PWM Controllers Are Green And Efficient

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The UCC28250 and UCC28950 green controllers integrate synchronous rectifier outputs and pre-bias start-up to support multiple isolated power supply topologies. Promising simplify design and boost efficiency in high-density isolated power supplies, the devices support topologies such as half-bridge, full-bridge, interleaved forward, and push-pull. The UCC28250, called 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, eliminates the need for external circuitry. It supports primary- or secondary-side control and delivers up to 95% efficiency. The UCC28950 provides two additional PWM outputs for phase-shifted full bridge control up to 600W. It achieves greater than 90% efficiency, integrates synchronous rectifier control, and provides adaptive zero voltage switching over a wide input and output voltage range. Prices for the UCC28250 and UCC28950 are $1.70 and $4.25 each/1,000, respectively. TEXAS INSTRUMENTS INC., Dallas, TX. (800) 477-8924.