Author Topic: LM324 Power Supply with variable voltage and current  (Read 19713 times)

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Online xavier60

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Re: LM324 Power Supply with variable voltage and current
« Reply #725 on: October 19, 2019, 12:56:29 pm »
I forgot to specify that the mentioned R25 voltage was measured with 100 mA load at 15V output voltage.
That's OK. The 1.35V was a result of my guess that the PNP driver's B-E was 0.5V.
Im certain that there will be no more problems to be found with the design.
You can easily use your basic electronics knowledge to work out why some things are the way they are.
 
Added: The output voltage has no affect on the operating conditions of Q1, only output current does.
With one exception, when regulation is lost due to dropout.
« Last Edit: October 26, 2019, 08:47:33 am by xavier60 »
Hioki AS100D vom, HP 54645A dso, Fluke 87V dmm, AN8008 dmm, Agilent U8002A psu,  FY6600 function gen, New! Brymen BM857S-(With Battery)
 

Online Cliff Matthews

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Re: LM324 Power Supply with variable voltage and current
« Reply #726 on: October 23, 2019, 09:26:52 pm »
OP: Are you sharing any final schematic or gerber files?  Did you resolve the final value of R32 or R25?
 

Offline mike_mike

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Re: LM324 Power Supply with variable voltage and current
« Reply #727 on: October 24, 2019, 11:07:39 am »
Please find attached the schematics in Eagle and in LTSPice.
Please ask if you need Eagle files.
I marked a few components with dnp - do not place and with strap - the component will be replaced by a wire.
« Last Edit: October 24, 2019, 11:36:52 am by mike_mike »
 
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Online xavier60

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Re: LM324 Power Supply with variable voltage and current
« Reply #728 on: October 28, 2019, 12:07:27 am »
I'm not certain of how the CC loop's settling time constant should be tested and how important it is, I suspect not very.
I used this test with my bench supply project and my Agilent U8002a.
I set the CV to 10V and CC to 1A. I manually connected a 5Ω load while capturing the voltage decay on my DSO.
I then noted the time taken for the voltage to drop from 10 to 6.8.

My bench supply project,  300µs
Agilent U8002a,    1.2ms

Hioki AS100D vom, HP 54645A dso, Fluke 87V dmm, AN8008 dmm, Agilent U8002A psu,  FY6600 function gen, New! Brymen BM857S-(With Battery)
 


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