Circuits and methods for measuring a cell voltage in a battery
First Claim
1. A circuit for measuring a cell voltage of a cell in a battery, said circuit comprising:
- a measurement circuit that comprises a first terminal selectively coupled to a positive terminal of said cell via a first resistive element and comprises a second terminal selectively coupled to a negative terminal of said cell via a second resistive element, and that consumes a first current flowing from said positive terminal through said first resistive element to said first terminal while said first terminal is coupled to said positive terminal; and
a current generator, selectively coupled to said positive terminal of said battery via said first terminal and said first resistive element, that generates a first compensation current according to said first current, wherein said first compensation current flows from said positive terminal through said first resistive element to said first terminal,wherein said measurement circuit obtains a first value indicative of a first voltage difference between said first terminal and said second terminal when said first compensation current is disabled, obtains a second value indicative of a second voltage difference between said first terminal and said second terminal when said first compensation current is enabled, calculates a third value proportional to said first value, and calculates said cell voltage by subtracting said second value from said third value.
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Accused Products
Abstract
A circuit measures a cell voltage of a cell in a battery. The circuit includes a measurement circuit and a current generator. The measurement circuit includes a first terminal coupled to a positive terminal of a cell via a first resistive element and includes a second terminal coupled to a negative terminal of the cell via a second resistive element. The measurement circuit consumes a first current. The current generator generates a first compensation current according to the first current. The first current and the first compensation current flow from the positive terminal through the first resistive element to the first terminal. The measurement circuit calculates the cell voltage according to a first voltage difference between the first and second terminals when the first compensation current is disabled and according to a second voltage difference between the first and second terminals when the first compensation current is enabled.
26 Citations
20 Claims
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1. A circuit for measuring a cell voltage of a cell in a battery, said circuit comprising:
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a measurement circuit that comprises a first terminal selectively coupled to a positive terminal of said cell via a first resistive element and comprises a second terminal selectively coupled to a negative terminal of said cell via a second resistive element, and that consumes a first current flowing from said positive terminal through said first resistive element to said first terminal while said first terminal is coupled to said positive terminal; and a current generator, selectively coupled to said positive terminal of said battery via said first terminal and said first resistive element, that generates a first compensation current according to said first current, wherein said first compensation current flows from said positive terminal through said first resistive element to said first terminal, wherein said measurement circuit obtains a first value indicative of a first voltage difference between said first terminal and said second terminal when said first compensation current is disabled, obtains a second value indicative of a second voltage difference between said first terminal and said second terminal when said first compensation current is enabled, calculates a third value proportional to said first value, and calculates said cell voltage by subtracting said second value from said third value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system comprising:
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a plurality of cells; a plurality of resistors coupled to said cells; a measurement circuit that comprises a first terminal coupled to a positive terminal of a cell of said cells via a first resistor of said resistors and comprises a second terminal coupled to a negative terminal of said cell via a second resistor of said resistors, and that consumes a first current flowing from said positive terminal through said first resistor to said first terminal; and a current generator, coupled to said cells, that generates a first compensation current according to said first current, wherein said first compensation current flows from said positive terminal through said first resistor to said first terminal, wherein said measurement circuit obtains a first value indicative of a first voltage difference between said first and second terminals when said first compensation current is disabled, obtains a second value indicative of a second voltage difference between said first and second terminals when said first compensation current is enabled, calculates a third value proportional to said first value, and calculates said cell voltage by subtracting said second value from said third value. - View Dependent Claims (11, 12, 13, 14)
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15. A method for measuring a cell voltage of a cell in a battery, said method comprising:
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consuming a first current flowing from a positive terminal of said cell through a first resistive element to a first terminal; consuming a second current flowing from a negative terminal of said cell through a second resistive element to a second terminal; generating a first compensation current according to said first current, wherein said first compensation current flows from said positive terminal through said first resistive element to said first terminal; obtaining a first value indicative of a first voltage difference between said first terminal and said second terminal when said first compensation current is disabled; obtaining a second value indicative of a second voltage difference between said first terminal and said second terminal when said first compensation current is enabled; calculating a third value proportional to said first value; and calculating said cell voltage by subtracting said second value from said third value. - View Dependent Claims (16, 17, 18, 19)
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20. A circuit for measuring a cell voltage of a cell in a battery, said circuit comprising:
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a measurement circuit that comprises a first terminal selectively coupled to a positive terminal of said cell via a first resistive element and comprises a second terminal selectively coupled to a negative terminal of said cell via a second resistive element, and that consumes a consumed current flowing from said positive terminal through said first resistive element to said first terminal while said first terminal is coupled to said positive terminal; and a current generator, selectively coupled to said positive terminal of said battery via said first terminal and said first resistive element, that generates a compensation current according to said consumed current to flow from said positive terminal through said first resistive element to said first terminal, wherein said measurement circuit obtains a first value indicative of a voltage difference between said first and second terminals when a switch coupled between said first and second terminals is turned off and said compensation current is disabled, obtains a second value indicative of a voltage difference between said first and second terminals when said switch is turned off and said compensation current is enabled, measures a voltage difference between said first and second terminals to obtain a first result when said switch is turned on and said compensation current is disabled, measures a voltage difference between said first and second terminals to obtain a second result when said switch is turned on and said compensation current is enabled, and calculates said cell voltage according to said first and second values and said first and second results.
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Specification