PWM signal generating circuit based on LM393

AI Thread Summary
The LM393-based PWM signal generating circuit operates efficiently at low power consumption, functioning across various voltages, but is unsuitable for switching power supplies due to the absence of dead time. Modifications are suggested to incorporate dead time, which is essential for certain applications, particularly in multi-phase PWM signals. The discussion highlights the need for appropriate gate driver circuits and clarifies the relevance of dead time in the context of the specific switching supply topology being considered. Experts recommend using dedicated ICs for SMPS design, as they offer improved functionality and simplicity compared to the LM393 circuit. The SG3525A is mentioned as a viable alternative that includes necessary features for two-phase PWM applications.
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This is a PWM signal generating circuit based on LM393 but cannot be used in switching power supplies. How can I do?
This is a PWM signal generating circuit based on LM393.
LM393 PWM Circuit.jpg


When I was running this LM393 circuit, I found that this circuit only consumes about 10 milliwatts of power at a voltage of 5V. Not only that, this circuit can work normally at 3.3V, 12V and 18V.
But later I found that this circuit cannot be used in switching power supplies.

It is missing something: dead time.So I would like to ask you how to make some changes to this circuit?
 
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A switching supply may only need uni-polar drive, so dead time may not be needed.
I think you must also show the gate driver and the output stage you will use.
Many gate drivers include a dead time circuit.
What type of switching supply are you considering, buck or boost ?
 
I'm not sure what you mean by dead time in a single PWM waveform. That concept is normally applied to a two phase PWM signal. So perhaps you could elaborate on your circuit requirements? What SMPS topology? What transistor drive circuits?

This circuit could be used in some SMPS, as @Baluncore said. But, no one designing a SMPS would use it. There are about million ICs dedicated to controlling power supplies which are simpler, work better, and usually will provide other necessary functions. You can start by looking at the TI website, they provide lots of parts and information about this stuff. Analog Devices is another good place to look.

One ancient IC that does provide two phase PWM with dead time (plus other stuff) is the SG3525A, have a look at that one.
 
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