News | March 17, 2008

Catalyst Quad-Mode LED Driver Offers Interface Control For Portable Device Backlighting

Santa Clara, CA — Catalyst Semiconductor, Inc. has expanded its line of patented Quad-Mode fractional charge pump LED drivers with a new device optimized for portable products. The new CAT3637 addresses the requirements for high-efficiency and easy LED programming in these products, with 10 percent higher efficiency (compared to three-mode charge pumps) and a simple, 1-wire EZDim interface control.

The CAT3637 is optimized for applications with one bank of five or six identical LED channels, a typical configuration for larger LED screen portable products. The device incorporates a simplified version of Catalyst's already easy-to-use, 1-wire EZDim interface, which supports 16 output power levels, from zero to 30mA full brightness 2mA resolution steps. With efficiency levels as high as 92 percent, no added capacitors required, and a tiny 3 x 3mm, low-profile TQFN package, the Quad-Mode CAT3637 saves significant board space and costs in next-generation portable products.

According to Scott Brown, Vice President of Marketing for Catalyst Semiconductor, "When it comes to LED-based products, we are seeing a wide variety of design approaches throughout the market, depending on the customer and application. The CAT3637 is the fifth device in Catalyst's Quad-Mode product line and exemplifies our strategy to be a "one-stop" vendor for a broad range of LED drivers which address this diversity of customer requirements."

The CAT3637 joins the following devices in Catalyst's Quad-Mode family of LED drivers: the CAT3604V four-channel LED driver with PWM dimming interface; and the CAT3636 six-channel, CAT3644 four-channel and CAT3643 three-channel devices with 1-wire EZDim interface.

Product Features

  • Patented Quad-Mode high-efficiency charge pump switching architecture
  • Easy-to-use, 1-Wire EZDim interface control
  • Fourth charge pump mode achieves 1.33x boost mode with only 2 flying capacitors
  • Power efficiency up to 92 percent
  • Drives up to 6 LEDs at 30mA each, in 2mA steps
  • Fully protected
  • Packaging: 16-pad TQFN, 3mm x 3mm

About Quad-Mode
Catalyst's patented Quad-Mode adaptive fractional charge pumps take LED driver performance to a new level by offering a 10 percent efficiency improvement, without the need for an additional capacitor, and with no price premium. The Quad-Mode switching architecture delivers efficiency levels as high as 92 percent, with a lifetime average efficiency of 84 percent, yet saves significant board space and costs.

Catalyst's innovative, patented Quad-Mode charge pump architecture delivers the high efficiency levels normally associated with inductor-based LED drivers, while eliminating the associated high-profile inductors and unwanted EMI. Most charge pump LED drivers today offer three modes of operation corresponding to the ratio of the output voltage to the input voltage: 1x, 1.5x and 2x. The Quad-Mode architecture adds a fourth mode of operation, 1.33x, without the need for the additional capacitor required by all existing four-mode charge pumps. The 1.33x fractional operating mode also reduces the input switching currents seen at the battery, minimizing the overall supply noise – a critical parameter in portable devices.

SOURCE: Catalyst Semiconductor, Inc.