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How to calculate the surge voltage using MOSFET to drive stepper motor?

Latest Updated:09/02/2013

Question:

I would like to calculate the surge voltage when using a MOSFET to drive a stepper motor. Specifically, how would I calculate it?

Answer:

If the circuit for driving the stepper motor is the same as the avalanche destruction resistance test circuit in figure 2.6 on page 16 of the Power MOSFET Application Note, as shown in figure 2.6 V(BR)DSS (breakdown voltage of the MOSFET) surge voltage will be produced. This is operation outside of the rated VDS. Since the 2SK2415 and 2SK2415-Z do not permit continuous avalanche operation, always connect a free wheel diode in parallel with the load (stepper motor) to make sure that surge voltage is not produced when the MOSFET is turned off.

This article is written based on not recommended products.

Suitable Products
Power MOSFETs for General Switching