PWM signal generating circuit based on LM393

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SUMMARY

The PWM signal generating circuit based on the LM393 operates efficiently at power levels around 10 milliwatts across multiple voltages (5V, 3.3V, 12V, and 18V). However, it is unsuitable for switching power supplies due to the absence of a dead time feature. For applications requiring dead time, utilizing dedicated ICs like the SG3525A is recommended, as they are specifically designed for power supply control and offer enhanced functionality. Alternative resources such as Texas Instruments and Analog Devices provide a wide range of suitable components for switching power supply designs.

PREREQUISITES
  • Understanding of PWM signal generation
  • Familiarity with LM393 operational amplifier
  • Knowledge of switching power supply (SMPS) topologies
  • Experience with gate driver circuits
NEXT STEPS
  • Research the SG3525A PWM controller for dual-phase operation
  • Explore Texas Instruments' resources on power supply ICs
  • Study Analog Devices' offerings for switching power supply components
  • Learn about implementing dead time in PWM circuits
USEFUL FOR

Electronics engineers, power supply designers, and hobbyists interested in PWM circuit design and switching power supply 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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