AD ADP1650ACPZ-R7

1.5 A LED Flash Driver with
I2C-Compatible Interface
ADP1650
FEATURES
APPLICATIONS
Camera-enabled cellular phones and smart phones
Digital still cameras, camcorders, and PDAs
FUNCTIONAL BLOCK DIAGRAM
INPUT VOLTAGE = 2.7V TO 5.0V
10µF
1.0µH
TX1/TORCH
VIN
GPIO1
SW
VOUT
TX2/ILED/ADC
GPIO2
10µF
ADP1650
STROBE
LED_OUT
MAX 1.5A
SCL
SGND
PGND
08837-001
SDA
EN
Figure 1.
Li-ION +
C1
L1
PGND
Li-ION +
C2
INDUCTOR
DIGITAL
INPUT/
OUTPUT
AREA = 16.4mm 2
LED
ANODE
08837-002
Ultracompact solution
Small, 2 mm × 1.5 mm, 12-ball WLCSP package
Thin, 3 mm × 3 mm × 0.75 mm, 10-lead LFCSP package
Smallest footprint, 1 mm height, 1 μH power inductor
LED current source for local LED grounding
Simplified routing to/from LED
Improved LED thermals
Synchronous 3 MHz PWM boost converter, no external diode
High efficiency: 90% peak
Reduces high levels of input battery current during flash
Limits battery current drain in torch mode
I2C programmable
Currents up to 1500 mA in flash mode for 1 LED with
±7% accuracy over all conditions
Currents up to 200 mA in torch mode
Programmable dc battery current limit (4 settings)
Programmable flash timer up to 1600 ms
Low VBAT mode to reduce LED current automatically
4-bit ADC for LED VF, die/LED temperature readback
Control
I2C-compatible control registers
External STROBE and torch input pins
2 transmitter mask (TxMASK) inputs
Safety
Thermal overload protection
Inductor fault detection
LED short-/open-circuit protection
Figure 2. PCB Layout (WLCSP)
GENERAL DESCRIPTION
The ADP1650 is a very compact, highly efficient, single white
LED flash driver for high resolution camera phones that
improves picture and video quality in low light environments.
The device integrates a programmable 1.5 MHz or 3 MHz
synchronous inductive boost converter, an I2C-compatible
interface, and a 1500 mA current source. The high switching
frequency enables the use of a tiny, 1 mm high, low cost, 1 μH
power inductor, and the current source permits LED cathode
grounding for thermally enhanced, low EMI, and compact
layouts.
The LED driver maximizes efficiency over the entire battery
voltage range to maximize the input-power-to-LED-power
conversion and to minimize battery current draw during flash
events. A programmable dc battery current limit safely maximizes
LED current for all LED VF and battery voltage conditions.
Two independent TxMASK inputs permit the flash LED current
and battery current to reduce quickly during a power amplifier
current burst. The I2C-compatible interface enables the programmability of timers, currents, and status bit readback for
operation monitoring and safety control.
The ADP1650 is available in a compact 12-ball, 0.5 mm pitch
WLCSP package and a 10-lead LFCSP package, and operates
within specification over the full −40°C to +125°C junction
temperature range.
Rev. C
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
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One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113 ©2010–2011 Analog Devices, Inc. All rights reserved.
ADP1650
TABLE OF CONTENTS
Features .............................................................................................. 1 Indicator LED Driver................................................................. 14 Applications....................................................................................... 1 Low Battery LED Current Foldback ........................................ 14 Functional Block Diagram .............................................................. 1 Programmable Battery DC Current Limit.............................. 15 General Description ......................................................................... 1 Analog-to-Digital Converter Operation ................................. 15 Revision History ............................................................................... 2 5 V Output Operation ............................................................... 16 Specifications..................................................................................... 3 Safety Features................................................................................. 18 Recommended Specifications: Input and Output Capacitance
and Inductance ............................................................................. 5 Short-Circuit Fault ..................................................................... 18 I2C-Compatible Interface Timing Specifications ..................... 5 Dynamic Overvoltage Mode (DOVP) .................................... 18 Absolute Maximum Ratings............................................................ 6 Timeout Fault.............................................................................. 18 Thermal Data ................................................................................ 6 Overtemperature Fault .............................................................. 18 Thermal Resistance ...................................................................... 6 Indicator LED Fault ................................................................... 18 ESD Caution.................................................................................. 6 Current Limit.............................................................................. 18 Pin Configurations and Function Descriptions ........................... 7 Input Undervoltage .................................................................... 18 Typical Performance Characteristics ............................................. 8 Soft Start ...................................................................................... 18 Theory of Operation ...................................................................... 12 Reset Using the Enable (EN) Pin ............................................. 18 White LED Driver ...................................................................... 12 Clearing Faults ............................................................................ 18 Modes of Operation ................................................................... 12 I2C Interface ................................................................................ 19 Assist Light .................................................................................. 13 I2C Register Map............................................................................. 20 Flash Mode .................................................................................. 13 Applications Information .............................................................. 26 Assist-to-Flash Operation ......................................................... 13 External Component Selection ................................................ 26 Torch Mode ................................................................................. 13 PCB Layout...................................................................................... 28 Torch-to-Flash Mode ................................................................. 14 Outline Dimensions ....................................................................... 29 TxMASK Operation................................................................... 14 Ordering Guide .......................................................................... 29 Overvoltage Fault ....................................................................... 18 Frequency Foldback ................................................................... 14 REVISION HISTORY
4/11—Rev. B to Rev. C
Added 10-Lead LFCSP Package........................................Universal
Changes to Features Section, General Description Section, and
Figure 2 Caption ............................................................................... 1
Changes to Table 1............................................................................ 3
Changes to Table 5............................................................................ 6
Added Figure 5; Renumbered Sequentially .................................. 7
Changes to Table 6............................................................................ 7
Changes to PCB Layout Section and Figure 45 Caption........... 28
Added Figure 46.............................................................................. 28
Updated Outline Dimensions ....................................................... 29
Changes to Ordering Guide .......................................................... 29
Changed GND to Power Ground Throughout .............................6
Changed IL to IL, ILED to ILED, LED OUT to LED_OUT, and
IBAT to IBAT Throughout ..................................................................8
Change to Figure 10 Caption ...........................................................8
Change to Figure 11 Caption ...........................................................9
Changed LED_MOD = 10 to LED_MOD = 11 in Figure 32 ... 14
Changes to Analog-to-Digital Converter Operation Section and
Figure 37 .......................................................................................... 15
Changes to Selecting the Output Capacitor Section.................. 26
2/11—Rev. A to Rev. B
Changes to Features Section and General Description Section . 1
Changes to Switching Regulator, Voltage Output Mode, VOUT
Voltage Parameter and Digital Inputs/GPIO, Torch Glitch
Filtering Delay Parameter, Table 1.................................................. 3
5/10—Revision 0: Initial Version
6/10—Rev. 0 to Rev. A
Changes to Contact Information.....................................................1
Rev. C | Page 2 of 32
ADP1650
SPECIFICATIONS
VIN 1 = 3.6 V, TJ = −40°C to +125°C for minimum/maximum specifications, and TA = 25°C for typical specifications, unless otherwise noted.
Table 1.
