AAT2863_202507A.pdf

DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
General Description
Features
The AAT2863 is a highly integrated charge pump-based
lighting management unit with four linear regulators optimized for single-cell lithium-ion/polymer systems. The
charge pump provides power for all LED outputs and
multiple LED configurations are available. The LED control current sinks can be programmed up to 30mA each
and the two AUX LED outputs can be programmed up to
60mA each.
• Input Voltage Range: 2.7V to 5.5V
• Tri-Mode Charge Pump
• Drives up to Six LEDs
• Programmable Backlight Current via I2C Interface
▪ 30mA Maximum Current per Channel
▪ 60mA Maximum Current per Auxiliary Channel
▪ 32 Linear Current Settings
• Independent Main/Sub Settings
▪ Main Backlight BL1-BL6
▪ Main Backlight BL1-BL5 + 1 AUX
▪ Main Backlight BL1-BL4 + 2 Sub (default)
▪ Main Backlight BL1-BL4 + 2 AUX
• PWM Control
▪ 60Hz to 100kHz
• 600k to 1.2MHz Switching Frequency
• Automatic Soft Start
•I2C Selectable Drivers
• Four Linear Regulators
▪ 1 x 300mA Output LDO
▪ 3 x 150mA Output LDOs
•I2C Programmable Output Voltage from 1.2V to 3.3V
• Output Auto-Discharge for Fast Shutdown
• Built-In Thermal Protection
• -40°C to 85°C Temperature Range
• TQFN34-24 Package
An I2C serial digital interface is used to enable, disable,
and set the LED current to one of 32 levels. In addition
the 6 LED channels, including two AUX channels, can be
configured between MAIN/SUB. High power auxiliary
channels' current matching is better than 5% for
matched LED color and brightness. A separate PWM
input allows the LED current sinks to be modulated at
high frequencies as required by CABC or Dynamic backlight power saving schemes.
The AAT2863 also provides four high-performance lownoise MicroPower™ low dropout (LDO) linear regulators.
The regulators are enabled and their output voltages are
I2C programmable. One MicroPower™ LDO has a load current rating of 300mA and three LDOs have load current
ratings of 150mA. Single LDO operating current is less
than 80µA, making the AAT2863 ideal for battery-operated applications.
The AAT2863 is available in a Pb-free, space-saving
TQFN34-24 package and operates over the -40°C to
85°C ambient temperature range.
Applications
• Camera Enabled Mobile Devices
• Digital Still Cameras
• Multimedia Mobile Phones
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202507A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • November 2, 2012
1
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Typical Application Circuit
VBAT
3.6V
CF1
1µF
CF2
1µF
C1+ C1IN
C2+ C2OUT
CIN
4.7µF
VOUT
WLEDs
COUT
2.2µF
IN
PWM
ENABLE
SDA
I2C Serial
Interface SCL
PWM
EN
BL1
BL2
BL3
BL4
BL5/AUX1
BL6/AUX2
SDA
LDOA
SCL
AAT2863
LDOB
VOUTA
at 300mA
COUTA
2.2µF
VOUTB
at 150mA
COUTB
2.2µF
LDOC
VOUTC
at 150mA
COUTC
2.2µF
LDOD
VOUTD
at 150mA
COUTD
2.2µF
AGND
2
PGND
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202507A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • November 2, 2012
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Pin Descriptions
Pin #
Symbol
Function
1
OUT
O
2
C2+
I
3
4
SDA
SCL
I
I
5
EN
I
6
7
AGND
IN
G
PI
8
LDOC
O
9
LDOB
O
10
LDOA
O
11
LDOD
O
12
BL1
O
13
BL2
O
14
BL3
O
15
BL4
O
18
BL6/
AUX2
BL5/
AUX1
N/C
19
PWM
I
20
21
22
PGND
C2C1-
G
I
I
23
IN
PI
24
C1+
I
16
17
EP
O
O
Description
Charge pump output. OUT supplies current to the backlight LEDs. Connect the backlight and flash
LED anodes to OUT. Bypass OUT to PGND with a 2.2μF or larger ceramic capacitor as close to the
AAT2863 as possible.
Positive terminal of charge pump capacitor 2. Connect the 1μF charge pump capacitor 2 from C2+
to C2-.
I2C serial data input. SDA is the data input of the I2C serial interface. Drive SDA with the I2C data.
I2C serial clock input. SCL is the clock input of the I2C serial interface. Drive SCL with the I2C clock.
Programming enable input. When EN is strobed high, the backlight and LDO registers can be programmed via the I2C serial interface. When EN is strobed low, all backlight and LDO outputs are
turned off and the backlight and LDO registers are reset to their default (POR) values and forces all
LDO outputs to 0V.
Analog ground. Connect to PGND as close to the AAT2863 as possible
Input power pin for all four LDOs. Connect Pin 7 to Pin 23 with as short a PCB trace as practical.
LDO C 150mA regulated voltage output. Bypass LDOA to AGND with a 2.2μF or larger ceramic
capacitor as close to the AAT2863 as possible.
LDO B 150mA regulated voltage output. Bypass LDOB to AGND with a 2.2μF or larger capacitor as
close to the AAT2863 as possible.
LDO A 300mA regulated voltage output. Bypass LDOC to AGND with a 2.2μF or larger capacitor as
close to the AAT2863 as possible.
LDO D 150mA regulated voltage output. Bypass LDOD to AGND with a 2.2μF or larger ceramic
capacitor as close to the AAT2863 as possible.
Backlight LED 1 current sink. BL1 controls the current through backlight LED 1. Connect the cathode of backlight LED 1 to BL1. If not used, connect BL1 to OUT.
Backlight LED 2 current sink. BL2 controls the current through backlight LED 2. Connect the cathode of backlight LED 2 to BL2. If not used, connect BL2 to OUT.
Backlight LED 3 current sink. BL3 controls the current through backlight LED 3. Connect the cathode of backlight LED 3 to BL3. If not used, connect BL3 to OUT.
Backlight LED 4 current sink. BL4 controls the current through backlight LED 4. Connect the cathode of backlight LED 4 to BL4. If not used, connect BL4 to OUT.
Backlight or auxiliary LED 6 current sink. BL6 controls the current through backlight LED 6. Connect
the cathode of backlight LED 6 to BL6. If not used, connect BL6 to OUT.
Backlight or auxiliary LED 5 current sink. BL5 controls the current through backlight LED 5. Connect
the cathode of backlight LED 5 to BL5. If not used, connect BL5 to OUT.
No connection.
PWM input pin. Apply a PWM signal of varying duty cycle to modulate the LED current on BL1, BL2,
BL3, BL4, BL5 & BL6 (Default). PWM frequency can vary up to 100kHz. The LED current maximum
will be set at the default setting if no programming is applied. If not used, connect PWM to IN.
Power ground. Connect to AGND as close to the AAT2863 as possible.
Negative terminal of charge pump capacitor 2.
Negative terminal of charge pump capacitor 1.
Power input. Connect IN to the input source voltage. Bypass IN to PGND with a 4.7μF or larger
ceramic capacitor as close to the AAT2863 as possible.
Positive terminal of charge pump capacitor 1. Connect the 1μF charge pump capacitor 1 from C1+
to C1-.
