Battery voltage measurement circuit, battery voltage measurement method, and battery electric control unit
First Claim
1. A battery voltage measurement circuit that measures a voltage between two electrodes of each unit battery in a battery assembly having a plurality of unit batteries which are connected in series, the battery voltage measurement circuit comprising:
- conversion units each provided respectively to each unit battery to convert a voltage between the two electrodes of each unit battery into respective predetermined physical quantities;
a level shifting unit to convert the physical quantities converted by the conversion units into voltages relative to a lowest electric potential of the battery assembly, wherein the level shifting unit is directly connected to the lowest electric potential of the battery assembly;
a measurement unit that processes and measures the physical quantities converted by the conversion units with respect to each of the unit batteries; and
a power source, isolated from the battery assembly, to supply power to the conversion units;
wherein the measurement unit sequentially outputs digital values corresponding to the converted voltages based on the lowest electric potential of the battery assembly with respect to the unit batteries; and
wherein each conversion unit includes a voltage-current conversion unit that converts the voltage between the two electrodes of each unit battery into a corresponding magnitude of an electric current.
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Accused Products
Abstract
A voltage between both terminals of each unit battery is amplified by a differential amplifier and is then converted by a converter into a predetermined physical quantity that corresponds to the voltage between both terminals of the unit battery. The converted physical quantity is then level-shifted by a detection circuit and is converted into a voltage on a reference potential of the lowest electric potential of the battery assembly. A control unit sequentially selects the converted voltages by a multiplexer, generates serial digital signals by an A/D conversion, and then transmits the serial digital signals to a control operation unit via an isolation buffer circuit. It is, therefore, possible to provide a battery voltage measurement circuit capable of measuring a voltage of each of unit batteries constituting a battery assembly with high accuracy by using a common measurement circuit in a relatively simple and inexpensive configuration.
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Citations
6 Claims
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1. A battery voltage measurement circuit that measures a voltage between two electrodes of each unit battery in a battery assembly having a plurality of unit batteries which are connected in series, the battery voltage measurement circuit comprising:
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conversion units each provided respectively to each unit battery to convert a voltage between the two electrodes of each unit battery into respective predetermined physical quantities; a level shifting unit to convert the physical quantities converted by the conversion units into voltages relative to a lowest electric potential of the battery assembly, wherein the level shifting unit is directly connected to the lowest electric potential of the battery assembly; a measurement unit that processes and measures the physical quantities converted by the conversion units with respect to each of the unit batteries; and a power source, isolated from the battery assembly, to supply power to the conversion units; wherein the measurement unit sequentially outputs digital values corresponding to the converted voltages based on the lowest electric potential of the battery assembly with respect to the unit batteries; and wherein each conversion unit includes a voltage-current conversion unit that converts the voltage between the two electrodes of each unit battery into a corresponding magnitude of an electric current. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification