MAX8795A Datasheet, PDF (15/31 Pages) Maxim Integrated Products – TFT-LCD DC-DC Converter with Operational Amplifiers

TFT-LCD DC-DC Converter with
Operational Amplifiers
Typical Operating Circuit
The MAX8795A typical operating circuit (Figure 1) is a
complete power-supply system for TFT LCDs. The circuit
generates a +14V source-driver supply and +25V and
-10V gate-driver supplies. The input voltage range for the
IC is from +2.5V to +5.5V. The listed load currents in
Figure 1 are available from a +4.5V to +5.5V supply.
Table 1 lists some recommended components, and Table
2 lists the contact information of component suppliers.
VIN
4.5V TO 5.5V
LX
C11
0.1µF
D3
VGOFF
-10V/50mA
C1
22µF
C12
220µF
C10
0.1µF
Q2
C9
0.22µF
R10
10Ω
C13
0.1µF
180kΩ
R9
6.8kΩ
R7
324kΩ
1%
R8
31.6kΩ
1%
C8
0.22µF
C7
0.033µF
TO VCOM
BACKPLANE
L1
LX
3.0µH
D1
R1
LX
137kΩ
1%
IN
FB
C2
LX
22µF
C3
0.1µF
R2
13.3kΩ
C4
1%
0.1µF
D2
COMP
AGND
C14
68pF
PGND
MAX8795A
DRVP
DRVN
FBP
FBN
R5
10.0kΩ
1%
R3
6.8kΩ
R4
191kΩ
1%
Q1
C5
0.47µF
SRC
REF
COM
DRN
CTL
DEL
SUP
NEG1
OUT1
NEG2
OUT2
OUT3
NEG4
OUT4
NEG5
OUT5
BGND
POS1
POS2
POS3
POS4
POS5
EP
C6
0.1µF
VGON
25V/20mA
R6
1kΩ
R19
100kΩ
R17
100kΩ
R15
100kΩ
R20
100kΩ
R18
100kΩ
R16
100kΩ
R13
100kΩ
R14
100kΩ
R11
100kΩ
R12
100kΩ
VMAIN
14V/500mA
Figure 1. Typical Operating Circuit
Table 1. Component List
DESIGNATION
DESCRIPTION
C1
22µF, 6.3V X5R ceramic capacitor (1210)
TDK C3225X5R0J227M
C2
22µF, 16V X5R ceramic capacitor (1812)
TDK C4532X5X1C226M
D1
3A, 30V Schottky diode (M-flat)
Toshiba CMS02
D2, D3
200mA, 100V, dual ultra-fast diodes (SOT23)
Fairchild MMBD4148SE
DESIGNATION
DESCRIPTION
L1
3.0µH, 3A inductor
Sumida CDRH6D28-3R0
Q1
200mA, 40V pnp bipolar transistor (SOT23)
Fairchild MMBT3906
Q2
200mA, 40V npn bipolar transistor (SOT23)
Fairchild MMBT3904
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