Electronics > Projects, Designs, and Technical Stuff
Linear Power Supply based on HP/Agilent E3610A
timsu:
Another update, now the digital circuit is done as well, with isolated serial port.
I decided to use an Arduino instead of using just an Atmega, because it does not really need that much more space.
The component selection is also mostly done.
Is the protection for all the op amps done right?
Kleinstein:
The protection at the OPs looks Ok. The current regulator might not need the diodes, as there usually will not be so much current to make the diodes work or even damage the OP.
If you want really low noise, RC filtering after the DAC might be helpful, but this slows down changes in the set voltage.
The TL072 can have quite some offset, this might limit the minimum current setting.
StillTrying:
You're asking too much of the LM393 to pull down 100R from 5V. (10mA max)
I'd try to invert the sense there and make the opto part of the pull up to 5V because I hate wasted milliamps. :)
R3 seems to have changed from 10K to 1K, needing the opto to sink ~28mA.
R22 doesn't do anything.
Didn't notice anything else.
Dave:
The serial interface isn't actually isolated.
timsu:
--- Quote from: Kleinstein on May 23, 2016, 06:10:40 pm ---The TL072 can have quite some offset, this might limit the minimum current setting.
--- End quote ---
Maybe the TLC 272?
--- Quote from: StillTrying on May 23, 2016, 08:13:26 pm ---You're asking too much of the LM393 to pull down 100R from 5V. (10mA max)
I'd try to invert the sense there and make the opto part of the pull up to 5V because I hate wasted milliamps. :)
--- End quote ---
Can you explain this a little bit more?
I thought about using something like this: http://www.mikrocontroller.net/attachment/45300/active-pullup.png
--- Quote from: StillTrying on May 23, 2016, 08:13:26 pm ---R22 doesn't do anything.
--- End quote ---
You're right, I forgot to remove it after I changed the protection diodes.
--- Quote from: StillTrying on May 23, 2016, 08:13:26 pm ---R3 seems to have changed from 10K to 1K, needing the opto to sink ~28mA.
--- End quote ---
Does 10K ensure fast enough switching of the MOSFET?
LTSpice shows about 2u seconds switching time with 10k.
--- Quote from: Dave on May 23, 2016, 09:02:50 pm ---The serial interface isn't actually isolated.
--- End quote ---
TX has to use an external 5V source, right?
Why did HP added resistors between GND and op amp input? (Example: R26 at the inverting input of the voltage error amp)
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