Help in selecting MOSFET for Project needs

Semiconductor Discrete Semiconductor Products
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11

Hello @Apex4446,

The circuit described by @rick_1976 is a classic and reliable solution. It works very well, but I once forgot the heatsink and burned my finger on the BJT.

Let me add two more thoughts to this conversation:

  1. The speed of turn on an off is dominated by the coil inductance. This article presents the situation for a coil. Another option is to focus on the tau = L/R aspects by adding a series resistor and increasing the drive voltage as described here.

  2. You could shift back to MOSFETS and PWM the coil directly as described in this note.

Welcome to open ended circuit design. May I recommend you refine your requirements to help guide you to a solution. Be sure to ask the meaning of a “wicked problem.”

While you are there, ask it why PWM drive of a 24 VDC via a series connected 240 VDC supply has merit. Know that it’s hardly ever done as it’s not worth the safety risk. Yet, you are on a quest for speed and should know di/dt.

Sincerely,

Aaron