Hi,

Can anyone suggest me a test circuit for measuring open loop gain in shunt regulator?

 

If you post a schematic, maybe we can try.

Are you working with a discrete design, or some IC?

 

Hi,

Can anyone suggest me a test circuit for measuring open loop gain in shunt regulator?

Need a schematic

Second page of this app note shows a typical method of measuring loop gain. You have to open the feedback loop and inject a signal. It takes a calibrated network analyzer.

http://www.ti.com/lit/an/snva020a/snva020a.pdf

 

Check app note
SLVA482–September 2011
for the TL431.