Patent ID: 7199579

Claim:
A proximity detector, comprising: a magnetic-field-to-voltage transducer for providing a magnetic field signal indicative of an ambient magnetic field; a peak detector responsive to said magnetic field signal for providing a tracking signal which substantially follows at least a portion of said magnetic field signal, wherein said peak detector comprises: a first digital-to-analog converter for providing a first output signal having a first step size; a second digital-to-analog converter for providing a second output signal having a second step size larger than said first step size; and a summation circuit coupled to said first and said second digital-to-analog converters for providing said tracking signal as a sum of said first and said second output signals, wherein said tracking signal is controlled to include steps associated with the first step size when said magnetic field signal varies from said tracking signal by less than a predetermined amount and to include larger steps associated with the second step size when said magnetic field signal varies from said tracking signal by more than the predetermined amount.