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amanning
Feb 21st, 2019, 11:20 PM
In a motor control design I am using the 6EDL04N02PR gate driver IC. The motor control software is working well and nearly finished, so far so good.
Yesterday I implemented a safety feature to disable the driver in case the motor voltage gets too high during braking. This resulted in fireworks and smoke! The output FETs and gate driver were destroyed.

Can the enable input be used to let the motor free wheel? Is it OK to re-enable the driver while the the motor is still turning? Do the 6 PWM inputs need to be synchronized to the enable input when enabled or disabled?

Srivatsa
Feb 22nd, 2019, 02:19 PM
The 6EDL04N02PR acts as per the input provided. All outputs are set to LOW, if EN is at LOW logic level. When EN is HIGH, the outputs are driven by the input. In the above case when enable is low, all the output FETs are in blocking state and they could have failed first due to over-voltage
when the motor is free wheeling followed by the failure of the gate driver.

Instead of using the EN pin for protection, you can try by switching OFF the high side FETs and keeping the low side FETs ON till the excess energy from the motor is released.

OR use a DC bus break switch to eliminate DC-bus over voltage when the motor is driven in generating mode.