pwm_code …
000b = … by 1/4th every 50 msec (total dim time 1.0s)
001b = … by 1/8th every 50 msec (total dim time 1.9s)
010b = … by 1/4th every 25 msec (total dim time 0.5s)
th
000b
R/W
011b = … by 1/8 every 25 msec (total dim time 0.95s)
100b = … by 1/4th every 5 msec (total dim time 100ms)
101b = … by 1/8th every 5 msec (total dim time 190ms)
th
110b = … by 1/4 every 2.5 msec (total dim time 50ms)
111b = … by 1/8th every 2.5 msec (total dim time 95ms)
al
id
Addr: 16h
Bit
Bit Name
7:0
adder_current1
Adder Current 1
This register defines the current which can be added to CURR1, CURR30
Default
Access
Description
Selects the added current value – do not exceed together
with currX_current the internal 8 Bit range (see text)
00h = 0 (represents 0mA)
00b
R/W
...
FFh = 255 (represents 38.25mA)
Adder Current 2
This register defines the current which can be added to CURR2, CURR31
Default
Access
Description
Selects the added current value – do not exceed together
with currX_current the internal 8 Bit range (see text)
00h = 0 (represents 0mA)
00b
R/W
...
FFh = 255 (represents 38.25mA)
ca
Addr: 31h
Pwm code
This register controls the Pwm code.
Default
Access
Description
Selects the PWM code
00h = Always 0
00b
R/W
...
FFh = Always 1
Bit Name
7:0
adder_current2
ch
ni
Bit
Te
Addr: 32h
Bit
Bit Name
7:0
adder_current3
Adder Current 3
This register defines the current which can be added to CURR6, CURR32
Default
Access
Description
Selects the added current value – do not exceed together
with currX_current the internal 8 Bit range (see text)
00h = 0 (represents 0mA)
00b
R/W
...
FFh = 255 (represents 38.25mA)
www.austriamicrosystems.com/AS3687
1v3-4
31 - 54
AS3687/87XM
Datasheet
0
curr1_adder
1
curr2_adder
2
curr6_adder
3
curr30_adder
4
curr31_adder
5
curr32_adder
Addr: 35h
Bit Name
0
sub_en1
1
sub_en2
2
sub_en3
Subtract Enable
Enable the inversion from the signal from the pwm generator
Default
Access
Description
Inverts the signal from the pwm generator
0 = Direct Operation (no inversion)
1 = The signal from the pwm generator for which the adder
0
R/W
is enabled (curr1_adder = 1, curr30_adder = 1)
is inverted
Inverts the signal from the pwm generator
0 = Direct Operation (no inversion)
0
R/W
1 = The signal from the pwm generator for which the adder
is enabled (curr2_adder = 1, curr31_adder = 1)
is inverted
Inverts the signal from the pwm generator
0 = Direct Operation (no inversion)
0
R/W
1 = The signal from the pwm generator for which the adder
is enabled (curr6_adder = 1, curr32_adder = 1)
is inverted
Te
ch
ni
ca
Bit
al
id
Bit Name
am
lc s
on A
te G
nt
st
il
Bit
Adder Enable 2
Enables the adder circuit for the selected current sources
Default
Access
Description
Enables adder circuit for current source CURR1
0
R/W
0 = Normal Operation of the current source
1 = adder_current1 gets added to the current source current
Enables adder circuit for current source CURR2
0
R/W
0 = Normal Operation of the current source
1 = adder_current2 gets added to the current source current
Enables adder circuit for current source CURR6
0
R/W
0 = Normal Operation of the current source
1 = adder_current3 gets added to the current source current
Enables adder circuit for current source CURR30
0
R/W
0 = Normal Operation of the current source
1 = adder_current1 gets added to the current source current
Enables adder circuit for current source CURR31
0
R/W
0 = Normal Operation of the current source
1 = adder_current2 gets added to the current source current
Enables adder circuit for current source CURR32
0
R/W
0 = Normal Operation of the current source
1 = adder_current3 gets added to the current source current
lv
Addr: 34h
www.austriamicrosystems.com/AS3687
1v3-4
32 - 54
AS3687/87XM
Datasheet
7.4
LED Test
Figure 25 – LED Function Testing
Detect Shorted LEDs
D1
From DCDC
Step Up
Converter
C9
4.7µF
I(step_up_vtuning)
al
id
R3
1M
DCDC_FB
Baseband
Processor
CPOUT
lv
From Charge
Pump
C8
2.2µF
Interface
ADC
am
lc s
on A
te G
nt
st
il
...
Detect Open LEDs
...
The AS3687/87XM supports the verification of the functionality of the connected LEDs (open and shorted LEDs
can be detected). This feature is especially useful in production test to verify the correct assembly of the LEDs,
all its connectors and cables. It can also be used in the field to verify if any of the LEDs is damaged. A damaged
LED can then be disabled (to avoid unnecessary currents).
The current sources, charge pump, dcdc converter and the internal ADC are used to verify the forward voltage of
the LEDs. If this forward voltage is within the specified limits of the LEDs, the external circuitry is assumed to
operate.
7.4.1 Function Testing for single LEDs connected to the Charge Pump
For any current source connected to the charge pump (CURR30-33) where only one LED is connected between
the charge pump and the current sink (see Figure 1) use:
Table 11 – Function Testing for LEDs connected to the Charge Pump
2.
Example Code
Reg 23h <- 14h (cp_mode = 1:2, manual)
Reg 00h <- 04h (cp_on = 1)
e.g. for register CURR31set to 9mA use
Reg 10h <- 0Fh (curr31_other = 9mA)
Reg 03h <- 0ch (curr31_mode = curr31_other)
Reg 26h <- 95h (adc_select=CP_OUT,start ADC)
Measure with the ADC the voltage on CP_OUT
Fetch the ADC result from Reg 27h and 28h
Measure with the ADC the voltage on the switched on Reg 26h <- 8bh (adc_select=CURR31,start ADC)
current sink
Fetch the ADC result from Reg 27h and 28h
Switch off the current sink for the LED to be tested
Reg 03h <- 00h (curr31_mode = off)
Compare the difference between the ADC
measurements (which is the actual voltage across the
Calculation performed in baseband uProcessor
tested LED) against the specification limits of the
tested LED
Do the same procedure for the next LED starting from
Jump to 2. If not all the LEDs have been tested
point 2
Switch off the charge pump
Reg 00h <- 00h (cp_on = 0)
set chargepump automatic mode
Reg 23h <- 00h
Switch on the current sink for the LED to be tested
ch
3.
ca
1.