Exposed paddle (bottom) Connect to PGND/AGND as close to the AAT2863 as possible.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202507A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • November 2, 2012
3
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Pin Configurations
TQFN34-24
(Top View)
PGND
C2C1IN
C1+
24
OUT
C2+
SDA
SCL
EN
AGND
IN
23
22
21
20
1
19
2
18
3
17
4
16
5
15
6
14
7
13
8
9
10
11
PWM
N/C
BL5/AUX1
BL6/AUX2
BL4
BL3
BL2
12
BL1
LDOD
LDOA
LDOB
LDOC
Programmable Current Sink Options
Main Channels
Sub Channels
Aux1 Channel
Aux2 Channel
6
5
4*
4
0
1
2*
0
0
0
0*
1
0
0
0*
1
* Default.
Absolute Maximum Ratings1
TA = 25°C unless otherwise noted.
Symbol
Description
IN, OUT, BL1, BL2, BL3, BL4, BL5/AUX1, BL6/AUX2 Voltage to PGND and AGND
C1+, C2+ Voltage to PGND and AGND
C1-, C2-, LDOA, LDOB, LDOC, LDOD, EN, PWM, SDA, SCL Voltage to PGND and AGND
PGND Voltage to AGND
Value
Units
-0.3 to 6.0
-0.3 to VOUT + 0.3
-0.3 to VIN + 0.3
-0.3 to 0.3
V
Thermal Information2,3
Symbol
ΘJA
PD
TJ
TLEAD
Description
Thermal Resistance
Maximum Power Dissipation
Operating Junction Temperature Range
Maximum Soldering Temperature (at Leads)
Value
50
2
-40 to 150
300
Units
O
C/W
W
°C
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent 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. Derate 20 mW/°C above 25°C ambient temperature.
3. Mounted on a FR4 circuit board.
4
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202507A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • November 2, 2012
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Electrical Characteristics1
VIN = 3.6V; CIN = COUT = 2.2μF; C1 = C2 = 1µF; TA = -40°C to +85°C, unless otherwise noted. Typical values are
TA = 25°C.
Symbol
VIN
IIN
Description
IN Operating Current
IIN(SHDN)
IN Shutdown Current
Over-Temperature Shutdown
TSD
Threshold
Over-Temperature Shutdown
TSD(HYS)
Hysteresis
Charge Pump Section
VOUT
OUT Output Voltage
IOUT(MAX)
OUT Maximum Output Current
BL1-BL6 Charge Pump Mode
VIN(TH_H, BL)
Transition Hysteresis
fOSC
Charge Pump Oscillator Frequency
tCP(SS)
Charge Pump Soft-start Time
BL1-BL4, BL5/AUX1, BL6/AUX2 LED Drivers
tLED(SU)
LED Output Current Start-up Time
IAUX[1/2](MAX)
IAUX[1/2](DATA13)
ΔIAUX[1/2]/
IAUX(AVG)
IBL_(MAX)
IBL_(DATA29)
ΔIPWM[BL1-BL6]/
IPWM[BL1-BL6]
VBL_(TH)
Conditions
Min
IN Operating Voltage Range
AUX Maximum Current
AUX Current
AUX1/AUX2 Current Matching
BL1-BL6 Maximum Current
BL1-BL6 Current
BL1-BL6 PWM Current Accuracy
BL1-BL6 Charge Pump Transition
Threshold
Typ
Max
Units
0.15
5.5
0.20
V
mA
3.0
mA
5.0
mA
225
µA
80
µA
1.0
µA
2.7
1X Mode; 3.0 ≤ VIN ≤ 5.5; LDOs OFF; No Load
1.5X Mode; 3.0 ≤ VIN ≤ 5.5; LDOs OFF; Charge
Pump ON; No Load
2X Mode; 3.0 ≤ VIN ≤ 5.5; LDOs OFF; Charge
Pump ON; No Load
2.7 ≤ VIN ≤ 5.5; All LDOs ON; Charge Pump
OFF; No Load
2.7 ≤ VIN ≤ 5.5; Any One LDO ON; Charge
Pump OFF; No Load
EN= GND
150
°C
15
°C
VIN = 3.0V, VOUT = 4.0V
5.2
800
V
mA
EN/SET = IN; VIN – VF = 1V
150
mV
TA = 25°C,
TA = 25°C,
TA = 25°C,
TA = 25°C,
TA = 25°C
Address
Address
Address
Address
07h
07h
07h
07h
Data=00
Data=10
Data=20
Data=30
(0000
(0001
(0010
(0011
OUT: 0V to IN
Address 05h Data=E0(1110 0000)
Address 06h Data=E0(1110 0000)
Address 05h Data=AC(1010 1100)
Address 06h Data=AC(1010 1100)
Address 05h Data=E0(1110 0000)
Address 06h Data=E0(1110 0000)
Address 03h, Data=E0 (1110 0000)
Address 03h, Data=FD (1111 1101)
Duty Cycle = 10%, FPWM = 10kHz,
VIN - VF = 1.5V
Address 03h, Data=E0 (1110 0000)
0000)
0000)
0000)
0000)
0.6
0.8
1.2
0.6
100
MHz
µs
20
54
60
µs
66
18.4
27
1.75
30
1.94
mA
mA
5
%
33
2.13
mA
mA
2.5
%
180
mV
1. The AAT2863 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.
3.VDO[A/B/C/D] is defined as VIN – LDO[A/B/C/D] when LDO[A/B/C/D] is 98% of nominal.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202507A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • November 2, 2012
5
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Electrical Characteristics (continued)1
VIN = 3.6V; CIN = COUT = 2.2μF; C1 = C2 = 1µF; TA = -40°C to +85°C, unless otherwise noted. Typical values are TA =
25°C.
Symbol
Description
Linear Regulators
ΔVOUT[A/B/C,D]/ LDOA, LDOB, LDOC, LDOD Output
VOUT[A/B/C,D]
Voltage Tolerance
IOUT[A](MAX)
LDOA Maximum Load Current
VOUT[A](DO)
LDOA Dropout Voltage3
LDOB, LDOC, LDOD Maximum Load
IOUT[B/C,D](MAX)
Current
VOUT[B/C,D](DO) LDOB, LDOC, LDOD Dropout Voltage3
∆VOUT/
Line Regulation
VOUT*∆VIN
LDOA, LDOB, LDOC, LDOD Power
PSRR[A/B/C,D]
Supply Rejection Ratio
LDOA, LDOB, LDOC, LDOD AutoROUT_(DCHG)