Parameter 2
SUPPLY
Input Voltage Range
Undervoltage Lockout Threshold
Undervoltage Lockout Hysteresis
Shutdown Current (IQ), EN = 0 V
Standby Current (ISTBY), EN = 1.8 V
Operating Quiescent Current
SW Switch Leakage
LED DRIVER
LED Current
Assist Light, Torch
Flash
LED Current Error—WLCSP
LED Current Error—LFCSP
LED Current Source Headroom—WLCSP
LED Current Source Headroom—LFCSP
LED_OUT Ramp-Up Time
LED_OUT Ramp-Down Time
SWITCHING REGULATOR
Switching Frequency
Minimum Duty Cycle
nFET Resistance—WLCSP
pFET Resistance—WLCSP
nFET Resistance—LFCSP
pFET Resistance—LFCSP
Voltage Output Mode
VOUT Voltage—WLCSP
VOUT Voltage—LFCSP
Output Current
Line Regulation
Load Regulation
Conditions
Min
VIN falling
2.7
2.3
50
TJ = −40°C to +85°C, current into VIN pin, VIN = 2.7 V to 4.5 V
TJ = −40°C to +85°C, current into VIN pin, VIN = 2.7 V to 4.5 V
Torch mode, LED current = 100 mA
TJ = −40°C to +85°C, VSW 3 = 4.5 V
TJ = 25°C, VSW 3 = 4.5 V
Assist light value setting = 0 (000 binary)
Assist light value setting = 7 (111 binary)
Flash value setting = 0 (00000 binary)
Flash value setting = 24 (11000 binary)
ILED = 700 mA to 1100 mA
ILED = 300 mA to 650 mA, 1150 mA to 1500 mA
ILED = 75 mA to 200 mA
ILED = 25 mA to 50 mA
ILED = 700 mA to 1100 mA
ILED = 300 mA to 650 mA, 1150 mA to 1500 mA
ILED = 75 mA to 200 mA
ILED = 25 mA to 50 mA
Flash, 1200 mA LED current
Torch, 200 mA LED current
Flash, 1200 mA LED current
Torch, 200 mA LED current
Typ
2.4
100
0.2
3
5.3
Max
Unit
5.0
2.5
150
1
10
V
V
mV
μA
μA
mA
μA
μA
2
0.5
25
200
300
1500
−6
−7
−10
−15
−6
−7
−10
−15
+6
+7
+10
+15
+6
+7
+10
+18
290
190
370
220
0.6
0.1
Switching frequency = 3 MHz
Switching frequency = 1.5 MHz
Switching frequency = 3 MHz
Switching frequency = 1.5 MHz
ILOAD at VOUT = 300 mA
Rev. C | Page 3 of 32
mA
mA
mA
mA
%
%
%
%
%
%
%
%
mV
mV
mV
mV
ms
ms
2.8
1.4
3
1.5
14
7
60
50
77
85
3.2
1.6
MHz
MHz
%
%
mΩ
mΩ
mΩ
mΩ
4.575
4.575
5.000
5.000
5.425
5.500
500
V
V
mA
%/V
%/A
0.3
−0.7
ADP1650
Parameter 2
Pass-Through Mode Transition, Flash
VIN to LED_OUT, Entry
VIN to LED_OUT, Exit
Pass-Through Mode Transition, Torch
VIN to LED_OUT, Entry
VIN to LED_OUT, Exit
DIGITAL INPUTS/GPIO
Input Logic Low Voltage
Input Logic High Voltage
GPIO1, GPIO2, STROBE Pull-Down
Torch Glitch Filtering Delay
INDICATOR LED
LED Current Accuracy
Short-Circuit Detection Threshold
Open-Circuit Detection Threshold
ADC
Resolution
Error
Input Voltage Range, GPIO2
SAFETY FEATURES
Maximum Timeout For Flash
Timer Accuracy
DC Current Limit
Low VBAT Mode Transition Voltage
Error
Hysteresis
Coil Peak Current Limit
Conditions
Min
Typ
Max
Unit
1200 mA LED current
1200 mA LED current
580
435
mV
mV
200 mA LED current
200 mA LED current
380
285
mV
mV
0.54
1.26
From torch rising edge to device start
5.5
390
7
−22
7.5
+22
1.2
2.45
4
External voltage mode
VF mode, TJ = 25°C
VF mode, TJ = −40°C to +125°C
External voltage mode
0
0
DC current value setting = 0 (00 binary)
DC current value setting = 1 (01 binary)
DC current value setting = 2 (10 binary)
DC current value setting = 3 (11 binary)
−7.0
1.35
1.55
1.8
2.02
Bits
LSB
LSB
LSB
V
+7.0
1.65
1.95
2.2
2.5
ms
%
A
A
A
A
3.2
Peak current value setting = 0 (00 binary)
Peak current value setting = 1 (01 binary)
Peak current value setting = 2 (10 binary)
Peak current value setting = 3 (11 binary)
Overvoltage Detection Threshold
LED_OUT Short-Circuit Detection
Comparator Reference Voltage
Thermal Shutdown Threshold
TJ Rising
TJ Falling
1.55
2.02
2.47
2.7
5.15
50
1.75
2.25
2.75
3.0
5.5
1.2
150
140
1
VIN is the input voltage to the circuit.
All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC).
3
VSW is the voltage on the SW switch pin.
2
Rev. C | Page 4 of 32
%
V
V
±1
±1
±1.5
0. 5
1600
1.5
1.75
2.0
2.25
V
V
kΩ
ms
1.95
2.5
3.0
3.3
5.9
1.3
%
mV
A
A
A
A
V
V
°C
°C
ADP1650
RECOMMENDED SPECIFICATIONS: INPUT AND OUTPUT CAPACITANCE AND INDUCTANCE
Table 2.
Parameter
CAPACITANCE
Input
Output
MINIMUM AND MAXIMUM INDUCTANCE
Symbol
CMIN
L
Conditions
Min
Typ
Max
Unit
TA = −40°C to +125°C
TA = −40°C to +125°C
TA = −40°C to +125°C
4.0
3.0
0.6
10
10
1.0
20
1.5
μF
μF
μH
I2C-COMPATIBLE INTERFACE TIMING SPECIFICATIONS
Table 3.
Parameter 1
fSCL
tHIGH
tLOW
tSU, DAT
tHD, DAT
tSU, STA
tHD, STA
tBUF
tSU, STO
tR
tF
tSP
CB 2
2
Max
400
0.6
1.3
100
0
0.6
0.6
1.3
0.6
20 + 0.1 CB 2
20 + 0.1 CB2
0
Unit
kHz
μs
μs
ns
μs
μs
μs
μs
μs
ns
ns
ns
pF
0.9
300
300
50
400
Description
SCL clock frequency
SCL high time
SCL low time
Data setup time
Data hold time
Setup time for repeated start
Hold time for start/repeated start
Bus free time between a stop and a start condition
Setup time for stop condition
Rise time of SCL and SDA
Fall time of SCL and SDA
Pulse width of suppressed spike
Capacitive load for each bus line
Guaranteed by design.
CB is the total capacitance of one bus line in picofarads.
SDA
tLOW
tR
tF
tSU, DAT
tF
tHD, STA
tSP
tBUF
tR
SCL
S
tHD, DAT
tHIGH
tSU, STA
Sr
S = START CONDITION
Sr = REPEATED START CONDITION
P = STOP CONDITION
tSU, STO
P
S
08837-003
1
Min
Figure 3. I2C-Compatible Interface Timing Diagram
Rev. C | Page 5 of 32
ADP1650
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 4.
Parameter
VIN, SDA, SCL, EN, GPIO1, GPIO2, STROBE,
LED_OUT, SW, VOUT to Power Ground
PGND to SGND
Ambient Temperature Range (TA)
Junction Temperature Range (TJ)
Storage Temperature
ESD Human Body Model
ESD Charged Device Model
ESD Machine Model
Rating
−0.3 V to +6 V
−0.3 V to +0.3 V
−40°C to +85°C
−40°C to +125°C
JEDEC J-STD-020
±2000 V
±500 V
±150 V
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
θJA of the package is based on modeling and calculation using
a 4-layer board. θJA is highly dependent on the application and
board layout. In applications where high maximum power dissipation exists, attention to thermal board design is required. The
value of θJA may vary, depending on PCB material, layout, and
environmental conditions. The specified value of θJA is based
on a 4-layer, 4 in × 3 in, 2 ½ oz copper board, per JEDEC
standards. For more information, see the AN-617 Application
Note, MicroCSP™ Wafer Level Chip Scale Package.
θJA is specified for a device mounted on a JEDEC 2S2P PCB.
Table 5. Thermal Resistance
Package Type
12-Ball WLCSP
10-Lead LFCSP
ESD CAUTION
THERMAL DATA
The ADP1650 may be damaged if the junction temperature
limits are exceeded. Monitoring TA does not guarantee that TJ
is within the specified temperature limits. In applications with
high power dissipation and poor thermal resistance, the maximum
TA may have to be derated. In applications with moderate power
dissipation and low PCB thermal resistance, the maximum TA
can exceed the maximum limit as long as the TJ is within specification limits. TJ of the device is dependent on the TA, the power
dissipation (PD) of the device, and the junction-to-ambient
thermal resistance (θJA) of the package. Maximum TJ is
calculated from the TA and PD using the following formula:
TJ = TA + (PD × θJA)
Rev. C | Page 6 of 32
θJA
75
42.5
Unit
°C/W
°C/W
ADP1650
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
BALL A1
INDICATOR
1
2
3
PGND
SGND
VIN
SW
GPIO2
GPIO1
VOUT
STROBE
EN
A
B
VIN 1
GPIO2 2
GPIO1 3
LED_OUT
SDA
SDA 4
SCL
SCL 5
D
ADP1650
TOP VIEW
9
EN
8
SW
7
VOUT
6
LED_OUT
NOTES
1. THE EXPOSED PADDLE MUST BE CONNECTED
TO GROUND.
