Hi team,
The customer's circuit design is as below, I cut the load off using a electrical load when testing.
I changed the Rfequ from 200kohm to 78.7kohm, copied other specifications to the EVM-017.
Test was down at Vin=5V, Vo=18V.
Here are the customer's circuit plots:
@Io=0.5A
- CH1: Vo
- CH2: SW
- CH4: current of L
It's not work in the frequency foldback area, and I thought this was caused by COMP specifications.
Then I did the load switching experiments, the load was changed from 0.5A to 0.1A at first, then changed from 0.1A to 0.5A, plots are as below:
The system is unstable for sure, so I want copy these specifications to EVM and adjust COMP, then copy the corrected specifications to customer's circuit. But when I finish the copy work, these specifications work stable at our EVM-017. Here are the load switching experiments plots:
- CH1: Vo
- CH2: SW
Above all, I wonder how to stable customer's circuit without a loop analyzer(in my opinion the response speed is too fast), why our EVM can't show the same plots with the same specifications?
Thanks for your help.
B R,
Owen Yan
