Catalyst Adds High-Power LED Driver Optimized for Rapidly Growing, Mid-Size LCD Panel Market

Many high-voltage boost converters typically use a simple variable-frequency switching scheme. This approach results in a wide range of unwanted harmonics, which are not easy to filter or eliminate. The CAT4139 uses a fixed frequency (1MHz) switching architecture making it ideal for low noise applications. A high voltage CMOS output stage in the device allows 5 LED strings (up to 22V) to be accurately biased and regulated from a low voltage input supply while still delivering efficiency levels of up to 87%. The CAT4139 follows Catalyst’s CAT4240 high-power boost converter introduced earlier this year, which drives 10 LED strings up to 38V each.

To eliminate excessive “in-rush” currents which can occur during initial power-up, the CAT4139 offers an integrated soft-start control. In the event of an open-LED fault condition, an internal over-voltage protection circuit will place the device into a low-power operating mode restricting the output voltage to safe levels without the need for external circuitry. Both of these features are fully integrated, eliminating the need for external components and the associated cost and board space overhead.

Designers have a choice of controlling LED dimming in the CAT4139 using a DC voltage, logic signal, or pulse width modulation (PWM) signal.

Product Features
- Switch current limit 750mA
- Drives high voltage LED strings up to 22V
- 1MHz fixed-frequency, low-noise operation
- Fully protected
- Packaging: 5-lead TSOT23 (1mm max height)

Price and Availability

The CAT4139 LED driver is priced at $0.64 each in 10,000 piece quantities. Samples are available now. Projected lead-time for production quantities is currently 6 to 8 weeks ARO.