Converting PWM to Analog

[[email protected]]

Hi all,

Currently, I have a microcontroller that puts out a 1000Hz signal but
the low-pass filter I have built only converts PWM to analog for a PWM
carrier frequency of about 10kHz. Is it possible to adjust the PWM
frequency that will work for the filter? I'm using a 3rd order, op-amp
LPF, shown in this link..

http://www.eetasia.com/ART_8800105813_499489_AN_785b6341.HTM

(hit view this PDF)

FIgure 8

Thanks.
Joe

 

[[email protected]]

Hi all,

Currently, I have a microcontroller that puts out a 1000Hz signal but
the low-pass filter I have built only converts PWM to analog for a PWM
carrier frequency of about 10kHz. Is it possible to adjust the PWM
frequency that will work for the filter? I'm using a 3rd order, op-amp
LPF, shown in this link..

http://www.eetasia.com/ART_8800105813_499489_AN_785b6341.HTM

(hit view this PDF)

FIgure 8

Increase the capacitors in the filter by a factor of ten to match the
frequency you can produce, or lower the resolution of the PWM scheme
so that you can run it at a repetition rate of 10kHz, or get a faster
mocrocontroller that offers a higher clock frequency, or run the PWM
process in a programmable chip which can be clocked more rapidly than
the (crap) microcontroller that your instructor offered you.

The possibilities are endless. The fact that you couldn't think of any
of them for yourself suggests that yours are rather more restricted.