Discharge Resistance
I2C Logic, PWM Input and Control Interface
SDA, SCL, PWM, EN Input Low
VIL
Threshold
SDA, SCL, PWM, EN Input High
VIH
Threshold
VOL
SDA Output Low Voltage
IIN
SDA, SCL, EN Input Leakage Current
fPWM
PWM input Frequency Range
fSCL
SCL Clock Frequency
tLOW
SCL Clock Low Period
tHIGH
SCL Clock High Period
tHD_STA
Hold Time START Condition
tSU_STA
Setup Time for Repeat START
tSU_DAT
SDA Data Setup Time
tHD_DAT
SDA Data HOLD Time
tSU_STO
Setup Time for STOP Condition
Bus Free Time Between STOP and
tBUF
START Conditions
Conditions
Min
IOUT = 1mA to 150mA; TA = 25°C
IOUT = 1mA to 150mA; TA = -40°C to +85°C
-1.5
-3.0
300
VOUT[A/B/C/D] ≥ 3.0V; IOUT = 300mA
Typ
60
Max
Units
1.5
3.0
%
%
mA
mV
150
150
VOUT[A/B/C/D] ≥ 3.0V; IOUT = 150mA
mA
60
VIN = (VOUT[A/B/C/D] + 1V) to 5V
IOUT[A/B/C/D] = 10mA, 1kHz
IPULLUP = 3mA
VSDA = VSCL = VPWM = VLED_SEL = VLDO_SEL = 5V
mV
0.09
%/V
50
dB
20
Ω
2.7V ≤ VIN ≤ 5.5V
2.7V ≤ VIN ≤ 5.5V
150
0.4
1.4
-1
0.6
0
1.3
0.6
0.6
0.6
100
0
0.6
V
V
0.4
1
100
400
0.9
1.3
V
µA
kHz
kHz
µs
µs
µs
µs
ns
µs
µs
µs
1. The AAT2863 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.
6
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202507A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • November 2, 2012
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
I2C Interface Timing Details
SDA
TSU_DAT
TLOW
THD_STA
TBUF
SCL
THD_STA
THD_DAT
THIGH
TSU_STA
TSU_STO
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202507A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • November 2, 2012
7
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Typical Characteristics
Backlight Efficiency vs. Input Voltage
Backlight Current Matching vs. Temperature
Backlight Output Current (mA)
(VIN = 3.6V; 30mA/ch)
100
90
Efficiency (%)
80
70
60
50
40
30
20
10
0
2.7
30mA/ch, VF = 3.25V
20.32mA/ch, VF = 3.14V
14.52mA/ch, VF = 3.05V
4.84mA/ch, VF = 2.85V
3.1
3.5
3.9
4.3
4.7
5.1
Input Voltage (V)
5.5
33
BL1
BL2
BL3
BL4
AUX1
AUX2
32
31
30
29
28
27
-40
-15
(VIN = 3.5V; 30mA/ch)
SDA
(2V/div)
0V
VOUT
(2V/div)
0V
VSINK
(2V/div)
0V
VSINK
(2V/div)
0V
IIN
(100mA/div)
0A
IIN
(100mA/div)
0A
Time (200µs/div)
60
Turn On to 1.5x Mode Backlight
(VIN = 4.5V; 30mA/ch)
VOUT
(2V/div)
35
Temperature (°C)
Turn On to 1x Mode Backlight
SDA
(2V/div)
10
Time (200µs/div)
Turn On to 2x Mode Backlight
(VIN = 3.2V; 30mA/ch)
SDA
(2V/div)
VOUT
(2V/div)
VSINK
(2V/div)
IIN
(200mA/div)
0V
0V
0A
Time (200µs/div)
8
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
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85
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Typical Characteristics
Charge Pump Output Turn On Characteristic
Turn Off from 1.5x Mode Backlight
(VIN = 3.6V; ILED = 0mA; COUT = 2.2µF)
(VIN = 3.5V; 30mA/ch)
0V
VEN (top) (V)
VDIODE
(2V/div)
4.0
0V
2.0
0.0
4.0
3.0
2.0
1.0
IIN
(200mA/div)
0.0
Charge Pump Output
(bottom) (V)
VEN
(2V/div)
0A
Time (200µs/div)
Time (50µs/div)
0
50
0
-50
Time (500ns/div)
10
0
20
10
0
-10
-20
Time (500ns/div)
LDO B/C/D Output Voltage vs. Temperature
(VIN = 3.6V; ILDO = 0mA)
(VIN = 3.6V; ILDO = 0mA)
1.5
LDOB/C/D Output
Voltage Deviation (%)
1.5
1
0.5
0
-0.5
VOUT = 3.3V
VOUT = 1.2V
-1
-1.5
-40
20
LDO A Output Voltage vs. Temperature
LDOA Output Voltage Deviatoin (%)
Input Voltage (AC coupled)
(top) (mV)
10
(VIN = 3.0V; 30mA/ch Backlight; 2x Mode;
COUT = 2.2µF; fOSC = 1.2MHz)
Charge Pump Output Voltage
(AC coupled) (bottom) (mV)
20
Operating Characteristic
Charge Pump Output Voltage
(AC coupled) (bottom) (mV)
Input Voltage (AC coupled)
(top) (mV)
Operating Characteristic
(VIN = 3.3V; 30mA/ch Backlight; 1.5x Mode;
COUT = 2.2µF; fOSC = 1.2MHz)
-15
10
35
Temperature (°C)
60
85
1
0.5
0
-0.5
VOUT = 3.3V
VOUT = 1.2V
-1
-1.5
-40
-15
10
35
60
85
Temperature (°C)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202507A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • November 2, 2012
9
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Typical Characteristics
LDO B/C/D Load Regulation
(VIN = 3.6V)
1.5
(VIN = 3.6V)
1.5
VOUT = 3.3V
VOUT = 1.2V
1.0
LDO B/C/D Output
Voltage Deviation (%)
LDO Output Voltage Deviation (%)
LDO A Load Regulation
0.5
0.0
-0.5
-1.0
-1.5
0.1
1
10
100
Load Current (mA)
0.5
0.0
-0.5
-1.0
-1.5
1000
0.1
LDO Output Deviation (%)
LDO Output Deviation (%)
VOUT = 3.3V
VOUT = 1.2V
1.0
0.5
0.0
-0.5
-1.0
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Load Current (mA)
LDO A Load Transient Response
VLDOA
(100mV/div)
10
(ILDO = 10mA)
1.0
0.5
0.0
-0.5
VOUT = 3.3V
VOUT = 1.8V
-1.0
-1.5
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Load Current (mA)
LDO B/C/D Load Transient Response
(ILDO = 10mA to 200mA; VIN = 3.6V; VOUT = 1.8V; CLDO = 2.2µF)
200
200
ILDOB/C/D
(200mA/div)
0
1.9
0
1.9
1.8
VLDOB/C/D
(100mV/div)
1.7
Time (10µs/div)
1000
1.5
(ILDO = 10mA to 200mA; VIN = 3.6V; VOUT = 1.8V; CLDO = 2.2µF)
ILDOA
(200mA/div)
100
Load Current (mA)
VOUT = 1.8V
VOUT = 3.3V
1.5
10
LDO B/C/D Line Regulation
(ILDO = 10mA)
2.7
1
LDO A Line Regulation
-1.5
VOUT = 3.3V
VOUT = 1.2V
1.0
1.8
1.7
Time (20µs/div)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202507A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • November 2, 2012
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Typical Characteristics
EN, SDA, SCL Input Low Threshold Voltage
vs. Input Voltage
1.4
1.2
1.3
1.1
VEN(L), VSDA(L), VSCL(L) (V)
VEN(H), VSDA(H), VSCL(H) (V)
EN, SDA, SCL Input High Threshold Voltage
vs. Input Voltage
1.2
1.1
1.0
0.9
0.8
0.7
-40°C
25°C
85°C
0.6
0.5
0.4
2.7 2.9 3.1 3.3
3.5 3.7 3.9 4.1 4.3 4.5
1.0
0.9
0.8
0.7
0.6
0.5
0.3
0.2
2.7 2.9 3.1 3.3
4.7 4.9 5.1 5.3 5.5
Input Voltage (V)
(VOUTA = 3.3V)
3.7
IOUT = 150mA
IOUT = 200mA
IOUT = 250mA
IOUT = 300mA
Output Voltage (V)
Output Voltage (V)
IOUT = 0mA
IOUT = 10mA
IOUT = 50mA
IOUT = 100mA
3.1
2.8
2.5
2.2
3.4
3.1
2.8
IOUT = 0mA
IOUT = 10mA
IOUT = 50mA
IOUT = 100mA
2.5
2.2
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
Input Voltage (V)
2.7
2.8
2.9
3.3
2.8
2.5
2.2
2.8
2.9
3.0
3.1
3.2
3.3
Input Voltage (V)
3.4
3.5
3.6
3.5
3.6
3.4
3.1
IOUT = 0mA
IOUT = 10mA
IOUT = 50mA
IOUT = 100mA
IOUT = 150mA
2.8
2.5
2.2
2.7
3.4
3.7
Output Voltage (V)
3.1
3.2
(VOUTA = 3.3V)
IOUT = 0mA
IOUT = 10mA
IOUT = 50mA
IOUT = 100mA
IOUT = 150mA
3.4
3.1
LDO B/C/D Dropout Characteristics
(VOUTA = 2.8V)
3.7
3.0
IOUT = 150mA
IOUT = 200mA
IOUT = 250mA
IOUT = 300mA
Input Voltage (V)
LDO B/C/D Dropout Characteristics
Output Voltage (V)
4.7 4.9 5.1 5.3 5.5
LDO A Dropout Characteristics
(VOUTA = 2.8V)
3.4
3.5 3.7 3.9 4.1 4.3 4.5
Input Voltage (V)
LDO A Dropout Characteristics
3.7
-40°C
25°C
85°C
0.4
3.7
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
Input Voltage (V)
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11
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Functional Block Diagram
