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ADUM3223 H-Bridge Turn off issue

Question asked by chinu_hark on Jan 20, 2015
Latest reply on Jan 21, 2015 by RSchnell

I am working on a simple H-bridge inverter with the sole aim of testing the ADUM3223. 2 ADUM3223s are being used and both recieve inputs from an Arduino. The uC, and input sides of both driver ICs share 1 power supply (the one on the Arduino Board) and I am using 4 isolated 12V supplies for driving each of the switches.

Resistor between output and gate is 10 ohm and between gate and source is 1k. I tested with all 4 switches and for input HIGH, the gate voltage is 12V but when input is LOW, rather than giving zero volts output, the the driver gives 6 V. Thus for 0V and 5V inputs, the outputs are 6V and 12V respectively. This is exactly same for all 4 MOSFETs (and thus both ADUM3223 ICs). The Drain to source resistance is thus varying between 0 ohm and 1.2k, which is obvious since it is not turning off completely due to being at 6V.

Please help. I can't conclude that the particular sample is faulty as the same thing is happening for both ICs.

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