Recommend IC for power supply 230/ 5V 400V 20W
I design power supply for electric fence.
Primari voltage 230V AC
1 Secondary +5V <100mA for control electronics
2 Secondary +400V for charging 70uF capacitor, capacitor must be recharged in less 1s
Other conditions and pitfalls
Control electronics must be able to source block for time <1ms, ie after the time when the capacitor discharges through the triac.
I suppose feedback through secondary +5 V supply should deal with the situation when after switching will be the second new work in the secondary circuit thus discharged into C 70uF.
Comments
Using feedback only from +5V I planned.
I was intrigued by folding 400V from 4 x 100.
What are the benefits of using 4x 100V compared to using 1x 400V secondary with diode VS-8EWX06FN-M3, (19ns, 800mV 100mA) http://www.vishay.com/docs/93244/8ewx06fn.pdf
?
Hi, Usually the high voltage diodes have slow reverse recovery time which causes power dissipation on the output diode. In your case 15ns seems OK.
Regards
Hi,
TOPSwitch-JX can be used for this application.
The feedback needs to come from 5V as you mentioned and for the 400 volt output will probably need to be four stacked 100 volt outputs to minimize diode reverse recovery issues.
It is recommended to use a current limiting resistor with the 400V for charging the capacitor so that peak power never exceed 20W.
rgds..