Circuit and method of monitoring battery cells
First Claim
1. A battery monitoring circuit, comprising:
- first and second multiplexers each having a first input, a second input and a select input, said first input of said first multiplexer being coupled for receiving a first battery voltage, said second input of said first multiplexer being coupled for receiving a second battery voltage, said first input of said second multiplexer being coupled for receiving said second battery voltage, said second input of said second multiplexer being coupled for receiving a third battery voltage, said select inputs being coupled for receiving a select signal that selects between said first and second inputs of said first and second multiplexers to sequentially sample said first and second battery voltages;
first and second conduction elements serially coupled between outputs of said first and second multiplexers for developing a voltage at an interconnection of said first and second conduction elements; and
a comparator having first and second inputs, and an output, said first input being coupled to said interconnection of said first and second resistors at, said second input being coupled for receiving a reference potential, said output providing a status signal indicating status of said first and second battery voltages.
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Accused Products
Abstract
A battery monitoring circuit (10) sequentially samples individual voltages across a string of serially coupled battery cells (12-18). A control circuit (32) controls first and second multiplexers (34,42) to sample each battery voltage for an over-voltage condition. A comparator (52) detects an over-voltage condition by comparing a divided down battery voltage against a reference. The conduction path through the battery cells is disabled upon detecting a fault condition by a transistor (26) in the battery cell conduction path. The battery cells are further sequentially sampled for an under-voltage fault. The comparator detects an under-voltage condition by comparing a second divided down battery voltage against the reference. The conduction path through the battery cells is disabled upon detecting a fault condition by a transistor (24) in the battery cell conduction path.
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Citations
23 Claims
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1. A battery monitoring circuit, comprising:
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first and second multiplexers each having a first input, a second input and a select input, said first input of said first multiplexer being coupled for receiving a first battery voltage, said second input of said first multiplexer being coupled for receiving a second battery voltage, said first input of said second multiplexer being coupled for receiving said second battery voltage, said second input of said second multiplexer being coupled for receiving a third battery voltage, said select inputs being coupled for receiving a select signal that selects between said first and second inputs of said first and second multiplexers to sequentially sample said first and second battery voltages; first and second conduction elements serially coupled between outputs of said first and second multiplexers for developing a voltage at an interconnection of said first and second conduction elements; and a comparator having first and second inputs, and an output, said first input being coupled to said interconnection of said first and second resistors at, said second input being coupled for receiving a reference potential, said output providing a status signal indicating status of said first and second battery voltages. - View Dependent Claims (2, 3, 4)
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5. A battery monitoring circuit, comprising:
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first and second multiplexers each having a first input, a second input and a select input, said first input of said first multiplexer being coupled for receiving a first battery voltage, said second input of said first multiplexer being coupled for receiving a second battery voltage, said first input of said second multiplexer being coupled for receiving said second battery voltage, said second input of said second multiplexer being coupled for receiving a third battery voltage, said select inputs being coupled for receiving a select signal that selects between said first and second inputs to sequentially sample said first and second battery voltages; first, second, and third conduction elements serially coupled between outputs of said first and second multiplexers for developing a first voltage at an interconnection of said first and second conduction elements at a first node and a second voltage at an interconnection of said second and third conduction elements at a second node; a comparator having first and second inputs, and an output, said second input being coupled for receiving a reference potential, said output providing a status signal indicating status of said first and second battery voltages; a charging conduction path coupled between first and second power supply conductors for providing said first, second and third battery voltages; circuit means responsive to said status signal for disabling said charging conduction path upon detecting a predetermined state of said status signal that indicates a fault condition; and a switching circuit with first and second input terminals and an output terminal, said first input terminal being coupled to said first node, said second input terminal being coupled to said second node, said output terminal being coupled to said first input of said comparator. - View Dependent Claims (6)
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7. A circuit for monitoring battery voltages, comprising:
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a charging conduction path providing first and second battery voltages; a multiplexer having a first input coupled for receiving said first battery voltage and a second input coupled for receiving said second battery voltage; a comparator having a first input coupled to a first output of said multiplexer, and a second input coupled for receiving a reference potential, and an output providing a status signal indicating a condition of said first battery voltage; and a charging protection circuit responsive to said status signal for disabling said charging conduction path upon detecting a predetermined condition of said status signal. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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16. A battery monitoring circuit, comprising:
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a charging conduction path providing first and second battery voltages; a first multiplexer having a first input coupled for receiving said first battery voltage and a second input coupled for receiving said second battery voltage; a comparator having a first input coupled to an output of said first multiplexer, and a second input coupled for receiving a reference potential, and an output providing a status signal indicating a condition of said first battery voltage; and circuit means responsive to said status signal for disabling said charging conduction path upon detecting a predetermined condition of said status signal. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A method of monitoring serial battery voltages, comprising the steps of:
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monitoring first and second battery voltages serially connected in a charging conduction path; sampling said first battery voltage; sampling said second battery voltage; comparing said first battery voltage against a reference potential to determine status of said first battery voltage; comparing said second battery voltage against said reference potential to determine status of said second battery voltage; and disabling said charging conduction path through said first and second battery voltages upon detecting a predetermined status of said first or second battery voltages. - View Dependent Claims (23)
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Specification