Re: Hard Limiter?
a_tek7
I don't have a schematic drawing tool, so this Viso drawing will have to do. There are two schematics. The top schematic is a hard limiter. It works as follows.
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When the input voltage is <= VLIM1 and >= VLIM2, the diodes are reverse biased, and the output follows the input. When the input exceeds VLIM1, the diode CR1 is forward biased, and the output is clamped (limited) to the value VLIM1. A similar action takes place when the input is less than (more negative than -VLIM1.
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The bottom schematic is a soft limiter. It works as follows.
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When the input is greater than Vlim1, diode CR1 becomes forward biased. R2 and R1 now form a voltage divider, and the slope of the output is equal to R2/(R1+R2).
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Let Rp be the equivalent of R2 in parallel with R4. Now, when the output voltage exceeds VLIM2, the slope of the output vs input becomes equal to Rp/(R1 + Rp).
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You can add as many breakpoints as you wish to provide a multi-segment output.
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This scheme works only if the voltages involved are large enough so that the forward voltage drops across the diodes can be ignored. If this is not the case, then more sophisticated circuits involving op-amps must be used. Let me know if you need and example.
Regards,
Kral
Added after 14 minutes:
a_tek7,
Sorry, the image from my last post did not get properly posted. Here it is:
Regards,
Kral