Analogic AAT2830IBK-T1 800ma total display solution for portable device Datasheet

AAT2830/31
800mA Total Display Solution
for Portable Devices
General Description
Features
The AAT2830/31 is a total solution IC for portable display applications. Based on a tri-mode charge pump
power engine, it is capable of delivering 800mA of
output current with individual driving circuitries for
light emitting diode (LED) backlights, photo flash, and
RGB. The high conversion efficiency and high level
of integration make the AAT2830/31 the optimum
solution for battery life and size-critical applications.
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•
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AnalogicTech's AS2Cwire™ (Advanced Simple Serial
Control™) serial digital input is used to enable, disable, and set current for all of the outputs. Each backlight LED output can be programmed to 30mA over 16
discrete steps. The AAT2830/31 can also deliver up to
600mA to drive flash LEDs over four individual channels, with excellent current matching between channels. A built-in safety timer function allows easy, onetrigger system control for photo flash applications.
The RGB output can be adjusted to handle up to
60mA, and the AS2Cwire signal can drive the RGB
module in up to 4096 (AAT2830) or 64 (AAT2831)
color intensity combinations.
•
The AAT2830/31 is available in a Pb-free, thermally-enhanced 24-pin 4x4x0.75mm TQFN package.
•
•
•
•
•
Applications
•
•
•
•
•
Digital Still Cameras
LCD Display Modules
MP3 Players
White LED Drivers
Wireless Handsets
ChargePump™
Input Supply Voltage Range: 2.7V to 5.5V
Tri-Mode (1X/1.5X/2X) Charge Pump:
— Delivers up to 800mA of Output Current
— Switching Frequency: Up to 2MHz
Total Display Solution for RGB and Backlight
Applications
— 6-Channel Backlight WLED Backlight
• User-Programmable Full-Scale Current,
up to 30mA
— 4-Channel Flash WLED Drive
• User-Programmable Full-Scale Current,
up to 150mA
• Torch/Flashlight/Movie Mode Operation
• Auto-/Safety Flash Timer
— 3-Channel RGB
• User-Programmable Full-Scale Output
Current/Duty Cycle
• AAT2830: 4096 Color/Intensity
Combinations
• AAT2831: 64 Color/Intensity
Combinations
Single-Wire AS2Cwire Serial Interface for
Configuration/Control
— Fourteen Addressable Registers
— Fast, 1MHz Serial Interface
True Load Disconnect in Shutdown, IIN < 1µA
Built-in Thermal Protection
Built-in Auto-Disable for Open LED Condition
Automatic Soft-Start Minimizes Inrush Current
Available in 4x4x0.75mm TQFN44-24 Package
Typical Application
...
COUT
2.2μF
OUT FL1 FL2 FL3 FL4
IN
VBATTERY
Single-Cell Li+
CIN
4.7μF
AS2Cwire
Serial Control
2830.2007.09.1.0
EN/SET
RGB LED
BL1…BL4 BL5 BL6
R G B
BSET
AAT2830 / 31
C1+ C1- C2+ C2-
C1
1μF
CT
PGND
AGND
CT
0.1μF
RSET
280kΩ
C2
1μF
1
AAT2830/31
800mA Total Display Solution
for Portable Devices
Pin Description
Pin #
Symbol
Function
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
EP
BL3
BL2
BL1
AGND
CT
EN/SET
R
G
B
C2+
C2OUT
IN
C1+
C1PGND
FL4
FL3
FL2
FL1
BSET
BL6
BL5
BL4
Power return (cathode) for backlight channel 3. If not used, connect to the OUT pin.
Power return (cathode) for backlight channel 2. If not used, connect to the OUT pin.
Power return (cathode) for backlight channel 1. If not used, connect to the OUT pin.
Signal ground.
Safety flash timer control capacitor input.
Enable and AS2Cwire serial interface control input.
Power return (cathode) for Red LED of the RGB module.
Power return (cathode) for Green LED of the RGB module.
Power return (cathode) for Blue LED of the RGB module.
Positive node of flying capacitor 2.
Negative node of flying capacitor 2.
Output voltage pin. Connect to anode of all LEDs.
Input voltage pin.
Positive node of flying capacitor 1.
Negative node of flying capacitor 1.
Power ground.
Power return (cathode) for flash channel 4. If not used, connect to the OUT pin.
Power return (cathode) for flash channel 3. If not used, connect to the OUT pin.
Power return (cathode) for flash channel 2. If not used, connect to the OUT pin.
Power return (cathode) for flash channel 1. If not used, connect to the OUT pin.
Maximum backlight current programming resistor input. Ground this pin to use default values.
Power return (cathode) for backlight channel 6. If not used, connect to the OUT pin.
Power return (cathode) for backlight channel 5. If not used, connect to the OUT pin.
Power return (cathode) for backlight channel 4. If not used, connect to the OUT pin.
Exposed pad (bottom); connect to GND directly beneath the package
Pin Configuration
TQFN44-24
(Top View)
FL2
FL1
BSET
BL6
BL5
BL4
19
20
21
22
23
24
BL3
BL2
BL1
AGND
CT
EN/SET
1
18
2
17
3
16
4
15
5
14
6
13
FL3
FL4
PGND
C1C1+
IN
12
11
9
10
8
7
OUT
C2C2+
B
G
R
2
2830.2007.09.1.0
AAT2830/31
800mA Total Display Solution
for Portable Devices
Absolute Maximum Ratings1
TA = 25°C, unless otherwise noted.
