I generate a PWM signal on a pin going from duty cycle 0 to 100 and back to 0% to generate a sine wave using an LC Filter. When I connect the LC filter, the output is still an PWM with some spikes. C = 147µF L = 47µH f = 1,91 kHz

[MSpir.2]

[waclawek.jan]

> When I connect the LC filter

How exactly?

JW

[TDK]

Did this really need another topic?

https://community.st.com/s/question/0D53W00001UWkTxSAL/pwm-signal-resonancedistorted-when-adding-lc-filter

[MSpir.2]

problem of that topic is solved

facing other now

[MSpir.2]

[TDK]

It's the same underlying issue as the other one. The STM32 isn't outputting the spikes, it's an artifact of how you're measuring.

Probably wise to reduce GPIO speed to mask some of the effect.

[MM..1]

You disconnect something ... Too maybe you need learn I=U/R (pin can drive only limited current)

Normal PWM use RC not LC .