# Laser diode driver circuit analysis help

I'm looking up for some circuitry to drive my laser diode and I came across this tutorial.

I understand the basic operation of this schematic; however, there's one thing that confuses me:

I cannot understand the purpose of R6 and the pair C3, R4. (Jt seems like a RC filter, doesn't it?)

• @KH $C_3$ is in-the-loop compensation. Oscillation often results without it. You can find it discussed here. – jonk Apr 6 at 6:16
• @Jonk Is it not coincidentally also an op-amp integrator? I even thought about how the integrator works and it appears to make sense but I'm definitely not sure. I'm going to go read that. – K H Apr 6 at 6:23