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Apparatus for detecting remaining charge of battery

  • US 6,252,377 B1
  • Filed: 01/27/2000
  • Issued: 06/26/2001
  • Est. Priority Date: 01/26/1999
  • Status: Expired due to Term
First Claim
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1. An apparatus for detecting a remaining charge in a battery, comprising:

  • a current detector for detecting an output electric current from and a regenerative electric current to said battery;

    a voltage detector for detecting a voltage output from said battery;

    a low-pass filter for filtering a plurality of detected current values and a plurality of detected voltage values;

    a time constant changer for changing a time constant of said low-pass filter;

    an integrator for calculating the remaining charge of said battery by integrating the plurality of detected current values detected by said current detector;

    a remaining charge detecting map for calculating a threshold voltage value corresponding to a specified value of the remaining charge, based on a filtered electric current value filtered by said low-pass filter;

    a comparator for comparing the threshold voltage value, calculated by said remaining charge detecting map, with a filtered voltage value filtered by said low-pass filter; and

    a resetter for resetting the remaining charge to said specified value of the remaining charge when the filtered voltage value exceeds said threshold voltage value.

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