Action
Switch on the charge pump and set it into manual 1:2
mode (to avoid automatic mode switching during
measurements)
ni
Step
4.
Te
5.
6.
7.
8.
www.austriamicrosystems.com/AS3687
1v3-4
33 - 54
AS3687/87XM
Datasheet
7.4.2 Function Testing for LEDs connected to the Step Up DCDC Converter
For LEDs connected to the DCDC converter (usually current sinks CURR1,CURR2 and CURR6) use the
following procedure:
Step
1.
2.
Action
Switch on the current sink for the LED string to be
tested (CURR1,2 or 6)
Select the feedback path for the LED string to be
tested (e.g. step_up_fb = 01 for LED string on
CURR1)
Set the current for step_up_vtuning exactly above the
maximum forward voltage of the tested LED string +
0.6V (for the current sink) + 0.25V; add 6% margin
(accuracy of step_up_vtuning); this sets the maximum
output voltage limit for the DCDC converter
Example Code
e.g. Test LEDs on CURR1:
Reg 01h <- 01h (curr1_mode=on)
Reg 09h <- 3ch (curr1 = 9mA)
Reg 21h <- 02h (feedback=curr1)
al
id
Table 12 – Function Testing for LEDs connected to the DCDC converter
Set stepup_prot = 1
5.
Switch on the DCDC converter
Reg 00h <- 08h
6.
Wait 80ms (DCDC_FB settling time)
7.
Measure the voltage on DCDC_FB (ADC)
9.
10.
11.
12.
13.
14.
am
lc s
on A
te G
nt
st
il
8.
Reg 26h <- 96h (adc_select=DCDC_FB, start
ADC; Fetch the ADC result from Reg 27h and
28h)
If the voltage on DCDC_FB is above 1.0V, the tested
LED string is broken – then skip the following steps
Switch off the overvoltage protection (stepup_prot = 0)
Reduce step_up_vtuning step by step until the
measured voltage on DCDC_FB (ADC) is above 1.0V.
After changing step_up_vtuning always wait 80ms,
before AD-conversion
Measure voltage on DCDC_FB
Switch off the DCDC converter
The voltage on the LED string can be calculated now
as follows (R4 = open):
VLEDSTRING = V(DCDC_FB) + I(step_up_vtuning) *
R3 – 0.5V (current sinks feedback voltage: VFB2).
V(DCDC_FB) = ADC Measurement from point 11
I(step_up_vtuing) = last setting used for point 10
Compare the calculated value against the
specification limits of the tested LEDs
(Code >199h)
Reg 22h <- 00h
e.g.: Reg 21h <- 62h (step_up_vtuning=12): ADC
result=1,602V
e.g. DCDC_FB=1.602V
Reg 00h <- 00h
e.g.: VLED = (1.602V + 12V – 0.5V) / 4 = 3.276V
ca
3.
lv
4.
e.g. 4 LEDs with UfMAX = 4.1V gives 17.25V
+6% = 18.29V; if R3=1MΩ and R4 = open, then
select step_up_vtuning = 18 (Reg 21h <- 92h;
results in 19.25V overvoltage protection voltage –
see table in DCDC section)
Reg 22h <- 04h
Analog-To-Digital Converter
ch
7.5
ni
With the above described procedures electrically open and shorted LEDs can be automatically detected.
Te
The AS3687/87XM has a built-in 10-bit successive approximation analog-to-digital converter (ADC). It is
internally supplied by V2_5, which is also the full-scale input range (0V defines the ADC zero-code). For input
signal exceeding V2_5 (typ. 2.5V) a resistor divider with a gain of 0.4 (Ratioprescaler) is used to scale the input of
the ADC converter. Consequently the resolution is:
Table 13 – ADC Input Ranges, Compliances and Resolution
Channels (Pins)
Input Range
VLSB
DCDC_FB
0V-2.5V
2.44mV
ADCTEMP_CODE
-30°C to 125°C
1 / ADCTC
www.austriamicrosystems.com/AS3687
1v3-4
Note
VLSB=2.5/1024
junction temperature
34 - 54
AS3687/87XM
Datasheet
Table 13 – ADC Input Ranges, Compliances and Resolution
Input Range
VLSB
0V-5.5V
6.1mV
0V-1.0V
2.44mV
Note
VLSB=2.5/1024 * 1/0.4;
internal resistor divider used
VLSB=2.5/1024
Table 14 – ADC Parameters
Parameter
Min
Resolution
10
Vin
Input Voltage Range
VSS
DNL
Differential Non-Linearity
± 0.25
LSB
INL
Integral Non-Linearity
± 0.5
LSB
Vos
Input Offset Voltage
± 0.25
LSB
Rin
Input Impedance
Cin
Input Capacitance
Vsupply (V2_5)
Power Supply Range
2.5
V
± 2%, internally trimmed.
Idd
Power Supply Current
500
µA
During conversion only.
Idd
Power Down Current
100
nA
TTOL
ADCTOFFSET
ADCTC
Ratioprescaler
Typ
Max
Unit
Note
Bit
100
V
MΩ
Vsupply = V2_5
lv
Vsupply
am
lc s
on A
te G
nt
st
il
Symbol
al
id
Channels (Pins)
CURR30-33
VBAT, CP_OUT
CURR1, CURR2, CURR6
9
Temperature Sensor
Accuracy
ADC temperature
measurement offset value
Code temperature
coefficient
Ratio of Prescaler
-10
pF
°C
+10
375
°C
1.2939
°C/Code
0.4
@ 25 °C
Temperature change per ADC
LSB
For all low voltage current sinks,
CP_OUT and VBAT
Transient Parameters (2.5V, 25 ºC)
Tc
Conversion Time
27
µs
fc
Clock Frequency
1.0
MHz
All signals are internally
generated and triggered by
start_conversion
ca
ts
Settling Time of S&H
16
µs
The junction temperature (TJUNCTION) can be calculated with the following formula (ADCTEMP_CODE is the adc
conversion result for channel 17h selected by register adc_select = 010111b):
ni
TJUNCTION [°C] = ADCTOFFSET - ADCTC · ADCTEMP_CODE
7.5.1 Application Hint: Extending to ADC input voltage range for CURR1,2,6
Te
ch
Under certain operating conditions, the input voltage range for the ADC input CURR1,2,6 (specified from 0.0V1.0V for all operating conditions in table “ADC Input Ranges, Compliances and Resolution” ) can be extended as
follows:
www.austriamicrosystems.com/AS3687
1v3-4
35 - 54
AS3687/87XM
Datasheet
am
lc s
on A
te G
nt
st
il
lv
al
id
Figure 26 –Internal voltage of the ADC vs. applied voltage on CURR1,2 or CURR6
Operating conditions: VBAT>=3.3V, TJUNC >= -20°C (one curve with charge pump operating in 1:2 mode ‘on’ and
one curve with charge pump in 1:1 mode ‘off’).
