Hi there!
I've used days searching and reading forums for finding a good solution to switch AC with mosfets in totem, source-to-source. TRIAC is not an option, as I want to switch of in other times than phase-over(PWM, reverse phase dimmer, etc). SSR are overkill, and to expensive.
Like many others, I stranded upon the problem with the floating source, and found solutions with a photovoltaic optocoupler. But, the photovoltaic optocouplers available from my supplier are pretty expensive.
So, I made a circuit with LTspice, using a rectifier and a optocoupler with transistor output. That way, I can feed the mosfet gate with a positive/negative pulse.
The cheap optocouplers usally have about 10+us on/off time, so that will be a limitation with high frequency switching(for example 100khz PWM).
This seems to work, but I wondered if any of you had real life experince with this type of setup?
The application will be fed with 12VAC. The load will be max 50-100W resistive. The models used are random, and I will adjust that to my application(Rds on, max current, max gate-source/drain-source voltage, type of optocoupler, etc).
I've used days searching and reading forums for finding a good solution to switch AC with mosfets in totem, source-to-source. TRIAC is not an option, as I want to switch of in other times than phase-over(PWM, reverse phase dimmer, etc). SSR are overkill, and to expensive.
Like many others, I stranded upon the problem with the floating source, and found solutions with a photovoltaic optocoupler. But, the photovoltaic optocouplers available from my supplier are pretty expensive.
So, I made a circuit with LTspice, using a rectifier and a optocoupler with transistor output. That way, I can feed the mosfet gate with a positive/negative pulse.
The cheap optocouplers usally have about 10+us on/off time, so that will be a limitation with high frequency switching(for example 100khz PWM).
This seems to work, but I wondered if any of you had real life experince with this type of setup?
The application will be fed with 12VAC. The load will be max 50-100W resistive. The models used are random, and I will adjust that to my application(Rds on, max current, max gate-source/drain-source voltage, type of optocoupler, etc).