Hello,
The attached schematic shows a 24W, 230VAC SMPS being switched on at the mains voltage peak.
If D13 is not in the circuit, then the resonant overvoltage at switch on is around 630V.
Why do diodes such as D13 not exist in the schematics of offline SMPS's generally?
-The diode is a very simple way of totally getting rid of the overvoltage problem...so why does nobody do it like this?
The 630V will probably end up being quashed by a MOV or TVS if fitted, but that won't do the lifetime of the MOV or TVS any good.
(LTspice simulation also supplied)
The attached schematic shows a 24W, 230VAC SMPS being switched on at the mains voltage peak.
If D13 is not in the circuit, then the resonant overvoltage at switch on is around 630V.
Why do diodes such as D13 not exist in the schematics of offline SMPS's generally?
-The diode is a very simple way of totally getting rid of the overvoltage problem...so why does nobody do it like this?
The 630V will probably end up being quashed by a MOV or TVS if fitted, but that won't do the lifetime of the MOV or TVS any good.
(LTspice simulation also supplied)