Complete Bias and White LED Power Supplies

for Small TFT Displays

8

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BIAS

REF

PWM

CONTROL

1MHz

OSCILLATOR

OSC

170mV

TIMER

CTRL

COMP

IN

OVERVOLTAGE

PROTECTION

OUT

PGND

LX

CS

CHARGE-PUMP

CONTROL

ONBIAS

SHUTDOWN

SEQUENCING

DIVIDE BY FOUR

OSC

MULTIMODE

CHARGE PUMP

1.5X/2X

C1P

C1N

C2P

5V LDO

C2N

GND

MAIN

SHUTDOWN

SHUTDOWN

3X POSITIVE

CHARGE PUMP

-2X INVERTING

CHARGE PUMP

DIVIDE BY 64

OSC

PMP

PMPB

CD1

CD2

CU1

CU2

CU3

NEG

POS

N

SHUTDOWN

N

N

N

MAX1578

MAX1579

Block Diagram