
Originally Posted by
Solarfire
Why use separate PSU on the modulation input:
Since your PSU appears to be running borderline it may not be a good idea to power the modulation input directly off of this PSU. Due to sagging of the PSU it will affect the modulation input which can lead to oscillation of the laser current regulation and PSU/modulation. It’s a similar effect like microphone feedback. This oscillation can get very high frequent, draw large ghost currents possibly explaining drastic overheating.