TT061: 1A Howland Current Source

For Leigh Martin, Lukin Group.  

A vanilla Howland made from OPA564_1590G, but with an extra feature: when the input voltage goes below ground, the driving opamp is disabled.

Schematics:

20240826

TT061B is a complete rethink, using ToprCS2P, a positive current source with an extra MOSFET to clamp the output to ground, and a comparator.

This has a max current capability of 4A, and Tr/Tf of less than 2 usec into a resistive load.

Schematics:

20241202 TT061C Doyle Howland