The UCC28951PWR device is an enhanced version of theUCC28950. It is a fullycompatible drop-in replacement for the UCC28950. Refer to application note SLUA853 to determine which controller to use. The UCC28951PWR uses advanced control of the full-bridge in addition to active control of thesynchronous rectifier (SR) output stage.
Programmable delays ensure ZVS operation over a wide range of operating conditions, whilethe load current naturally tunes the switching delays of the secondary-side synchronousrectifiers(SR). This functionality maximizes overall system efficiency.
The UCC28951PWR has many light-load management features includingburst-mode operation and dynamic SR ON and OFF control during transition into and out ofdiscontinuous current mode (DCM) operation. The device operates in current-mode or voltage-modecontrol. The switching frequency can be programmed up to 1 MHz. The device has protection featuresincluding cycle-by-cycle current limit, UVLO, and thermal shutdown.
The 24-pin, TSSOP package complies with RoHS requirements .
Feature
- Enhanced Zero-Voltage Switching (ZVS) Range
- Direct Synchronous Rectifier (SR) Control
- Light-Load Efficiency Management Including:
- Burst Mode Operation
- Discontinuous Conduction Mode (DCM), Dynamic SR On/Off Control With Programmable Threshold
- Programmable Adaptive Delay
- Average- or Peak-Current Mode Control With Programmable Slope Compensation and Voltage-Mode Control
- Closed-Loop Soft-Start and Enable Function
- Programmable Switching Frequency up to 1 MHz With Bidirectional Synchronization
- (±3%) Cycle-by-Cycle Current Limit Protection With Hiccup Mode Support
- 150-μA Start-Up Current
- VDD Undervoltage Lockout
- Wide Temperature Range: –40°C to +125°C