Above curve represent the worst case and therefore are guaranteed by design under the above operating
conditions (ADC input range for CURR1,2,6 is between 0V and 1.5V).
7.5.2 ADC Registers
Addr: 27h
Bit
6:0
Bit Name
D9:D3
7
result_not_ready
Bit Name
D2:D0
Te
ch
ni
Bit
2:0
ADC_LSB Result
Together with Register 28h, this register contains the results (LSB) of an ADC cycle
Default
Access
Description
N/A
R
ADC result register.
ca
Addr: 28h
ADC_MSB Result
Together with Register 27h, this register contains the results (MSB) of an ADC cycle.
Default
Access
Description
N/A
R
ADC results register.
Indicates end of ADC conversion cycle.
0 = Result is ready.
N/A
R
1 = Conversion is running.
www.austriamicrosystems.com/AS3687
1v3-4
36 - 54
AS3687/87XM
Datasheet
Addr: 26h
Bit Name
5:0
adc_select1
am
lc s
on A
te G
nt
st
il
6
lv
al
id
Bit
ADC_control
This register input source selection and initialization of ADC.
Default
Access
Description
Selects input source as ADC input.
000000 (00h) = reserved
000001 (01h) = reserved
000010 (02h) = reserved
000011 (03h) = reserved
000100 (04h) = reserved
000101 (05h) = reserved
000110 (06h) = reserved
000111 (07h) = reserved
001000 (08h) = CURR1
001001 (09h) = CURR2
001010 (0Ah) = CURR30
001011 (0Bh) = CURR31
0
R/W
001100 (0Ch) = CURR32
001101 (0Dh) = CURR33
001110 (0Eh) = reserved
001111 (0Fh) = reserved
010000 (10h) = reserved
010001 (11h) = reserved
010010 (12h) = reserved
010011 (13h) = CURR6
010100 (14h) = VBAT
010101 (15h) = CP_OUT
010110 (16h) = DCDC_FB
010111 (17h) = ADCTEMP_CODE (junction temperature)
011xxx, 1xxxxx = reserved
reserved – don’t use; always write 0 to this register
Writing a 1 into this bit starts one ADC conversion cycle.
7
start_conversion
N/A
W
Notes:
1. See Table ‘ADC Input Ranges, Compliances and Resolution’ for ADC ranges and possible
Figure 27 – ADC Circuit
V2_5
CURR1
CURR2
CURR6
DCDC_FB
ca
vtemp
nc
D9:D0
result_not_ready
1MHz
180k
ni
CURR30
CURR31
CURR32
CURR33
VBAT
VCP
10bit SAR
ADC
Te
ch
120k
adc_select
start_conversion
Control
7.6
Audio controlled RGB LEDs (only AS3687XM)
Up to 2 RGB LEDs (connected to the pins CURR30-CURR32 and/or CURR1,2,6) can be controlled by an audio
source (connected to pin CURR33/AUDIO_IN). The color of the RGB LED(s) is depending on the input
amplitude and it starts from black transitions to blue, green, cyan, yellow, red and for high amplitudes white is
used (internal lookup table if audio_color=000b).
www.austriamicrosystems.com/AS3687
1v3-4
37 - 54
AS3687/87XM
Datasheet
Figure 28 – Audio controlled RGB LED application circuit
AS3687XM
CPOUT
Current Sinks
each 0.15-38.25mA
DRGB1
C5
1.0µF
CURR30
CURR32
CURR33/AUDIO_IN
C10
100nF
Audio IN
lv
Alternative:
2nd Audio or Backlight
al
id
CURR31
am
lc s
on A
te G
nt
st
il
Audio Processing
HV Current Sinks
each 0.15-38.25mA
DRGB2
D2
D3
D4
CURR1
CURR2
Te
ch
ni
ca
CURR6
www.austriamicrosystems.com/AS3687
1v3-4
38 - 54
AS3687/87XM
Datasheet
The internal circuit has the following functions:
Figure 29 – Audio controlled RGB LED internal circuit
audio_gain
-12dB...+30dB
CURR33/AUDIO_IN
optional
Audio IN
al
id
ADC
1.25V
aud_buf_on adc_select
Level
Detect /
Fadeout
AGC
Look
Up
Table
audio_speed
agc_ctrl
audio_color
DC
Remove
lv
rgb_amplitude
am
lc s
on A
te G
nt
st
il
CURR30
other modes
CURR31
other modes
CURR32
other modes
CURR1
curr3x_out
other modes
CURR2
other modes
CURR6
other modes
curr126_out
ca
The audio controlled LED block is enabled if any of the registers curr3x_out or curr126_out is not zero.
The audio input amplifier (enabled by aud_buf_on=1) is used to allow the attenuation (or amplification of the input
signal) and has the following parameters:
Table 15 – Audio input Parameters
Vin
Parameter
Min
Input Voltage Range
0
ni
Symbol
Rin_min
min. Input Impedance
Typ
20
Max
Unit
2.5
V
kΩ
Note
at max. input gain (30dB)
Te
ch
When audio control RGB LED is active, the internal ADC is continuously running at a sample frequency of
45.5kHz. In this case the ADC cannot be used for any other purpose.
