Charge/discharge control circuit and battery device
In order to provide a charge/discharge control circuit capable of controlling a charge/discharge current of secondary batteries that are connected in parallel, the charge/discharge control circuit includes: a first power supply terminal and a second power supply terminal to which a respective first electrode of each of secondary batteries which are connected in parallel is connected; a third power supply terminal to which second electrodes of the secondary batteries are connected; a connection circuit configured to connect the first power supply terminal and the second power supply terminal to generate an electric potential for an output; and a controller configured to operate on a potential difference between the electric potential supplied from the connection circuit and an electric potential supplied from the third power supply terminal, and to control charging/discharging of the first secondary battery and the second secondary battery.
1. A charge/discharge control circuit configured to control charging/discharging of a first secondary battery and a second secondary battery which are connected in parallel to each other between a first external terminal and a second external terminal, the charge/discharge control circuit comprising:
a first power supply terminal to which a first electrode of the first secondary battery is connected;
a second power supply terminal to which a first electrode of the second secondary battery is connected;
a third power supply terminal to which a second electrode of the first secondary battery and a second electrode of the second secondary battery are connected;
a first voltage detector configured to detect a voltage of the first secondary battery based on an electric potential of the first power supply terminal and an electric potential of the third power supply terminal;
a second voltage detector configured to detect a voltage of the second secondary battery based on an electric potential of the second power supply terminal and the electric potential of the third power supply terminal;
a connection circuit configured to connect the first power supply terminal and the second power supply terminal to generate an electric potential for an output; and
a controller configured to operate on a power supply voltage that is a potential difference between the electric potential output from the connection circuit and the electric potential supplied from the third power supply terminal, and to control charging/discharging of the first secondary battery and the second secondary battery based on a result of detection by the first voltage detector and a result of detection by the second voltage detector.
2. The charge/discharge control circuit according to claim 1 , wherein the connection circuit comprises:
a first resistor including a first terminal connected to the first power supply terminal and a second terminal connected to the controller; and
a second resistor including a first terminal connected to the second power supply terminal and a second terminal connected to the controller.
3. The charge/discharge control circuit according to claim 1 , wherein the connection circuit comprises:
a first diode including a cathode terminal connected to the first power supply terminal and an anode terminal connected to the controller; and
a second diode including a cathode terminal connected to the second power supply terminal and an anode terminal connected to the controller.
4. The charge/discharge control circuit according to claim 1 , wherein the connection circuit comprises:
a first constant current diode including an anode terminal connected to the first power supply terminal and a cathode terminal connected to the controller; and
a second constant current diode including an anode terminal connected to the second power supply terminal and a cathode terminal connected to the controller.
5. A battery device, comprising:
the charge/discharge control circuit of claim 1 ;
the first secondary battery;
the second secondary battery;
the first external terminal;
the second external terminal;
a first charge/discharge control switch controlled by the controller and configured to control a charge/discharge current to/from the first secondary battery; and
a second charge/discharge control switch controlled by the controller and configured to control a charge/discharge current to/from the second secondary battery.
6. A battery device, comprising:
the charge/discharge control circuit of claim 2 ;
the first secondary battery;
the second secondary battery;
the first external terminal;
the second external terminal;
a first charge/discharge control switch controlled by the controller and configured to control a charge/discharge current to/from the first secondary battery; and
a second charge/discharge control switch controlled by the controller and configured to control a charge/discharge current to/from the second secondary battery.
7. A battery device, comprising:
the charge/discharge control circuit of claim 3 ;
the first secondary battery;
the second secondary battery;
the first external terminal;
the second external terminal;
a first charge/discharge control switch controlled by the controller and configured to control a charge/discharge current to/from the first secondary battery; and
a second charge/discharge control switch controlled by the controller and configured to control a charge/discharge current to/from the second secondary battery.
8. A battery device, comprising:
the charge/discharge control circuit of claim 4 ;
the first secondary battery;
the second secondary battery;
the first external terminal;
the second external terminal;
a first charge/discharge control switch controlled by the controller and configured to control a charge/discharge current to/from the first secondary battery; and
a second charge/discharge control switch controlled by the controller and configured to control a charge/discharge current to/from the second secondary battery.