Symbol
VN
VN
VN
TJ
TLEAD
Description
[OUT, IN, BL1-BL6, FL1-FL4, R, G, B] to GND
[C1+, C2+] to GND
[EN/SET, CT, BSET, C1-, C2-] to GND
Operating Junction Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
Value
Units
-0.3 to 6.0
-0.3 to VOUT + 0.3
-0.3 to VIN + 0.3
-40 to +150
300
V
V
V
°C
°C
Value
Units
50
2.0
°C/W
W
Value
Units
-40 to +85
°C
Thermal Characteristics2
Symbol
θJA
PD
Description
Maximum Thermal Resistance
Maximum Power Dissipation
Recommended Operating Conditions
Symbol
T
Description
Ambient Temperature Range
1. Stresses above those listed in Absolute Maximum Ratings may cause damage to the device. Functional operation at conditions other
than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
2. Mounted on a demo board (FR4, in still air).
2830.2007.09.1.0
3
AAT2830/31
800mA Total Display Solution
for Portable Devices
Electrical Characteristics1
VIN = 3.6V; CIN = 4.7µF; C1 = C2 = 1µF; COUT = 2.2µF; TA = -40°C to +85°C, unless otherwise noted. Typical
values are TA = 25°C.
Symbol
Description
Conditions
Charge Pump Section
VIN
IN Operating Supply Voltage Range
IIN
IN Operating Supply Current
ISHDN
IOUT
IN Shutdown Current
OUT Maximum Output Current
BL1-BL6, RGB Charge Pump
VTH(HYS)
Mode Transition Hysteresis
VBSET
BSET Pin Voltage
fOSC
Charge Pump Oscillator Frequency
tSS
Charge Pump Soft-Start Delay
TSD
Over-Temperature Shutdown Threshold
TSD(HYS)
Over-Temperature Shutdown Hysteresis
BL1-BL6 Backlight LED Outputs
IBL_(MAX)
BL1-BL6 Maximum Current
ΔIBL
BL1-BL6 Current Matching2
Min Typ Max Units
2.7
Address = 0, Data = 1,
VIN - VF = 1.5V
Address = 0, Data = 1,
VIN - VF = 1.5V
4
mA
5
0.3
1
27
BL1-BL6 Charge Pump Mode
Transition Threshold
FL1-FL4 Flash LED Outputs
FL1-FL4 Maximum Current
ΔIFL
FL1-FL4 Current Matching2
135
FL1-FL4 Charge Pump Mode
Transition Threshold
ICT
Flash Timer Current
RGB LED Outputs
VFL_(TH)
IRGB_(MAX)
R-G-B Maximum Current
VRGB_(TH)
RGB Charge Pump Mode
Transition Threshold
240
µA
mA
500
mV
0.7
2
200
140
15
V
MHz
µs
°C
°C
30
33
mA
1
%
100
Address = 4, Data = 1,
VIN - VF = 1.5V
Address = 4, Data = 1,
VIN - VF = 1.5V
Address = 12, Data = 7,
VIN - VF = 1.5V
V
0.6
VBL_(TH)
IFL_(MAX)
5.5
1X Mode, Address = 0, Data = 1,
VEN/SET = VIN
1.5X Mode, Address = 0, Data = 1,
VEN/SET = VIN
2X Mode, Address = 0, Data = 1,
VEN/SET = VIN
1X LL Mode, Address = 3,
Data = 1, VEN/SET = VIN
VEN/SET = 0V, TA = 25°C
51
150
mV
165
mA
4
%
300
mV
3.4
μA
60
100
69
mA
mV
1. The AAT2830/31 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is
assured by design, characterization, and correlation with statistical process controls.
2. Current matching is defined as the deviation of any sink current from the average of all active channels.
4
2830.2007.09.1.0
AAT2830/31
800mA Total Display Solution
for Portable Devices
Electrical Characteristics1
VIN = 3.6V; CIN = 4.7µF; C1 = C2 = 1µF; COUT = 2.2µF; TA = -40°C to +85°C, unless otherwise noted. Typical
values are TA = 25°C.
