Passing through/blocking a high voltage dual polarity signal

Question

Good day. The question I have is regarding a device the function of which my employer asked not to discuss in too much detail. But I believe the engineering problem itself is general enough and I will try to give as much engineering data as I can without disclosing any commercially sensitive info. The device I am designing at the moment has to switch the following waveform on or off:

This is a high impedance differential signal (10kOhm) with voltage of 72 Vpp, that can reach 400 Vpp. The load for this signal is also high impedance (I am using a 1 MOhm resistor as a model). I am trying to achieve a switch-like functionality in my circuit that will be controlled by a microcontroller. In one state it will pass the signal to the load, in another it will block the signal.

I was thinking about different approaches from primitive to more complex:

1. Mechanical relays - Pros: easy to operate. Cons: bit expensive at the voltage specification, have a clicking sound that might not be suitable for the product, wear out
2. SSR - Very expensive at the specified voltage
3. Optocouplers - Pros: also easy to operate, cheap, solid state. Cons: usually has a low reverse voltage limit
4. Discrete transistors (BJT, FET)- This might be a solution but most of the components I've looked at also have a low reverse voltage breakdown. Maybe I'm missing some specific type?

I have experimented a bit with optocouplers in a simulator as well as on a breadboard.

Here's an LTSpice setup with an MOC205 (datasheet):

According to the simulation the circuit works just as I intend it to:

Voltage across the load with 5 volts at the MOC205 input:

Voltage across the load with 0 volts at the MOC205 input:

I couldn't get my hands on MOC205 in the current state of lockdown, so I used K1010 (datasheet) that I had on hand.

The result was quite a bit different. With 5 Volts at the input the signal was identical to the first picture in the question, so it was completely passed through. With 0 volts at the input:

I guess this result should be expected due to the nature of the transistor in the optocoupler. Both MOC205 and K1010 list their reverse voltages to be 6V, so I'm not sure I can trust the result of the MOC205 simulation either. So the question is: are there any optocouplers, or other devices that would be able to pass/block such high voltages? Or maybe I should change the topology? I thought of connecting two optocouplers back to back but the result wasn't perfect either (still was passing some negative voltage pulses), plus it seems like there should be a more elegant solution. Or maybe I should ditch the idea of optocouplers alltogether and work with a different device? Any help would be highly appreciated!

EDIT from the comments:

The rise time of the signal is 500ns.

The output impedance of the device is about 10k, which I guess is not too high an impedance.

Load is not returned to the ground but I guess, I can ground one of the differential signals, grounding the voltage.

If 90% of the signal goes through in the on-state, I would call it acceptable for the application. Inversely of 10% goes through in the off-state, that is also acceptable.

Answer 1

OptoMOS is somewhere between an optocoupler and a SSR. It is a packaged version of what Russel describes. Here is what Digi-Key has in stock that are in-stock, active part numbers rated over 100 V.

https://www.digikey.com/products/en/relays/solid-state-relays/183?FV=-8%7C183%2C41%7C307140%2C41%7C307321%2C1989%7C0%2Cyr0V+%7E+1000V%7C2133%2Cyr0V+%7E+230V%7C2133%2Cyr0V+%7E+250V%7C2133%2Cyr0V+%7E+280V%7C2133%2Cyr0V+%7E+300V%7C2133%2Cyr0V+%7E+350V%7C2133%2Cyr0V+%7E+400V%7C2133%2Cyr0V+%7E+500V%7C2133%2Cyr0V+%7E+600V%7C2133%2Cyr0V+%7E+800V%7C2133&quantity=0&ColumnSort=0&page=1&stock=1&k=optomos&pageSize=500&pkeyword=optomos