08837-004
TOP VIEW
(BALL SIDE DOWN)
Not to Scale
10 STROBE
Figure 4. WLCSP Pin Configuration
08837-070
C
Figure 5. LFCSP Pin Configuration
Table 6. Pin Function Descriptions
WLCSP
A1
A2
A3
B1
B2
Pin No.
LFCSP
N/A 1
N/A1
1
8
2
Mnemonic
PGND
SGND
VIN
SW
GPIO2
B3
3
GPIO1
C1
7
VOUT
C2
10
STROBE
C3
9
EN
D1
D2
D3
6
4
5
0
LED_OUT
SDA
SCL
EPAD
1
Description
Power Ground.
Signal Ground.
Input Voltage for the Device. Connect an input bypass capacitor close to this pin.
Boost Switch. Connect the power inductor between SW and the input capacitor.
ILED/TX2/ADC. Mode is register selectable. Red indicator LED current source or
TxMASK2 or ADC input.
ILED Mode. Connect to red LED anode. Connect the LED cathode to power ground.
TxMASK2 Mode. Reduces the current to the programmable TxMASK2 current.
ADC Mode. This pin is used as the input pin for the ADC.
Torch/TX1. Mode is register selectable. External torch mode or TxMASK1 input.
Torch Mode. Enables the integrated circuit (IC) in direct torch mode.
TxMASK1 Mode. Reduces the flash current to the programmable TxMASK1 current.
Boost Output. Connect an output bypass capacitor very close to this pin. This is the
output for the 5 V external voltage mode.
Strobe Signal Input. This pin synchronizes the flash pulse to the image capture. In
most cases, this signal comes directly from the image sensor.
Enable. Set EN low to bring the quiescent current (IQ) to <1 μA. Registers are set to
their defaults when EN is brought from low to high.
LED Current Source. Connect this pin to the anode of the flash LED.
I2C Data Signal in I2C Mode.
I2C Clock Signal in I2C Mode.
Exposed Pad. Connect the exposed pad to the ground plane for the LFCSP version.
N/A means not applicable.
Rev. C | Page 7 of 32
ADP1650
TYPICAL PERFORMANCE CHARACTERISTICS
IL = inductor current, ILED = LED current, LED_OUT = LED output, IBAT = battery current.
IL
ILED
4
LED_OUT
3
SW
4
ILED
2
IL
CH2 1A Ω
CH4 500mA Ω
1
M100µs
A CH1
T
402.2µs
400mV
08837-025
CH1 5V
CH3 1V
08837-031
2
STROBE
1
CH1 2V
CH2 100mA Ω
CH4 25mA Ω
M100ns
A CH1
T
4.16007ms
1.6V
Figure 9. Switching Waveforms, Flash Mode, ILED = 1500 mA
Figure 6. Startup Flash Mode, VIN = 3.6 V, ILED = 1500 mA
VIN
LED_OUT
LED_OUT
3
3
ILED
4
IL
IL
ILED
CH1 5V
CH3 2V
CH2 100mA Ω
CH4 100mA Ω
M1.00ms
A CH1
T
4.16ms
08837-032
GPIO1 (Torch)
1
2
08837-026
2
1
4
600mV
CH1 5V
CH3 2V
Figure 7. Startup Torch Mode, VIN = 3.6 V, ILED = 100 mA
CH2 100mA Ω
CH4 100mA Ω
M1ms
T 30.40%
A CH2
88mA
Figure 10. Pass-Through to Boost Mode Transition, ILED = 100 mA
VIN = 3.6V
LED_OUT
LED_OUT
IBAT
3
3
ILED
4
ILED
4
GPIO1 (TxMASK1)
STR
CH1 2V
CH3 1V
CH2 1A Ω
CH4 500mA Ω
M100µs
A CH1
T
394.6µs
08837-035
1
08837-028
2
2
IL
1
CH1 2V
CH3 1V
440mV
Figure 8. 100 mA Torch to 1500 mA Flash Transition
CH2 1A Ω
CH4 500mA Ω
M10µs
T 30.60%
A CH1
Figure 11. Entry into TxMASK1 Mode
Rev. C | Page 8 of 32
680mV
ADP1650
100
90
LED_OUT
80
EFFICIENCY (%)
70
IBAT
2
ILED
40
30
08837-036
20
1
CH2 2V
CH4 1V
CH2 1A Ω
CH4 500mA Ω
M40µs
T 16%
A CH1
0
0.3
680mV
100
–40°C
+25°C
+85°C
+125°C
3.03
3.02
80
EFFICIENCY (%)
3.00
2.99
2.98
1.3
1.5
60
50
40
2.97
30
2.96
20
2.95
10
3.0
3.3
3.6
3.9
4.2
4.5
4.8
5.1
5.4
0
0.01
08837-038
0.1
1
OUTPUT CURRENT (A)
Figure 16. Voltage Regulation Mode Efficiency vs. Load Current
Figure 13. Switching Frequency vs. Supply Voltage (3 MHz Mode)
1111
VIN = 2.7V
VIN = 3.6V
VIN = 4.5V
1110
ADC RESULT (Binary)
1100
4
3
2
1010
1000
0110
0100
1
0000
–20
0
20
40
60
80
100
TEMPERATURE (°C)
120
08837-043
0
–40
0010
0
50
100
150
200
250
300
350
400
450
500
550
ADC INPUT VOLTAGE (mV)
Figure 17. ADC External Voltage Mode Transfer Characteristic
Figure 14. Standby Current vs. Temperature
Rev. C | Page 9 of 32
08837-059
fSW (MHz)
1.1
70
INPUT VOLTAGE (V)
STANDBY CURRENT (µA)
0.9
VIN = 2.7V
VIN = 3.0V
VIN = 3.6V
VIN = 4.2V
90
3.01
5
0.7
Figure 15. Flash Mode Efficiency vs. LED Current
3.04
6
0.5
LED CURRENT (A)
Figure 12. Exit from TxMASK1 Mode
2.94
2.7
VIN = 4.2V
VIN = 3.6V
VIN = 3.4V
VIN = 3.2V
10
08837-044
GPIO1 (TxMASK1)
4
50
08837-045
3
60
ADP1650
295
1111
293
CODE 1000 MIDPOINT (mV)
1010
1000
0110
0100
292
291
290
VIN = 3.6V
289
288
0010
50
75
100
125
150
Figure 18. ADC Die Temperature Mode Transfer Characteristic
10
60
110
TEMPERATURE (°C)
Figure 21. ADC External Voltage Mode, Code 1000, Midpoint vs. Temperature
1111
1.0
1110
0.5
LED CURRENT ERROR (%)
1100
ADC RESULT (Binary)
286
–40
08837-063
25
08837-060
0
DIE TEMPERATURE (°C)
1010
1000
0110
0100
VIN = 3.2V
VIN = 3.6V
VIN = 4.2V
0
–0.5
–1.0
–1.5
–2.0
0010
3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
–2.5
–40
08837-061
0000
2.8
LED_OUT VOLTAGE (V)
0.5
VIN = 5.0V
0
LED CURRENT ERROR (%)
3.750
3.745
3.740
VIN = 3.6V
3.735
3.730
VIN = 2.7V
3.725
60
110
Figure 22. LED Current Accuracy vs. Temperature, ILED = 1200 mA
3.760
3.755
10
TEMPERATURE (°C)
Figure 19. ADC LED VF Mode Transfer Characteristic
CODE 1000 MIDPOINT (V)
VIN = 2.7V
287
08837-066
ADC RESULT (Binary)
1100
0000
VIN = 5V
294
1110
3.720
VIN = 3.2V
VIN = 3.6V
VIN = 4.2V
–0.5
–1.0
–1.5
–2.0
–2.5
10
60
TEMPERATURE (°C)
110
Figure 20. ADC LED VF Mode, Code 1000, Midpoint vs. Temperature
–3.0
–40
10
60
110
TEMPERATURE (°C)
Figure 23. LED Current Accuracy vs. Temperature, ILED = 800 mA
Rev. C | Page 10 of 32
08837-067
3.710
–40
08837-062
3.715
ADP1650
3.0
2.5
1.0
VIN = 3.2V
VIN = 3.6V
VIN = 4.2V
0.5
VIN = 3.2V
VIN = 3.6V
VIN = 4.2V
LED CURRENT ERROR (%)
1.5
1.0
0.5
0
–0.5
0
–0.5
–1.0
–1.5
–1.0
–2.0
–40
10
60
TEMPERATURE (°C)
110
–2.5
–40
10
60
110
TEMPERATURE (°C)
Figure 24. LED Current Error vs. Temperature, ILED = 1500 mA
Figure 25. LED Current Error vs. Temperature, ILED = 1000 mA
Rev. C | Page 11 of 32
08837-069
–2.0
–1.5
08837-068
LED CURRENT ERROR (%)
2.0
ADP1650
THEORY OF OPERATION
The ADP1650 is a high power, I2C programmable white LED
driver ideal for driving white LEDs for use as a camera flash.