Symbol
EN/SET Logic
VENS(L)
VENS(H)
IEN/SET
TEN/SET_LO
TEN/SET_HI_MIN
TEN/SET_HI_MAX
TOFF
TLAT
2830.2007.09.1.0
Description
Control
EN/SET Input Low Threshold Voltage
EN/SET Input High Threshold Voltage
EN/SET Input Leakage Current
EN/SET Low Time
Minimum EN/SET High Time
Maximum EN/SET High Time
EN/SET Off Timeout
EN/SET Latch Timeout
Conditions
Min Typ Max Units
0.4
1.4
-1
0.3
1
75
50
75
500
500
V
V
µA
µs
ns
µs
µs
µs
5
AAT2830/31
800mA Total Display Solution
for Portable Devices
Typical Characteristics
AAT2830 Backlight Section Efficiency
Backlight Current Matching vs. Temperature
32
100
30mA/Channel
LED Current (mA)
Efficiency (%)
90
31.5
19mA/Channel
80
70
60
50
2.1mA/Channel
40
31
30.5
Channel 5 Channel 6
30
29.5
29
Channel 3
28.5
30
2.7
3.1
3.5
3.9
4.3
4.7
5.1
Channel 4
28
-40
5.5
Channel 1
-15
10
Input Voltage (V)
85
55
54
80
LED Current (mA)
90
Efficiency (%)
60
Flash Current Matching vs. Temperature
100
Data 6, 75mA/Channel
70
60
50
Data 16, 19mA/Channel
40
53
52
Channel 2
51
Channel 4
50
49
Channel 1
48
Channel 3
47
46
45
30
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
-40
-15
10
Input Voltage (V)
35
60
85
Temperature (°C)
BL1-BL6 Mode Transition Threshold
vs. Current Setting
1X Mode Hysteresis vs. Current Settings
500
140
450
120
400
Threshold (mV)
Hysteresis (mV)
35
Temperature (°C)
AAT2830 Flash Section Efficiency
350
300
250
200
150
100
100
80
60
40
20
50
0
2
4
6
8
10
12
14
Current Setting (Address 0, Data #)
6
Channel 2
16
0
2
4
6
8
10
12
14
16
Current Setting (Address 0, Data #)
2830.2007.09.1.0
AAT2830/31
800mA Total Display Solution
for Portable Devices
Typical Characteristics
1.2
25°C
-40°C
1.1
EN/SET Low Threshold Voltage
vs. Input Voltage
EN/SET Low Threshold (V)
EN/SET High Threshold (V)
EN/SET High Threshold Voltage
vs. Input Voltage
1.0
0.9
0.8
0.7
85°C
0.6
0.5
0.4
0.3
0.2
2.7
3.1
3.5
3.9
4.3
4.7
5.1
1.2
1.0
0.9
0.8
0.7
85°C
0.6
0.5
0.4
0.3
0.2
5.5
2.7
3.1
3.5
Input Voltage (V)
3.9
600
450
550
500
TOFF (µs)
25°C
85°C
350
300
4.7
5.1
5.5
EN/SET Off Timeout vs. Input Voltage
500
400
4.3
Input Voltage (V)
EN/SET Latch Timeout vs. Input Voltage
TLAT (µs)
25°C
-40°C
1.1
-40°C
250
25°C
450
-40°C
85°C
400
350
300
250
200
150
2.7
200
3.1
3.5
3.9
4.3
4.7
5.1
5.5
150
2.7
3.1
Input Voltage (V)
3.5
3.9
4.3
4.7
5.1
Input Voltage (V)
Turn On to 1X Mode Backlight
Turn On to 1.5X Mode Backlight
(30mA/channel; Address 0, Data 16; VIN = 4.4V)
(30mA/channel; Address 0, Data 16; VIN = 3.5V)
VEN/SET
(2V/div)
VEN/SET
(2V/div)
VOUT
(2V/div)
VOUT
(2V/div)
VBLX
(0.5V/div)
VBLX
(0.5V/div)
IIN
(0.1A/div)
IIN
(0.2A/div)
Time (200µs/div)
2830.2007.09.1.0
5.5
Time (200µs/div)
7
AAT2830/31
800mA Total Display Solution
for Portable Devices
Typical Characteristics
Turn On to 2X Mode Backlight
Turn On to 1X Mode Flash
(30mA/channel; Address 0, Data 16; VIN = 2.7V)
(150mA/channel; Address 4, Data 1; VIN = 4.2V)
VEN/SET
(2V/div)
VEN/SET
(2V/div)
VOUT
(2V/div)
VOUT
(2V/div)
VBLX
(0.5V/div)
VFLX
(500mV/div)
IIN
(0.2A/div)
IIN
(500mA/div)
Time (200µs/div)
Time (100µs/div)
Turn On to 2X Mode Flash
Turn Off from 1.5X Mode Backlight
(150mA/channel; Address 4, Data 1; VIN = 3.7V)
(30mA/channel; Address 0, Data 16)
VEN/SET
(2V/div)
VEN/SET
(2V/div)
VOUT
(2V/div)
VDIODE
(2V/div)
VFLX
(500mV/div)
ILED
(0.02A/div)
IIN
(1A/div)
Time (500µs/div)
Operating Characteristics
Operating Characteristics
(VIN = 3.4V; 1.5X Mode;
30mA/channel; AC Coupled)
(VIN = 2.7V; 2X Mode;
30mA/channel; AC Coupled)
VIN
(100mV/div)
VIN
(100mV/div)
VOUT
(100mV/div)
VOUT
(100mV/div)
IIN
(20mA/div)
IIN
(20mA/div)
Time (500ns/div)
8
Time (100µs/div)
Time (500µs/div)
2830.2007.09.1.0
AAT2830/31
800mA Total Display Solution
for Portable Devices
Functional Block Diagram
C1+ C1–
IN
C2+ C2–
OUT
CT
FL1
Tri-Mode Charge
Pump Control
FL2
Flash Ref
VF Monitoring
FL3
FL4
4
3
6
PGND
BL1
EN/SET
AS2Cwire
Control
Main Ref
BL2
BL3
BL4
Sub Ref
BL5
BL6
BSET
DAC
R
RGB Ref
G
B
AGND
Functional Description
The AAT2830/31 is a multi-function power solution
for display systems in portable devices. It includes
six individual driving channels for backlight LEDs,
four for flash LEDs, and three for RGB fashion or
auxiliary, or status LEDs. All of these functions are
powered by a high efficiency tri-mode charge pump
engine that is capable of 800mA load current, ideal
for driving high brightness white LEDs.
