PWM controller offers 95% efficiency

Texas Instruments has introduced two high efficiency pwm power supply controllers with integrated programmable delay synchronous rectifier control outputs and pre bias start up circuitry.

The UCC28250 and UCC28950 'green controllers' are said to simplify design and boost efficiency in high density isolated power supplies for telecommunications, server and industrial systems. They support multiple high frequency topologies, such as half bridge, full bridge, interleaved forward and push pull.

Ti claims the UCC28250 is the industry's first half bridge or full bridge pwm controller with the ability to maintain a monotonic output voltage ramp under pre biased load conditions, eliminating the need for external circuitry. It can support primary or secondary side control and delivers up to 95% efficiency.

The UCC28950, which provides two additional pwm outputs for phase shifted full bridge control up to 600W, is designed to achieve greater than 90% efficiency. The controller integrates synchronous rectifier control and provides adaptive zero voltage switching to reduce switching loss. It is targeted at high density power architectures in industrial, telecom and dc motor drives.