Pwm to linear voltage

hi all,

i am using 8051 and making a pwm of 0 to 1ms varyation. this pwm output need to convert it to linear voltage (dc). what i need to do?? rc filter ? if yes how can i measure the values of components.


10x :wink:

If your frequency is 1kHz, R=158K, C=0.1uF will put the ripple down 40 dB (1/100) at 1 kHz. In general, if you want the ripple to be down 20dB (1/10) use the formula: R*C = 1.58/F Where F is the 20dB frequency. To be down 40dB (1/100) use: R*C = 15.8/F and for each 20 dB lower, move the decimal point one place to the right. This formula is not accurate for frequencies less than F=1.58/R/C.

Check the MicroChip website, they have an application note about filtering PWM.

do you have the link of the micro chip application?
10x

bajgik said:

do you have the link of the micro chip application?
10x

Click to expand...

I didn't, but a simple search under their documants section soon finds **broken link removed**