The six backlight outputs can be turned on or off
together (BL1-BL6), in two groups or individually. The
two-group operation allows LEDs to be turned on and
off in two banks: the main group (BL1-BL4) and subgroup (B5-B6) displays. An individual on/off feature
supports applications other than main/sub-display
backlights, such as keypad, navigate key, side key
backlight, and RGB LEDs. The maximum backlight
current is programmable with an external resistor.
The maximum flash current is set by the AS2Cwire
interface, and the four flash LED outputs can be
turned on or off together (FL1-FL4) or as a group of
one (FL1) and three (FL2-FL4). The flash time can
either be controlled via the EN/SET pin or by an
2830.2007.09.1.0
internal programmable timer. Maximum flash time
is set by an external capacitor, CT. The RGB outputs can programmed with up to 4096 (AAT2830)
or 64 (AAT2831) different combinations of colors
and intensities. R, G, and B outputs are individually
controlled and can be used for alternative functions, such as keyboard lighting, "fun" lights, etc.
The RGB channels can be programmed with up to
4096 or 64 different combinations of colors and lighting intensities (brightness). R, G, and B channels are
individually controlled and can be used for alternative
functions, such as keyboard lighting, "fun" lighting, etc.
AS2Cwire Serial Interface
Each current channel input on the AAT2830/31 is
controlled by AnalogicTech's AS2Cwire serial digital
interface. The AS2Cwire interface uses the number of
rising edges on the EN/SET pin to address and load
the LED configuration registers. AS2Cwire latches
data or addresses after the EN/SET pin has been
held logic high for longer than TLAT (500µs).
Addresses and data are differentiated by the number
of EN/SET rising edges. Since the data registers are
4 bits each, the differentiating number of pulses is 24
9
AAT2830/31
800mA Total Display Solution
for Portable Devices
or 16, so that Address 0 is signified by 17 rising
edges, Address 1 by 18 rising edges, Address 2 by
19 rising edges, and so on. Data is set to any number of rising edges between 1 and including 16.
A typical write protocol consist of the following: first a
burst of EN/SET rising edges that identify/target a
particular address followed by EN/SET being held
logic high for the TLAT timeout period to latch the
address value in the registers, then another burst of
rising edges that signify data with the accompanying
TLAT timeout period to latch the data value in the registers. Once an address is set, then multiple writes
to the corresponding data register are allowed without having to write to the address for every change
in data values. When EN/SET is held low longer
than TOFF (500µs), the AAT2830/31 enters shutdown
mode operation and draws less than 1µA from the
input supply voltage. Data and address registers are
cleared (reset to 0) in shutdown mode operation.
Table 1a contains the AS2Cwire serial interface
address functionality when independent channel
control is disabled (independent channel control is
disabled by default) and conversely Table 1b contains the AS2Cwire serial interface address functionality when independent channel control is enabled.
EN/SET
Rising
Address Edges
0
1
17
18
2
3
4
5
6
7
8
9
10
11
12
15
19
20
21
22
23
24
25
26
27
28
29
32
Function
Backlight Current BL1-BL6
Main Backlight Current
BL1-BL4
Sub Backlight Current BL5-BL6
Low Backlight Current
Flash Current
Flash Channel Control
Flash Timer
Red Color
Green Color
Blue Color
RGB Intensity
RGB Mode
RGB Current
Backlight Independent
Channel Control
Address
EN/SET
Rising
Edges
Function
0
1
2
3
4
5
6
7
8
9
10
11
12
15
17
18
19
20
21
22
23
24
25
26
27
28
29
32
Not Applicable
Backlight Current BL1-BL6
BL1-BL4 On/Off Control
BL5-BL6 On/Off Control
Flash Current
Flash Channel Control
Flash Timer
Red Color
Green Color
Blue Color
RGB Intensity
RGB Mode
RGB Current
Not Applicable
Table 1b: AS2Cwire Serial Interface Addressing
with Independent Channel Control Enabled.
Backlight Current Control (Addresses 0-2)
The six channel backlight inputs, BL1-BL6, can
drive six individual LEDs to a maximum current of
30mA per channel. The EN/SET AS2Cwire serial
interface enables all channels and sets the current
magnitude as a percentage of the maximum current, programmed by an external resistor at BSET
(see Figure 5). To set the backlight current (minimum to maximum current) of the main display
LEDs (BL1-BL4), the user would write data to
Address 1. To set the backlight current for the sub
display LEDs (BL5-BL6), the user would write data
to Address 2. To write to both main display and sub
display LEDs (BL1-BL6) at the same time, the user
would write to Address 0.
Table 1a: AS2Cwire Serial Interface Addressing
with Independent Channel Control Disabled.