C1+ C1- C2+ C2-
1x/1.5x/2x
Tri-Mode
Charge Pump
IN
IN
OUT
MAIN
BL1
EN
PWM
SDA
SCL
BL2
I2C Serial
Interface
and PWM
Control
BL3
Constant
Current Sink
Control Logic
BL4
AUX1/BL5
AUX1
AUX2/BL6
AUX2
300mA Linear Regulator
LDOA
LDOA
150mA Linear Regulator
LDOB
LDOB
150mA Linear Regulator
LDOC
LDOC
150mA Linear Regulator
LDOD
LDOD
AGND
Functional Description
The AAT2863 is a highly integrated white LED backlight
driver with four LDO regulators intended for applications
in portable products such as cell phone handsets. A multimode 1x/1.5x/2x fractional charge pump provides LED
backlight power from a 2.7V to 5.5V input voltage
source. The white backlight LED current (brightness) is
then controlled by dedicated programmable constant
current sinks. Three 150mA LDO regulators and one
300mA LDO regulator are powered from the same input
12
PGND
and produce regulated output voltages between 1.2V
and 3.3V. Control of the LEDs and the LDO output voltages is through an industry standard I2C serial interface
for easy programming and system control.
LED Drivers
The AAT2863 drives up to six backlight LEDs up to 30mA
each. The LEDs are driven from a multimode fractional
charge pump to insure that constant current is maintained for all possible LED forward voltage over the
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
entire battery voltage range. The charge pump automatically switches from 1x, to 1.5x, to 2x modes and
back to maintain the LED current while minimizing power
loss for high efficiency. The charge pump operates at the
high 1MHz switching frequency allowing the use of small
1μF ceramic capacitors.
Depending on the battery voltage and LED forward voltage, the charge pump drives the LEDs directly from the
input voltage (1x or bypass mode) or steps up the input
voltage by a factor of 1.5 (1.5x mode) or 2 (2x mode).
The charge pump requires only two tiny 2.2μF ceramic
capacitors, making a more compact solution than an
inductor-based step-up converter solution. Each individual LED is driven by a current sink to GND, allowing
individual current control with high accuracy over a wide
range of input voltages and LED forward voltages while
maintaining high efficiency.
The charge pump is controlled by the voltage across the
LED current sinks. When any one of the active backlight
current sink voltages drops below 150mV, the charge
pump will switch to the next higher mode (from 1x to
1.5x or from 1.5x to 2x mode) to maintain sufficient LED
voltage for constant LED current. The AAT2863 continuously monitors the LED forward voltages and uses the
input voltage to determine when to reduce the charge
pump mode for better efficiency. There is also a 500mV
mode-transition hysteresis that prevents the charge
pump from oscillating between modes.
LED Current Control
LED backlight current is programmed and controlled
through the I2C serial interface as is the fade in/out function. The constant current sinks can be set between 0.5
and 30mA in approximate 1mA steps. Refer to the constant current sink I2C serial interface programming table
for detailed programmable current levels.
PWM Controlled Dimming
As an alternative to digital dimming via the I2C interface,
the AAT2863 also provides an additional PWM dimming
input pin, which allows the user to control BL1-BL6 or
the main BL1-BL4 and sub BL5-BL6 independently. The
PWM signal will modulate the LED current set by the I2C
interface programming, making the AAT2863 compatible
with various content adjusted backlight control (CABC)
and ambient light sensor (ALS) auxiliary dimming control
systems. The useable input PWM frequencies frequency
range for this device is 600Hz to 100kHz. The constant
current sinks are proportional to the duty cycle of the
PWM signal.
Fade In/Fade Out Function
An LED current sink fade in/fade out function is provided
for smooth turn on and turn off dimming of the backlight
LEDs. This function is enabled and disabled through the
I2C interface. Additionally, the LED Fade function can be
applied to the main, sub or both backlights. There are
four user selectable fade in/out times available.
LDO Regulators
The AAT2863 includes four low dropout (LDO) linear
regulators. LDO regulator A has a 300mA output current
capability and LDO regulators B, C and D can provide up
to 150mA of load current. These regulators are powered
from the battery and produce a fixed output voltages set
through the I2C serial interface. The output voltage of
any LDO regulator can be independently set to one of 16
output voltages between 1.2V and 3.3V. The LDO regulators can also be turned on/off through the I2C serial
interface.
The LDO regulators require only a small 2.2μF ceramic
output capacitor for stability. If improved load transient
response is required, larger-valued capacitors can be
used without stability degradation.
I2C Serial Interface
The AAT2863 uses an I2C serial interface to set the LED
currents, the LDO on/off and output voltage, as well as
other housekeeping functions. The I2C interface takes
input from a master device while the AAT2863 acts as a
target to the master.
The I2C protocol uses two open-drain inputs; SDA (serial data line) and SCL (serial clock line). Both inputs
require an external pull up resistor, typically to the input
voltage. The I2C protocol is bidirectional and allows target devices and masters to both read and write to the
bus. The AAT2863 only supports the write protocol and
therefore the Read/Write bit must always be set to “0”.
Figure 1 shows the typical transmission protocol.
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
start
w
msb Chip Address lsb
ack
msb Register Add lsb
ack
msb DATA lsb
ack
stop
SCL
SDA
start
AAT2863
Device Address Id = 60 h
w
ack
Addr =00h
ack
Address = 00 h Data = 06h
ack
stop
Figure 1: Typical I2C Timing Diagram.
I2C Serial Interface Protocol
START and STOP Conditions
The I2C serial interface protocol is shown in Figure 1.
Devices on the bus can be either master or target devices. Both master and target devices can both send and
receive data over the bus, with the difference being that
the master device controls all communication on the
bus. The AAT2863 acts as a target device on the bus and
is only capable of receiving data and does not transmit
data over the bus.
START and STOP conditions are always generated by the
master. Prior to initiating a START, both the SDA and SCL
pin are inactive and are pulled high through external pullup resistors. As shown in Figure 1, a START condition is
when the master pulls the SDA line low and, after the
start condition hold time (tHT_STA), the master strobes the
SCL line low. A START condition acts as a signal to devices on the bus that the device producing the START condition is active and will be communicating on the bus.
