202276A.pdf

EVALUATION BOARD DATA SHEET
EV153
Evaluation Board for the AAT2847 Four-Channel Backlight Driver with Dual LDOs
Introduction
The AAT2847 is a highly integrated power solution for single cell Li-Ion/Polymer based liquid crystal display (LCD) display applications. It includes a four channel light emitting diode (LED) backlight driver and two integrated 200mA low
dropout voltage regulators (LDOs) as additional power supplies for display and camera related chipsets.
The backlight driver in the AAT2847 is a low noise tri-mode DC/DC charge pump converter. Each of the four channels
of the backlight driver is capable of delivering up to 20mA of bias current for white LEDs. The white LED (WLED)
backlight bias current matching is 1%, which helps provide uniform display brightness.
Skyworks' AS2Cwire™ (Advanced Simple Serial Control) serial digital interface is used to enable, disable, and set the
current for each backlight LED channel. Each LED channel has sixteen available current level settings in three separate
current scales, plus four available current level settings on a low level current scale.
Each LED channel is equipped with built-in short circuit protection and auto disable functionality. A low shutdown current feature disconnects the load from the input and reduces quiescent current to less than 1µA.
The AAT2847 is available in the thermally enhanced 20-pin 3x4x0.75mm TQFN package.
Getting Started
To apply power to the board, connect the supply by shorting the ON prong to the other prongs in the J1 header. After
shorting the ON prong, the red LED7 should illuminate which indicates that power is connected to the AAT2847 and
microcontroller (MCU). To allow the MCU to interact with the AAT2847, connect/short the ON prong to the other prongs
in the J4 header. Also to enable LDOA, connect/short the ON prong to the middle prong on the J2 header. Conversely
to enable LDOB, connect/short the ON prong to the middle prong on the J3 header.
The user interface is provided by three buttons. The buttons are DATA, LIGHT, and SW. The modes of operation are
detailed in Table 1. Each button handles a particular function: LIGHT turns on/off the D1-D4 LEDs, DATA increments
the data register value of the targeted address, SW increments the target address of the AS2Cwire interface, and
LIGHT+DATA+SW resets the MCU and turns off the AAT2847.
When the DATA button is pressed and not released, the MCU will incrementally auto-cycle through the available values
of the data register for the target address after a short delay. For a detailed device functionality description, regarding address functionality and available data register values, please consult the AAT2847 data sheet.
Button(s) Pressed/Released
LIGHT
DATA
SW
LIGHT+DATA+SW
Description
Turns on/off D1-D4 LEDs
Increments [cycles through when not released] data of targeted address (previously
pressed/released SW button): see “SW”
Increments the target address [default (address 0)]:
Button Press/Release
Address
Decription
1st
3
Max Current Scale
2nd
4
Low Current Scale
3rd
5
Independent LED Control
4th, repeat
0
D1-D4 Current Control
Reset. EN/SET is held logic low
Table 1: User Interface Functionality.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202276A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 17, 2012
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EVALUATION BOARD DATA SHEET
EV153
Evaluation Board for the AAT2847 Four-Channel Backlight Driver with Dual LDOs
Schematic
DC+
1
DC+
DC+
2
3
1
D1
D2
D3
2
1
3
2
3
D4
J1
J3
J2
6
C4
18
17
D3
19
IN
14
PGND
12
C1-
IN
11
OUT
7
EN/SET
C1
13
C1+
FBA
R11
15
EN/SET
C3
C2+
5
R10
LDOB
16
10
4
ENB
C2-
3
C6
D4
D1
8
LDOB
R13
U1
AAT2847
D2
9
2
GND
FBB
1
L DOA
R14
ENA
20
R12
C2
LDOA
C5
R8
R9
Figure 1: AAT2847 Section Schematic of the Evaluation Board.
J4
R6
EN/SET
3
2
1
R7
DC+
R1
R3
R2
DATA
DC+
1
2
3
4
C8
U2
VDD
GP5
GP4
GP3
PIC12F675
VSS
GP0
GP1
GP2
8
7
6
5
R5
LED7
RED
LIGHT
SW
Figure 2: PIC12F675 Section Schematic of the Evaluation Board.
