Depending on the orientation of a nulling coil I need an adjustable voltage supply from ~+5V to -5V upto ~200mA. I've tried a few circuits similar to Class AB amplifiers such as the one shown below, but these normally expect an AC coupled input. Has anybody got any other suggestions?
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1\$\begingroup\$ for a one-off lab application at 200mA x 10V, you can go with class A and a heat sink... i.e. simply an OPA with a BJT or MOS follower and a resitive minimum load \$\endgroup\$– Pete WCommented Jan 4, 2021 at 17:50
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3\$\begingroup\$ but wait, what are the available voltage rails from which you want to feed your adjustable supply? \$\endgroup\$– Marcus MüllerCommented Jan 4, 2021 at 17:53
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1 Answer
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You may want to consider a unipolar to bipolar level shifting circuit that is based on a power op amp. An example schematic is shown below. Instead of the DAC, you could simply use a potentiometer.
Regarding calculations, there is a good application note here, which should help you hit the ground running.
Keep in mind that you will need to ensure that the op amp can source/sink the necessary load current.
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1\$\begingroup\$ The app note you recommended is very good and inspiring: APPLICATION NOTE 5581 CHALLENGE THE CONVENTIONAL - MAKE UNIPOLAR DACS BIPOLAR By: Yuriy Kurtsevoy - Maxim Integrated, 2015 maximintegrated.com/en/design/technical-documents/app-notes/5/…. Thank you very much. Cheers. \$\endgroup\$– tlfong01Commented Jan 5, 2021 at 1:25