The input amplitude is mapped into different colors for RGB LED(s) or brightness for single color LED(s). The
mapping is controlled by the register audio_color. If audio_color = 000, then the mapping is done as follows:
Very low amplitudes are mapped to black, for higher amplitudes, the color smoothly transitions from blue, green,
cyan, yellow, red and eventually to white (for high input amplitudes). Otherwise the output is mapped to the
brightness of a single color.
7.6.1 AGC
The AGC is used to ‘compress’ the input signal and to attenuate very low input amplitude signals (this is
performed to ensure no light output for low signals especially for noisy input signals).
The AGC monitors the input signal amplitude and filters this amplitude with a filter with a short attack time, but a
long decay time (decay time depends on the register agc_ctrl). This amplitude measurement (represented by an
www.austriamicrosystems.com/AS3687
1v3-4
39 - 54
AS3687/87XM
Datasheet
integer value from 0 to 15) is then used to amplify or attenuate the input signal with one of the following
amplification ratios (output to input ratio) – the curve A, B, or C is selected depending on the register agc_ctrl:
am
lc s
on A
te G
nt
st
il
lv
al
id
Figure 30 – AGC curve A (x-axis: input amplitude, y-axis: output amplitude; actual value: gain between output to input)
Figure 31 – AGC curve B (x-axis: input amplitude, y-axis: output amplitude; actual value: gain between output to input)
Te
ch
ni
ca
Figure 32 – AGC curve C (x-axis: input amplitude, y-axis: output amplitude; actual value: gain between output to input)
www.austriamicrosystems.com/AS3687
1v3-4
40 - 54
AS3687/87XM
Datasheet
7.6.2 Audio Control Registers
Audio Control (only AS3687XM)
Audio Controlled LED Mode control
Addr: 46h
Bit
Bit Name
Default
Access
0
aud_buf_on
0b
R/W
4:2
audio_color
000b
R/W
Description
0 off
1 on
audio controlled LED color selection
000 color scheme defined by lookup table
001-111 fixed color scheme (b2=R, b1=G, b0=B) – single
color only (e.g. Red: 100b)
R/W
00
01
10
11
none
200ms
400ms
800ms
Audio Input (only AS3687XM)
Audio controlled LED input control
Addr: 47h
Bit
00b
am
lc s
on A
te G
nt
st
il
audio_speed
lv
Audio controlled LED persistence time
7:6
al
id
Audio input buffer enable
Bit Name
Default
Access
Description
Audio input buffer gain control
2:0
audio_gain
000b
R/W
000
001
010
011
100
101
110
111
-12dB
-6dB
0dB
+6dB
+12dB
+18dB
+24dB
+30dB
Audio input buffer AGC function
controls AGC transfer function
000
001
000b
ca
agc_ctrl
ni
5:3
R/W
audio_man_start
0b
R/W
7
audio_dis_start
0b
R/W
Te
ch
6
010
011
100
101
110
111
AGC off
attenuate low amplitude signals otherwise linear
response (to remove e.g. noise)
AGC curve A; slow decay of amplitude detection
AGC curve A; fast decay of amplitude detection
AGC curve B; slow decay of amplitude detection
AGC curve B; fast decay of amplitude detection
AGC curve C; slow decay of amplitude detection
AGC curve C; fast decay of amplitude detection
Startup Control of audio input buffer (for charging of
external AC-coupling capacitor)
0 automatic precharging 300us (if audio_dis_start = 0)
1 continuously precharging (if audio_buf_on = 1)
Disable Startup Control of audio input buffer
www.austriamicrosystems.com/AS3687
0 precharging enabled
1 precharging disabled
1v3-4
41 - 54
AS3687/87XM
Datasheet
Audio output (only AS3687XM)
Audio controlled LED input control
Addr: 48h
Bit
Bit Name
Default
Access
Description
2:0
rgb_amplitude
000b
R/W
3
curr3x_out
0b
R/W
4
curr126_out
0b
R/W
000
001
010
011
100
101
110
111
6.25%
12.5%
25%
50%
75%
87.5%
93.75%
100%
Audio sync enable for CURR30-CURR32
al
id
RGB output amplitude control (in % of selected output
current) – master amplitude control
lv
0 off
1 on, ADC continuously running with f=500kHz
Audio sync enable for CURR1, CURR2, CURR6
am
lc s
on A
te G
nt
st
il
7.7
0 off
1 on, ADC continuously running with f=500kHz
Power-On Reset
The internal reset is controlled by two sources:
VBAT Supply
Serial interface state (SCL, SDA)
The internal reset is forced if VBAT is low or if both interface pins (SCL, SDA) are low for more than 100ms. The
device enters shutdown mode, when SCL and SDA remain low.
The reset levels control the state of all registers. As long as VBAT and SCL/SDA are below their reset thresholds,
the register contents are set to default. Access by serial interface is possible once the reset thresholds are
exceeded.
ca
Figure 33 – Zero Power Device Wakeup block diagram
power-on to internal
references and V2_5 LDO
VBAT
ni
VBAT
Zero Power
Device Wakeup
shutdn_disab
on
VBAT
ch
VDD_I/F
R4
1-10k
Te
DATA
CLK
debounce
timer
1ms/100ms
fast_shutdwn
R5
V2_5
V2_5
DATA
Serial
Interface
Logic
V2_5
CLK
VBAT
www.austriamicrosystems.com/AS3687
1v3-4
42 - 54
AS3687/87XM
Datasheet
Table 16 – Reset Levels
Symbol
Parameter
Min
Typ
Max
Unit
Note
Overall Power-On
Reset
1.8
2.15
2.4
V
VPOR_PERI
Reset Level for pins
SCL, SDA
0.29
1.0
1.38
V
Monitor voltage on pins SCL, SDA
tPOR_DEB
Reset debounce time
for pins SCL, SDA
80
100
120
ms
tSTART
Interface Startup Time
4
6
8
ms
al
id
VPOR_VBAT
Monitor voltage on V2_5; power-on
2
reset for all internal functions.
Addr: 29h
Bit Name
4
shutdwn_enab
7.8
Overtemp Control
This register reads and resets the overtemperature flag.
Default
Access
Description
Enable Shutdown mode and serial interface reset.
