DS3991

Low-Cost CCFL Controller

Full-Featured Single-Channel CCFL Controller

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Overview

CCFL Controller for Backlighting LCD Panels
Minimal External Components Required
Lamp Fault Monitoring for Lamp-Open, Lamp-Overcurrent, Failure-to-Strike, and Overvoltage Conditions
Accurate (±5%) On-Board Oscillator for Lamp Frequency (40kHz to 80kHz)
Accurate (±5%) On-Board Oscillator for DPWM Burst-Dimming Frequency (80Hz to 300Hz)
Device Supply Undervoltage Lockout
Inverter Supply Undervoltage and Overvoltage Lockouts
Soft-Start on Burst-Dimming Minimizes Audible Transformer Noise
Strike Frequency Boost
100% to < 10% Dimming Range
Low Cost
Single-Supply Operation Range: 4.5V to 5.5V
Temperature Range: -40°C to +85°C
16-Pin SO Package (150 mils)

The DS3991 is a controller for cold-cathode fluorescent lamps (CCFLs) that are used to backlight liquid-crystal displays (LCDs). The DS3991 is available for both push-pull and half-bridge drive topologies.

The DS3991 converts a DC voltage (5V to 24V) to the high-voltage (300V_RMS to 1400V_RMS) AC waveform that is required to power the CCFLs. The push-pull and halfbridge drive schemes use a minimal number of external components, which reduces component and assembly cost and makes the printed circuit board (PCB) design easy to implement. Both drive schemes provide an efficient DC to AC conversion and produce near-sinusoidal waveforms.

Applications