10
2830.2007.09.1.0
AAT2830/31
800mA Total Display Solution
for Portable Devices
Data BL % of BSET
1
2
3
4
5
6
7
8
Data
BL % of BSET
9
10
11
12
13
14
15
16
44
51
56
63
71
79
89
100
0
21
22
25
29
32
35
40
Table 2a: Addresses 0-2 with Independent
Channel Control Disabled, Backlight Current
Level.
Data BL % of BSET
1
2
3
4
5
6
7
8
Data
BL % of BSET
9
10
11
12
13
14
15
16
44
51
56
63
71
79
89
100
0
21
22
25
29
32
35
40
Data
BL1-BL4
Current On
BL5-BL6
Current On
BL %
of BSET
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
Yes
Yes
Yes
Yes
No
No
No
No
Yes
Yes
Yes
Yes
0
0
0
0
0.2
1.7
3.5
7.0
0.2
1.7
3.5
7.0
0.2
1.7
3.5
7.0
Table 3: Address 3 with Independent Channel
Control Disabled, Low-Backlight Current
Levels (RBSET = 280kΩ).
Table 2b: Address 1 with Independent
Channel Control Enabled, Backlight
Current Level.
Backlight Independent Channel Control
(Address 15)
120
IBLED (% of BSET)
For example, to toggle between 1.7% and 25% of the
maximum backlight current on all LEDs, write Data =
14 to Address 3 and Data 4 to Address 0. To set BL1BL4 to 25% and BL5-BL6 to 0.2%, write Data = 5 to
Address 3, and Data = 4 to Address 2.
100
80
60
40
20
0
1
2
3
4
5
6
7
8
9
10
11
12 13
14 15
16
Data Code
The AAT2830/31 can also individually control each
backlight channel. This mode allows the user to turn
on some or all of the channels in any desired combination. This control is achieved by changing the
functionality of the AS2Cwire registers. To enable
individual LED control mode, a user would write
Data 8 to Address 15. All channels that are enabled
must carry the same current, which is set using the
new functionality of Address 1 (see Table 2b).
Figure 1: Addresses 0-2 Backlight Current Level.
Low Backlight Current (Address 3)
In addition to the current levels set by Addresses 0,
1, and 2 (shown in Table 2a and Figure 1), there is
also a low backlight current level that can be set. To
set the low backlight current level, the user would
write data to Address 3, as shown in Table 3.
2830.2007.09.1.0
Data
Individual BL Control
8
On
Table 4: Address 15, Backlight Independent
Channel Control
11
AAT2830/31
800mA Total Display Solution
for Portable Devices
Data
BL6
BL5
BL4
BL3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Off
Off
Off
Off
Off
Off
Off
Off
On
On
On
On
On
On
On
On
Off
Off
Off
Off
On
On
On
On
Off
Off
Off
Off
On
On
On
On
Off
Off
On
On
Off
Off
On
On
Off
Off
On
On
Off
Off
On
On
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Table 5: Address 2 with Independent
Channel Control Enabled, BL3-BL6
On/Off Control.
Data
BL2
BL1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Off
Off
Off
Off
Off
Off
Off
Off
On
On
On
On
On
On
On
On
Off
Off
Off
Off
On
On
On
On
Off
Off
Off
Off
On
On
On
On
Table 6: Address 3 with Independent
Channel Control Enabled, BL1-BL2
On/Off Control.
With independent channel control enabled, the
functionality of Addresses 1, 2, and 3 will conform to
what is described in Tables 2b, 5, and 6. Also,
Addresses 0 and 15 are no longer applicable after
independent channel control has been enabled. As
indicated by the possible settings listed in the
tables, any combination of backlight channels can
be enabled and disabled. The original functionalities (Sub Backlight Current BL5-BL6 and Low
Backlight Current) of Addresses 2 and 3 are no
longer available unless the internal state machine
has been reset to default mode operation (when
EN/SET is logic low for >500µs). The functionality
of Addresses 7-12 are unmodified by the enabling of
independent channel control.
Flash/Movie Mode Operation
The flash current level is set via the serial interface
according to a logarithmic scale where each code
is 1.5dB lower than the previous code. By writing in
Address 4, a total flash current of 19mA to 150mA
can be programmed to each of the four flash output
channels (see Table 7 and Figure 3). For lower current applications, such as torch, flashlight, or movie
light, write to Address 5 to enable FL1 only, or FL2FL4 only (see Table 8). Higher flash currents can
be produced by combining one or more of the FL1FL4 flash current outputs.
Data
Flash Current (mA)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
150
130
114
99
86
75
65
57
50
43
38
33
28
25
22
19
Table 7: Address 4, Flash Current Level.
12
2830.2007.09.1.0
AAT2830/31
800mA Total Display Solution
for Portable Devices
Data
Address
THI
TLO
TLAT
EN/SET
1
2
17
18
1
0
Address
2...
n ≤ 16
1
DATA1
1
DATA0
1
n
Figure 2: AS2Cwire Serial Interface Timing Details.
160
140
IFLED (mA)
120
100
80
60
40
20
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
Data Code
Figure 3: Address 4, FL1-FL4 Flash
Current Level.