0 Serial Interface reset disabled. Device does not enter
Shutdown mode
0
R/W
1 Serial Interface reset enabled, device enters shutdown
when SCL and SDA remain low for min. 120ms
am
lc s
on A
te G
nt
st
il
Bit
lv
7.7.1 Reset control register
Temperature Supervision
An integrated temperature sensor provides over-temperature protection for the AS3687/87XM. This sensor
generates a flag if the device temperature reaches the overtemperature threshold of 140º. The threshold has a
hysteresis to prevent oscillation effects.
If the device temperature exceeds the 140º threshold all current sources, the charge pump and the dcdc
converter is disabled and the ov_temp flag is set. After decreasing the temperature by 5º (typically) operation is
resumed.
The ov_temp flag can only be reset by first writing a 1 and then a 0 to the bit rst_ov_temp.
Bit ov_temp_on = 1 activates temperature supervision.
Symbol
Parameter
Min
ov_temp Rising Threshold
ni
T140
ca
Table 17 – Overtemperature Detection
ov_temp Hystersis
Max
Unit
140
ºC
5
ºC
Note
Te
ch
Thyst
Typ
2
Guaranteed by design – not production tested.
www.austriamicrosystems.com/AS3687
1v3-4
43 - 54
AS3687/87XM
Datasheet
7.8.1 Temperature Supervision Registers
Bit Name
0
ov_temp_on
1
ov_temp
2
rst_ov_temp
Serial Interface
am
lc s
on A
te G
nt
st
il
7.9
lv
Bit
Overtemp Control
This register reads and resets the overtemperature flag.
Default
Access
Description
Activates/deactivates device temperature supervision.
Default: Off - all other bits are only valid if this bit is set to 1.
1
W
0 = Temperature supervision is disabled. No reset will be
generated if the device temperature exceeds 140ºC.
1 = Temperature supervision is enabled.
1 = Indicates that the overtemperature threshold has been
reached; this flag is not cleared by an overtemperature
N/A
R
reset. It has to be cleared using bit rst_ov_temp.
The ov_temp flag is cleared by first setting this bit to 1, and
0
R/W
then setting this bit to 0.
al
id
Addr: 29h
The AS3687/87XM is controlled using serial interface pins CLK and DATA:
Figure 35 – Serial interface block diagram
VDD_I/F
R4
1-10k
R5
DATA
DATA
Serial
Interface
Logic
CLK
CLK
The clock line CLK is never held low by the AS3687/87XM (as the AS3687/87XM does not use clock stretching of
the bus).
Table 18 – Serial Interface Timing
VIHI/F
VILI/F
Min
High Level Input voltage
Low Level Input voltage
Max
Unit
1.38
VBAT
V
0.0
0.52
V
Hysteresis
ni
VHYSTI/F
Parameter
ca
Symbol
Typ
0.1
V
Rise Time - VILI/F to VIHI/F
0
1000
ns
tFALL
Fall Time - VIHI/F to VILI/F
0
300
ns
ch
tRISE
Spike Filter on CLK
100
ns
tDATA_FILTER
Spike Filter on DATA
300
ns
Pins DATA and CLK
Te
tCLK_FILTER
Note
7.9.1 Serial Interface Features
Fast Mode Capability (Maximum Clock Frequency is 400 kHz)
7-bit Addressing Mode
Write Formats
− Single-Byte Write
− Page-Write
www.austriamicrosystems.com/AS3687
1v3-4
44 - 54
AS3687/87XM
Datasheet
Read Formats
− Current-Address Read
− Random-Read
− Sequential-Read
DATA Input Delay and CLK Spike Filtering by Integrated RC Components
7.9.2 Device Address Selection
al
id
The serial interface address of the AS3687/87XM has the following address:
80h – Write Commands
81h – Read Commands
lv
Figure 36 – Complete Serial Data Transfer
CLK
S
Start
Condition
am
lc s
on A
te G
nt
st
il
DATA
1-7
8
Address
R/W
9
ACK
8
1-7
9
Data
ACK
1-7
8
9
Data
P
ACK
Stop
Condition
7.9.2.1 Serial Data Transfer Formats
Definitions used in the serial data transfer format diagrams are listed in the following table:
Table 19 – Serial Data Transfer Byte Definitions
Definition
R/W (AS3687/87XM
Slave)
R
Notes
Start Condition after Stop
Sr
Repeated Start
R
1 bit
DW
Device Address for Write
R
10000000b (80h).
DR
Device Address for Read
R
10000001b (81h)
WA
Word Address
R
8 bits
A
Acknowledge
W
1 bit
N
Not Acknowledge
R
1 bit
ca
S
ni
Symbol
1 bit
reg_data
Register Data/Write
R
8 bits
data (n)
Register Data/read
R
1 bit
Stop Condition
R
8 bits
R
During Acknowledge
ch
P
Increment Word Address Internally
Te
WA++
www.austriamicrosystems.com/AS3687
1v3-4
45 - 54
AS3687/87XM
Datasheet
Figure 37 – Serial Interface Byte Write
DW
A
WA
AS3687/87XM
AS3687/87XM
A
reg_data
A P
Write Register
WA++
(= Slave) receives data
(= Slave) transmits data
Figure 38 – Serial Interface Page Write
DW
A
WA
A
reg_data 1
A
reg_data 2
Write Register
WA++
…
Write Register
WA++
(= Slave) receives data
(= Slave) transmits data
reg_data n
A P
Write Register
WA++
am
lc s
on A
te G
nt
st
il
AS3687/87XM
AS3687/87XM
A
lv
S
al
id
S
Byte Write and Page Write formats are used to write data to the slave.
The transmission begins with the START condition, which is generated by the master when the bus is in IDLE
state (the bus is free). The device-write address is followed by the word address. After the word address any
number of data bytes can be sent to the slave. The word address is incremented internally, in order to write
subsequent data bytes on subsequent address locations.
For reading data from the slave device, the master has to change the transfer direction. This can be done either
with a repeated START condition followed by the device-read address, or simply with a new transmission START
followed by the device-read address, when the bus is in IDLE state. The device-read address is always followed
by the 1st register byte transmitted from the slave. In Read Mode any number of subsequent register bytes can
be read from the slave. The word address is incremented internally.
The following diagrams show the serial read formats supported by the AS3687/87XM.
