Texas Instruments Incorporated announced the industry´s first single-chip, interleaved pulse-width modulation (PWM) controllers for 50-A to 100-A high current power supplies in off-line and DC/DC converters used in computer servers, telecom, datacomm and consumer systems such as plasma display products. TI’s new UCC28220 and UCC28221 peak current-mode controllers use advanced interleaving tech niques to control two isolated power stages to maximize power density, reduce output current ripple and improve transient response. The devices, available in either interleaved forward or interleaved fly-back isolated topologies, integrate two PWM channels operating at 180 degrees out of phase to control one high current output. In addition, the controllers provide programmable internal slope compensation with an internal circuit to precisely match currents between the two channels. The controllers also include programmable soft start and highly accurate (within one percent) input line under-voltage (UV) and over-voltage (OV) thresholds with programmable hysteresis for each thresh old. Additionally, the UCC28221 has a 110-V start-up device that removes the need for an external trickle charge bootstrap resistor to help save cost.
The first single – chip interleaved PWM controllers
1 JANUARY 2003