EEVblog Electronics Community Forum

EEVblog => EEVblog Specific => Topic started by: SZA on October 09, 2013, 03:52:02 am

Title: Buck boost using 555 timer / PWM - 555
Post by: SZA on October 09, 2013, 03:52:02 am

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) :-//

Title: Re: Buck boost using 555 timer / PWM - 555
Post by: poorchava on October 09, 2013, 08:59:15 am

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).

Title: Re: Buck boost using 555 timer / PWM - 555
Post by: Psi on October 09, 2013, 10:28:56 am

TL494 is another useful PWM psu control chip.
You can often salvage them from old electronics, ATX power supplies, car amps, etc.