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8 years, 10 months ago.

PWM triggering pulse for mosfet gate switching

I nees to generate pwm pulse of frequency 15kHz (constant) for three different phases say 0, 120, -120/240. How to do that? Does it require three separate ARM LPC1768 microcontrollers for three mosfets or is it possible to trigger three mosfets with a single microcontroller.

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Last updated: 30 Apr 2020
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2 Answers

Erik -
8 years, 10 months ago.

The LPC1768 can on its regular PWM outputs create a three-phase PWM signal, however you need to dive into the hardware or see if someone else made a library for it already. It will cost you all 6 of the normal PWM outputs. (Only three are obviously used, but the other three cannot be used anymore). To do this you need to use the PWM block in dual-edge mode. More information is in the reference manual, and here is an example: https://developer.mbed.org/users/Lerche/notebook/double-edge-triggered-pwm/

Aditionally I believe the LPC1768 also has a motor control PWM, maybe this can also help, but I never looked at this myself.

Erastus Coetzee
8 years, 10 months ago.

Thanks nice info!!