AATIAN46 Datasheet, PDF (1/4 Pages) SiGe Semiconductor, Inc. – Multi-Mode Charge Pump For White LED Backlight and Flash Applications

EV-113
AAT2801 EVAL: Multi-Mode Charge Pump For
White LED Backlight and Flash Applications
Introduction
The AAT2801 EVAL board demonstrates the functionality of the AAT2801 and its application as a white LED
backlight driver with flash capability. The backlighting section of the AAT2801 uses a low-noise, constant fre-
quency charge pump DC/DC converter with tri-mode load switch (1X), fractional (1.5X) and doubling (2X) con-
version to maximize efficiency and operate over a wide input voltage range. Dedicated to the flash section is a
low-noise, constant frequency, doubling (2X) charge pump that is capable of delivering 300mA of pulsed current.
The backlighting section is programmable with the S²Cwire™ (Simple Serial Control™) serial interface and is
capable of driving up to four independent LED channels. LED current levels are set from a 32-level logarith-
mic scale, giving a range of 30mA down to 100µA.
This document describes the evaluation board and its accompanying user interface. In addition, a brief
“Getting Started” section is included to help the user begin operating the evaluation board. A schematic of the
complete circuit is shown in Figure 1, and the actual board layout is given in Figures 2 and 3. For additional
information, please consult the AAT2801 product datasheet.
Schematic
Flash LED
D0
AAT9513
EN3
R4 R5
1Ω 20Ω
GND
U2
C6
1µF
GND
GND
DC+
J1
C3
1µF
C1
1µF
C4
1µF
GND
C5
1µF
GND
U1
AAT2801
1 _C3-
EN_FL ¹⁶
2 _C3+
D2 ¹⁵
3 _{VOUT_FL}
D4 ¹⁴
4 _VIN
D1 ¹³
5 _C1+
D3 ¹²
6 _C1-
EN/SET ¹¹
7 _CP
GND ¹⁰
8 _C2+
C2- ⁹
C2
1µF
LT
GND
MV
R3 R2 R1
1kΩ 1kΩ 1kΩ
LIGHT
SW3
0
21
43
5
MOVIE
SW2
0
21
43
5
FLASH
SW1
0
21
43
5
FL
U3
1 _VDD
2 _GP5
3 _GP4
4 _GP3
VSS ⁸
GP0 ⁷
GP1 ⁶
GP2 ⁵
PIC12F675
GND
DC-
D3 D1 D4 D2
JPx
DC+
C7 R6
10µF 330Ω
LED7
RED
GND
GND
GND
Figure 1: Evaluation Board Schematic.
EV-113.2005.06.1.0
1