search

stockmann-lab / shim_amp_hardware_linear

Hardware related to open-source shim amplifier development for MRI research
1 stars 0 forks source link

Make paralleling output channels work #19

Open dcstraney opened 6 months ago

dcstraney commented 6 months ago

Oscillation or high current draw with multiple paralleled output channels.

Simulated loop gain shows equivalent half load looks ok, but small load (looking into other op-amp output during transients) shows stability problems, with gain plateau @ ~20 dB. Adding C7 = 1 nF fixes this by giving it a single-pole roll-off: image

Testing: Ganged 2x channels to 10µH+0.75Ω load: 1.7A draw @ 10VDC.

dcstraney commented 6 months ago

Adding C7 = 1 nF on two paralleled channels doesn't make a difference