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How can I explan this simple PWM creator Circuit

harli03

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Can you say me how to explain the Uoutput of this circuit?How it works?
 

betwixt

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It doesn't.

If 'Uoutput' is the voltage at the drain of M1, it will be V1 divided by R1 and the Rds of M1 . Probably just a much smaller version of V1.
It doesn't generate PWM at all.

Brian.
 

d123

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Hi,

Swap V1 and V2 over to begin with, or make V2 switch faster and slower to get a feel for the very rough idea of pwm. The mosfet has to switch on and off to pass more or less of a varying supply voltage to maintain a constant voltage or current at the drain, sensing feedback at the source would be easier. Mosfet switching between time on to time off has to be based on a feedback signal that senses Vout and compares it to a reference value.
 

KlausST

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Hi,

PWM generation with discrete parts needs at least a capacitor for timing setup.

(I gues I have not designed an active circuit in the past 30 years without a capacitor. At least a power supply decoupling capacitor is essential...)

Klaus
 

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