Bidirectional DC-DC power board based on UCC21520

A bidirectional DC/DC converter enables bidirectional energy transfer. Forward discharge typically requires an adjustable output voltage, while reverse charging usually requires a constant charging current. The bidirectional energy transfer can be controlled via PWM control through a microcontroller using the provided interface.
 
The gate driver chip is the UCC21520DWR, an isolated dual-channel gate driver with 4A source current and 6A sink current capability, supporting high switching frequencies and providing high isolation.
R1 and R2 provide impedance matching and limiting circuitry, protecting the microcontroller's I/O ports and reducing reflections to prevent oscillations during high-speed control signal generation.
D1 and C6 form a bootstrap circuit. D1 is a CD4148WSP switching diode with a forward voltage drop of 75V and a direction recovery time of 4ns, meeting the control frequency and voltage requirements. C6 acts as the bootloader with a capacitance of 100nF. This capacitor should not be too large, as this would reduce the charging time, and the low-side conduction time might be insufficient to reach the bootstrap voltage.
D2 and R5 constitute a MOSFET fast turn-off circuit, accelerating the MOSFET's turn-off speed and reducing losses. If R5 is too large, it will increase switching losses and pose a risk of parasitic conduction; if it is too small, it will cause circuit oscillation. Therefore, in actual circuits, the value of R5 needs to be adjusted by measuring the gate signal with an oscilloscope, finding a suitable compromise.
In the DC-DC converter circuit, the 30N06 MOSFET is selected as the DC-DC conversion control element. This MOSFET has a drain-source voltage of 60V, a continuous drain current of 30A, and a Vgs of 29mΩ@15A, 10V.