Lithium battery control circuit and lithium battery charger with surge current protection
First Claim
1. A lithium battery control circuit, adapted to control a lithium battery charger and receive a sense current signal from a current sense circuit, a feedback signal from a feedback circuit and a duty ratio signal from a logic control circuit, and comprising:
- a smooth transition circuit, generating a first voltage according to the sense current signal and the feedback signal, generating a second voltage according to a mode signal, and comparing the first voltage with the second voltage to generate a reset signal, wherein the sense current signal is related to an output current, the feedback signal is related to an output voltage, the mode signal is configured to indicate whether or not in a first charging mode, and the second voltage in the first charging mode is less than the second voltage in a non-first charging mode; and
an off-time control circuit, converting the feedback signal to generate a first current by a voltage-to-current mechanism, and generating a set signal by using the first current and the duty ratio signal, and controlling a driving circuit and an output stage according to the duty ratio signal to prevent the battery control circuit from subharmonic oscillation.
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Accused Products
Abstract
A lithium battery control circuit and a lithium battery charger are provided. The lithium battery charger includes the lithium battery control circuit. The lithium battery control circuit includes a smooth transition circuit and an off-time control circuit. The smooth transition circuit generates a first voltage according to a sense current signal and a feedback signal, and generates a second voltage according to a mode signal. The smooth transition circuit compares the first voltage with the second voltage to generate a reset signal. The off-time control circuit converts the feedback signal to generate a first current by a voltage-to-current mechanism, and generates a set signal by using the first current and a duty ratio signal. The invention may prevent a surge current and an oscillation phenomenon by the smooth transition circuit. A switching frequency and a ripple size of an output current are controlled by the off-time control circuit.
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Citations
12 Claims
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1. A lithium battery control circuit, adapted to control a lithium battery charger and receive a sense current signal from a current sense circuit, a feedback signal from a feedback circuit and a duty ratio signal from a logic control circuit, and comprising:
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a smooth transition circuit, generating a first voltage according to the sense current signal and the feedback signal, generating a second voltage according to a mode signal, and comparing the first voltage with the second voltage to generate a reset signal, wherein the sense current signal is related to an output current, the feedback signal is related to an output voltage, the mode signal is configured to indicate whether or not in a first charging mode, and the second voltage in the first charging mode is less than the second voltage in a non-first charging mode; and an off-time control circuit, converting the feedback signal to generate a first current by a voltage-to-current mechanism, and generating a set signal by using the first current and the duty ratio signal, and controlling a driving circuit and an output stage according to the duty ratio signal to prevent the battery control circuit from subharmonic oscillation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A lithium battery charger, comprising:
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a lithium battery control circuit, comprising; a smooth transition circuit, generating a first voltage according to a sense current signal and a feedback signal, generating a second voltage according to a mode signal, and comparing the first voltage with the second voltage to generate a reset signal, wherein the feedback signal is related to an output voltage, the mode signal is configured to indicate whether or not in a first charging mode, and the second voltage in the first charging mode is less than the second voltage in a non-first charging mode; an off-time control circuit, converting the feedback signal to generate a first current by a voltage-to-current mechanism, and generating a set signal by using the first current and a duty ratio signal; a current sense circuit, configured to generate the sense current signal according to an output current; and a feedback circuit, configured to generate the feedback signal according the output voltage. - View Dependent Claims (12)
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Specification