Circuit Design of 16.5W Forward Synchronous Rectifier DC-DC Converter

GW MB10F 0.8A 1000V rectifier bridge

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

Summary:

DPA-Swi tch greatly simplifies the design compared to designs that use separate devices. Resistor R1 sets the under/overvoltage protection and linearly reduces the maximum duty cycle as the input voltage changes, preventing saturation of the core during load transients. Resistor R3 sets the internal current limit of DPA-Swi t ch to 60% of the nominal value, limiting the power at fault and overload. Zener VR1 clamps the drain voltage. The gate capacitance of Q1 controls the core reset.

Resistor R15 charges the gate of forward synchronous rectification MOSFET Q2. The transformer (T1) reset voltage directly drives the freewheeling synchronous rectification MOSFET (Q1) and only operates when Q2 is turned off. When the transformer reset is complete, diode D2 provides a path for the output inductor.

design feature

• low cost
• 400 kHz synchronous rectification design
• Small number of components
• Efficiency - 87% at 48 VDC input
• No need for current sense resistors or current transformers
• Output overload, open loop and over temperature protection
• Integrated UV function in accordance with ETSI standards

3.3V, 5A DC-DC converter circuit diagram

See the uploading documentation for details (click to download)