Preference of one circuit over another

Thread Starter

kiwi101

Joined Feb 18, 2014
38
Hey guys

In order to get a PWM signal I have chosen to use the second circuit with the Schmitt Trigger and Comparators. However the 555 timer circuit is also a valid method to obtain a PWM Signal. My question is are there any drawbacks of the 555 timer circuit so that I may explain why I chose to go with my circuit implementation. I have to make a Pugh matrix for these circuits so in terms of flexibility, cost, implementation which one do you guys think is better, and why?
The only point I have right now is that I need a 200kHz signal and since the frequency is large the second circuit is easy to go with. Is this a valid assumption or no?

Thanks guys.
 

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Dodgydave

Joined Jun 22, 2012
11,285
go with the 555 timer, its designed for timers and oscillators, less components,less to go wrong, to alter the speed change C1.
 
Last edited:

OBW0549

Joined Mar 2, 2015
3,566
I'd say go with the 555 circuit, but make one change: use a CMOS 555 like the LMC555 or the TLC555. They take less power and they can work at higher frequencies.
 

Thread Starter

kiwi101

Joined Feb 18, 2014
38
I already went ahead with the other configuration and after slaving for hours got my simulations to work and so I can't really go with the 555 timer, I wish I would've done that before.
Is there any justification I can give for going with the other circuit configuration?
I basically have to explain why I chose this over the 555 timer circuit.
 
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