Phase-Shifted Full Bridge Converter (Synchronous FETs)
Description
This circuit has a phase shift between the left and right legs on the primary side and provides power to the secondary side only during the overlapping period. Since the duty of each leg is fixed at close to 50%, zero voltage switching (ZVS) operation is possible, which is suitable for high voltage (400VDC series, etc.) and several kW applications. It is often used for EV OBC and server DC-DC. The inductor at primary side is required for ZVS operation.
Overview
- Implementation with SJ MOSFETs (primary) and LV MOSFETs (secondary)
- Zero voltage switching (ZVS)
- Phase shift between both half-bridges for voltage / current control.
- Isolation transformer enables large step-down ratios
- Efficiency around 96%
- Frequency: 100..150 kHz
- SJ MOSFETs with robust & fast body-diode required --> PrestoMOS
Circuit
Key Products
| Product Category | Product family | Product Number | Feature |
|---|---|---|---|
| Primary Side (HV) | 600V SJ MOS | PrestoMOS (JNx series) | excellent switching behaviour (low Qrr, short Trr) |
| Secondary Side (LV) | 100V MOSFET | RQ3P300BH | 100V MOSFET in small HSMT8 package |
| 40V MOSFET | RS1G300GN | 40V MOSFET in HSOP8 package | |
| Gate Driver | HV side | BM60212FV-C | Dual driver, ideal for half- and full-bridge topologies. |
| LV Side | BD85506F | Synchronous rectification controller IC |
Simulation
Coming soon
Related Topologies
LLC Converter (Full Bride, Synchronous FETs)