The ADP1650 includes a boost converter and a current
regulator suitable for powering one high power white LED.
MODES OF OPERATION
WHITE LED DRIVER
LED_MOD = [00] sets the device in standby mode, consuming
3 μA (typical).
Once the enable pin is high, the device can be set into the four
modes of operation using the LED_MOD bits in Register 0x04,
via the I2C-compatible interface.
The ADP1650 drives a synchronous 3 MHz boost converter as
required to power the high power LED. If the sum of the LED
forward voltage and current regulator voltage is higher than
the battery voltage, the boost turns on. If the battery voltage is
higher than the sum of the LED VF and current regulator voltage, the boost is disabled and the part operates in pass-through
mode. The ADP1650 uses an integrated PFET high-side current
regulator for accurate brightness control.
LED_MOD = [01] sets the device in fixed VOUT = 5 V output
mode.
LED_MOD = [10] sets the device in assist light mode with
continuous LED current.
LED_MOD = [11] sets the device in flash mode with current up
to 1.5 A available for up to 1.6 sec.
INPUT VOLTAGE = 2.7V TO 5.0V
CIN
10µF
L1
1µF
COUT
10µF
PGND
PGND
VIN
VOUT
SW
5.5V
2.4V
CURRENT
SENSE
UVLO
HPLED
DRIVER
OVP
CURRENT
SENSE
PWM
CONTROLLER
LED_OUT
EN
FAULT
REGISTER
SCL
HPLED
SHORT
INTERFACE
AND
CONTROL
SDA
STROBE
TXMASK1
TORCH
25mA TO 1.5A
HIGH POWER LED
CURRENT CONTROL
TXMASK2
VIN
4-BIT
ADC
PGND
IC THERMAL
SENSING
ILED
LED_OUT PIN
IO2_CFG[7:6]
GPIO1
SGND
GPIO2
AGND
Figure 26. Detailed Block Diagram
Rev. C | Page 12 of 32
PGND
PGND
08837-006
IO1_CFG[5:4]
ADP1650
I(FLASH)
ASSIST LIGHT
The assist light provides continuous current programmable
from 25 mA to 200 mA. Set the assist light current using the
I_TOR bits (in Register 0x03). To enable assist, set LED_MOD
to assist light mode and set OUTPUT_EN = 1 (in Register 0x04).
Disable assist light mode by setting LED_MOD to standby
mode or setting OUTPUT_EN = 0.
LED CURRENT
0A
FL_TIM
STROBE
I2C DATA BUS
REG 0x02, FL_TIM = XXXX ms
REG 0x03, I_FL = XXXXX mA
I(ASSIST)
LED CURRENT
ADP1650 SETS OUTPUT_EN TO 0.
ADP1650 SETS LED_MOD TO 00.
08837-009
REG 0x04, OUTPUT_EN = 1
STR_LV = 0
LED_MOD = 11
0A
Figure 29. Flash Operation: Edge-Sensitive Mode
I2C DATA BUS
REG 0x04, OUTPUT_EN = 0
REG 0x04, OUTPUT_EN = 1
LED_MOD = 10
08837-007
ASSIST-TO-FLASH OPERATION
I(FLASH)
Figure 27. Enabling Assist Light Mode
LED CURRENT
I(ASSIST)
FLASH MODE
Flash mode provides 300 mA to 1.5 A for a programmable time
of up to 1.6 seconds. Set the flash current using the I_FL bits (in
Register 0x03) and the maximum flash duration with the FL_TIM
bits (in Register 0x02). To enable flash mode, set LED_MOD
to flash mode and set OUTPUT_EN = 1. Enable flash without
STROBE by setting STR_MODE (in Register 0x04) to 0 (software
strobe). When STR_MODE is in hardware strobe mode, setting
the STROBE pin high enables flash and synchronizes it to the
image sensor. Hardware strobe mode has two modes for timeout:
level sensitive and edge sensitive.
I(FLASH)
0A
STROBE
I2C D ATA BUS
REG 0x02, FL_TIM = XXXX ms
REG 0x03, I_TOR = XXX mA
REG 0x03, I_FL = XXXXX mA
ADP1650 SETS OUTPUT_EN TO 0.
ADP1650 SETS LED_MOD TO 00.
REG 0x04, OUTPUT_EN = 1
STR_LV = 1
LED_MOD = 10
08837-010
REG 0x03, I_TOR = XXX mA
In edge-sensitive mode, a positive edge on the STROBE pin
enables the flash, and the FL_TIM bits set the flash duration.
Figure 30. Enabling Assist to Flash (Level-Sensitive) Mode
The STR_POL bit in Register 0x07 changes the default enable of
STROBE from low to high to high to low. Additional image
sensor-specific assist/flash enable modes are included in the
device, and information on these is available on request from
the Analog Devices, Inc., sales team.
LED CURRENT
0A
STROBE
TORCH MODE
I2C DATA BUS
ADP1650 SETS OUTPUT_EN TO 0.
ADP1650 SETS LED_MOD TO 00.
08837-008
REG 0x04, OUTPUT_EN = 1
STR_LV = 1
LED_MOD = 11
Figure 28. Flash Operation: Level-Sensitive Mode
In level-sensitive mode, the duration of STROBE high sets the
duration of the flash up to the maximum time set by the
FL_TIM timeout. If STROBE is kept high longer than the
duration set by FL_TIM, a timeout fault disables the flash.
I(ASSIST)
LED CURRENT
0A
GPIO1 (TORCH)
I2C DATA BUS
REG 0x03, I_TOR = XXX mA
ADP1650 SETS OUTPUT_EN TO 0
REG 0x04, OUTPUT_EN = 1
LED_MOD = 00
Figure 31. Enabling External Torch Mode Using GPIO1
Rev. C | Page 13 of 32
08837-065
REG 0x02, FL_TIM = XXXX ms
REG 0x03, I_FL = XXXXX mA
Set the assist/torch light current using the I_TOR bits. To enable
torch mode using a logic signal, set LED_MOD to standby mode
and OUTPUT_EN = 1, and then bring GPIO1 high. Disable
external torch mode by setting GPIO1 low or programming
OUTPUT_EN = 0. Bringing GPIO1 low during torch mode
automatically sets OUTPUT_EN = 0. To enable torch mode
again, program OUTPUT_EN = 1, and bring GPIO high again.
ADP1650
TORCH-TO-FLASH MODE
FREQUENCY FOLDBACK
The driver can move directly from external torch mode (using
GPIO1) to flash mode by bringing STROBE high before GPIO1
= torch is brought low. Bringing torch low before STROBE goes
high prevents the flash from firing when STROBE goes high.
Frequency foldback is an optional mode that optimizes
efficiency by reducing the switching frequency to 1.5 MHz
when VIN is slightly less than VOUT. Enable frequency
foldback by setting FREQ_FB = 1 in Register 0x04.
The ADP1650 returns to standby mode after a successful flash
and sets OUTPUT_EN = 0.
INDICATOR LED DRIVER
The indicator LED driver on GPIO2 provides a programmable
current source of between 2.75 mA and 11 mA for driving a red
privacy LED. The current level is programmed by the I_ILED
bits in Register 0x07. The circuit consists of a programmable
current source and a monitoring circuit that uses comparators
to determine whether the indicator LED is shorted or open. The
threshold for detection of a short is 1.2 V (maximum) and an
open circuit is 2.45 V (minimum). The indicator LED must not
be used at the same time as a flash or assist/torch event.
I(FLASH)
LED CURRENT
I(ASSIST)
0A
STROBE
TORCH
I2C DATA BUS
REG 0x02, FL_TIM = XXXX ms
ADP1650 SETS OUTPUT_EN TO 0
IO1_CFG = 01, TORCH
REG 0x03, I_TOR = XXX mA
REG 0x03, I_FL = XXXXX mA
REG 0x04, OUTPUT_EN = 1
STR_LV = 1
LED_MOD = 00
08837-064
LOW BATTERY LED CURRENT FOLDBACK
Figure 32. Enabling Flash Mode from External Torch Mode
As the battery discharges, the lower battery voltage results in
higher peak currents through the battery ESR, which may cause
early shutdown of the phone. The ADP1650 features an optional
low battery detection option, which reduces the flash current
(to a programmable level) when the battery voltage falls below a
programmable level.
