I read OPA627 datasheet.
This datasheet mentioned over voltage protected with 2 diode in figure 33a:
I can understand how it do.
Vi will be clamp when Vi > |Vs| .
But the figure 33b:
Datasheet said it's a over current protected.
How does it work?
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\$\begingroup\$ I don't find the datasheet says so. I find input protection [for] I/V converters of inverting amplifiers \$\endgroup\$– greybeardCommented Feb 26, 2023 at 12:52
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\$\begingroup\$ OK! let me modify title \$\endgroup\$– curlyweiCommented Feb 26, 2023 at 13:17
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1 Answer
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Datasheet said it's a over current protected. How does it work?
When the input current is within the limits of the op-amp's output sink or source capabilities, the inverting input becomes a virtual ground. This means that the op-amp is successfully holding the inverting input (via the feedback resistor) at 0 volts (the same voltage as the no-inverting input).
This is a useful configuration for a current to voltage converter because the back-to-back diodes play no role and do not conduct.
However, when the input current goes beyond what the op-amp output can sink or source, the virtual ground is lost and, the inverting input may rise to a voltage that can damage the op-amp. Hence, adding back-to-back diodes prevents this from happening (providing the diodes don't get damaged by excessive overload current).
answered Feb 26, 2023 at 12:52