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Circuit arrangement for evaluating the output signal of an active sensor

  • US 5,880,614 A
  • Filed: 05/07/1997
  • Issued: 03/09/1999
  • Est. Priority Date: 09/24/1994
  • Status: Expired due to Term
First Claim
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1. A circuit for evaluating an output signal of an active sensor which is configured as a binary current signal having a square-wave output signal with two different current levels, comprising:

  • means for producing a signal current proportional to the sensor output signal by way of a current mirror circuit,the signal current induced by a first circuit branch of said current mirror circuit is drawn from a voltage source by way of an ohmic resistance, whereby a binary voltage signal corresponding to the sensor output signal is generated,comparator means having a first input coupled to said binary voltage signal, wherein said comparator means includes hysteresis characteristics which are implemented by comparing the binary voltage signal with a reference signal, wherein said reference signal is composed of a serial connection of a reference voltage and a hysteresis voltage, wherein the change-over threshold of the comparator means is responsive to the reference value signal, whereinthe reference voltage is varied as a function of the sensor output signal, and wherein the reference voltage is produced by way of a capacitor which is connected to a second input of said comparator means.

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