CCT. Protection switch
- From: Hammy <spamme@xxxxxxxxxxx>
- Date: Tue, 01 Apr 2008 13:39:20 GMT
I'm using a User activated mechanical DPDT to apply a 9VDC alkaline
battery to a L7805 regulator.This in turn applies 5V to a pulsed one
shot current source 50mA (20mA steady state) ;LOAD #1 on the
schematic. The pulsed current is fed to a photovoltaic driver which
drives a high side Mosfet (FCD5N60) inserted between the bridge
rectifier and the bulk input cap of a flyback converter (flyback ON).
This gives a 750uS rise-time to 13V gate to source of the FET.
I'm using the other channel of the driver for a dynamic discharge cct
for the FET this gets its power when the switch is flipped to LOAD #2
which is just a 25mA JFET current source. This discharges the FET in
10uS (flyback OFF).
The schematic is here;
http://i32.tinypic.com/2evdc1i.png
It shows the output of the flyback from C1 to C4 ;( D1 is a TVS
diode).
What I would like to be able to do is in the event of a sustained
overvoltage to switch from LOAD #1 to LOAD #2 which shuts the flyback
down. What would be the most efficient method of doing this?
Thanks
.
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