The I2C communications begins by the master making a
START condition. Next the master transmits the 7-bit
device address and a Read/Write bit. Each target device
on the bus has a unique address. The AAT2863 device
address is 60h.
If the address transmitted by the master matches the
device address, the target device transmits an Acknowledge
(ACK) signal to indicate that it is ready to receive data.
Since the AAT2863 only reads from the master, the Read/
Write bit must be set to “0”. Next, the master transmits
the 8-bit register address, and the target device transmits
an ACK to indicate that it received the register address.
Next, the master transmits the 8-bit data word, and again
the target device transmits an ACK indicating that it
received the data. This process continues until the master
is finished writing to the target device at which time the
master generates a STOP condition.
14
A STOP condition, as shown in Figure 1, is when SCL
changes from low to high followed after the STOP condition setup time (tSU_STO), by an SDA low-to-high transition. The master does not issue an ACK and releases SCL
and SDA.
Transferring Data
Addresses and data are sent with the most significant bit
first transmitted and the least significant bit transmitted
last. After each address or data transmission, the target
device transmits an ACK signal to indicate that it has
received the transmission. The ACK signal is generated
by the target after the master releases the SDA data line
by driving SDA low.
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
STOP
START
SDA
SDA
SCL
SCL
THD_STA
TSU_STO
Figure 2: I2C STOP and START Conditions;
START: A High “1” to Low “0” Transition on the SDA Line While SCL is High “1”
STOP: A Low “0” to High “1” Transition on the SDA Line While SCL is High “1”.
SCL
1
2
3
4
5
6
7
MSB
SDA
A6
8
9
LSB
A5
A4
A3
A2
A1
A0
R/W
ACK
Device Address
Figure 3: I2C Address Bit Map;
7-bit Slave Address (A6-A0), 1-bit Read/Write (R/W), 1-bit Acknowledge (ACK).
SCL
1
2
3
4
5
6
7
MSB
SDA
D7
8
9
LSB
D6
D5
D4
D3
D2
D1
D0
ACK
Register Address /
Data
Figure 4: I2C Register Address and Data Bit Map;
8-bit Data (D7-D0), 1-bit Acknowledge (ACK).
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Application Information
Backlight Control Registers
The AAT2863 has five backlight registers:
I2C Serial Programmed Registers
• REG3 (I2C address 03h) controls the MAIN backlight.
• REG4 (I2C address 04h) controls the SUB backlight.
• REG5 (I2C address 05h) controls the auxiliary AUX1
backlight.
• REG6 (I2C address 06h) controls the auxiliary AUX2
backlight.
• REG7 (I2C address 07h) controls the MAIN, SUB fade
in/out function.
The AAT2863's I2C programming registers are listed in
Table 1. There are eight registers: five for the backlight
LED control, and three to control the four LDO regulators.
All backlight channels can be easily configured in many
different ways through the I2C inerface. The default
assignment for the drivers is four backlight for main, two
backlight for sub, and two extra that can be applied to
main, sub, or auxiliary. All eight backlights can be driven
to the same current level by writting the MEQS = 1
option in REG3. The MAIN and SUB backlights can be
programmed independently to one of 32 levels described
in Table 2.
Table 3 describes the floor current per channel for the
fade-in and fade-out functions. In fade-out sequence floor
will be the final current that will continue to be present
until the Main, Sub or Aux1,2 channels are disabled by
writing MAIN_ON=0 to REG3, SUB_ON=0 to REG4, A1_
ON=0 to REG5, and/or A2_ON=0 to REG6. In fade-in
sequence floor is the direct current all channels will be
turned on by writing MAIN_ON=1 to REG3, SUB_ON=1 to
REG4, A1_ON=1 to REG5, and/or A2_ON=1 to REG6.
Register
Number
Hex
Code
Function
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
LDOA[3]
LDOA[2]
LDOA[1]
LDOA[0]
LDOB[3]
LDOB[2]
LDOB[1]
LDOB[0]
LDOC[2]
LDOC[1]
LDOC[0]
LDOD[3]
LDOD[2]
LDOD[1]
LDOD[0]
REG0
00h
LDO A & B Output
Voltage Control
REG1
01h
LDO C & D Output
Voltage Control
LDOC[3]
REG2
02h
LDO EN CONTROL
X
X
X
X
ENLDO_D
ENLDO_C
ENLDO_B
ENLDO_A
REG3
03h
Backlight Current
Control MAIN
MEQS
DISABLE
FADE_MAIN
MAIN_ON
BLM[4]
BLM[3]
BLM[2]
BLM[1]
BLM[0]
REG4
04h
Backlight Current
Control SUB
X
DISABLE
FADE_SUB
SUB_ON
BLS[4]
BLS[3]
BLS[2]
BLS[1]
BLS[0]
05h
Backlight Current
Control AUX1
AUX1[1]
AUX1[0]
A1_ON
BLA1[4]
BLA1[3]
BLA1[2]
BLA1[1]
BLA1[0]
REG6
06h
Backlight Current
Control AUX2
AUX2[2]
AUX2[0]
A2_ON
BLA2[4]
BLA2[3]
BLA2[2]
BLA2[1]
BLA2[0]
REG7
07h
Backlight Fade
Control
X
X
FADE_TIME[1]
FADE_TIME[0]
FADE_MAIN
FADE_SUB
FLOOR[1]
FLOOR[0]
REG5
Table 1: AAT2863 Configuration/Control Register Allocation
(“X” = Reserved).
16
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Bit4
Bit3
Bit2
Bit1
Bit0
LED Current (mA)
BLM[4]
BLS[4]
BLA1[4]
BLA2[4]
BLM[3]
BLM[3]
BLA1[3]
BLA2[3]
BLM[2]
BLS[2]
BLA1[2]
BLA2[2]
BLM[1]
BLS[1]
BLA1[1]
BLA2[1]
BLM[0]
BLS[0]
BLA1[0]
BLA2[0]
REG3
REG4
REG5
REG6
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
30*
29.03
28.06
27.10
26.13
25.16
24.19
23.23
22.26
21.29
20.32
19.35
18.38
17.42
16.45
15.48
14.52
13.55
12.58
11.61
10.65
9.68
8.71
7.74
6.77
5.81
4.84
3.87
2.9
1.94
0.97
0.48
Table 2: Main/Sub/Aux Backlight LED Current - BLM/BLS/BLA [4:0].
Bit1
Bit 0
Fade Out Current Level (mA)
FLOOR 1
FLOOR 0
REG7
0*
0
1
1
0*
1
0
1
0.48*
0.97
1.94
2.90
Table 3: Main/Sub LED Current Fade OUT Level Control.
* Denotes default (power-on-reset) value.
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Table 4 describes the final current per channel after the
fade out sequence that will continue to be present until
the MAN, SUB or AUX1,2 channels are disabled by writing to Bit 5 = 1 to REG3, REG4, REG5 or REG6. Fade OUT
can be initiated only after Bit2 or Bit3 of REG7 have been
programmed for fade in sequence first by writing FADE_
MAIN = 1 or FADE_SUB = 1.
Fade IN / OUT Control
REG7
Bit3
Bit 2
FADE_MAIN
FADE_SUB
MAIN
SUB
0*
0
1
1
0*
1
0
1
Fade OUT
Fade OUT
Fade IN
Fade IN
Fade OUT
Fade IN
Fade OUT
Fade IN
Table 4: Main/Sub LED Current
Fade IN/OUT Control.
