Charge and discharge control circuit having an intermediate terminal disconnection detecting circuit for detecting disconnection with secondary batteries
View Patent ↗The present invention provides a charge and discharge control circuit and a battery device capable of detecting an intermediate terminal disconnection without causing the balance between battery voltages to collapse and shortening the service life of the battery device. A charge and discharge control circuit which controls charging/discharging of a plurality of secondary batteries connected in series is equipped with intermediate terminal disconnection detecting circuits each of which is provided between a positive electrode terminal and a negative electrode terminal of each secondary battery and detects an intermediate terminal disconnection of each intermediate terminal by intermittently equal detection currents.
1. A charge and discharge control circuit comprising at least:
a positive power supply connection terminal;
an intermediate terminal;
a negative power supply connection terminal respectively connected with a positive electrode terminal;
an inter-battery connection terminal and a negative electrode terminal of each of a plurality of secondary batteries connected in series;
intermediate terminal disconnection detecting circuits each allowing a detection current to flow by switching at every predetermined time between the positive power supply connection terminal and the intermediate terminal, between the intermediate terminals adjacent to each other and between the intermediate terminal and the negative power supply connection terminal;
a plurality of voltage detection circuits respectively connected in parallel with the secondary batteries;
a control circuit inputted with outputs of the voltage detection circuits;
wherein the control circuit comprises an intermediate terminal disconnection control circuit that controls the intermediate terminal disconnection detecting circuits.
2. The charge and discharge control circuit according to claim 1 , wherein each of the intermediate terminal disconnection detecting circuits is controlled by a signal from the intermediate terminal disconnection control circuit and has a period during which the detection current is made not to flow.
3. The charge and discharge control circuit according to claim 1 , wherein the intermediate terminal disconnection detecting circuits are provided in plural form in parallel with the voltage detection circuits respectively.
4. A battery device comprising:
a plurality of secondary batteries connected in series;
a charge and discharge control circuit, which controls charge and discharge of the secondary batteries; and
charge and discharge control switches each controlled by the charge and discharge control circuit;
wherein the charge and discharge control circuit comprises:
a positive power supply connection terminal, an intermediate terminal and a negative power supply connection terminal respectively connected with a positive electrode terminal, an inter-battery connection terminal and a negative electrode terminal of each of a plurality of secondary batteries connected in series;
intermediate terminal disconnection detecting circuits each allowing a detection current to flow by switching at every predetermined time between the positive power supply connection terminal and the intermediate terminal, between the intermediate terminals adjacent to each other and between the intermediate terminal and the negative power supply connection terminal;
a plurality of voltage detection circuits respectively connected in parallel with the secondary batteries;
a control circuit inputted with outputs of the voltage detection circuits;
wherein the control circuit comprises an intermediate terminal disconnection control circuit that controls the intermediate terminal disconnection detecting circuits.