I was wondering if there was any way of driving back-to-back MOSFETs (with their sources and gates tied together as shown in the following image) without using an optocoupler?
The reason is that optocouplers are slow, I want to use a SSR to short out a ultrasound transducer after sending a transmit pulse-train to shorten the ring time (to get the receiver set-up quicker to measure shorter distances).
Assuming N-Channel MOSFETs, I can't think of a way of biasing the gate to say +5V relative to the source (which is changing all the time), without using an isolation technique like optocouplers or a transformer.
Is there a simple way to do this if you don't require isolation?
I intend to drive the transducer with something like shown below, where Cp and Rl models the piezo-electric transducer, and Cl/transformer is to make the load purely "resistive" and then match the impedance.