New Industry Products

TI Intros UCC2891/2892/2893/2894 PWM Controllers

December 14, 2003 by Jeff Shepard

Texas Instruments Inc. (TI, Dallas, TX) announced four new pulse-width modulation (PWM) controllers (the UCC2891, UCC2892, UCC2893 and UCC2894) that significantly simplify implementation of active clamp/reset topologies for high-efficiency switching power supplies. The peak current-mode controllers increase efficiency in off-line power supplies and dc/dc converters used in high-end desktops, servers, 48V telecomm, data communications and 42V automotive systems.

Suitable for active-clamp forward or flyback converters, the UCC2891, UCC2892, UCC2893 and UCC2894 feature an auxiliary active-clamp output driver for efficient single-ended transformer reset; an internal, programmable, slope compensation circuit; a precise maximum duty-cycle limit; a 1MHz synchronizable oscillator with an internal timing capacitor; a programmable soft-start and shutdown functionality; and an accurate line-monitoring function that can program a converter’s on/off transitions when determining bulk input-voltage levels. The controllers reduce switching losses of the converters by programming critical delays to achieve proper active clamp operation and deliver zero-voltage switching to the primary side MOSFET switches.

The new UCC289x PWM controllers are available in volume, in both 16-pin SOIC package and low-profile TSSOP packages. Pricing for the UCC2892 and UCC2894 is $1.49 in quantities of 1,000 units. Pricing for the UCC2891 and UCC2893 with internal 110V startup is $1.57 in quantities of 1,000 units. Evaluation modules of a 100W, 48V to 3.3V converter in a half-brick format are available in less than 24 hours.