Phase-Shifted Full-Bridge Controller with Synchronous Rectification using UCC28950

This Phase-shifted Full-Bridge controller with synchronous rectification carrier board contains all of the features necessary to implement a phase-shifted full-bridge with a synchronous rectification topology power converter. All inputs and output pins are accessible using a header connector. A High-efficiency DC-DC converter can be created using this carrier board + external H-Bridge and Transformer. Refer to the datasheet of UCC28950 and schematic to configure the various frequencies, current feedback, voltage feedback and delays.

Features

• Operating power supply 12V (Range 8V to 17V DC)
• Internal reference voltage 5V
• Converter switching frequency setting range, FSW (nom) 50-1000Khz
• Programmable delay range between OUTA, OUTB and OUTC, OUTD set by resistors DELAB and DELCD and parameter KA(1) : 30ns-1000ns
• Programmable delay range between OUTA, OUTF and OUTB, OUTE set by resistor DELEF, and parameter KEF(1): 30ns-1400ns
• Programmable DCM range as percentage of voltage at CS(1) : 5% – 30%
• Programmable TMIN range: 100ns-800ns
• Enhanced Wide Range Resonant Zero Voltage Switching (ZVS) Capability
• Direct Synchronous Rectifier (SR) Control
• Light-Load Efficiency Management Including
• Burst Mode Operation
• Discontinuous Conduction Mode (DCM), Dynamic SR On and Off Control with Programmable Threshold
• Programmable Adaptive Delay
• Average or Peak Current Mode Control with Programmable Slope Compensation and Voltage Mode Control
• Naturally Handles Pre-Biased Start Up with DCM Mode
• Closed Loop Soft Start and Enable Function
• Programmable Switching Frequency up to 1 MHz with Bi-Directional 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
• PCB Dimensions 36.20 x  25.24 mm

Connections: Connectors CN1

• Pin 1 VS = Voltage Sense (Voltage Feedback)
• Pin 2 VCC = Power Supply 12V DC (Range 8V-17VDC)
• Pin 3 = GND
• Pin 4 = Enable/Soft start
• Pin 5 = Output A
• Pin 6 = Output B
• Pin 7 = Output C
• Pin 8 = Output D
• Pin 9 = Output E
• Pin 10 = Output F
• Pin 11 = SYNC
• Pin 12 = GND
• Pin 13 = Current Sense (Current Feedback)
• Pin 14 = VREF 5V DC

The UCC28950 enhanced phase-shifted controller builds upon Texas Instrument’s industry standard UCCxx8950 phase-shifted controller family with enhancements that offer best-in-class efficiency in today’s high-performance power systems. The UCC28950 implements advanced control of the full-bridge along with active control of the synchronous rectifier output stage.

The primary-side signals allow programmable delays to ensure ZVS operation over wide-load current and input voltage range, while the load current naturally tunes the secondary-side synchronous rectifiers switching delays, maximizing overall system efficiency.

The UCC28950 also offers multiple light-load management features including burst mode and dynamic SR on/off control when transitioning in and out of Discontinuous Current Mode (DCM) operation, ensuring ZVS operation is extended down to much lighter loads.

In addition, the UCC28950 includes support for current or voltage mode control. Programmable switching frequency up to 1 MHz and a wide set of protection features including cycle-by-cycle current limit, UVLO and thermal shutdown. A 90-degree phase-shifted interleaved synchronized operation can be easily arranged between two converters.

Schematic

Parts List

Connections

Block Diagram

Typical Application

Timing Diagrams

Gerber View

Photos

Video

UCC28950 Datasheet

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