Data
FL1
FL2-FL4
1
2
3
4
Off
Off
On
On
Off
On
Off
On
Table 8: Address 5, Torch/Flashlight/Movie Mode
Control; All Channels ON when CT Enabled.
A timer function that enables the flash current sinks
for a programmed amount of time is incorporated in
the AAT2830/31. The on-time is programmed by
loading the timing register at Address 6 with a value
from 1 to 16 and by choosing a value for the external
timing capacitor, CT (see Table 9). When data is
latched into the Flash Timing Register, the flash current sinks are automatically enabled for the duration
of the programmed time and then disabled. The timing feature eliminates the need for an external controller to keep track of flash duration. This function
also serves as a protection feature to avoid thermal
damage to the flash LEDs because of software-related errors in or disconnection from an external processor. The flash section's safety timer will only be initiated if writing data to Address 6.
The flash time base T can be calculated by the following equation:
T = 10 · CT
Where, T is in seconds and CT is in µF.
For example, for a 0.1µF capacitor:
T = 10 · 0.1
= 1s
2830.2007.09.1.0
13
AAT2830/31
800mA Total Display Solution
for Portable Devices
Data
FL1-FL4 Flash On Time
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
16/16 x T
15/16 x T
14/16 x T
13/16 x T
12/16 x T
11/16 x T
10/16 x T
9/16 x T
8/16 x T
7/16 x T
6/16 x T
5/16 x T
4/16 x T
3/16 x T
2/16 x T
1/16 x T
Table 9: Address 6, Programmable Flash Timer
Duration; Time T is Determined by External
Capacitor, CT.
Activating the timer will automatically reset the
Flash ON/OFF control (Register 5).
respective LED by 128µs. The settings can be calculated as follows:
R = (DATA7 - 1) · 128μs
G = (DATA8 - 1) · 128μs
B = (DATA9 - 1) · 128μs
Where R, G, and B are the on-times of the respective LEDs and DATA7, DATA8, and DATA9 are the
data inputs into Registers 7, 8, and 9, respectively.
DATAN can be set to a value from 1 to 16 with the
default DATAN value equal to 1. Since the AAT2831
supports 64 color/brightness combinations, DATAN
can be set from 1 to 4.
Address 10: RGB Timebase Register - T
The overall period is set by the AAT2830/31's T register. Adjusting this register allows a user to adjust
how often the RGB LED sequence is repeated. The
longer the period, the smaller the effective duty cycle,
and thus RGB light intensity (brightness) is reduced.
The RGB period can be calculated using the following equation:
T = [(DATA10 - 1) · 3 + 15] · 128μs
RGB Control
The Red, Green, and Blue LED PWM timing, along
with the overall period, is controlled by five registers.
The current level for the RGB LEDs is controlled by
another register (Address 12) which makes it possible to change the peak currents from 33% up to
200% of the backlight maximum current set by
RBSET. A mode register (Address 11) sets the
method of update for the color and intensity registers. All registers are updated simultaneously or individually, depending on how the mode register is set.
If updated simultaneously, the color registers are
updated when the period register is updated. Up to
4096 different color/brightness combinations are programmable in the AAT2830 and 64 color/brightness
combinations are programmable in the AAT2831.
Address 7, 8, 9: RGB Color Registers
The AAT2830's RGB color registers store up to 16
levels of lighting intensity for a given color channel.
The first level (DATA = 1) is reserved for the off-state.
Every setting thereafter increases the on-time of the
14
Where T is the period of repetition and DATA10 is
the data input into Register 10. In the AAT2830,
DATA10 can be set to a value from 1 to 16, with the
default DATA10 value equal to 1. In the AAT2831,
DATA10 can be set from 1 to 4, with the default
DATA10 value equal to 1.
Please note that if the user sets the period to be
smaller than the combined on-times (R+G+B),
then the RGB sequence will automatically begin
again once time T has been reached, whether or
not all on-times have been completed.
Address 11: RGB Mode Register
The AAT2830/31's RGB mode register can have
one of two DATA11 values. If DATA11 is set to 1 (the
default), then each RGB LED on-time will be updated immediately after their respective register is set.
If DATA11 is set to 2, then as the user sets the Red,
Green, and Blue on-time registers, none of the
LEDs will be updated until the timebase register is
set. For example, if the user wants to set a certain
Red-Green-Blue combinations, the Red on-time
2830.2007.09.1.0
AAT2830/31
800mA Total Display Solution
for Portable Devices
can be programmed first, followed by the Green ontime, followed by the Blue on-time, and then the
RGB period T last. If DATA11 is set to 1, then after
the Red on-time is programmed the user will see
the Red LED turn on immediately. After the Green
on-time is programmed, the Red-Green color combinations will appear, etc. If DATA11 is set to 2, then
none of those intermediate colors will appear until
the RGB period register T has been set and loaded.
RGB LED Current Calculation
The average current in a particular color channel is
a function of the values in the R, G, B, T, and ISINK
registers, as follows:
IR = ISINK ·
G
T
B
IB = ISINK ·
T
IG = ISINK ·
Address 12: RGB Current Level Register, ISINK
The ISINK current level in the RGB LED can be
adjusted by writing data to Register 12. The maximum current is two times (200%) the maximum
backlight current set by RBSET (see Table 10). By
increasing or decreasing the current, the brightness
level can easily be changed for any particular color
combination.