Figure 39 – Serial Interface Random Read
DW
A
WA
A Sr
DR
ca
S
data
N P
Read Register
WA++
(= Slave) receives data
(= Slave) transmits data
ch
ni
AS3687/87XM
AS3687/87XM
A
Random Read and Sequential Read are combined formats. The repeated START condition is used to change the
direction after the data transfer from the master.
Te
The word address transfer is initiated with a START condition issued by the master while the bus is idle. The
START condition is followed by the device-write address and the word address.
In order to change the data direction a repeated START condition is issued on the 1st CLK pulse after the
ACKNOWLEDGE bit of the word address transfer. After the reception of the device-read address, the slave
becomes the transmitter. In this state the slave transmits register data located by the previous received word
address vector. The master responds to the data byte with a NOT ACKNOWLEDGE, and issues a STOP
condition on the bus.
www.austriamicrosystems.com/AS3687
1v3-4
46 - 54
AS3687/87XM
Datasheet
Figure 40 – Serial Interface Sequential Read
S
DW
A
WA
A Sr
DR
A
data 1
A
data 2
...
A
data n
N P
Read Register
WA++
(= Slave) receives data
(= Slave) transmits data
al
id
AS3687/87XM
AS3687/87XM
Sequential Read is the extended form of Random Read, as multiple register-data bytes are subsequently
transferred.
lv
In contrast to the Random Read, in a sequential read the transferred register-data bytes are responded by an
acknowledge from the master. The number of data bytes transferred in one sequence is unlimited (consider the
behavior of the word-address counter). To terminate the transmission the master has to send a NOT
ACKNOWLEDGE following the last data byte and subsequently generate the STOP condition.
S
DR
am
lc s
on A
te G
nt
st
il
Figure 41 – Serial Interface Current Address Read
A
data 1
Read Register
WA++
A
data 2
…
Read Register
WA++
A
data n
N P
Read Register
WA++
AS3687 (= slave) receives data
AS3687 (= slave) transmits data
To keep the access time as small as possible, this format allows a read access without the word address transfer
in advance to the data transfer. The bus is idle and the master issues a START condition followed by the DeviceRead address.
Analogous to Random Read, a single byte transfer is terminated with a NOT ACKNOWLEDGE after the 1st
register byte. Analogous to Sequential Read an unlimited number of data bytes can be transferred, where the
data bytes must be responded to with an ACKNOWLEDGE from the master.
For termination of the transmission the master sends a NOT ACKNOWLEDGE following the last data byte and a
subsequent STOP condition.
ca
7.10 Operating Modes
If the voltage on SCL and SDA is less than 1V (for > tPOR_DEB), the AS3687/87XM is in shutdown mode and its
current consumption is minimized (IBAT = ISHUTDOWN) and all internal registers are reset to their default values.
Charge pump
ch

ni
If the voltage at SCL or SDA rises above 1V, the AS3687/87XM serial interface is enabled and the AS3687/87XM
and the standby mode is selected. The AS3687/87XM is switched automatically from standby mode (I(BAT) =
ISTANDBY) into normal mode (I(BAT) = IACTIVE) and back, if one of the following blocks are activated:
Step up regulator

Any current sink

ADC conversion started

PWM active

Pattern mode active.
Te

If any of these blocks are already switched on the internal oscillator is running and a write instruction to the
registers is directly evaluated within 1 internal CLK Cycle (typ. 1μs)
If all these blocks are disabled, a write instruction to enable these blocks is delayed by 64 CLK cycles (oscillator
will startup, within max 200μs).
www.austriamicrosystems.com/AS3687
1v3-4
47 - 54
AS3687/87XM
Datasheet
8 Register Map
Table 20 – Registermap
Ad
dr.
Def
ault
Content
b7
Name
Reg. control
00h
b6
b5
b4
00
curr12 control
01h
00h
curr rgb control
02h
00h
curr6_mode
curr3 control1
03h
00h
curr33_mode
b3
b2
step_up
_on
cp_on
curr2_mode
curr32_mode
curr31_mode
00h
curr1_current
0Ah
00h
curr2_current
Curr3x strobe
0Eh
00h
curr3x_strobe
Curr3x preview
0Fh
00h
curr3x_preview
Curr3x other
10h
Curr3 strobe
control
11h
Pwm control
16h
pwm code
17h
Pattern control
18h
19h
Pattern data1
1Ah
Pattern data2
1Bh
Pattern data3
1Ch
DCDC control1
21h
DCDC control2
22h
00h
strobe_timing
strobe_mode
curr3x_
strobe_
high
00h
00h
00h
00h
preview
_off_aft
er
strobe
pwm_dim_mode
pwm_code
curr33_
pattern
curr32_
pattern
curr31_
pattern
curr30_
pattern
softdim
_patter
n
00h
pattern_data[7:0]
00h
pattern_data[15:8]
00h
pattern_data[23:16]
00h
pattern_data[31:24]
00h
04h
strobe_ctrl
preview_ctrl
pwm_dim_speed
step_up_vtuning
step_up
_fb_aut
o
ni
23h
00h
curr6_p
rot_on
curr2_p
rot_on
curr1_p
rot_on
cp_auto
_on
cp_start
_debou
nce
cp_mode_switchin
g
24h
00h
CP mode Switch2
25h
00h
curr6_o
n_cp
ADC_control
26h
00h
start_co
nversio
n
adc_on
ADC_MSB result
27h
NA
result_n
ot_read
y
D9
ADC_LSB result
28h
NA
www.austriamicrosystems.com/AS3687
step_up
_lowcur
curr33_
on_cp
CP mode Switch1
Te
ch
CP control
curr3x_other
ca
Pattern data0
am
lc s
on A
te G
nt
st
il
12h
curr30_mode
lv
09h
Curr2 current
00h
b0
curr1_mode
Curr1 current
Curr3 control2
b1
al
id
Register Definition
pattern_delay
pattern
_color
step_up_fb
step_up
_frequ
step_up
_prot
skip_fa
st
cp_mode
curr32_
on_cp
step_up
_res
cp_clk
curr31_
on_cp
curr30_
on_cp
curr2_o
n_cp
curr1_o
n_cp
D5
D4
D3
D2
D1
D0
adc_select
D8
1v3-4
D7
D6
48 - 54
AS3687/87XM
Datasheet
Table 20 – Registermap
Register Definition
Ad
dr.