TxMASK OPERATION
GLITCH < 50µs IGNORED
VIN
When the ADP1650 is in flash mode, the TxMASK1 and
TxMASK2 functions reduce the battery load in response to the
system enabling a power amplifier. The device remains in flash
mode, but the LED driver output current reduces to the programmed TxMASK light level in less than 21 μs.
50mV HYS
V(V_VB_LO)
STROBE
I2C D ATA BUS
LED CURRENT
I(TXMASK1)
REG 0x09, I_VB_LO = XXXX mA
V_VB_LO = XXX V
0A
REG 0x04, OUTPUT_EN = 1
LED_MOD = 10
TXMASK1
(GPIO1)
FL_VB_LO = 1
ADP1650 SETS OUTPUT_EN TO 0.
ADP1650 SETS LED_MOD TO 00.
08837-012
I(FLASH)
Figure 34. Register 0x09 Sets the Battery Voltage Threshold Level and the
Reduced LED Current Level
STROBE
Table 7. VDD Level at Which the VBAT Low Function Is
Enabled
I2C D ATA BUS
Bit Name
V_VB_LO
FL_TX1 = 1
ADP1650 SETS OUTPUT_EN TO 0.
ADP1650 SETS LED_MOD TO 00.
REG 0x04, OUTPUT_EN = 1
STR_LV = 1
LED_MOD = 11
08837-011
REG 0x02, IO1_CFG = 10
FL_TIM = XXXX ms
REG 0x03, I_FL = XXXXX mA
REG 0x06, I_TX1 = XXXX mA
Figure 33. TxMASK1 Operation During Flash (Level-Sensitive) Mode
The device selects the TxMASK1 or TxMASK2 current level
based on whether the TxMASK1 or TxMASK2 input is used.
After a TxMASK1 or TxMASK2 occurs, a flag is set in the fault
information register. When the TxMASK signal goes low again,
the LED current goes back to the full flash level in a controlled
manner to avoid overshoots on the battery current. If both
TxMASK inputs are set high simultaneously, the TXMASK1
current level is used.
VDD Level
000 = disabled (default)
001 = 3.3 V
010 = 3.35 V
011 = 3.4 V
100 = 3.45 V
101 = 3.5 V
110 = 3.55 V
111 = 3.6 V
Set V_VB_LO = 000 to disable the low battery current foldback.
Rev. C | Page 14 of 32
ADP1650
PROGRAMMABLE BATTERY DC CURRENT LIMIT
ANALOG-TO-DIGITAL CONVERTER OPERATION
The ADP1650 has four optional programmable input dc current
limits that limit the maximum battery current that can be taken
over all conditions. This allows higher LED currents to be used
in a system with significant variation in LED forward voltage
(VF) and supply battery voltage without risk of the current
allocated to the flash being exceeded.
The internal 4-bit analog-to-digital converter (ADC) is configurable to measure the LED VF, integrated circuit (IC) die temperature,
or an external voltage using the GPIO2 pin. Read the 4-bit
resolution output code back from Register 0x08 using the I2C
interface.
EN
Table 8. Input DC Current Limit Setting the LED Current
Current Limit
00 = 1.5 A
01 = 1.75 A
10 = 2.0 A (default)
11 = 2.25 A
IC TEMPERATURE
SENSOR
SDA
SCL
During startup of the flash, if the battery current does not reach
the dc current limit, the LED current is set to the current value
of the I_FL bits. If the battery current does hit the programmed
dc current limit on startup, the LED current does not increase
further. The dc current limit flag is set in the fault information
register. The I_FL bits in Register 0x03 are set to the actual LED
current and are available for readback.
NO LIMIT LED CURRENT
ACTUAL LED CURRENT
STROBE
I2C DATA BUS
ADP1650 SETS OUTPUT_EN TO 0.
ADP1650 SETS LED_MOD TO 00.
ADP1650 SETS FL_IDC (REG 0x05) TO 1.
ADP1650 SETS I_FL TO ACTUAL LED CURRENT.
08837-013
REG 0x02, FL_TIM = XXXX ms
REG 0x03, I_FL = XXXXX mA
IL_DC_EN = 1
IL_DC = XX A
REG 0x04, OUTPUT_EN = 1
STR_LV = 1
LED_MOD = 11
PTC
Figure 37. Available ADC Modes in the ADP1650
The ADC can perform the conversion either immediately on an
I2C command, or it can delay the conversion until the next time
the ADP1650 exits an active mode. Delayed conversion can be
useful, for example, for measuring the IC temperature at the
end of a timed flash period. To set up a delayed conversion, set
ADC_EN to the required mode while OUTPUT_EN = 0. Then
set the ADP1650 to the desired output mode (torch, flash assist
light, or 5 V output) and set OUTPUT_EN = 1. The ADC conversion is performed when the ADP1650 exits the chosen mode.
The ADC can measure the LED VF in both flash and assist/
torch modes. In torch mode, set ADC_EN = 01 to begin a
conversion. The value can be read back from the ADC_VAL[5:2]
bits 1 ms after the conversion has started. Assist/torch mode,
rather than flash mode, is best in the handset production test to
verify the LED VF.
PREFLASH STROBE
STROBE
4-BIT ADC
LED VF Mode
SELECT FLASH CURRENT
SELECT MAX BATTERY CURRENT
LED CURRENT =
PROGAMMED LED
CURRENT
ADC_VAL[5:2]
Note that an ADC conversion cannot be performed when the
ADP1650 is idle. This is interpreted as an attempt to set up a
delayed conversion.
The camera system shown in Figure 36 can adjust the image
sensor settings based on the known reduced LED current for a
low battery and a high VF LED.
DC LIMIT HIT?
LED_OUT
ADC_EN[1:0]
To perform an immediate conversion, set ADC_EN to the
required mode during ADP1650 operation (OUTPUT_EN = 1).
Figure 35. DC Current Limit Operation in a Low Battery, High LED VF Case
NO
GPIO2
INTERFACE/
CONTROL
08837-015
Bit Name
IL_DC
YES
LED CURRENT =
REDUCED LED CURRENT
1ms
START CONVERSION
(INTERNAL SIGNAL)
BATTERY CURRENT =
PROGRAMMED DC LIMIT
I2C READ LED CURRENT
08837-014
STROBE
REG 0x08, ADC_EN = 01
Figure 36. Use of the DC Current Limit in an Optimized Camera System
ADC_VAL[5:2]
AVAILABLE FOR READ
08837-016
I2C DATA BUS
ADJUST IMAGE SENSOR
Figure 38. ADC Timing for All Modes Except VF Measurement in Flash Mode
In flash mode, set ADC_EN = 01. The conversion happens just
before the timeout occurs; therefore, the FL_TIM bits set when
the ADC sample occurs. This allows the VF to settle from the
Rev. C | Page 15 of 32
ADP1650
Write ADC_EN = 10 to begin a die temperature measurement.
The value can be read back from the ADC_VAL[5:2] bits 1 ms
after the conversion has started. The most stable and accurate
value of die temperature is available at the end of the flash pulse.
initial peak as the junction temperature of the LED stabilizes.
An LED temperature vs. flash time profile for the handset PCB
design can be generated during the design phase by varying the
FL_TIM bits from the lowest to the highest setting and collecting a
VF sample on each flash.
External Voltage Mode
I(FLASH)
The ADC measures the voltage on the GPIO2 pin when the
GPIO2 is configured as an ADC input by setting IO2_CFG =
11. One example is using an external temperature-dependent
resistor to create a voltage based on the temperature of the flash
LED. The EN line can be used for biasing to reduce leakage
current when the flash is not being used.
LED CURRENT
0A
FL_TIM
STROBE
tS = 1ms
START CONVERSION
(INTERNAL SIGNAL)
5 V OUTPUT OPERATION
The ADP1650 can be used as a 5 V boost to supply up to 500 mA
for an audio voltage rail or keypad LED driver voltage. To move
into voltage regulation mode, the OUTPUT_EN bit must be set
to 0. To enable the 5 V output, set LED_MOD[1:0] = 01, and set
OUTPUT_EN = 1. The ADP1650 sets the VOUT pin to 5 V
and disconnects VOUT from LED_OUT. The VOUT pin is
connected to the SW node when the ADP1650 is not enabled.
VOUT should not be connected directly to a positive external
voltage source because this causes current to flow from VOUT
to the battery.