Data
RGB Current as % of BSET
1
2
3
4
5
6
7
0
33
66
100
133
167
200
R
T
Shutdown
Since the channel backlight power returns are the
only power returns for all the LEDs, there is no
leakage current if all channels are disabled.
Applying a HIGH-to-LOW transition on the EN/SET
pin and holding LOW for at least TOFF (500µs) will
activate the AAT2830/31's shutdown mode. Data
and Address registers are cleared (reset to 0) during shutdown.
Table 10: Address 12, RGB Current Level
Register (ISINK).
R
Red
ISINK
ISINK
T
G
Green
ISINK
B
Blue
ISINK
Figure 4: RGB Diode Current Timing.
2830.2007.09.1.0
15
AAT2830/31
800mA Total Display Solution
for Portable Devices
Applications Information
Adjusting the Maximum Backlight LED
Current Level
The value of RBSET determines the maximum LED
current level for the backlight section. In the typical
application, selecting RBSET = 280kΩ results in a
maximum 30mA/channel LED current level.
The relationship between RBSET and the maximum
backlight current is illustrated graphically in Figure 5.
The AAT2830/31's LED current control circuits have
been optimized for full-scale current settings higher
than 15mA, RBSET > 550kΩ.
PLEDs VLED1 · ILED1 + ... + VLED4 · ILED4
=
PIN
VIN · IIN
η=
4 · VLEDX · ILEDX
; x = 1, 2, 3 or 4 and IIN = 4 · ILEDX
VIN · IIN
VLEDX
η= V
IN
Due to the very low 1X mode quiescent current, the
input current nearly equals the total output current
delivered to the LEDs. Further, the low resistance
bypass switch introduces a negligible voltage drop
from input to output.
The AAT2830/31 further maintains optimized performance and efficiency by detecting when the
input voltage is not sufficient to sustain the LED
bias current. The device automatically switches to
1.5X mode when the input voltage drops too low in
relation to the LED forward voltages.
45
40
35
IBLED (mA)
η=
30
25
20
15
10
5
0
100
200
300
400
500
600
700
800
900
1000
RBSET (kΩ
Ω)
Figure 5: Maximum Backlight LED
Current vs RBSET.
In 1.5X mode, the output voltage can be boosted to
1.5X the input voltage. The 1.5X conversion ratio
introduces a corresponding 0.5X increase in input
current. For ideal conversion, the 1.5X mode efficiency is given by:
η=
η=
Device Power Efficiency
The AAT2830/31's power conversion efficiency
depends on the charge pump mode of operation.
By definition, device efficiency is expressed as the
output power delivered to the LEDs divided by the
total input power consumed.
η=
PLEDs VLED1 · ILED1 + ... + VLED4 · ILED4
=
PIN
VIN · IIN
When the input voltage is sufficiently greater than
the LED forward voltages, the device optimizes
efficiency by operating in 1X mode. In 1X mode,
the device is working as a bypass switch and passing the input supply directly to the output. By simplifying the conditions such that the LEDs have uniform VF, the power conversion efficiency can be
approximated by:
16
PLEDs VLED1 · ILED1 + ... + VLED4 · ILED4
=
PIN
VIN · IIN
4 · VLEDX · ILEDX
; x = 1, 2, 3 or 4 and IIN = 1.5(4 · ILEDX)
VIN · IIN
VLEDX
η = 1.5V
IN
Similarly, when the input falls further, such that
1.5X mode can no longer sustain the LED bias currents, the AAT2830/31 will automatically switch to
2X mode. In 2X mode, the output voltage can be
boosted to 2X the input voltage. The 2X conversion
ratio introduces a corresponding 1X increase in
input current. For ideal conversion, the 2X mode
efficiency is given by:
η=
PLEDs VLED1 · ILED1 + ... + VLED4 · ILED4
=
PIN
VIN · IIN
η=
4 · VLEDX · ILEDX
; x = 1, 2, 3 or 4 and IIN = 2(4 · ILEDX)
VIN · IIN
VLEDX
η = 2V
IN
2830.2007.09.1.0
AAT2830/31
800mA Total Display Solution
for Portable Devices
LED Selection
PCB Layout
The AAT2830/31 is designed to drive high-intensity
white LEDs. It is particularly suitable for LEDs with
an operating forward voltage in the range of 4.2V
to 1.5V.
To achieve adequate electrical and thermal performance, careful attention must be given to the
printed circuit board (PCB) layout. In the worst-case
operating condition, the chip must dissipate considerable power at full load. Adequate heat-sinking
must be achieved to ensure intended operation.
The AAT2830/31 can also drive other loads that
have similar characteristics to white LEDs. For various load types, the AAT2830/31 provides a high
current, programmable, ideal constant current
channel/sink.
Capacitor Selection
Careful selection of the four external capacitors
CIN, C1, C2, and COUT are important because they
will affect turn-on time, output ripple, and transient
performance. Optimum performance will be
obtained when low equivalent series resistance
(ESR) ceramic capacitors are used. In general, low
ESR is defined as a resistance that is less than
100mΩ.
