Hi, could anyone help me with SG3525? I have a PWM circuit with SG3525 and need to modify the circuit so that I can get ~0.2 Hz cycle period. This is very slow compared to most of the circuits that I can get. Probably, I can change the frequency by changing the capacitor or resistor at Rt and Ct (pin 5 and 6), but I don't know the equation to calculate those. Please help me!!!
PWM with SG3525
Aug 13, 2004
1 Replies
How do. For questions like this, nothing beats the data sheet:
formatting link
It says the approximate frequency is:
1 f = 1/(CT (0.7 RT + 3 RD))However, the datasheet also says the minimum practical frequency for the SG3525 is about 100 Hz. If you're looking for 0.2 Hz, you'll have to look for another PWM IC, roll your own PWM with an op amp or comparator, or just use a PIC. The last solution is probably the preferred one if you need a PWM which has a 5 second cycle time.
Good luck Chris
Join the Discussion
Have something to add? Share your thoughts — no account required.
Didn't find your answer?
Ask the community — no account required