I2C DATA BUS
ADC_VAL[5:2]
AVAILABLE FOR READ
08837-017
REG 0x08, ADC_EN = 01
Figure 39. ADC Timing for VF Measurement in Flash Mode
Die Temperature Mode
The ADC measures the IC die temperature and provides the
result to the I2C interface. This is useful during the design phase
of the flash system to optimize PCB layout for the best thermal
design.
3.2 MEGAPIXEL
TO 5.0 MEGAPIXEL
CMOS IMAGE SENSOR
INPUT VOLTAGE = 2.7V TO 5.0V
ON
OFF
10µF
1.0µH
STROBE
SW
VIN
VOUT*
GPIO2
10µF
APPLICATIONS PROCESSOR
I2C BUS
POWER-ON RESET
EN
VDD
ADP1650
SCL
SDA, SCL
VOUT = 5.0V
KEYPAD
LED DRIVER
SDA
LED_OUT
EN
GPIO1
SGND
PGND
GND
*THE VOUT PIN IS CONNECTED TO THE SW NODE WHEN THE ADP1650 IS NOT ENABLED. VOUT SHOULD NOT BE CONNECTED DIRECTLY TO A POSITIVE
EXTERNAL VOLTAGE SOURCE BECAUSE THIS WILL CAUSE CURRENT TO FLOW FROM VOUT TO THE BATTERY.
Figure 40. ADP1650 Voltage Regulation Mode: LED Driver Application
Rev. C | Page 16 of 32
08837-018
REG 0x02, FL_TIM = XXXX ms
REG 0x03, I_FL = XXXXX mA
REG 0x04, OUTPUT_EN = 1
STR_LV = 0
LED_MOD = 11
ADP1650
10µF
1.0µH
STROBE
SW
VIN
VOUT = 5.0V ±8.5%, IMAX = 500mA
VOUT
GPIO2
SCL
SDA, SCL
I2C BUS
POWER-ON
RESET
EN
0.1µF
10µF
APPLICATIONS PROCESSOR
ADP1650
VDD
47nF
AUDIO IN+
SDA
LED_OUT
IN– 80kΩ
AUDIO IN–
SSM2315
160kΩ
IN+ 80kΩ
OUT+
MODULATOR
FET
(Σ-∆)
DRIVER
OUT–
47nF
EN
GPIO1
160kΩ
SGND
PGND
SHUTDOWN
SD
BIAS
INTERNAL
OSCILLATOR
POP/CLICK
SUPPRESSION
GND
Figure 41. ADP1650 Voltage Regulation Mode: Class-D Audio Application
Rev. C | Page 17 of 32
08837-019
3.2 TO 5.0 MEGAPIXEL
CMOS IMAGE SENSOR
INPUT VOLTAGE = 2.7V TO 5.0V
ON
OFF
ADP1650
SAFETY FEATURES
For critical fault conditions, such as output overvoltage, flash
timeout, LED output short circuit, and overtemperature
conditions, the ADP1650 has built-in protection modes. If a
critical fault occurs, OUTPUT_EN (Register 0x04) is set to 0,
and the driver shuts down. The appropriate fault bit is set in the
fault information register (Register 0x05). The processor can
read the fault information register through the I2C interface to
determine the nature of the fault condition. When the fault
register is read, the corresponding fault bit is cleared.
If a noncritical event such as an indicator LED open/short or a
TxMASK1 or TxMASK2 event occurs, or the dc current limit or
soft inductor current limit is hit, the LED driver continues
operating. The corresponding information bits are set in the
fault information register until the processor reads them.
SHORT-CIRCUIT FAULT
When the flash driver is disabled, the high-side current regulator
disconnects the dc path between the battery and the LED, protecting the system from an LED short circuit. The LED_OUT
pin features short-circuit protection that monitors the LED
voltage when the LED driver is enabled. If the LED_OUT pin
remains below the short-circuit detection threshold, a short
circuit is detected. Bit 6 of the fault information register is set
high. The ADP1650 remains disabled until the processor clears
the fault register.
OVERVOLTAGE FAULT
The ADP1650 contains a comparator at the VOUT pin that
monitors the voltage between VOUT and GND. If the voltage
exceeds 5.5 V (typical), the ADP1650 shuts down. Bit 7 in the
fault information register is read back as high. The ADP1650 is
disabled until the fault is cleared, ensuring protection against an
open circuit.
DYNAMIC OVERVOLTAGE MODE (DOVP)
Dynamic OVP mode is a programmable feature that limits the
VOUT voltage exceeding the OVP level while maintaining as
much current as possible through the LED. This mode prevents
an overvoltage fault in the case of a much higher than expected
LED forward voltage. If the LED forward voltage reduces due to
the LED temperature rising, the ADP1650 moves out of DOVP
mode and regulates the LED at the programmed current level.
Set Bit 7 of Register 0x07 high to enable dynamic OVP mode.
OVERTEMPERATURE FAULT
If the junction temperature of the ADP1650 rises above 150°C,
a thermal protection circuit shuts down the device. Bit 5 of the
fault information register is set high. The ADP1650 remains
disabled until the processor clears the fault register.
INDICATOR LED FAULT
The GPIO2 pin features open- and short-circuit protection in
the indicator LED mode. If a short or open circuit occurs, Bit 2
of the fault information register is set high. The indicator LED
regulator ensures that no damage occurs to the IC during a fault.
CURRENT LIMIT
The internal switch limits battery current by ensuring that the
peak inductor current does not exceed the programmed limit
(current limit is set by Bit 6 and Bit 7 in Register 0x04). The
default mode of the ADP1650 is soft current limit mode. If the
peak inductor current hits the limit, Bit 1 of the fault information register is set, and the inductor and LED current cannot
increase further. The ADP1650 continues to operate. If the
ADP1650 has soft current limit disabled and the peak inductor
current exceeds the limit, the part shuts down and Bit 1 of the
fault information register is set high. In this case, ADP1650
remains disabled until the processor clears the fault register.
INPUT UNDERVOLTAGE
The ADP1650 includes a battery undervoltage lockout circuit.
During 5 V or LED operation, if the battery voltage drops below
the 2.4 V (typical) input UVLO threshold, the ADP1650 shuts
down. A power-on reset circuit resets the registers to their
default conditions when the voltage rises above the UVLO
rising threshold.
SOFT START
The ADP1650 has a soft start mode that controls the rate of
increase of battery current at startup by digitally controlling the
output current ramp. The maximum soft start time is 0.6 ms.
RESET USING THE ENABLE (EN) PIN
A low-to-high transition on the EN pin resets all registers to
their default values. Bringing EN low reduces the IQ to 0.2 μA
(typical).
CLEARING FAULTS
The information bits and faults in Register 0x05 clear
automatically when the processor reads the fault register.
TIMEOUT FAULT
When external strobe mode is enabled (Register 0x04, Bit 2),
and strobe is set to level-sensitive mode (Register 0x04, Bit 5),
if the strobe pin remains high for longer than the programmed
timeout period, the timeout fault bit (Register 0x05, Bit 4) is
read back as high. The ADP1650 remains disabled until the
processor clears the fault register.
Rev. C | Page 18 of 32
ADP1650
I2C INTERFACE
Figure 42 illustrates the I2C write sequence to a single register.
The subaddress content selects which of the nine ADP1650
registers is written to. The ADP1650 sends an acknowledgment
to the master after the 8-bit data byte has been written. Figure 43
shows the I2C read sequence of a single register.
The ADP1650 includes an I2C-compatible serial interface for
control of the LED current, as well as for readback of system
status registers. The I2C chip address is 0x30 (0x60 in write
mode and 0x61 in read mode). Additional I2C addresses are
available on request.
The register definitions are shown in the I2C Register Map
section.
MASTER
STOP
1
0
0
0
0
CHIP ADDRESS
0
0
0
SUBADDRESS
0
ADP1650 RECEIVES
DATA
S
P
ADP1650 ACK
1
ADP1650 ACK
0
ADP1650 ACK
S
T
08837-021
0 = WRITE
Figure 42. I2C Single Register Write Sequence
SUBADDRESS
CHIP ADDRESS
Figure 43. I2C Single Register Read Sequence
Rev. C | Page 19 of 32
ADP1650 SENDS
DATA
S
P
08837-020
CHIP ADDRESS
1
0 1 1 0 0 0 0 1 0 0
ADP1650 ACK
0 S
T
0 0 0
ADP1650 ACK
0 1 1 0 0 0
ADP1650 ACK
S
T
MASTER
STOP
1 = READ
MASTER ACK
0 = WRITE
ADP1650
I2C REGISTER MAP
The lowest bit number (0) represents the least significant bit, and the highest bit number (7) represents the most significant bit.
