Battery fuel gauge
First Claim
Patent Images
1. A system, comprising:
- a battery;
an analog-to-digital converter coupled to the battery and capable of measuring an output voltage of the battery;
a processor, receiving measured battery output voltages from the analog-to-digital converter;
the processor using a first equivalent circuit model of the battery to estimate battery current when the battery operation is static;
the processor using a second equivalent circuit model of the battery to estimate battery current when the battery operation is dynamic, where the second equivalent circuit model comprises a voltage source, and a series resistor in series with at least one resistor in parallel with a capacitor where the first equivalent circuit model is used by the processor when an estimated voltage across the parallel resistor and capacitor is substantially constant, and where the second equivalent circuit model is used by the processor when the estimated voltage across the parallel resistor and capacitor is varying.
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Abstract
A system includes a battery; an analog-to-digital converter coupled to the battery and capable of measuring an output voltage of the battery; a processor, receiving measured battery output voltages from the analog-to-digital converter; the processor using a first equivalent circuit model of the battery to estimate battery current when the battery operation is static; and the processor using a second equivalent circuit model of the battery to estimate battery current when the battery operation is dynamic.
10 Citations
15 Claims
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1. A system, comprising:
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a battery; an analog-to-digital converter coupled to the battery and capable of measuring an output voltage of the battery; a processor, receiving measured battery output voltages from the analog-to-digital converter; the processor using a first equivalent circuit model of the battery to estimate battery current when the battery operation is static; the processor using a second equivalent circuit model of the battery to estimate battery current when the battery operation is dynamic, where the second equivalent circuit model comprises a voltage source, and a series resistor in series with at least one resistor in parallel with a capacitor where the first equivalent circuit model is used by the processor when an estimated voltage across the parallel resistor and capacitor is substantially constant, and where the second equivalent circuit model is used by the processor when the estimated voltage across the parallel resistor and capacitor is varying. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system, comprising:
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a battery; an analog-to-digital converter coupled to the battery and capable of measuring an output voltage of the battery; a processor, receiving measured battery output voltages from the analog-to-digital converter; the processor using a first equivalent circuit model of the battery to estimate battery current when the battery operation is static; and the processor using a second equivalent circuit model of the battery to estimate battery current when the battery operation is dynamic; further comprising; a temperature sensor to measure the temperature of the battery; the processor receiving the battery temperature measurement; where the first equivalent circuit model is used by the processor when an estimated voltage across the first parallel resistor and first capacitor is substantially constant, and the second equivalent circuit model is used by the processor when the estimated voltage across the first parallel resistor and first capacitor is varying and where the second equivalent circuit model comprises a voltage source and a series resistor in series with at least one resistor in parallel with a capacitor, where the resistance of the series resistor and the resistance of the at least one resistor in parallel with a capacitor vary as a function of temperature of the battery. - View Dependent Claims (9)
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10. An integrated circuit, comprising:
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an analog-to-digital converter couplable to a battery and capable of measuring an output voltage of the battery; a processor, configured to receive measured output voltages from a battery; the processor using a first equivalent circuit model of the battery to estimate battery current when the battery operation is static; and the processor using a second equivalent circuit model of the battery to estimate battery current when the battery operation is dynamic, where the second equivalent circuit model comprises a voltage source, and a series resistor in series with at least one resistor in parallel with a capacitor and where the first equivalent circuit model is used by the processor when an estimated voltage across the parallel resistor and capacitor is substantially constant, and the second equivalent circuit model is used by the processor when the estimated voltage across the parallel resistor and capacitor is varying.
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11. A method of estimating state of charge of a battery, comprising:
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measuring, by a processor, an output voltage of the battery; estimating, by the processor, during static battery operation, current from the battery using a first equivalent circuit model; estimating, by the processor, during dynamic battery operation, current from the battery using a second equivalent circuit model; and integrating, by the processor, the estimated current to estimate state of charge of the battery; further comprising; calculating, by the processor, an estimated voltage across a first parallel R-C circuit in the second equivalent circuit model; using, by the processor, the first equivalent circuit model to estimate current from the battery when the estimated voltage across the first parallel R-C circuit in the second equivalent circuit model is substantially constant; and using, by the processor, the second equivalent circuit model to estimate current from the battery when the estimated voltage across a first parallel R-C circuit in the second equivalent circuit model is varying. - View Dependent Claims (12, 13, 14, 15)
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Specification