Table 5 describes Data Bit4 and Data Bit5 of REG7 control the duration of the fade-in/out function. The default
timing is 850ms with options for 650ms and 425ms
according to Table 5. The charge pump oscillator frequency is related to the fade-in/out timing as follows:
For the 850ms fade-in/out timer, typical fOSC = 600kHz
For the 650ms fade-in/out timer, typical fOSC = 800kHz
For the 425ms fade-in/out timer, typical fOSC = 1.2MHz
Bit5
Bit 4
FADE_TIME[1]
FADE_TIME[0]
Fade IN and OUT
Timing (ms)
0*
0
1
1
0*
1
0
1
850*
650
425
850
Table 5: Main/Sub LED current Fade IN /OUT
Timing Selection.
Data Bit5 of REG3, REG4, REG4 and REG5 controls the
turn on/off of the MAIN, SUB, AUX1 and AUX2 channels.
Bit 5
Backlight Channel ON/OFF
MAIN_ON
SUB_ON
AUX1_ON
AUX1_ON
REG3
REG4
REG5
REG6
0*
1
OFF
ON
Table 6: Main/Sub/Aux LED Current
ON/OFF Control.
Data Bit6 of REG3 and REG4 enable the fade control of
the MAIN and SUB channels. Fade function can be explicitly disabled by writing DISABLE FADE_MAIN = 1 and
DISABLE FADE_SUB = 1.
Bit 6
Backlight Channel Fade
Enable/Disable
DISABLE FADE_MAIN
DISABLE FADE_SUB
REG3
REG4
0*
1
Enable
Disable
Table 7: Main/Sub Current Fade ON/OFF Control.
Data Bit7 of REG3 programs all SUB channels as MAIN
backlight. In this case if the MAIN fade function is
enabled all MAIN and SUB channels will be faded simultaneously.
Bit 7
MAIN Equal SUB
MEQS
REG3
0*
1
False
True
Table 8: Main/Sub Current Fade ON/OFF Control.
*Denotes default (power-on-reset) value.
18
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Examples of Fade-Out Programming
Main Only (Sub is OFF):
Address
Address
Address
Address
Address
03h,
07h,
03h,
03h,
07h,
Data
Data
Data
Data
Data
40: Disable fade
08: Fade-in is programmed
6F: Turn on directly to 15.48mA/ch
20: Re-enable fade
00: Fade-out to 0.48mA/ch
Sub Only (Main is OFF):
Address
Address
Address
Address
Address
04h,
07h,
04h,
04h,
07h,
Data
Data
Data
Data
Data
40: Disable fade
04: Fade-in is programmed
6F: Turn on directly to 15.48mA/ch
2F: Enable fade
02: Fade-out to 1.94mA/ch
Main and Sub (as shown in Figure 5):
Address
Address
Address
Address
Address
03h,
07h,
03h,
03h,
07h,
Data
Data
Data
Data
Data
C0:
0C:
60:
20:
03:
Disable fade
Fade-in is programmed
Turn on directly to 30mA/ch
Enable fade
Fade-out to 2.90mA/ch
Examples of Fade-In/Out Programming
Main Only (Sub is OFF):
Address 03h, Data 20: Main backlight is turned on with 0.48mA/ch
Address 07h, Data 08: Fade-in to 30mA/ch
Address 07h, Data 03: Fade-out to 2.90mA/ch
Sub Only (Main is OFF):
Address
Address
Address
Address
07h,
04h,
07h,
07h,
Data
Data
Data
Data
02:
2E:
04:
02:
Fade-in is programmed to 1.94mA/ch
Sub backlight is turned on with 1.94mA/ch
Fade-in to 16.45mA/ch
Fade-out to 1.94mA/ch
Main and Sub (as shown in Figure 6):
Address
Address
Address
Address
07h,
03h,
07h,
07h,
Data
Data
Data
Data
01: Fade-in is programmed to 0.97mA/ch
AA: Main and Sub backlight is turned on with 0.97mA/ch
0C: Fade-in to 20.32mA/ch
01: Fade-out to 0.97mA/ch
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Main and Sub Fade Out Only
Max. 30mA /ch to 2.90mA/ch
I2C
Sequence:
AAT2863 Chip Address 60h
REG3 Address 03h, Data C0(0100 0000): Disable fade function
REG7 Address 07h, Data 0C(0000 1100): Fade-in is programmed
REG3 Address 03h, Data 60(0110 0000): Main/Sub is turned on with 30mA/ch
Main/Sub Backlight
30mA/ch
REG3 Address 03h, Data 20(0010 0000): Enable fade function
REG7 Address 07h, Data 03(0000 0011): Fade-out is programmed to 2.90mA/ch
Main/Sub Backlight
2.90mA/ch
REG3 Address 03h Data 00(0000 0000 )
REG3 Address 03h, Data 20(0010 0000): Enable fade function
REG3 Address 03h, Data 60(0110 0000): Main/Sub is turned on with 30mA/ch
REG7 Address 07h, Data 08(0000 1000): Fade-in is programmed
Main/Sub Backlight
Off
REG3 Address 03h, Data C0(0100 0000): Disable fade function
REG7 Address 07h, Data 0C(0000 1100): Fade-in is programmed
REG3 Address 03h, Data 60(0110 0000): Main/Sub is turned on with 30mA/ch
Figure 5: Example of AAT2863 Fade Out Programming.
Main and Sub Fade In/Out
Max. 20.32mA/ch to 0.97mA/ch
I2C Sequence:
AAT2863 Chip Address 60h
REG7 Address 07h, Data 01(0000 0001): Fade-in is programmed as 0.97mA/ch
REG3 Address 03h, Data AA(1010 1010): Main/Sub backlight is turned on with 0.97mA/ch
REG7 Address 07h, Data 0C(0000 1100): Fade-in programmed to 20.32mA/ch
Main/Sub Backlight
20.32mA/ch
REG7 Address 07h, Data 01(0000 0001): Fade-out is programmed to 0.97mA/ch
REG7 Address 07h, Data 0C(0000 1100):
Fade-in is programmed as 20.32mA/ch
Main/Sub Backlight
0.97mA/ch
REG3 Address 03h Data 80(1000 0000)
REG7 Address 07h, Data 01(0000 0001): Fade-in is programmed as 0.97mA/ch
REG3 Address 03h, Data AA(1010 1010): Main/Sub backlight is turned on with 0.97mA/ch
REG7 Address 07h, Data 0C(0000 1100): Fade-in is programmed to 20.32mA/ch
Main/Sub Backlight
Off
Figure 6: Example of AAT2863 Fade In/Out Programming.
20
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
LDO Control Registers
The four LDO regulators each have three dedicated control registers:
• REG0 (I2C address 00h) and REG1 (I2C address 01h)
set the output voltages of LDOA/B/C/D to one of 16
pre-set values according to Table 9 and Table 10.
•REG2 (I2C address 02h) controls turning on/off of
LDOA/B/C/D regulators according to Table 11.
Bit7
Bit6
Bit5
Bit4
LDO VOUT[A/C] (V)
LDOA[3]
LDOC[3]
LDOA[2]
LDOC[2]
LDOA[1]
LDOC[1]
LDOA[0]
LDOC[0]
REG0
REG1
0*
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0*
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0*
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0*
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1.2*
1.3
1.5
1.6
1.8
2.0
2.2
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
Table 9: LDOA/LDOC Output Voltage Control Data.
