AHPF opamp input voltage protection with clamp diodes sinking source

[electronx]

I am designing an iepe signal conditioner and as seen in the introduction I have a 2nd order butterworth high pass filter..
When the sensor (load) is not connected, the current source with 24 V supply with 4mA constant current will completely turn on the MOSFET and the output will be 24 volts (xtr111 output will not give exactly 24 volts, it will give a value of approximately 21.6V), but let's assume that there is a 24V input.

 

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If we look at the OPA192 datasheet, the entry values in the Absolute Maximum Ratings section are limited as follows. Since we are supplying (V–) – 0.5 and (V+) + 0.5 +15V )(-15V ), -15.5 and 15.5 are the maximum limits we can apply to the inputs

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If we focus on transient analysis, when the 24V input signal comes, the current will pass through the clamp diode (BAT64) through the 2k limiting resistor and go to the +15 line. The simulation is here.
Accordingly, the 15V power supply will need to sink a value such as 3.315mA. I use a UWE1215S-3WR3 supply that can output +-15 V to feed the opamp. However, I am not sure how much source sinking it can do, maybe it does not do it at all.

 


 

graph of the +15 volt source

 


 

u can see the +15v source is sinking  You can see that it is sinking for up to  20ms.

Briefly, how can I protect the inputs of the opamp when we apply 24v? Do I need to add a 15V zener diode reverse connected to the power rails for sinking?
I don't want the opamp to burn out when there is no load.

If you notice any other errors in the circuit, please let me know.

[dobsonr741]

What is the normal, not disconnected, range of the input? Might want to put a TVS diode on the input before the first capacitor. A better protection then letting the transient go deep into your circuit.

If the supply rail lifting concern still exists after that, model the power supply as well. The Mornsun presumably have an LDO inside, will not prevent lifting. The load current and the rail bypass capacitors will limit the lifting, specially as it is a transient only. Might add another TVS after the capacitors and before the opamp. The Zener on the rail should be the last resort IMO, as it will not prevent just limit the lift. Thus allow other parts to be impacted on the same rail.