鈥?/div>
DESCRIPTION
The TPS6512x DC-DC converter supplies all three voltages required by amorphous-silicon (a-Si) and
low-temperature poly-silicon (LTPS) TFT-LCD displays. The compact layout of the TPS6512x uses a single
inductor to generate independently-regulated positive and negative outputs. A free-running variable peak current
PWM control scheme time-multiplexes the inductor between outputs. This control architecture operates at a
pseudo-fixed-frequency to provide fast response to line and load transients while maintaining a relatively
constant switching frequency and high efficiency over a wide range of input and output voltages. Due to the high
switching frequency capability of the device, inexpensive and ultra-thin 8.2 or 10 碌H inductors can be used.
The main output, V
MAIN
, is post-regulated to provide a low-ripple source drive voltage for the LCD display. The
auxiliary outputs generate a boosted output voltage, V
GH
, up to 20 V, and a negative output voltage, V
GL
, down to
-18 V for the LCD gate drive. The device has internal current limiting for high reliability under fault conditions.
Additionally, the device offers a fixed output linear regulator for the LCD logic circuitry.
100
TPS65123
V
IN
2.7 V to 5.5 V
VIN
C1
2.2
碌
F
RUN
EN
GATE
V
GH
up to 20 V/2 mA
C2
100 nF
R1
FBH
R2
VGH
SWP
FBL
VMAIN
FBM
BOOT
V
MAIN
R5
C4 R6
1
碌
F
3.0 V to 5.3 V/25 mA
C5
220 nF
SWN
L1
10
碌
H
D1
V
GL
R3
R4
down to 鈭?8 V/2 mA
C3
100 nF
90
80
70
60
50
40
30
20
10
0
5.5
5.2
4.7
4.0
3.2
2.8
2.6
2.4
2.3
24.0
20.0
16.0
12.0
8.0
4.0
AGND
A
PGND
A
V
IN
鈭?Input Voltage 鈭?V
I
BOOT
鈭?Load Current 鈭?mA
Figure 1. Typical Application
Figure 2. Core Converter Efficiency
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright 漏 2004, Texas Instruments Incorporated
Core Converter Efficiency 鈭?%
0.9
0.5
0.1