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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202276A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 17, 2012
EVALUATION BOARD DATA SHEET
EV153
Evaluation Board for the AAT2847 Four-Channel Backlight Driver with Dual LDOs
Bill of Materials (BOM)
Component
U1
U2
C1-C3, C8
C4
C5, C6
D1-D4
LED7
R1-R3
R4
R5
R6
R7
R8-R11
R12-R13
R14
DATA, LIGHT, SW
J1-J4
Part Number
Description
AAT2847-QI/QG
PIC12F675
0603ZD105K
C1608X5R1E105K
GRM188R61C105K
C1608X5R1A475K
LMK107BJ475K
0603ZD225K
C1608X5R1C225K
GRM188R61A225K
LW M67C
CMD15-21SRC
CRCW06031001F
N/A
CRCW0603330RF
CRCW06030000F
CRCW06031003F
Open
CRCW06031002F
CRCW120650000F
PTS645TL50
PRPN401PAEN
4-Channel Backlight Driver with Fixed Output Voltage Dual LDOs
Microcontroller
1µF, ≥10V, X5R or X7R
4.7µF, ≥10V, X5R or X7R
2.2µF, ≥10V, X5R or X7R
White LED
Red LED; 1206
1kΩ, 1%, 1/10W, 0603
N/A
330Ω, 1%, 1/10W, 0603
0Ω, 1%, 1/10W, 0603
100kΩ, 1%, 1/10W, 0603
N/A
10kΩ, 1%, 1/10W, 0603
0Ω, 1%, 1/4W, 1206
Switch Tact, SPST, 5MM
Connecting Header, 2mm
Manufacturer
Skyworks
Microchip
AVX
TDK
Murata
TDK
Taiyo Yuden
AVX
TDK
Murata
Osram
CML Innovative Tech, Inc
Vishay
N/A
Vishay
Vishay
Vishay
N/A
Vishay
Vishay
ITT Industries
Sullins Electronics
Table 2: AAT2847-QI/QG Component Listing.
Component
Part Number
U1
AAT2847-EE
U2
PIC12F675
0603ZD105K
C1608X5R1E105K
GRM188R61C105K
C1608X5R1A475K
LMK107BJ475K
0603ZD225K
C1608X5R1C225K
GRM188R61A225K
LW M67C
CMD15-21SRC
CRCW06031001F
N/A
CRCW0603330RF
CRCW06030000F
CRCW06031003F
CRCW06036042F
CRCW06031203F
CRCW06031603F
CRCW06031002F
CRCW120650000F
PTS645TL50
PRPN401PAEN
C1-C3, C8
C4
C5, C6
D1-D4
LED7
R1-R3
R4
R5
R6
R7
R8
R9, R11
R10
R12-R13
R14
DATA, LIGHT, SW
J1-J4
Description
4-Channel Backlight Driver with Adjustable Output Voltage
Dual LDOs
Microcontroller
1µF, ≥10V, X5R or X7R
4.7µF, ≥10V, X5R or X7R
2.2µF, ≥10V, X5R or X7R
White LED
Red LED; 1206
1kΩ, 1%, 1/10W, 0603
N/A
330Ω, 1%, 1/10W, 0603
0Ω, 1%, 1/10W, 0603
100kΩ, 1%, 1/10W, 0603
60.4kΩ, 1%, 1/10W, 0603
120kΩ, 1%, 1/10W, 0603
160kΩ, 1%, 1/10W, 0603
10kΩ, 1%, 1/10W, 0603
0Ω, 1%, 1/4W, 1206
Switch Tact, SPST, 5MM
Connecting Header, 2mm
Manufacturer
Skyworks
Microchip
AVX
TDK
Murata
TDK
Taiyo Yuden
AVX
TDK
Murata
Osram
CML Innovative Tech, Inc
Vishay
N/A
Vishay
Vishay
Vishay
Vishay
Vishay
Vishay
Vishay
Vishay
ITT Industries
Sullins Electronics
Table 3: AAT2847-EE Component Listing.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202276A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 17, 2012
3
EVALUATION BOARD DATA SHEET
EV153
Evaluation Board for the AAT2847 Four-Channel Backlight Driver with Dual LDOs
Printed Circuit Board
Figure 3: AAT2847 Evaluation Board Top Layer (not to scale)
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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202276A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 17, 2012
EVALUATION BOARD DATA SHEET
EV153
Evaluation Board for the AAT2847 Four-Channel Backlight Driver with Dual LDOs
Figure 4: AAT2847 Evaluation Board Bottom Layer (not to scale).
Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved.
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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202276A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 17, 2012
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