Battery charging circuit for charging NIMH and NICD batteries
First Claim
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1. A battery charging circuit for charging a battery, comprising:
- a voltage drop detection circuit for producing a first detection signal on detecting a drop in battery voltage with respect to time;
a peak voltage detection circuit for producing a second detection signal on detecting a period of constant battery voltage with respect to time;
means for enabling said detection circuits to operate simultaneously and to enable both of said detection circuits to be responsive to the battery voltage from a battery to be charged; and
battery charging means connected to receive said first and second detection signals, said battery charging means being arranged to charge the battery until either one of said first and second detection signals is generated and to terminate fast charging on receipt of either one of said first and second signals.
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Abstract
An improved battery charging circuit provides a single circuit for charging both Ni-MH and Ni-Cd batteries. Separate circuits are provided for sensing an end of charge sequence for both battery types. Both circuits operate simultaneously, and one circuit will generate and end of charge signal when a battery corresponding to its type is fully charged. When either circuit signals that a sequence is complete, charging ends. This provides for charging either type of battery without the necessity for determining the type of battery being charged.
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Citations
15 Claims
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1. A battery charging circuit for charging a battery, comprising:
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a voltage drop detection circuit for producing a first detection signal on detecting a drop in battery voltage with respect to time; a peak voltage detection circuit for producing a second detection signal on detecting a period of constant battery voltage with respect to time; means for enabling said detection circuits to operate simultaneously and to enable both of said detection circuits to be responsive to the battery voltage from a battery to be charged; and battery charging means connected to receive said first and second detection signals, said battery charging means being arranged to charge the battery until either one of said first and second detection signals is generated and to terminate fast charging on receipt of either one of said first and second signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A battery charging circuit for charging Ni-MH batteries and Ni-Cd batteries, said battery charging circuit comprising:
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a first detection circuit for producing a first detection signal on detecting when a battery to be charged is near to an end-of-charge point; a voltage drop detection circuit for producing a second detection signal on detecting a drop in battery voltage with respect to time; a peak voltage detection circuit for producing a third detection signal on detecting a period of constant battery voltage with respect to time; means for enabling, on receipt of the first detection signal from said first detection circuit, said voltage drop detection circuit and said peak voltage detection circuit to operate simultaneously and to enable both said voltage drop detection circuit and said peak voltage detection circuit to be responsive to the the voltage from said battery to be charged; and battery charging means connected to receive the second and third detection signals, said battery charging means being arranged to charge the battery until either one of the second and third detection signals is generated and to terminate fast charging on receipt of one of said second and third signals. - View Dependent Claims (13, 14, 15)
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Specification