Two-Channel, Push-Pull CCFL Controller

6

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GAn

GBn

OVDn

OVERVOLTAGE

DETECTION

LCMn

LAMP CURRENT

MONITOR

[20.48MHz TO 40.96MHz]

90Hz TO 220Hz OR

180Hz TO 440Hz

EXTERNAL

RESISTOR LAMP

FREQUENCY SET

[4.5V TO 5.5V]

GND

TWO

INDEPENDENT

CCFL

CONTROLLERS

(SEE FIGURE 2)

EXTERNAL

RESISTOR DPWM

FREQUENCY SET

ANALOG

BRIGHTNESS

CONTROL

SVM

SUPPLY VOLTAGE

MONITOR

[40kHz TO 80kHz]

CHANNEL FAULT

CHANNEL ENABLE

MOSFET

GATE DRIVERS

LOSC

BRIGHT

POSC

DPWM

SIGNAL

2.0V

40kHz TO 80kHz

OSCILLATOR (±10%)

90Hz TO 220Hz OR

180Hz TO 440Hz

OSCILLATOR (±10%)

RAMP

GENERATOR

x512

PLL

FAULT

HANDLING

SYSTEM

ENABLE /

POR

VREF

UVLO

DS3992

Functional Diagrams

Figure 1. DS3992 Functional Diagram