Small highly accurate battery temperature monitoring circuit
First Claim
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1. A circuit, comprising:
- an input node coupled to receive a measured voltage corresponding to battery temperature;
a cold voltage comparator coupled to the input node to generate a cold trip point signal based on the measured voltage relative to a cold reference voltage corresponding to a pre-defined too cold condition;
a hot voltage comparator coupled to the input node to generate a hot trip point signal based on the measured voltage relative to a hot reference voltage corresponding to a pre-defined too hot condition; and
current source circuitry coupled to the input node and responsive to the measured voltageto selectively source a first constant current to the cold voltage comparator when the measured voltage is within a pre-defined range of the cold reference voltage, andto selectively source a second constant current to the hot voltage comparator when the measured voltage is within a pre-defined range of the hot reference voltage.
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Abstract
A battery temperature monitoring circuit, which has a cold comparator and a hot comparator, achieves high accuracy in a small cell size by utilizing a cold current optimized for the cold comparator and a cold reference voltage, and a hot current optimized for the hot comparator and a hot reference voltage, along with switching circuitry that provides the cold current to the cold comparator as the battery temperature approaches the cold trip temperature, and the hot current to the hot comparator as the battery temperature approaches the hot trip temperature.
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Citations
17 Claims
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1. A circuit, comprising:
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an input node coupled to receive a measured voltage corresponding to battery temperature; a cold voltage comparator coupled to the input node to generate a cold trip point signal based on the measured voltage relative to a cold reference voltage corresponding to a pre-defined too cold condition; a hot voltage comparator coupled to the input node to generate a hot trip point signal based on the measured voltage relative to a hot reference voltage corresponding to a pre-defined too hot condition; and current source circuitry coupled to the input node and responsive to the measured voltage to selectively source a first constant current to the cold voltage comparator when the measured voltage is within a pre-defined range of the cold reference voltage, and to selectively source a second constant current to the hot voltage comparator when the measured voltage is within a pre-defined range of the hot reference voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method suitable for measuring battery temperature during charging comprising:
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generating a measured voltage representative of battery temperature; generating a cold trip point signal based on a comparison of the measured voltage relative to a cold reference voltage corresponding to a pre-defined too cold condition; generating a hot trip point signal based on a comparison of the measured voltage relative to a hot reference voltage corresponding to a pre-defined too hot condition; selectively sourcing a first constant current, used in the comparison of the measured voltage relative to the cold reference voltage, when the measured voltage is within a pre-defined range of the cold reference voltage, and a second constant current, used in the comparison of the measured voltage relative to the hot reference voltage, when the measured voltage is within a pre-defined range of the hot reference voltage. - View Dependent Claims (9, 10)
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11. A system suitable for charging a battery including monitoring battery temperature during charging, comprising:
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a temperature monitoring device coupled to a battery to output a measured voltage representative of battery temperature; a temperature monitoring circuit, including an input node coupled to receive the measured voltage; a cold voltage comparator coupled to the input node to generate a cold trip point signal based on the measured voltage relative to a cold reference voltage corresponding to a pre-defined too cold condition; a hot voltage comparator coupled to the input node to generate a hot trip point signal based on the measured voltage relative to a hot reference voltage corresponding to a pre-defined too hot condition; and current source circuitry coupled to the input node and responsive to the measured voltage to selectively source a first constant current to the cold voltage comparator when the measured voltage is within a pre-defined range of the cold reference voltage, and to selectively source a second constant current to the hot voltage comparator when the measured voltage is within a pre-defined range of the hot reference voltage. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification