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| Limit the output voltage of current sense opamp |
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| exe:
--- Quote from: xavier60 on July 23, 2018, 04:58:34 am ---In my experience, allowing a PIC's input protection diode to be forward biased causes offsets in other ADC channels. --- End quote --- Well can be, one forum member with the name I cannot spell (but seems to be read as "teslacoil") wrote recently the same. From what I remember, these esd diodes are actually bjts (with collector tight to Vcc) and any bias causes more current drained from supply pins. So, offset issues are more than likely. |
| mikerj:
Can you reduce the negative rail voltage to limit the negative swing to a safe value? |
| exe:
BTW, here is the post I mentioned: https://www.eevblog.com/forum/projects/strange-circuit/msg1690556/#msg1690556 |
| npelov:
I was looking at precision rectifier circuits and most of them are inverters. The non-inverting circuits have gain = 1. Is there any reason non-inverting precision rectifier can't have gain > 1? |
| npelov:
I guess resistor is the best choice. I only need clamping for protection, so nothing (else) will blow up when bad voltage comes out of the opamp. If negative voltage comes from the opamp then the circuit is not properly connected and the thole system won't work correctly, so ADC error is not a big deal if it recovers when everything gets back to normal. |
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