Def
ault
Content
b7
Name
b6
b5
b4
b3
shutdw
n_enab
b2
b1
b0
rst_ov_t
emp
ov_tem
p
ov_tem
p_on
curr32_l
ow_v
curr31_l
ow_v
curr30_l
ow_v
curr2_lo
w_v
curr1_lo
w_v
29h
01h
Curr low voltage
status1
2Ah
NA
Curr low voltage
status2
2Bh
NA
gpio current
2Ch
00h
curr6 current
2Fh
00h
curr6_current
Adder Current 1
30h
00h
adder_current1 (can be enabled for CURR30, CURR1)
Adder Current 2
31h
00h
adder_current2 (can be enabled for CURR31, CURR2)
Adder Current 3
32h
00h
adder_current3 (can be enabled for CURR32, CURR6)
Adder Enable 2
34h
Subtract Enable
35h
ASIC ID1
3Eh
ASIC ID2
3Fh
Curr30 current
40h
Curr31 current
41h
Curr32 current
42h
Curr33 current
43h
Audio Control
(only AS3687XM)
46h
Audio input
(only AS3687XM)
47h
Audio output
(only AS3687XM)
48h
curr6_lo
w_v
curr33_l
ow_v
lv
pattern
_delay2
am
lc s
on A
te G
nt
st
il
pattern
_slow
al
id
Overtemp control
curr32_
adder
00h
curr31_
adder
curr30_
adder
00h
CAh
1
1
0
0
50h
0
1
0
1
1
curr30_current
00h
curr31_current
00h
curr32_current
00h
curr33_current
00h
audio_speed
audio_d
is_start
curr2_a
dder
curr1_a
dder
sub_en
3
sub_en
2
sub_en
1
0
1
0
revision
00h
00h
curr6_a
dder
aud_buf
_on
audio_color
audio_
man_st
art
agc_ctrl
curr126
_out
curr3x_
out
rgb_amplitude
ca
00h
audio_gain
Te
ch
ni
Note: If writing to register, write 0 to unused bits
Note: Write to read only bits will be ignored
Note: y yellow color = read only
www.austriamicrosystems.com/AS3687
1v3-4
49 - 54
AS3687/87XM
Datasheet
9 External Components
Table 21 – External Components List
min
Value
typ
max
Tol
(min)
Rating
(max)
Package
(min)
Notes
Ceramic, X5R (V2_5 output)
(e.g. Taiyo Yuden
JMK105BJ105KV-F)
Ceramic, X5R (VBAT) (e.g.
Taiyo Yuden
JMK107BJ225MA-T)
Ceramic, X5R (Charge Pump)
(e.g. Taiyo Yuden
JMK107BJ225MA-T)
Ceramic, X5R (Charge Pump)
(e.g. Taiyo Yuden
JMK107BJ225MA-T)
Ceramic, X5R (Charge Pump
Output) (e.g. Taiyo Yuden
JMK107BJ225MA-T)
Ceramic, X5R (Step Up
DCDC input) (e.g. Taiyo
Yuden JMK107BJ225MA-T)
Ceramic, X5R (Step Up
DCDC Feedback, 150pF for
overvoltage protection)
C1
1µF
+/-20%
6.3V
C2
1µF
+/-20%
6.3V
C3
500nF
+/-20%
6.3V
C4
500nF
+/-20%
6.3V
C5
1µF
+/-20%
6.3V
1µF
+/-20%
6.3V
1.5nF
+/-20%
25V
15nF
+/-20%
6.3V
4.7µF
+/-20%
25V
100nF
+/-20%
6.3V
100mΩ
+/-5%
1MΩ
+/-1%
Step Up DC/DC Converter
Voltage Feedback
0201
ca
Part Number
+/-1%
Step Up DC/DC Converter
Voltage Feedback - not
required for overvoltage
protection
0201
1-10kΩ
+/-1%
I2C Bus DATA Pullup resistor
– usually already inside I2C
master
0201
al
id
0402
lv
0402
0402
am
lc s
on A
te G
nt
st
il
C6
C7
C8
C9
C10
R1
R2
100kΩ
ch
ni
R3
R4
0402
Te
R5
L1
10µH
Q1 (+ D1)
FDFMA3N109
D2:D14
LED
www.austriamicrosystems.com/AS3687
+/-20%
Ceramic, X5R (Step Up
DCDC Feedback, 1.5nF for
overvoltage protection)
Ceramic, X5R, X7R (Step Up
DCDC output)
(e.g. Taiyo Yuden
TMK316BJ475KG)
Ceramic, X5R, X7R (Audio
DC Block capacitor) – only for
AS3687XM
Shunt Resistor
I2C Bus CLK Pullup resistor –
usually already inside I2C
master
Panasonic ELLSFG100MA
or TDK VLF3012A or
LQH3NPN100NJ0
Integrated NMOS and
Schottky diode
0403
0402
0402
0402
1206
(0805)
0402
0603
0201
MicroFET
2x2mm
As required by application
1v3-4
50 - 54
AS3687/87XM
Datasheet
10 Pinout and Packaging
10.1 Pin Description
Table 22 – Pinlist WL-CSP 4x5 balls
Name
Type
A1
C2_N
AIO
Charge Pump flying capacitor; connect a ceramic capacitor of 500nF to this pin.
A2
C1_P
AIO
Charge Pump flying capacitor; connect a ceramic capacitor of 500nF to this pin.
A3
CP_OUT
AO
Output voltage of the Charge Pump; connect a ceramic capacitor of 1µF (±20%).
A4
DATA
DIO
Serial interface data input/output.
B1
C1_N
AIO
Charge Pump flying capacitor; connect a ceramic capacitor of 500nF to this pin.
B2
C2_P
AIO
Charge Pump flying capacitor; connect a ceramic capacitor of 500nF to this pin.
B3 DCDC_GATE
AO
DCDC gate driver.
B4
CLK
DI
Clock input for serial interface.
C1
VSS
C2
VBAT
C3
CURR30
C4
DCDC_SNS
lv
am
lc s
on A
te G
nt
st
il
CURR33
Description
al
id
Bmp
GND
Ground pad
S
Supply pad. Connect to battery.
