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PWMMAC eTPU API inconsistent behavior

Question asked by PRAMOD ukirde on Dec 3, 2018
Latest reply on Dec 10, 2018 by David Tosenovjan

We are using PWMMAC etpu library functions. We have observed the unclear behavior of this API.

 

Our assumptions based on application note (AN2969) is - 

When the duty cycle is configured in such a way that the On time of pulse is lower than half the dead time, the PWM turns off.

 

But our observations are different,

e.g.

When we try to give switching frequency of 20 Khz, dead time of 3.2 microseconds,  Duty cycle = 10% (5 microsecond),

we expect the pulse width of 1.8 microsecond, but we get 2.79 Microseconds.

 

we exercise this for different duty cycles but we didn't observe the consistency. 

 

Can you please explain this behavior?

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