LM2904: LM2904+TL072 stability

Hi Zoe,

I would remove C2.

Kai

Hello Zoe,

If removing C2 does not solve the issue, leave C2 off because it is a problem. Then add a 330pF or larger capacitor between OUT and IN- pins of U1. Positive feedback op amp circuits tend to have low phase margin.

Hi Zoe,

can you share the TSC-file?

Kai

Hi Ronald, Kai,

Thanks for your reply and we will try your suggestion.

Below is the TSC file, FYI.

Thanks!

AO- VM3.TSC

1. remove c2 ,

2. CH2 is VM3

Carson

Hi Ronald

1)  Remove c2 . As below  test waveform. [quote user="Ron Michallick"]

2) LM2904 change to TL072 .As below  test waveform.

CH2 is VM3.

Carson hsu

1)  Remove c2 . As below  test waveform.

2) LM2904 change to TL072 .As below  test waveform.

Hello Carson & Zoe,

Is the circuit working as intended now? The goal of the circuit is not obvious; a simple math or text description would be helpful. My guess the input pulses are used to create a pulsed output current.