Power Electronics

Single-Chip Interleaved PWM Controllers

The new UCC28220 and UCC28221 from Texas Instruments (TI) is 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.

These peak current-mode controllers use advanced interleaving techniques 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.

Enabling higher power density than competing two- or three-chip solutions, the UCC28220 and UCC28221 PWM controllers provide an accurate maximum duty clamp, which can be programmed between 60% to 90% duty cycles per channel. The controllers also include programmable soft start and highly accurate (within 1%) input line undervoltage (UV) and overvoltage (OV) thresholds with programmable hysteresis for each threshold. Additionally, the UCC28221 has a 110-V start-up device that removes the need for an external trickle charge boot strap resistor to help save cost.

For more information, visit www.ti.com.

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