Low noise charging method and device for portable devices
First Claim
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1. A method for charging a battery, comprising:
- charging said battery by an external power source via a switch;
generating an output signal indicating whether a battery voltage of said battery is higher than a predetermined voltage;
generating a signal having a plurality of pulses;
generating a control signal according to said output signal and said plurality of pulses by a latch for controlling said switch;
enabling said switch in response to said plurality of pulses and said control signal if said battery voltage is higher than said predetermined voltage;
measuring a time period when said control signal remains substantially constant; and
stopping charging said battery if said time period exceeds a first predetermined period of time.
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Abstract
A method is used for charging a battery. According to the method of the present invention, the battery is first charged to a predetermined voltage at a substantially constant current. Then, the charging current is disabled. A pulsing current is applied to the battery for charging the battery.
20 Citations
25 Claims
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1. A method for charging a battery, comprising:
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charging said battery by an external power source via a switch; generating an output signal indicating whether a battery voltage of said battery is higher than a predetermined voltage; generating a signal having a plurality of pulses; generating a control signal according to said output signal and said plurality of pulses by a latch for controlling said switch; enabling said switch in response to said plurality of pulses and said control signal if said battery voltage is higher than said predetermined voltage; measuring a time period when said control signal remains substantially constant; and stopping charging said battery if said time period exceeds a first predetermined period of time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for charging a battery, comprising:
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a first comparator for determining whether a battery voltage of said battery is lower than a first predetermined voltage; a switch coupled to said first comparator for coupling an external power source to said battery; a timer coupled to said switch for generating a signal having a plurality of pulses; a latch for receiving an output from said first comparator and for receiving said signal from said timer, and for generating a control signal to control said switch; and a counter for measuring a time period when said control signal remains substantially constant, wherein said switch is enabled in response to said plurality of pulses of said signal and said control signal if said battery voltage of said battery is higher than said first predetermined voltage, and wherein said system stops charging said battery if said time period exceeds a predetermined period of time. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 23, 24, 25)
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20. A method for charging a battery, comprising:
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generating an output signal indicating whether a battery voltage of said battery is higher than a predetermined voltage; charging said battery by a substantially continuous charging current via a switch until said battery voltage is higher than said predetermined voltage; generating a discrete voltage having a plurality of voltage pulses; generating a signal having a plurality of pulses; charging said battery by said plurality of voltage pulses via said switch; generating a control signal according to said output signal and said plurality of pulses by a latch for controlling said switch; enabling said switch in response to said plurality of pulses of said signal and said control signal if said battery voltage is higher than said predetermined voltage; measuring a time period when said control signal remains substantially constant; and stopping charging said battery if said time period exceeds a first predetermined period of time. - View Dependent Claims (21, 22)
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Specification