Hi, I have a simple circuit that is used to switch a 31kHz PWM @12V on a low resistance inductive load. I understand that I have to put a fast switching diode across the inductive load and also a TVS diode across the Mosfet's source and drain. My problem is that I have no idea how to work out which diodes I need.
The Mosfet is a P-Channel IRF9540
The load's inductance and resistance can vary, typically will be about 1.5 ohms and 120uH but can be as low as 0.7 ohms.
Can anyone enlighten me as to which diodes I should select in order to protect the Mosfet from damage?
The inductive load is held in the hand and its casing is grounded. I can feel a tingle from the thing when the PWM signal is flowing through it. Is this because of the back emf problem? Would attaching the protection diodes stop this happening?
Thanks,
Jim
The Mosfet is a P-Channel IRF9540
The load's inductance and resistance can vary, typically will be about 1.5 ohms and 120uH but can be as low as 0.7 ohms.
Can anyone enlighten me as to which diodes I should select in order to protect the Mosfet from damage?
The inductive load is held in the hand and its casing is grounded. I can feel a tingle from the thing when the PWM signal is flowing through it. Is this because of the back emf problem? Would attaching the protection diodes stop this happening?
Thanks,
Jim
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