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Electronics => Projects, Designs, and Technical Stuff => Topic started by: perdrix on December 09, 2023, 05:44:46 am

Title: High voltage, high current MOSFET based analogue switch
Post by: perdrix on December 09, 2023, 05:44:46 am

I'm trying to find an analogue switch that will handle at least 30V_rms, and at least 3.5A_rms (100Watts into 8 Ohms).

If there ain't no such animal off the shelf, how would I build one? 

Do the available power supply/gate drive limit this?

Failing that are there any relays that don't suffer from dry-switching problems at low signal levels but that can handle with this type of signal?

PS if could find these packaged as the equivalent of a DPCO (DPDT) relay even better, but I doubt that exists.

Title: Re: High voltage, high current MOSFET based analogue switch
Post by: moffy on December 09, 2023, 06:26:03 am

The following reference shows a photovoltaic operated MOSFET AC switch: https://toshiba.semicon-storage.com/ap-en/semiconductor/application/smart-plug/articles/ac-switch-example-using-photovoltaic-coupler-and-mosfet.html (https://toshiba.semicon-storage.com/ap-en/semiconductor/application/smart-plug/articles/ac-switch-example-using-photovoltaic-coupler-and-mosfet.html)

also: https://www.bristolwatch.com/ele3/1g.htm (https://www.bristolwatch.com/ele3/1g.htm)
has an example.

Photovoltaic switches are relatively slow to switch.

P.S. You will need to choose the devices to suit your application.