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No. Any MOSFET has an integrated substrate diode, the switch will work as a rectifier in off-state. You have to add a second MOSFET to form an anti-serial circuit (both sources and gates connected).
You should consider, that an electronic switch can't replace a mains switch in cases where safety regulations require an emergency stop.
FvM....thankyou for your reply....i will look into the second switch.....d'you mean two N channel mosfets...or an n channel and a p channel.
...this "switch" is to be used to switch out the inrush resistor so it won't be the main switch of the supply.
Awarapunshee: thanks for this.....i will consider though i think Triac has higher series loss than Mosfet ?
...Also, when the supply goes into "no load" or light load, the current into the supply won't be enough to keep the Triac ON..as it will be below the triac's latching current ?
also, those opto triacs don't seem to be able to ship more than a few hundred mA ?
Did you consider NTC? Look **broken link removed**, read **broken link removed** for implementation.
Also there are simpler ways of driving mosfet gate over isolation barrier. For example, opto with photo diode used in photovoltaic mode can generate power for gate driving, or two capacitors with high frequency which is rectified after. You can use two N mosfets or one N mosfet with bridge rectifier.
Still, if you can select appropriate NTC, that would be by far simplest inrush limiting solution.
NTC is in fact the most easy solution, higher power loads as VFD inverters often use a relay/contactor to bypass the current limiting resistor. As important advantage, it can bear high inrush currents in case of unintentionally switching.
A MOSFET solid state relay in contrast (also a triac) would need a fuse for full protection. A triac, particularly when controlled by an opto triac, generates transients at the zero crossing and has at least 1 V voltage drop, with a generously dimensioned MOSFET SSR it can be much lower.
You can disable SMPS when power is lost and match capacitor bleeder resistors to NTC cooling. If you switch power on again, either capacitor will remain charged or NTC will be cool and ready, depending on length of off state. Both NTC temperature and capacitor voltage curves would follow close to e^-t/τ curve.
If you still don't think NTC would work for you, I would recommend relay over mosfet too. If you still want mosfet solution, makes more sense to use mosfet as current limiting device instead of just using it to bypass resistor.
Sinisa: thankyou , though i am also trying to prevent inrush into the EMC filter which is in the AC lines.......so i cannot do the bleeder resistor one.
the problem with really is that it will have to be a normally open relay and when switched on it will constantly draw power ....whereas mosfet is more efficient for this.
i know latching relay's exist but they are incredibly expensive
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