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Charger system switchably connects a smoothing capacitor and resistor and charging controller based on a detected secondary battery voltage

  • US 5,982,153 A
  • Filed: 03/05/1998
  • Issued: 11/09/1999
  • Est. Priority Date: 03/13/1997
  • Status: Expired due to Term
First Claim
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1. A charger system for charging a secondary battery with an AC voltage, comprising:

  • a rectifier diode for rectifying said AC voltage into a DC voltage;

    a smoothing capacitor having high impedance as compared with an impedance of said secondary battery, for smoothing said DC voltage outputted from said rectifier diode;

    charging control means for receiving said smoothed DC voltage from said smoothing capacitor and supplying a predetermined constant voltage to said secondary battery;

    first switch means connected in parallel with said charging control means;

    detector means for detecting a terminal voltage of said secondary battery;

    switch control means for supplying a control signal to control an opening/closing state of said first switch means in accordance with a detection result of said detector means, for switching said first switch means to a closing state to supply said smoothed DC voltage to said secondary battery through said first switch means when said detected terminal voltage is lower than a predetermined charging standard voltage, and for switching said first switch means to an opening state to supply said DC voltage to said secondary battery through said charging control means when said detected terminal voltage reaches the predetermined charging standard voltage;

    second switch means connected in series between said smoothing capacitor and a ground potential; and

    a resistor element connected in parallel with said second switch means,wherein said smoothing capacitor has one end connected to an output end of said rectifier diode and the other end connected to said ground potential, and said second switch means is controlled in accordance with said control signal to connect said smoothing capacitor to said ground potential via said resistor element when said detected terminal voltage is lower than the predetermined charging standard voltage and to connect said smoothing capacitor to said ground potential without connecting through said resistor element when said detected terminal voltage reaches the charging standard voltage.

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