AATIAN59 Datasheet, PDF (1/4 Pages) SiGe Semiconductor, Inc. – High Efficiency 1X/1.5X/2X Charge Pump For White LED Applications

EV-117
AAT3151 EVAL: High Efficiency 1X/1.5X/2X
Charge Pump For White LED Applications
Introduction
The AAT3151 EVAL board demonstrates the functionality of the AAT3151 and its application as a white LED
backlight driver. The AAT3151 is a low-noise, constant frequency charge pump DC/DC converter with tri-mode
load switch (1X), fractional (1.5X), and doubling (2X) conversion to maximize efficiency and operate over a
wide input voltage range.
The AAT3151 is programmable with the AS²Cwire™ (Advanced Simple Serial Control™) serial interface and
is capable of driving up to four independent LED channels. LED constant current levels are set from a 16-level
logarithmic scale, and four additional low-current settings are available down to 50µA.
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 informa-
tion, please consult the AAT3151 product datasheet.
Schematic
C1
1µF
C3
1µF
GND
JP5
U1
1 _D4
2 _EN/SET
3 _C1+
4 _C1-
5 _VOUT
6 _C2+
D3 ¹²
D2 ¹¹
D1 ¹⁰
GND ⁹
VIN ⁸
C2- ⁷
AAT3151
C2
1µF
DC+
JP6
DC+
DC-
J1
C4
1µF
D1 D2 D3
JPx
D4
GND
EV-117.2005.06.1.0
R7
J2
R6
220Ω
100kΩ
GND
DC+
R3 R2 R1
1kΩ 1kΩ 1kΩ
CYCLE
SW3
0
21
43
5
UP
SW2
0
21
43
5
DOWN
SW1
0
21
43
5
GND
U2
1 _VDD
2 _GP5
3 _GP4
4 _GP3
VSS ⁸
GP0 ⁷
GP1 ⁶
GP2 ⁵
PIC12F675
VR4
POT 10K
C5 R5
10µF 330Ω
LED7
RED
R4
330Ω
GND
LED0
GRN
GND
GND
Figure 1: Evaluation Board Schematic.
1