Battery charging circuit
First Claim
1. A circuit for controlling fast charging of battery cells to prevent damage to said cells comprising:
- (a) charging means for producing a rectified charging voltage and applying said charging voltage to said cells,(b) first comparison means for detecting when the charging voltage is at or below a selected value corresponding to a minimum trough voltage value and producing an output indicative thereof,(c) second comparison means for detecting when the trough voltage of said cells exceeds a reference voltage corresponding to the full charge value of said cells and producing an output indicative thereof,(d) means responsive only to the combined outputs of said first and second comparison means for terminating charging of said cells by disabling said charging means,whereby fast charging is terminated only if the trough voltage exceeds said reference voltage during a time period when the charging voltage is below said selected value.
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Accused Products
Abstract
The invention relates to a fast charge circuit suitable for use with battery cells which can be charged at a 4C rate. Line voltage is transformed, full wave rectified and applied to the battery pack. A pair of voltage comparators monitor a sensing voltage which is indicative of the charging voltage and the trough voltage of the battery cells. During a "window" when the sensing voltage is less than a predetermined threshold and through voltage exceeds this threshold, the comparators indicate that charging should be terminated. Alternatively, if excessive temperature on the cells is detected or a selected amount of time passes without reaching full charge, fast charging is also terminated. After the fast charging interval trickle charging of the cells is employed to bring the battery pack to full charge and maintain it there.
19 Citations
8 Claims
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1. A circuit for controlling fast charging of battery cells to prevent damage to said cells comprising:
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(a) charging means for producing a rectified charging voltage and applying said charging voltage to said cells, (b) first comparison means for detecting when the charging voltage is at or below a selected value corresponding to a minimum trough voltage value and producing an output indicative thereof, (c) second comparison means for detecting when the trough voltage of said cells exceeds a reference voltage corresponding to the full charge value of said cells and producing an output indicative thereof, (d) means responsive only to the combined outputs of said first and second comparison means for terminating charging of said cells by disabling said charging means, whereby fast charging is terminated only if the trough voltage exceeds said reference voltage during a time period when the charging voltage is below said selected value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification