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I wanted to control electric door lock (12V, 1.5A peak, unlocking time < 200ms) with Self-Protected Low Side Driver like NCV8412 (https://hr.mouser.com/datasheet/2/308/1/NCV8412_D-2317556.pdf). One of driver's feature is: Integrated Clamp for Overvoltage Protection and Inductive Switching. Is driver safe when locker coil is not energized. Do I need flyback diode on locker contacts or driver's protection will be enough?

low side driver electric door lock

JYelton
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nikomas
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  • Consider availability/stocking. This protected driver is very neat, and a joy to use. Yet you can get equivalent functionality with a darlington, a resistor, and a TVS diode. Cost difference will be a wash, but you’ll never run out of those parts unless the civilization is gone or the design uses some very unpopular packages/footprints. – Kuba hasn't forgotten Monica Apr 20 '22 at 21:15

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Fig. 39 of the datasheet shows the voltage at the drain of the switching MOSFET rising to V(BR)DSS, which can be as high as 49V. This will protect the MOSFET, but if additional protection for attached circuitry is needed, then a flyback diode on the coil will clamp the voltage at that node to one diode drop above VDD.

vir
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