Battery charging circuit with charging rate control
First Claim
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1. A battery charger for a battery, comprising:
- a charging circuit which receives a charging current through induction from a power supply and applies said charging current to said battery;
a charge detection circuit which detects a charge state of said battery and outputs a charge state signal corresponding to said charge state; and
a charging form control circuit which receives said charge state signal from said charge detection circuit and which selects between one of a rapid charging rate and a trickle charging rate by adjusting an amount of said charging current in correspondence with said charge state signal from said charge detection circuit, said charging form control circuit including;
a signal generator which generates a pulse signal having either a high or a low frequency according to said charge state signal outputted from said charge detection circuit, anda power supply controller which adjusts said amount of said charging current induced by said charging circuit by controlling an amount of power supply current flowing through said charging circuit according to said pulse signal outputted from said signal generator.
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Abstract
A battery charging circuit controls between rapid charging and trickle charging used to charge a NiCd/NiMH battery. The circuit perceives when the rapid charging operation has completely charged the battery and thereafter converts the charging operation to a trickle charging in order to compensate for the charging loss of a battery due to the leakage discharge. The form of charging is controlled by restricting the maximum amount of current provided to the battery using current-mode pulse width modulation.
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Citations
21 Claims
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1. A battery charger for a battery, comprising:
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a charging circuit which receives a charging current through induction from a power supply and applies said charging current to said battery; a charge detection circuit which detects a charge state of said battery and outputs a charge state signal corresponding to said charge state; and a charging form control circuit which receives said charge state signal from said charge detection circuit and which selects between one of a rapid charging rate and a trickle charging rate by adjusting an amount of said charging current in correspondence with said charge state signal from said charge detection circuit, said charging form control circuit including; a signal generator which generates a pulse signal having either a high or a low frequency according to said charge state signal outputted from said charge detection circuit, and a power supply controller which adjusts said amount of said charging current induced by said charging circuit by controlling an amount of power supply current flowing through said charging circuit according to said pulse signal outputted from said signal generator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A battery charger for a battery, comprising:
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a charging circuit which receives a charging current through induction from a power supply and applies said charging current to said battery, said charging circuit including; a first coil having one terminal coupled to said power supply; a second coil in which said charging current is induced from said first coil; a diode coupled between said second coil and a first terminal of said battery; a capacitor coupled between said first terminal of said battery and a ground potential; and a resistance coupled between a second terminal of said battery and said ground potential; a charge detection circuit which detects a charge state of said battery and outputs a charge state signal corresponding to said charge state; and a charging form control circuit which receives said charge state signal from said charge detection circuit and which selects between one of a rapid charging rate and a trickle charging rate by adjusting an amount of said charging current in correspondence with said charge state signal from said charge detection circuit. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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Specification