Bit3
Bit2
Bit1
Bit0
LDO VOUT[B/D] (V)
LDOB[3]
LDOD[3]
LDOB[2]
LDOD[2]
LDOB[1]
LDOD[1]
LDOB[0]
LDOD[0]
REG0
REG1
0*
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0*
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0*
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0*
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1.2*
1.3
1.5
1.6
1.8
2.0
2.2
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
Table 10: LDOB/LDOD Output Voltage Control Data.
*Denotes default (power-on-reset) value.
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Bit3
Bit2
Bit1
Bit0
ENLDO_D
ENLDO_C
ENLDO_B
ENLDO_A
LDOD
LDOC
LDOB
LDOA
0*
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0*
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0*
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0*
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
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 11: LDOA/LDOB/LDOC/LDOD ON/OFF Control Data.
Auxiliary Backlight Selection
LED Selection
Each of the auxiliary drivers (AUX) can also be programmed to one of 32 levels described in Table 2. The
auxiliary drivers can be driven independently, or combined with the main or sub by changing Bit6 and Bit7 in
REG5 (I2C address 05h) and REG6 (I2C address 06h)
according to Table 12. The auxiliary drivers can also be
set to operate at twice their programmed current if
Bit6=1 and Bit7=1 in REG5 and REG6.
The AAT2863 is specifically intended for driving white
LEDs. However, the device design will allow the AAT2863
to drive most types of LEDs with forward voltage specifications ranging from 2.0V to 4.7V. LED applications may
include mixed arrangements for display backlighting,
color (RGB) LEDs, infrared (IR) diodes and any other load
needing a constant current source generated from a varying input voltage. Since the D1 to D8 constant current
sinks are matched with negligible voltage dependence,
the constant current channels will be matched regardless
of the specific LED forward voltage (VF) levels.
Bit7
Bit6
Auxiliary Channel Assignment
AUX1[1]
AUX2[1]
AUX1[0]
AUX2[0]
REG5
REG6
0*
0
1
1
0*
1
0
1
SUB
MAIN
AUX
AUX * 2
The low-dropout current sinks in the AAT2863 maximize
performance and make it capable of driving LEDs with
high forward voltages. Multiple channels can be combined to obtain a higher LED drive current without complication.
Table 12: Auxiliary Channels Assignment.
*Denotes default (power-on-reset) value.
22
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Device Switching Noise Performance
1x Mode Efficiency
The AAT2863 operates at a fixed frequency of approximately 1MHz to control noise and limit harmonics that
can interfere with the RF operation of cellular telephone
handsets or other communication devices. Back-injected
noise appearing on the input pin of the charge pump is
20mV peak-to-peak, typically ten times less than inductor-based DC/DC boost converter white LED backlight
solutions. The AAT2863 soft-start feature prevents noise
transient effects associated with in-rush currents during
the start up of the charge pump circuit.
The AAT2863's 1x mode is operational at all times and
functions alone to enhance device power conversion efficiency when VIN is greater then the voltage across the
load. When in 1x mode, the voltage conversion efficiency
is defined as output power divided by input power:
Power Efficiency and Device Evaluation
Charge-pump efficiency discussion in the following sections accounts only for the efficiency of the charge pump
section itself. Due to the unique circuit architecture and
design of the AAT2863, it is very difficult to measure
efficiency in terms of a percent value comparing input
power over output power.
Since the AAT2863 outputs are pure constant current
sinks and typically drive individual loads, it is difficult to
measure the output voltage for a given output (BL1 to
BL8) to derive an overall output power measurement.
For any given application, white LED forward voltage
levels can differ, yet the output drive current will be
maintained as a constant.
This makes quantifying output power a difficult task
when taken in the context of comparing to other white
LED driver circuit topologies. A better way to quantify
total device efficiency is to observe the total input power
to the device for a given LED current drive level. The
best White LED driver for a given application should be
based on trade-offs of size, external component count,
reliability, operating range and total energy usage...Not
just “% efficiency”.
The AAT2863 efficiency may be quantified under very
specific conditions and is dependent upon the input voltage versus the output voltage seen across the loads
applied to outputs D1 through D8 for a given constant
current setting. Depending on the combination of VIN
and voltages sensed at the current sinks, the device will
operate in load switch mode. When any one of the voltages sensed at the current sinks nears dropout the
device will operate in 1.5x or 2x charge pump mode.
Each of these modes will yield different efficiency values.
One should refer to the following two sections for explanations for each operational mode.
η=
POUT
PIN
The expression to define the ideal efficiency (η) can be
rewritten as:
η=
POUT VOUT · IOUT VOUT
=
=
PIN
VIN · IOUT
VIN
-or-
η(%) = 100
 VOUT 
 VIN 
1.5x/2x Charge Pump Mode Efficiency
The AAT2863 contains a fractional charge pump which
will boost the input supply voltage in the event where VIN
is less then the voltage required to supply the output.
The efficiency (η) can be simply defined as a linear voltage regulator with an effective output voltage that is
equal to one and a half or two times the input voltage.
Efficiency (η) for an ideal 1.5x charge pump can typically be expressed as the output power divided by the
input power.
η=
POUT
PIN
In addition, with an ideal 1.5x charge pump, the output
current may be expressed as 2/3 of the input current.
The expression to define the ideal efficiency (η) can be
rewritten as:
η=
POUT
VOUT · IOUT
VOUT
=
=
PIN
VIN · 1.5IOUT
1.5VIN
η(%) = 100
 VOUT 
 1.5VIN
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23
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
For a charge pump with an output of 5V and a nominal
input of 3.5V, the theoretical efficiency is 95%. Due to
internal switching losses and IC quiescent current consumption, the actual efficiency can be measured at 93%.
These figures are in close agreement for output load
conditions from 1mA to 100mA. Efficiency will decrease
substantially as load current drops below 1mA or when
level of VIN approaches VOUT.
The same calculations apply for 2x mode where the
output current then becomes 1/2 of the input current.
Capacitor Selection
Careful selection of the four external capacitors CIN, C1,
C2, COUT is important because they will affect turn on
time, output ripple and transient performance. Optimum
performance will be obtained when low ESR (<100mΩ)
ceramic capacitors are used. In general, low ESR may be
defined as less than 100mΩ. A capacitor value of 1µF for
all four capacitors is a good starting point when choosing
capacitors. If the constant current sinks are only programmed for light current levels, then the capacitor size
may be decreased.
Capacitor Characteristics
Ceramic composition capacitors are highly recommended
over all other types of capacitors for use with the
AAT2863. 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 nonpolarized. Low ESR ceramic capacitors help to maximize
charge pump transient response. Since ceramic capacitors are non-polarized, they are not prone to incorrect
connection damage.
Equivalent Series Resistance (ESR)
ESR is an important characteristic to consider when
selecting a capacitor. ESR is a resistance internal to a
capacitor, which is caused by the leads, internal connections, size or area, material composition and ambient
temperature. Capacitor ESR is typically measured in milliohms for ceramic capacitors and can range to more
than several ohms for tantalum or aluminum electrolytic
capacitors.
24
Ceramic Capacitor Materials
Ceramic capacitors less than 0.1µF are typically made
from NPO or COG materials. NPO and COG materials
typically have tight tolerance and are stable over temperature. Larger capacitor values are typically composed
of X7R, X5R, Z5U or Y5V dielectric materials. Large
ceramic capacitors, typically greater than 2.2µF are
often available in low cost Y5V and Z5U dielectrics, but
capacitors greater than 1µF are typically not required for
AAT2863 applications.
