AATIAN58 Datasheet, PDF (1/4 Pages) SiGe Semiconductor, Inc. – High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications

EV-126
AAT3143 EVAL: High Efficiency 1X/1.5X/2X
Charge Pump for White LED Applications
Introduction
The AAT3143 EVAL board demonstrates the func-
tionality of the AAT3143 and its application as a
white LED backlight driver. The AAT3143 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 AAT3143 can provide dimming control by driv-
ing the EN/PWM pin with a PWM signal. The EVAL
board is equipped to offer this through its user-
interface. The user-interface has three brightness
Schematic
settings available. The brightness levels are
achieved by varying the duty-cycle of a PWM sig-
nal with a frequency of approximately 1kHz.
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. The actual board layout is also provided.
For additional information, please consult the
AAT3143 product datasheet.
BT- BT+
BT=3 X (AAA)
GND
3 ^J1
2
1 J_Blk3
R3 R2
1k 1k
SW3
0 21
43
5
SW-SPST
SW2
0 21
43
5
SW-SPST
SW1
0 21
43
5
SW-SPST
GND GND
D3
D2
D1
D4
1
Vdd
U2
8
Vss
R1
C5
PIC12F675
1k
1µF
GND
2
Gp5/Osc1/Clkin
7
GP0/An0
3
6
Gp4/Osc2/An3/ClkOut Gp1/An1/Vref
4
Gp3/MClr/Vpp
5
Gp2/T0Cki/An2/Int
J2
J_Blk_3
R6
220
3
2
1
R7
100k
JP3¹
JP2¹
JP1¹
JP4¹
GND
GND
C3
1µF ^C1
1µF
C2
U1
1
2
3
4
5
6
C2+
CP
C1-
C1+
D3
D2
1µF
C2-
GND
IN
EN/SET
D1
D4
12
11
10
9
8
7
AAT3143
GND
VR4
R5
POT1
330
LED7
RED
GND
R4
LED0
330 GREEN
GND
GND _JP51
C4
1µF
GND
GND
1. Jumpers may be removed to make current measurements.
Figure 1: Evaluation Board Schematic.
EV-126.2006.02.1.0
1