Patent ID: 11867768
Assignee: DENSO TEN LIMITED
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A battery voltage measurement circuit comprising:
a first switch configured to be connected to a positive electrode of a battery;
a second switch configured to be connected to a negative electrode of the battery;
detection resistances that are connected in series between the first switch and the second switch;
capacitors that are connected in parallel to the detection resistances; and
a measurement circuit that measures a voltage applied to the detection resistances, wherein
the battery voltage measurement circuit has a plurality of measurement modes depending upon status of the first and second switches, and further has a failure detection mode for the capacitors based on a change in the voltage measured by the measurement circuit after switching from one to an other of the measurement modes, and
the battery voltage measurement circuit has, of the plurality of measurement modes, at least two measurement modes of
(i) a first measurement mode in which (1) the first switch is turned on and the second switch is turned off to form a first series-connected circuit consisting of the battery, one of the detection resistances, and an insulation member on a negative electrode side of the battery that comes into electrical contact with the negative electrode of the battery, and (2) an insulation resistance of the insulation member on the negative electrode side is calculated based on a first voltage measured by the measurement circuit,
(ii) a second measurement mode in which (1) the first switch is turned off and the second switch is turned on to form a second series-connected circuit consisting of the battery, one of the detection resistances, and an insulation member on a positive electrode side of the battery that comes into electrical contact with the positive electrode of the battery, and (2) an insulation resistance of the insulation member on the positive electrode side is calculated based on a second voltage measured by the measurement circuit, and
(iii) a third measurement mode in which (1) the first switch and the second switch are turned off, and (2) an offset voltage is calculated based on a third voltage measured by the measurement circuit.