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Bipolar current driver

A bipolar current driver that can output up to 8A continouosly if you can cool it. It is based on the opa549 OPamp. The idea comes from the paper “Ultra-low noise and high bandwidth bipolar current driver for precise magnetic field control”, https://doi.org/10.1063/1.5046484. Have fun.

Up to now it has only been tested for current up to 1A and in the electronic workshop.

Date

Start of the project: Middle of 2021

Author

Martin Quensen, quensen@iqo.uni-hannover.de

Anwender

None, so far.

Schematic and layout

A OPA549 gives out some current that is send through some device (e.g. a coil) and finally a reference resistor. The voltage drop there is measured with an instrumentation amplifier. At an OPamp in PI-controller circuit is is compared to a setpoint signal and the difference signal is proportionally amplified and integrated over. The resulted voltage is now applied at the OPA549, in voltage follower circuit. The setpoint signal can be applied via BNC, and there is also the option to use a trimmer for a constant offset.

The layout is designed as two boards. One for the control (reference resistor, PI OPamp, instr. amps …) and the other for the OPA549.

It is meant to fit inside a standard 19“ 1 HE casing.

Issue list

What to improve: (:no:: discarded, :Ok:: at work, :OK:: done 8-) )

  • There are too many pads for the output current. Not needed.
  • The PI-controller OPamp has a pin distribution that does not fit to its footprint, I think.