Patent ID: 7982454

Claim:
A proximity detector, comprising: a magnetic field transducer for providing a magnetic field signal indicative of a changing magnetic field; a first peak detector circuit responsive, during a determined time period, to the magnetic field signal, for providing a first tracking signal, which, at a first time, holds a first value corresponding to a positive peak of the magnetic field signal, and which holds, at a second different time, a second value corresponding to a negative peak of the magnetic field signal; a second peak detector circuit responsive, during the determined time period and also after the determined time period, to the magnetic field signal, for providing a second tracking signal, which holds a third value corresponding to a positive peak of the magnetic field signal, and for providing a third tracking signal, which holds a fourth value corresponding to a negative peak of the magnetic field signal, wherein the second tracking signal has an upward excursion limit and a downward excursion limit, wherein the upward excursion limit of the second tracking signal is smaller than the downward excursion limit of the second tracking signal, and wherein the third tracking signal has an upward excursion limit and a downward excursion limit, wherein the upward excursion limit of the third tracking signal is larger than the downward excursion limit of the third tracking signal; and an output control circuit coupled to the first and second peak detector circuits and coupled to receive the magnetic field signal, wherein the output control circuit is configured to provide an output signal, which, during the determined time period, changes state in response to the first peak detector circuit, and which, after the determined time period, changes state in response to the second peak detector circuit.