Original question:
Dears:
Input voltage is 15V, C102 voltage set value is 22V, when add 60mA load , C102 voltage will drop to 20.9V, I have checked schematic, seems it's OK. I wonder if it can be improved by adjust transformer.
Could you please help advise how to improve it ? customer want to improve drop to 21.5V.
The configuration you've shows is set up to post regulate the negative output voltage rail but the positive voltage rail is unregulated. One method to improve the positive voltage regulation is shown below. In this scenario, you are not necessarily improving the regulation at C102 but you are improving the VDD/VEE regulated voltage seen by the gate driver. See section 6.3 of the app note here:
Regards,
Steve
