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ADuM3220 driving H-bridge N-mosfet

Question asked by DDer on Jan 20, 2014
Latest reply on Jan 21, 2014 by RSchnell



I am having problem when driving my half bridge of N-mosfet using ADuM3220. Hope to have advice from here.

Adum3220 driving bridge PNG.png


I would like to ask whether:

- Is there any problem with the circuit?

- Is it a must to add a diode between the gate and source of the MOSFET?

- During testing, my output (load + or load -) is clipped at the my gate voltages instead of my bridge voltage, why is this so?

- There are times, my gate driver was damaged with output latch high, is there any way to mitigate it?

- Can I use 1 ADuM3220 to drive half bridge?


Detail of the circuit:

No load is connected yet.

Input driver voltage = 5V

Output driver voltage = 12V

Bridge voltage = 75V

Switching frequency = 50kHz and 400kHz (tried there 2 frequencies)

1A = signal 1

1B = inverted 1A

2A = signal 2

2B = inverted 2A


Previously, I have successfully used a separate opto-couplers and gate drivers to drive the bridge and was hoping that the smaller form factor of ADuM3220 can improve my circuitry.