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[HELP] Variable output power supply design

Posted by: plasma.87 on

Hi all,

I am designing a power supply that must deliver 70 VDC at 25 W. The load is a LED flash circuit that will drain 300 W during 1 milisecond, at a ratio of 60 Hz. I expect the output of the power supply to fall from 70 V to 10 V during the flash on period. The remaining 15.6 ms is the expected time to recharge the output capacitor to 70 V.
The problem is the protection circuit. TopSwitch family has internal current protection. Giving that, the circuit would obviously enter restart after all flash shots.
Is there a way to make the circuit let the output voltage drop, maintaining the current flow (maximum possible below the limit), without entering restart?
Please give-me a light, I am reading for days the documents and can not find a way.
PS.: I am new to power supply design.

Comments

Submitted by PI-KSAN on 12/04/2014

Hi,
Thanks for posting your comment into forum and we appreciate your time and patience.
For your design Specification , with the recommnended value of Control Pin Capacitor of 47uF, the topswitch doesn't go into Autorestart for 32ms. In your design, the output capacitor is expected to recharge to 70V in 15.6ms in which optocoupler is open, the control pin capacitor(47uF) is the one which is providing the current to the controller which keeps in normal operation for 32ms. please go through the remote on/off section in topswitch data sheet , it's mentioned about control capacitor.

Regards,
PI-KSAN.