Voltage measuring apparatus
View Patent ↗A voltage measuring apparatus is configured to measure voltages of respective battery cells of a battery cell array including a plurality of battery cell groups each including a predetermined number of battery cells connected in series. The voltage measuring apparatus includes a plurality of measuring units each provided for each of the battery cell groups. The adjacent measuring units are connected through a communication channel so as to perform current communication therebetween. A bidirectional diode circuit element is connected to the communication channel extending between the adjacent measuring units.
1. A method of controlling currents in an integrated circuit device provided at each of a plurality of battery cell groups of a battery system including a battery cell array including the plurality of battery cell groups,
the integrated circuit device comprising a measuring unit configured to measure a voltage of one of battery cells of a corresponding one of the battery cell groups,
the method comprising:
outputting from the measuring unit a current for first communication by which the measuring unit transmits a measurement result of the voltage of the one battery cell or a current for second communication by which the measuring unit receives a drive command; and
in at least one of the first communication and the second communication, allowing a reverse current to flow in a direction opposite to a direction of the current for a corresponding one of the first communication and the second communication.
2. The method according to claim 1 , wherein:
the measuring unit is a first measuring unit;
a measuring unit of another integrated circuit device is a second measuring unit; and
a current generated by a potential difference between a power supply voltage input to the second measuring unit and a reference voltage input to the first measuring unit is not input to the second measuring unit.
3. The method according to claim 1 , wherein:
the measuring unit is a first measuring unit;
a measuring unit of another integrated circuit device is a second measuring unit; and
the first measuring unit includes a transmitting portion configured to transmit a current signal.
4. The method according to claim 3 , wherein the first measuring unit further includes:
a current source configured to generate the current signal; and
a switch connected to the current source.
5. The method according to claim 3 , wherein the first measuring unit further includes a diode configured to prevent an electrostatic discharge failure.
6. The method according to claim 1 , wherein:
the measuring unit is a first measuring unit;
a measuring unit of another integrated circuit device is a second measuring unit; and
the second measuring unit includes a receiving portion configured to receive a current signal.
7. The method according to claim 6 , wherein the second measuring unit further includes:
a comparator; and
a pull-down resistor connected to the comparator.
8. The method according to claim 7 , wherein the second measuring unit compares a voltage between the comparator and the pull-down resistor with a reference voltage.
9. The method according to claim 7 , wherein the second measuring unit switches a voltage level output based on a differential input of a voltage between the comparator and the pull-down resistor.
10. The method according to claim 7 , wherein the comparator includes a hysteresis.
11. The method according to claim 6 , wherein the second measuring unit further includes:
a clamp circuit; and
a MOS transistor configured to prevent an electrostatic discharge failure.
12. The method according to claim 1 , wherein the integrated circuit device is connected to another integrated circuit device by a daisy chain.
13. The method according to claim 1 , wherein:
the measuring unit is a first measuring unit;
a measuring unit of another integrated circuit device is a second measuring unit; and
the second measuring unit includes a transmitting portion configured to transmit a current signal.
14. The method according to claim 13 , wherein the second measuring unit further includes:
a current source configured to generate the current signal; and
a switch connected to the current source.
15. The method according to claim 13 , wherein the second measuring unit further includes a diode configured to prevent an electrostatic discharge failure.
16. The method according to claim 1 , wherein:
the measuring unit is a first measuring unit;
a measuring unit of another integrated circuit device is a second measuring unit; and
the first measuring unit includes a receiving portion configured to receive a current signal.
17. The method according to claim 16 , wherein the first measuring unit further includes:
a comparator; and
a pull-up resistor connected to the comparator.
18. The method according to claim 17 , wherein the first measuring unit compares a voltage between the comparator and the pull-up resistor with a reference voltage.
19. The method according to claim 17 , wherein the first measuring unit switches a voltage level output based on a differential input of a voltage between the comparator and the pull-up resistor.
20. The method according to claim 17 , wherein the comparator includes a hysteresis.
21. The method according to claim 16 , wherein the first measuring unit further includes:
a clamp circuit; and
a MOS transistor configured to prevent an electrostatic discharge failure.
22. The method according to claim 1 , wherein the reverse current is a current generated by static electricity.
23. The method according to claim 1 , wherein:
the measuring unit is a first measuring unit;
a measuring unit of another integrated circuit device is a second measuring unit; and
a current generated by a disturbance or a current ripple is not input to the second measuring unit.
24. The method according to claim 1 , wherein the battery system includes at least one controller configured to perform measurement control of the measuring units and measured value management.
25. The method according to claim 24 , wherein the at least one controller is one controller configured to control the plurality of measuring units.
26. The method according to claim 1 , wherein the battery cells are lithium ion battery cells.