Table 9. Design Information Register (Register 0x00)
Bit
[7:0]
R/W
R
Reset State
00100010
Table 10. VREF and Timer Register (Register 0x02)
Bit Name
IO2_CFG
Bit
[7:6]
R/W
R/W
IO1_CFG
[5:4]
R/W
FL_TIM
[3:0]
R/W
Description
GPIO2 configuration
00 = high impedance (default)
01 = indicator LED
10 = TxMASK2 operation mode
11 = analog input (to ADC)
GPIO1 configuration
00 = high impedance (default)
01 = torch
10 = TxMASK1 operation mode
11 = reserved
Flash timer value setting
0000 = 100 ms
0001 = 200 ms
0010 = 300 ms
0011 = 400 ms
0100 = 500 ms
0101 = 600 ms
0110 = 700 ms
0111 = 800 ms
1000 = 900 ms
1001 = 1000 ms
1010 = 1100 ms
1011 = 1200 ms
1100 = 1300 ms
1101 = 1400 ms
1110 = 1500 ms
1111 = 1600 ms (default)
Rev. C | Page 20 of 32
ADP1650
Table 11. Current Set Register (Register 0x03)
Bit Name
I_FL
Bit
[7:3]
R/W
R/W
I_TOR
[2:0]
R/W
Description
Flash current value setting
00000 = 300 mA
00001 = 350 mA
00010 = 400 mA
00011 = 450 mA
00100 = 500 mA
00101 = 550 mA
00110 = 600 mA
00111 = 650 mA
01000 = 700 mA
01001 = 750 mA
01010 = 800 mA
01011 = 850 mA
01100 = 900 mA
01101 = 950 mA
01110 = 1000 mA (default)
01111 = 1050 mA
10000 = 1100 mA
10001 = 1150 mA
10010 = 1200 mA
10011 = 1250 mA
10100 = 1300 mA
10101 = 1350 mA
10110 = 1400 mA
10111 = 1450 mA
11000 = 1500 mA
Torch and assist light current value setting
000 = 25 mA
001 = 50 mA
010 = 75 mA
011 = 100 mA (default)
100 = 125 mA
101 = 150 mA
110 = 175 mA
111 = 200 mA
Rev. C | Page 21 of 32
ADP1650
Table 12. Output Mode Register (Register 0x04)
Bit Name
IL_PEAK
Bit
[7:6]
R/W
R/W
STR_LV
5
R/W
FREQ_FB
4
R/W
OUTPUT_EN
3
R/W
STR_MODE
2
R/W
LED_MOD
[1:0]
R/W
Description
Inductor peak current limit setting
00 = 1.75 A
01 = 2.25 A
10 = 2.75 A (default)
11 = 3.0 A
0 = edge sensitive
1 = level sensitive (default)
0 = frequency foldback to 1.5 MHz not allowed (default)
1 = frequency foldback to 1.5 MHz allowed
0 = output off (default)
1 = output on
0 = software strobe mode (software flash occurs when output is enabled in flash mode)
1 = hardware strobe mode (the STROBE pin must go high for flash) (default)
Configures LED output mode
00 = standby mode (default)
01 = voltage output mode, VOUT = 5 V
10 = assist light mode
11 = flash mode
Table 13. Fault Information Register (Register 0x05)
Bit Name
FL_OVP
Bit
7
R/W
R
FL_SC
6
R
FL_OT
5
R
FL_TO
4
R
FL_TX1
3
R
FL_IO2
2
R
FL_IL
1
R
FL_IDC
0
R
Description
0 = no fault (default)
1 = overvoltage fault
0 = no fault (default)
1 = short-circuit fault
0 = no fault (default)
1 = overtemperature fault
0 = no fault (default)
1 = timeout fault
0 = no TxMASK1 operation mode during last flash (default)
1 = TxMASK1 operational mode occurred during last flash
If GPIO2 is configured as TxMASK2
0 = no TxMASK2 operations mode during last flash (default)
1 = TxMASK2 operational mode occurred during last flash
If GPIO2 is configured as ILED
0 = no fault (default)
1 = indicator LED fault
0 = no fault (default)
1 = inductor peak current limit fault
0 = programmed dc current limit not hit (default)
1 = programmed dc current limit hit
Rev. C | Page 22 of 32
ADP1650
Table 14. Input Control Register (Register 0x06)
Bit Name
I_TX2
Bit
[7:4]
R/W
R/W
I_TX1
[3:0]
R/W
Description
TxMASK2 operational mode foldback current
0000 = 100 mA
0001 = 150 mA
0010 = 200 mA
0011 = 250 mA
0100 = 300 mA
0101 = 350 mA
0110 = 400 mA (default)
0111 = 450 mA
1000 = 500 mA
1001 = 550 mA
1010 = 600 mA
1011 = 650 mA
1100 = 700 mA
1101 = 750 mA
1110 = 800 mA
1111 = 850 mA
TxMASK1 operational mode foldback current
0000 = 100 mA
0001 = 150 mA
0010 = 200 mA
0011 = 250 mA
0100 = 300 mA
0101 = 350 mA
0110 = 400 mA (default)
0111 = 450 mA
1000 = 500 mA
1001 = 550 mA
1010 = 600 mA
1011 = 650 mA
1100 = 700 mA
1101 = 750 mA
1110 = 800 mA
1111 = 850 mA
Rev. C | Page 23 of 32
ADP1650
Table 15. Additional Mode Register, AD_MOD (Register 0x07)
Bit Name
DYN_OVP
Bit
7
R/W
R/W
SW_LO
6
R/W
STR_POL
5
R/W
I_ILED
[4:3]
R/W
IL_DC
[2:1]
R/W
IL_DC_EN
0
R/W
Description
Dynamic OVP
0 = dynamic OVP off (default)
1 = dynamic OVP on
Force 1.5 MHz switching frequency
0 = disabled (default)
1 = enabled
Strobe polarity
0 = active low
1 = active high (default)
Indicator LED current
00 = 2.75 mA (default)
01 = 5.5 mA
10 = 8.25 mA
11 = 11 mA
Input dc current limit setting LED current
00 = 1.5 A
01 = 1.75 A
10 = 2.0 A (default)
11 = 2.25 A
Input dc current limit
0 = disabled (default)
1 = enabled
Table 16. Additional Mode Register, ADC (Register 0x08)
Bit Name
Reserved
Bit
7
R/W
R/W
FL_VB_LO
6
R
ADC_VAL
ADC_EN
[5:2]
[1:0]
R/W
R/W
Description
Test mode
0 = disabled (default)
1 = enabled
Programmed VBAT low threshold status; low battery mode must be enabled in Register 0x09
0 = VDD is greater than the VBAT low threshold (default)
1 = VDD is less than the VBAT low threshold
ADC readback value; four bits (see Figure 17, Figure 18, and Figure 19)
ADC enable mode
00 = disabled (default)
01 = LED VF measurement
10 = die temperature measurement
11 = external voltage mode
Rev. C | Page 24 of 32
ADP1650
Table 17. Battery Low Mode Register (Register 0x09)
Bit Name
CL_SOFT
Bit
7
R/W
R/W
I_VB_LO
[6:3]
R
V_VB_LO
[2:0]
R/W
Description
Soft inductor peak current limit
0 = disabled (ADP1650 is disabled when the inductor peak current limit is hit)
1 = enabled (default)
Current setting for VBAT low mode
0000 = 300 mA
0001 = 350 mA
0010 = 400 mA
0011 = 450 mA
0100 = 500 mA
0101 = 550 mA
0110 = 600 mA
0111 = 650 mA
1000 = 700 mA
1001 = 750 mA
1010 = 800 mA (default)
1011 = 850 mA
1100 = 900 mA
1101 = 950 mA
1110 = 1000 mA
1111 = 1050 mA
VDD level where VBAT low function is enabled
000 = disabled (default)
001 = 3.3 V
010 = 3.35 V
011 = 3.4 V
100 = 3.45 V
101 = 3.5 V
110 = 3.55 V
111 = 3.6 V
Rev. C | Page 25 of 32
ADP1650
APPLICATIONS INFORMATION
capacitor, a low ESR capacitor is required. Table 19 provides a
list of suggested input capacitors.
EXTERNAL COMPONENT SELECTION
Selecting the Inductor
The ADP1650 boost converter increases the battery voltage
to allow driving of one LED, whose voltage drop is higher than
the battery voltage plus the current source headroom voltage.
This allows the converter to regulate the LED current over the
entire battery voltage range and with a wide variation of LED
forward voltage.
