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Applying PWM to load while controlling its current

farzadlatifeh

Dec 1, 2019
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Dec 1, 2019
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Hey there
I have an electrolysis cell to produce brown's gas from water, in the process gas barrier decreases efficiency of cell while it may consume huge amounts of current too.
So, I need to apply PWM pulses to increase electrode efficiencies and control current consumption in one circuit.
I have this current limiter example "circuit one"
And this simple PWM generator "circuit two"
But I have no clue how to couple them in one circuit for load full control, I mean can I just use one FET in series with load that PWM circuit controls it? Is that so simple though? Or I should do some modifications to reach the target!
If anyone here can help me, I'll be really appreciated.
 

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duke37

Jan 9, 2011
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Q1 is always turned off, it needs several volts on the gate to turn on. You could use a p-channel for Q1
A low pass filter is shown. Will this compete with the 555 output frequency and just give a smoothed output.
I see no circuit to turn Q1 on and off quickly to minimise heating in the transistor.
What is brown's gas, is that the colour or should it be Brown's gas?
 

Alec_t

Jul 7, 2015
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Jul 7, 2015
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As suggested on another forum, you could PWM another FET in parallel with Q2.
 
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