AI
Analog current sink input, intended for activity icon LED
AI
Sense input of shunt resistor for Step Up DC/DC Converter.
AS3687: Analog current sink input, intended for activity icon LED
D1
CURR33
/AUDIO_IN
D2
CURR31
D3
CURR2
D4
DCDC_FB
E1
CURR32
E2
CURR6
AI_HV Analog current sink input (intended for Keyboard backlight)
E3
CURR1
AI_HV Analog current sink input (intended for Keyboard backlight)
E4
V2_5
AI
AS3687XM: Analog current sink input, intended for activity icon LED or audio signal
input
AI
Analog current sink input, intended for activity icon LED
AI_HV Analog current sink input (intended for Keyboard backlight)
AI
DCDC feedback. Connect to resistor string.
AI
Analog current sink input, intended for activity icon LED
Output voltage of the Low-Power LDO; always connect a ceramic capacitor of 1µF
(±20%) or 2.2µF (+100%/-50%).
Do not load this pin during device startup.
ni
ca
AO3
Table 23 – Pin Type Definitions
Type
Digital Input
DO
Digital Output
DIO
Digital Input/Output
AIO
Te
ch
DI
Analog Pad
S
Supply Pad
GND
Ground Pad
AI
AI_HV
AO3
Description
Analog Input
High-Voltage (15V) Pin
Analog Output (3.3V)
www.austriamicrosystems.com/AS3687
1v3-4
51 - 54
AS3687/87XM
Datasheet
10.2 Package Drawings and Markings
am
lc s
on A
te G
nt
st
il
lv
al
id
Figure 42 – WL-CSP 4x5 Balls Package Drawing
Marking:
Line 1: austriamicrosystems logo
Line 2: AS36
Line 3: 87
(for AS3687)
87XM (for AS3687XM)
Line 4: <Code>
4 Letter Encoded Datecode
Figure 43 – WL-CSP 4x5 Balls Detail Dimensions
282.5
µm
A4
A3
A2
A1
B3
B4
B4
B3
B2
B1
C4
C3
C2
C1
Te
D1
E1
250
+/-20
µm
500µm
500µm
C3
C4
D2
D3
D4
D4
D3
D2
D1
E2
E3
E4
E4
E3
E2
E1
500µm
500µm
C2
350
+/-10
µm
282.5
µm
+/ Ø3
- 1 11
0µ
m
C1
500µm
2065 +/-20µm
2065 +/-20µm
272.5
µm
B2
500µm
A4
2545 +/-20µm
B1
500µm
Side View
A3
ca
A2
ni
A1
ch
2545 +/-20µm
Pin A1
Indicator
Bottom View (Ball Side)
272.5
µm
Top View (through)
600 +/-30µm
The coplanarity of the balls is 40µm.
www.austriamicrosystems.com/AS3687
1v3-4
52 - 54
AS3687/87XM
Datasheet
11 Ordering Information
Table 24 – Delivery Information
Marking
Package Type
Delivery Form
AS3687-ZWLT1
AS3687
WL-CSP
4x5 balls
Tape&Reel
WL-CSP
4x5 balls
Tape&Reel
AS3687XM-ZWLT AS3687XM
1
Description
AS3687
Wafer Level Chip Scale Package,
Size 4x5 balls, 0.5mm pitch,
RoHS compliant, Pb-Free
AS3687XM
Wafer Level Chip Scale Package,
Size 4x5 balls, 0.5mm pitch,
RoHS compliant, Pb-Free
al
id
Part Number
lv
Do not use AS3687 for new designs – use AS3687XM (drop in pin to pin compatible replacement for
AS3687) instead.
Description:
AS3687
AS3687XM
Z
WL
AS3687 Lighting Management Unit
AS3687XM Lighting Management Unit (including audio controlled light)
…
Temperature range:
Z = -30°C – 85°C
…
Package:
WL = Wafer Level Chip Scale Package
…
Delivery Form:
T = Tape&Reel
Te
ch
ni
ca
T
am
lc s
on A
te G
nt
st
il
AS3687-ZWLT
www.austriamicrosystems.com/AS3687
1v3-4
53 - 54
AS3687/87XM
Datasheet
Copyright
Copyright © 1997-2010, austriamicrosystems AG, Tobelbaderstrasse 30, 8141 Unterpremstaetten, AustriaEurope. Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted,
merged, translated, stored, or used without the prior written consent of the copyright owner.
All products and companies mentioned are trademarks or registered trademarks of their respective companies.
al
id
Diclaimer
ni
Contact Information
ca
am
lc s
on A
te G
nt
st
il
lv
Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions
appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by
description regarding the information set forth herein or regarding the freedom of the described devices from
patent infringement. austriamicrosystems AG reserves the right to change specifications and prices at any time
and without notice. Therefore, prior to designing this product into a system, it is necessary to check with
austriamicrosystems AG for current information. This product is intended for use in normal commercial
applications. Applications requiring extended temperature range, unusual environmental requirements, or high
reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not
recommended without additional processing by austriamicrosystems AG for each application. For shipments of
less than 100 parts the manufacturing flow might show deviations from the standard production flow, such as test
flow or test location.
The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However,
austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not
limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect,
special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing,
performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise
or flow out of austriamicrosystems AG rendering of technical or other services
ch
Headquarters
austriamicrosystems AG
Tobelbaderstrasse 30
Schloss Premstätten
A-8141 Austria
+43 (0) 3136 500 0
+43 (0) 3136 525 01
Te
Tel:
Fax:
For Sales Offices, Distributors and Representatives, please visit:
http://www.austriamicrosystems.com/contact
www.austriamicrosystems.com/AS3687
1v3-4
54 - 54

Open as PDF

Similar pages: AMSCO AS3682-EA2; AS3649 Datasheet; AS3665 Data Sheet; AMSCO AS3661-BWLT; PDF; ams AG; PDF; PCM-9375 User Manual; Datasheet; Datasheet; PDF; AS3677 Data Sheet; MPM82 Datasheet; AMSCO AS3689; AMSCO AS3688; AMSCO AS3681; AMSCO AS3691B-ZSDF; AMSCO AS3668-BQFT; AS3910 Data Sheet