Catalyst LED driver optimized for rapidly growing, mid-size LCD panel market

Content Dam Leds En Ugc 2007 11 Catalyst Led Driver Optimized For Rapidly Growing Mid Size Lcd Panel Market Leftcolumn Article Thumbnailimage File
15676 0 thumb Date Announced: 14 Nov 2007

SANTA CLARA, Calif., -- Catalyst Semiconductor, Inc. (NASDAQ:CATS) a supplier of analog, mixed-signal and non-volatile memory semiconductors has expanded its line of high-power LED drivers with a new device optimized for the rapidly growing mid-size LCD panel market. The new CAT4139 boost converter provides a switch current up to 750mA and drives LED strings up to 22V, making it an ideal choice for digital photo frames and other backlighting applications where high LED counts (up to 40 LEDs) are emerging.

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.

About Catalyst Semiconductor
Headquartered in Santa Clara, California, Catalyst Semiconductor designs and markets analog, mixed-signal and non-volatile memory products, including Digitally Programmable Potentiometers (DPP™), white and color LED drivers, DC/DC converters, LDO regulators, voltage supervisors, bus expanders, serial and parallel EEPROMs, Flash and NVRAM. Many of Catalyst’s products incorporate the Company’s Quantum Charge Programmable™ technology, to deliver Adaptive Analog™ products, which offer a new level of customer flexibility, lower power and smaller die size. Catalyst products are used in telecommunications, computer, automotive, industrial and consumer markets. Typical applications include LCD displays, automotive lighting, optical networks, printers, modems, wireless LANs, network cards, DIMM modules, cellular telephones, navigation systems, set-top boxes and Internet routers.

Catalyst Semiconductor, Inc. Telephone: +(1) 408-542-1080


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