The inductor saturation current should be greater than the sum
of the dc input current and half the inductor ripple current. A
reduction in the effective inductance due to saturation increases
the inductor current ripple. Table 18 provides a list of recommended inductors.
Selecting the Input Capacitor
The ADP1650 requires an input bypass capacitor to supply
transient currents while maintaining constant input and output
voltages. The input capacitor carries the input ripple current,
allowing the input power source to supply only the dc current.
Increased input capacitance reduces the amplitude of the
switching frequency ripple on the battery. Due to the dc bias
characteristics of ceramic capacitors, a 0603, 6.3 V, X5R/X7R,
10 μF ceramic capacitor is preferable.
Higher value input capacitors help to reduce the input voltage
ripple and improve transient response.
Selecting the Output Capacitor
The output capacitor maintains the output voltage and supplies
the LED current during the NFET power switch on period. It also
stabilizes the loop. The recommended capacitor is a 10 μF, 6.3 V,
X5R/X7R ceramic capacitor.
Note that dc bias characterization data is available from capacitor manufacturers and should be taken into account when
selecting input and output capacitors. The 6.3 V capacitors are
best for most designs. Table 20 provides a list of recommended
output capacitors.
Higher output capacitor values reduce the output voltage ripple
and improve load transient response. When choosing this value,
it is also important to account for the loss of capacitance due to
output voltage dc bias.
Ceramic capacitors have a variety of dielectrics, each with different
behavior over temperature and applied voltage. Capacitors must
have a dielectric that ensures the minimum capacitance over the
necessary temperature range and dc bias conditions. X5R or X7R
dielectrics with a voltage rating of 6.3 V or 10 V are recommended
for best performance. Y5V and Z5U dielectrics are not recommended for use with any dc-to-dc converter because of their
poor temperature and dc bias characteristics.
To minimize supply noise, place the input capacitor as close to
the VIN pin of the ADP1650 as possible. As with the output
Table 18. Suggested Inductors
Vendor
Toko
Toko
Coilcraft
Murata
FDK
Value (μH)
1.0
1.0
1.0
1.0
1.0
Part No.
FDSD0312
DFE2520
XFL3010
LQM32P_G0
MIPS3226D
DCR (mΩ)
41.5
50
43
60
40
ISAT (A)
4.5
3.4
2.4
3
3
Part No.
GRM188R60J106ME47
C1608JB0J106K
JMK107BJ106MA
Dimensions L × W × H (mm)
1.6 × 0.8 × 0.8
1.6 × 0.8 × 0.8
1.6 × 0.8 × 0.8
Part No.
GRM188R60J106ME47
C1608JB0J106K
JMK107BJ106MA
Dimensions L × W × H (mm)
1.6 × 0.8 × 0.8
1.6 × 0.8 × 0.8
1.6 × 0.8 × 0.8
Table 19. Suggested Input Capacitors
Vendor
Murata
TDK
Taiyo Yuden
Value
10 μF, 6.3 V
10 μF, 6.3 V
10 μF, 6.3 V
Table 20. Suggested Output Capacitors
Vendor
Murata
TDK
Taiyo Yuden
Value
10 μF, 6.3 V
10 μF, 6.3 V
10 μF, 6.3 V
Rev. C | Page 26 of 32
Dimensions L × W × H (mm)
3.0 × 3.0 × 1.2
2.5 × 2.0 × 1.2
3.0 × 3.0 × 1.0
3.2 × 2.5 × 1.0
2.5 × 2.0 × 1.2
ADP1650
CEFF = COUT × (1 − TEMPCO) × (1 − TOL)
where:
CEFF is the effective capacitance at the operating voltage.
TEMPCO is the worst-case capacitor temperature coefficient.
TOL is the worst-case component tolerance.
TEMPCO from −40°C to +85°C is 15%.
TOL is 10%.
COUT at VOUT (MAX) = 5 V, is 3 μF, as shown in Figure 44.
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
0
1.26
2.52
3.78
5.04
DC BIAS VOLTAGE (V)
6.30
08837-022
In this example, the 10 μF X5R capacitor has the following
characteristics:
10
CAPACITANCE CHANGE (%)
The worst-case capacitance accounting for capacitor variation
over temperature, component tolerance, and voltage is calculated using the following equation:
Figure 44. DC Bias Characteristic of a 3 × 6.3 V, 10 μF Ceramic Capacitor
Substituting these values in the equation yields
CEFF = 3 μF × (1 − 0.15) × (1 − 0.1) = 2.29 μF
The effective capacitance needed for stability, which includes
temperature and dc bias effects, is 3.0 μF.
Rev. C | Page 27 of 32
ADP1650
PCB LAYOUT
Poor layout can affect performance, causing electromagnetic
interference (EMI) and electromagnetic compatibility (EMC)
problems, ground bounce, and power losses. Poor layout can
also affect regulation and stability. Figure 45 shows optimized
layouts implemented using the following guidelines:
•
•
•
•
C1
Li-ION +
L1
PGND
Li-ION +
C2
INDUCTOR
DIGITAL
INPUT/
OUTPUT
AREA = 16.4mm 2
LED
ANODE
08837-023
•
Place the inductor, input capacitor, and output capacitor
close to the IC using short tracks. These components carry
high switching frequencies and large currents.
Route the trace from the inductor to the SW pin with as
wide a trace as possible. The easiest path is through the
center of the output capacitor.
Route the LED_OUT path away from the inductor and SW
node to minimize noise and magnetic interference.
Figure 45. Layout of the ADP1650 Driving a High Power White LED (WLCSP)
Li-ION +
L1
C1
PGND
VIN
STROBE
GPIO2
EN
GPIO1
SW
GND
SDA
VOUT
SCL
LED_OUT
ADP1650
PGND
INDUCTOR
C2
VOUT
08837-024
•
•
Maximize the size of ground metal on the component side
to help with thermal dissipation.
Use a ground plane with two to three vias connecting to the
component side ground near the output capacitor to
reduce noise interference on sensitive circuit nodes.
With the LFCSP package, six to eight thermal vias connect
the ground paddle to the main PCB ground plane.
Analog Devices applications engineers can be contacted
through the Analog Devices sales team to discuss different
layouts based on system design constraints.
Figure 46. Example Layout of the ADP1650 Driving a High Power White LED (LFCSP)
Rev. C | Page 28 of 32
ADP1650
OUTLINE DIMENSIONS
0.660
0.602
0.544
1.54
1.50
1.46
0.022
REF
SEATING
PLANE
3
2
1
A
BALL A1
IDENTIFIER
2.04
2.00
1.96
0.330
0.310
0.290
B
1.50
REF
C
D
0.380
0.352
0.324
0.04 MAX
COPLANARITY
BOTTOM VIEW
(BALL SIDE UP)
1.00
REF
0.280
0.250
0.220
020409-B
TOP VIEW
(BALL SIDE DOWN)
0.50
REF
Figure 47. 12-Ball Wafer Level Chip Scale Package [WLCSP]
(CB-12-4)
Dimensions shown in millimeters
2.48
2.38
2.23
3.10
3.00 SQ
2.90
0.50 BSC
6
1.74
1.64
1.49
EXPOSED
PAD
0.50
0.40
0.30
5
TOP VIEW
0.80
0.75
0.70
0.05 MAX
0.02 NOM
SEATING
PLANE
0.30
0.25
0.20
1
BOTTOM VIEW
PIN 1
INDICATOR
(R 0.15)
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
0.20 REF
121009-A
PIN 1 INDEX
AREA
10
Figure 48. 10-Lead Lead Frame Chip Scale Package [LFCSP_WD]
3 mm × 3 mm Body, Very Very Thin, Dual Lead
(CP-10-9)
Dimensions shown in millimeters
ORDERING GUIDE
Model 1
ADP1650ACBZ-R7
ADP1650ACPZ-R7
ADP1650CB-EVALZ
ADP1650CP-EVALZ
1
2
Temperature Range
−40°C to +125°C
−40°C to +125°C
Package Description
12-Ball Wafer Level Chip Scale Package [WLCSP]
10-Lead Frame Chip Scale Package [LFCSP_WD]
Evaluation Board WLCSP Package
Evaluation Board LFCSP Package
Z = RoHS Compliant Part.
This package option is halide free.
Rev. C | Page 29 of 32
Package Option 2
CB-12-4
CP-10-9
Branding
LE4
LGX
ADP1650
NOTES
Rev. C | Page 30 of 32
ADP1650
NOTES
Rev. C | Page 31 of 32
ADP1650
NOTES
©2010–2011 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D08837-0-4/11(C)
Rev. C | Page 32 of 32