Capacitor area is another contributor to ESR. Capacitors
that are physically large will have a lower ESR when compared to an equivalent material smaller capacitor. These
larger devices can improve circuit transient response
when compared to an equal value capacitor in a smaller
package size.
Evaluation Board User Interface
The user interface for the AAT2863 evaluation board is
provided by three buttons and three connection terminals. The board is operated by supplying external power
and pressing individual buttons or button combinations.
Table 14 indicates the function of each button or button
combination.
To power-on the evaluation board, connect a power supply or battery to the DC- and DC+ terminals. Close the
board’s supply connection by positioning the J1 jumper
to the ON position. A red LED indicates that power is
applied.
The evaluation board is made flexible so that the user
can disconnect the data, clock and enable lines from the
microcontroller and apply external signal sources by
removing the jumpers from J2, J3 and/or J4. External
enable signal must be applied to the ON pin of J4 terminal. External I2C clock SCL can be applied to J2 pin and
data SDA to J3 pin.
When applying external enable signals, consideration
must be given to the voltage levels. The externally
applied voltages should not exceed the supply voltage
that is applied to the IN pins of the device (DC+). The
LDO loads can be connected directly to the evaluation
board. For adequate performance, be sure to connect
the load between LDOA/LDOB/LDOC/LDOD and DC- as
opposed to some other GND in the system.
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Manufacturer
AVX
TDK
Murata
Taiyo Yuden
Part Number
Value
Voltage
0603ZD105K
0603ZD225K
C1608X5R1E105K
C1608X5R1C225K
C1608X5R1A475K
GRM188R61C105K
GRM188R61A225K
LMK107BJ475KA
1uF
2.2μF
1μF
2.2μF
4.7μF
1μF
2.2μF
4.7μF
10
10
25
16
10
16
10
10
Temp. Co.
Case
X5R
0603
X5R
0603
X5R
0603
X5R
0603
Table 13: Surface Mount Capacitors.
Button(s) Pushed
SW1 (LDOs)
SW2 (Main Backlight)
SW3 (Sub/Aux Backlight)
SW1+SW2
SW1+SW3
SW1+SW2+SW3
Description
[Push/Release once] All LDOs will be turned on with default output voltage 1.2V. Every push release
will increment output voltage according to datasheet table.
[Push/Release once] Turning on the Main and Sub backlight LEDs with default current 30mA per channel. Every push release will increment output voltage according to datasheet table.
[Push/Release once] Turning on only the Sub/Aux backlight LEDs with default current 30mA. Every
push release will increment output voltage according to datasheet table.
[Push/Release once] Turning on the fade-out sequence of the backlight LEDs with default current
30mA down to 0.5mA per channel.
[Push/Release once] Turning on the fade-in sequence of the backlight LEDs with default current
0.5mA up to 30mA per channel.
[Push/Release once] Reset all registers to default.
Table 14: AAT2863 Evaluation Board User Interface Functionality.
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25
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
C2+
C1+
DC+
C1
1µF
C1-
J1
DC+
C1+
C1-
23
7
C5
4.7µF
IN
IN
20
AGND
6
PGND
AGND
3
2
1
24
22
VIN
DC-
C4
4.7µF
EN/SET
V_MCU
EN
PWM
SCL
R8
10K
R6
10K
5
19
4
SDA 3
R9
10K
R10
10K
PWM
U1
AAT2863
18
VOUT
1
N/C
EP
SDA
VIN
C2
1µF
C2C3
1µF
EN
PWM
SCL
SDA
SCL
2
21
1
C2+
C2OUT
BL1
BL2
BL3
BL4
BL5/AUX1
BL6/AUX2
12
13
14
15
17
16
LDOA
LDOB
LDOC
LDOD
10
9
8
11
D1
D2
D3
D4
D5
D6
2
R24 R25 R26
0
0
0
D1
D4
1
2
LDOD
C9
2.2µF
U2
S1
SW1
SELECT
SW2
DETAIL
SW3
SEND
1
2
3
4
PIC12F675
VDD
GP5
GP4
GP3
VSS
GP0
GP1
GP2
8
7
6
5
D2
1
D3
2
1
2
1
2
2
LDOA
LDOB
LDOC
C8
2.2µF
D5 1 D6
C7
2.2µF
C6
2.2µF
GND
VMCU
R1 R2 R3
1k 1k 1k
VOUT
R21 R22 R23
0
0
0
C10
1µF
R7
1k
GND
LED1
Red
S2
S3
Figure 7: AAT2863 Evaluation Board Schematic.
26
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Figure 8: AAT2863 Evaluation Board
Top Side Layout.
Figure 9: AAT2863 Evaluation Board Layout
Bottom Side Layout.
Component
Part Number
Description
Manufacturer
U1
U2
SW1 – SW3
R1, R2, R3, R7
R6, R8, R9, R10
R21 – R26
C6, C7, C8, C9
C1, C2, C3, C10
C4, C5
D1-D4
D5, D6
LED1
J1
AAT2863IMK
PIC12F675
PTS645TL50
Chip Resistor
Chip Resistor
Chip Resistor
GRM188R71A225K
GRM188R61A105K
GRM188R61A475K
LW M673
LS-SF687DBW71
CMD15-21SRC/TR8
PRPN401PAEN
Backlight LED driver with 4 LDOs
8-bit CMOS, Flash-based μC; 8-pin PDIP package
Switch Tact, SPST, 5mm
1kΩ, 1%, 1/4W; 0603
10kΩ, 1%, 1/4W; 0603
0Ω, 1%, 1/4W; 0603
2.2μF, 10V, X7R, 0603
1μF, 10V, X5R, 0603
4.7μF, 10V,X5R, 0603
Mini TOPLED White LED; SMT
Power Top View White LED; SMT
Red LED; 1206
Conn. Header, 2mm zip
Skyworks
Microchip
ITT Industries
Vishay
Vishay
Vishay
Murata
Murata
Murata
Osram
Longsum
Chicago Miniature Lamp
Sullins Electronics
Table 15: AAT2863 Evaluation Board Bill of Materials (BOM).
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27
DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Ordering Information
Package
Marking1
Part Number (Tape and Reel)2
TQFN34-24
F1XYY
AAT2863IMK-T1
Skyworks Green™ products are compliant with
all applicable legislation and are halogen-free.
For additional information, refer to Skyworks
Definition of Green™, document number
SQ04-0074.
Package Information
TQFN34-243
3.000 ± 0.050
1.700 ± 0.050
Index Area
0.400 ± 0.050
R(5x)
2.700 ± 0.050
4.000 ± 0.050
0.210 ± 0.040
0.400 BSC
Detail “A”
Bottom View
Detail “A”
0.750 ± 0.050
Top View
0
+ 0.10
- 0.00
0.203 REF
Side View
All dimensions in millimeters.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
3.The leadless package family, which includes QFN, TQFN, DFN, TDFN, and STDFN, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing
process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required to ensure a proper bottom solder connection.
28
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DATA SHEET
AAT2863
Backlight LED Driver and Multiple LDO Lighting Management Unit
Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved.
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design, or damage to any equipment resulting from the use of Skyworks products outside of stated published specifications or parameters.
Skyworks, the Skyworks symbol, and “Breakthrough Simplicity” are trademarks or registered trademarks of Skyworks Solutions, Inc., in the United States and other countries. Third-party brands and names are for
identification purposes only, and are the property of their respective owners. Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202507A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • November 2, 2012
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