Buck boost using 555 timer / PWM - 555

• Buck boost using 555 timer / PWM - 555
  Posted by SZA on 09 Oct, 2013 03:52
• Im currently using a similar circuit to drive a MOSFET. The required frequency is 50kHz, how do i achieve this (calculations / formula)?
  
  IS there any way to obtain variable frequency? (what if we replace the 1k with pot)

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• #1 Reply
  Posted by poorchava on 09 Oct, 2013 08:59
• Why an NE555? It's good for many things, but you can make way better SMPS with dedicated chips (starting with a $0.10 MC34063).
  
  
• #2 Reply
  Posted by Psi on 09 Oct, 2013 10:28
• TL494 is another useful PWM psu control chip.
  You can often salvage them from old electronics, ATX power supplies, car amps, etc.