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Portable battery charger

  • US 4,727,306 A
  • Filed: 06/26/1986
  • Issued: 02/23/1988
  • Est. Priority Date: 06/26/1986
  • Status: Expired due to Fees
First Claim
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1. Automatic battery charging apparatus for charging a battery from a supply voltage generated by a voltage source, said battery including temperature sensing means for generating a first output signal having a magnitude related to the temperature of the battery, said apparatus comprising:

  • first source means coupled between the supply voltage and the battery for generating a first charging current;

    second source means coupled between the supply voltage and the battery for generating a second charging current in response to a first state of a control signal and disabling generation of the second charging current in response to a second state of the control signal, said second charging current having a magnitude greater than the first charging current;

    means for generating a reference voltage;

    selecting means responsive to the supply voltage for selecting one of first and second thresholds, said selecting means further including first means coupled to said reference voltage for producing the first threshold and second means coupled to said reference voltage and the supply voltage for producing the second threshold;

    comparing means for producing a second output signal when the first output signal of the temperature sensing means exceeds said selected one of the first and second thresholds; and

    control means for generating the first state of the control signal initially and the second state of the control signal in response to the second output signal of the comparing means, whereby the battery is protected from damage due to charging current and temperature.

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