I know you guys always have good ideas and I need one. I have a circuit on the breadboard which ultimately generates a +/-150v square wave used to control some LCD samples in a research setting. The HV is output from a DC-DC converter that takes 3.7vdc and generates 300vdc. It's a center-tapped which when used as the 0v reference, gives me the voltages I need. I should mention that there is a mpu that is used to generate/select the frequency but I'm working with 1khz for now.
The issue is how to create the square wave. I originally used a dual opto SSR (Avago/Broadcom ASSR-302C) where the micro drives each half in alternative phase (pins 1,3) - thereby generating a high pulse for 500us, then a low pulse for 500us. This works, but I'm blanking on a good way to "or" together the SSR outputs without messing each other up. The circuit fragment I attached sort of works but I lose a lot of voltage - I suspect because voltage on the inactive diode is biasing the other output?
This is one of those things where there must be an obvious better way but I'm not getting it. Urg.
. View attachment 150843
The issue is how to create the square wave. I originally used a dual opto SSR (Avago/Broadcom ASSR-302C) where the micro drives each half in alternative phase (pins 1,3) - thereby generating a high pulse for 500us, then a low pulse for 500us. This works, but I'm blanking on a good way to "or" together the SSR outputs without messing each other up. The circuit fragment I attached sort of works but I lose a lot of voltage - I suspect because voltage on the inactive diode is biasing the other output?
This is one of those things where there must be an obvious better way but I'm not getting it. Urg.
. View attachment 150843
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