X7R and X5R ceramic capacitors are highly recommended over all other types of capacitors for
use with the AAT2830/31. For the input (CIN) and
output (COUT) capacitors, a 2.2µF or greater value
is recommended, and a 1µF or greater value is recommended for the flying (C1/C2) capacitors.
Ceramic capacitors offer many advantages over
their tantalum and aluminum electrolytic counterparts. A ceramic capacitor typically has very low
ESR, is lowest cost, has a smaller PCB footprint,
and is non-polarized. Low ESR ceramic capacitors
help maximize charge pump transient response.
Figures 7 and 8 illustrate an example PCB layout.
The bottom of the package features an exposed
metal pad. The exposed pad acts, thermally, to
transfer heat from the chip and, electrically, as a
ground connection.
The junction-to-ambient thermal resistance (θJA) for
the AAT2830/31 package can be significantly
reduced by following a couple of important PCB
design guidelines. The PCB area directly underneath the package should be plated so that the
exposed pad can be mated to the top layer PCB
copper during the reflow process. Multiple copper
plated thru-holes should be used to electrically and
thermally connect the AAT2830/31’s exposed pad
area to additional ground plane(s).
The chip ground is internally connected to both the
paddle and to the AGND and PGND pins. It is good
practice to connect the GND pins to the exposed
pad area with traces as shown in Figure 6.
The flying capacitors (C1 and C2), input capacitor
(C4), and output capacitor (C3) should be connected as close as possible to the IC. In addition to the
external passive components being placed as
close as possible to the IC, all traces connecting
the AAT2830/31 should be as short and wide as
possible to minimize path resistance and potential
coupling.
Pin #1
Figure 6: AAT2830/31 Package PCB Layout.
2830.2007.09.1.0
17
AAT2830/31
800mA Total Display Solution
for Portable Devices
Evaluation Board Layout
Figure 7: AAT2830/31 Evaluation Board
Component Side Layout.
Figure 8: AAT2830/31 Evaluation Board
Solder Side Layout.
Evaluation Board Schematic
VOUT
LXCL-PWF1
D1
D2
D3
D4
D5
D6
D8
DC+
VIN
R9 = 280K for
30mA/channel backlight
J1
R9
1
20
21
19
F2
F1
22
D6
PGND
EN/SET
VIN
17
D7
16
15
C1
14
13
1.0μF
C4
4.7μF
12
8
4
1
C2
1.0μF
11
7
3
2
R
C5
0.1μF
LXCL-PWF1
18
OUT
C1+
C2-
C1-
CT
C2+
AGND
B
6
F4
D1
10
5
D2
G
4
U1
AAT2830/31
F3
9
3
Optional footprints for
auxiliary lighting LEDs
BSET
D3
2
EN
D5
D4
24
C7
100μF
23
280K
optional 100μF
lab supply bypass
C3
2.2μF
RGB
R
G
B
Figure 9: AAT2830/31 Evaluation Board Schematic.
18
2830.2007.09.1.0
AAT2830/31
800mA Total Display Solution
for Portable Devices
R7
EN
220
J2
R8
100K
VIN
VIN
R1 R2 R3 R4 R5
1K 1K 1K 1K 1K
U2
SW1
SW2
1
2
3
4
VDD
GP5
GP4
GP3
VSS
GP0
GP1
GP2
8
7
6
5
C6
1μF
R6
330
PIC12F675
LED7
RED
SW3
SW4
SW5
Figure 9: AAT2830/31 Microcontroller Section Schematic.
2830.2007.09.1.0
19
AAT2830/31
800mA Total Display Solution
for Portable Devices
Options
Option
Flash
Backlight
RGB
Package
AAT2830
AAT2831
Y
Y
Y
Y
Y
Y
TQFN44-24
TQFN44-24
Function
Total Solution, 4096-Combination RGB
Total Solution, 64-Combination RGB
Ordering Information
Package
Marking1
Part Number (Tape and Reel)2
TQFN44-24
TQFN44-24
SUXYY
AAT2830IBK-T1
AAT2831IBK-T1
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means
semiconductor products that are in compliance with current RoHS standards, including
the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more
information, please visit our website at http://www.analogictech.com/pbfree.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
3. Contact factory for AAT2831 availability.
20
2830.2007.09.1.0
AAT2830/31
800mA Total Display Solution
for Portable Devices
Package Information
Pin 1 Identification
Chamfer 0.300 ×45°
0.255 ± 0.025
1
2.700 ± 0.050
4.000 ± 0.050
2.700 ± 0.050
Top View
0.000 −0.050
Bottom View
0.214 ± 0.036
0.750 ± 0.050
4.000 ± 0.050
Pin 1 Dot By Marking
0.500 BSC
0.400 ± 0.050
TQFN44-24
Side View
All dimensions in millimeters.
© Advanced Analogic Technologies, Inc.
AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work
rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Except as provided in AnalogicTech’s terms and conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent,
copyright or other intellectual property right. In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the
customer to minimize inherent or procedural hazards. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty.
Specific testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated.
All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders.
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Phone (408) 737- 4600
Fax (408) 737- 4611
2830.2007.09.1.0
21