Charge/discharge control circuit and secondary battery
AssigneeFujitsu Limited
InventorsAkira Haraguchi, Takashi Matsumoto
Life of this patent
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Abstract
A charge/discharge control circuit for controlling charging and discharging of a secondary battery that includes a cell. The charge/discharge control circuit includes an overdischarge detection circuit for detecting an overdischarged state of the battery, and an overcharge detection circuit for detecting an overcharged state of the battery. A discharge control switch is deactivated in the overdischarged state. A first charge control switch is deactivated in the overdischarged state. A second charge control switch is activated in the overdischarged state. A current-limiting circuit is connected in series with the second charge control switch for limiting the charging current when charging is performed.
Claims16
A charge/discharge control circuit for controlling charging and discharging of a secondary battery, wherein the secondary battery includes a cell, the control circuit comprising:
- an overdischarge detection circuit for comparing a voltage of the cell with a predetermined discharge reference voltage, determining whether the secondary battery is in an overdischarged state, and generating an overdischarge determination signal;
- an overcharge detection circuit for comparing the voltage of the cell with a predetermined charge reference voltage, determining whether the secondary battery is in an overcharged state, and generating an overcharge determination signal;
- a discharge control switch connected to the overdischarge detection circuit and deactivated in the overdischarged state based on the overdischarge determination signal;
- a first charge control switch deactivated in the overdischarged state based on the overdischarge determination signal and the overcharge determination signal;
- a second charge control switch activated in the overdischarged state based on the overdischarge determination signal and the overcharge determination signal;
- and
- a current-limiting circuit connected in series with the second charge control switch for limiting a charging current when charging is performed.
A charge/discharge control circuit for controlling charging and discharging of a secondary battery, wherein the secondary battery includes a cell, the control circuit comprising:
- an overdischarge detection circuit for comparing a voltage of the cell with a predetermined discharge reference voltage, determining whether the secondary battery is in an overdischarged state, and generating an overdischarge determination signal;
- an overcharge detection circuit for comparing the voltage of the cell with a predetermined charge reference voltage, determining whether the secondary battery is in an overcharged state, and generating an overcharge determination signal;
- a discharge control switch connected to the overdischarge detection circuit and deactivated in the overdischarged state based on the overdischarge determination signal;
- a first charge control switch deactivated in the overdischarged state based on the overdischarge determination signal and the overcharge determination signal;
- a second charge control switch activated in the overdischarged state based on the overdischarge determination signal and the overcharge determination signal;
- a current-limiting circuit connected in series with the second charge control switch for limiting a charging current when charging is performed;
- and
- an erroneous functioning prevention circuit for controlling activation and deactivation of the first charge control switch in the overdischarged state based on a level of a voltage supplied by the secondary battery.
A secondary battery including:
- a cell;
- and
- a charge/discharge control circuit connected to the cell for controlling charging and discharging of the cell, the charge/discharge control circuit comprising:
- an overdischarge detection circuit for comparing a voltage of the cell with a predetermined discharge reference voltage, determining whether the secondary battery is in an overdischarged state, and generating an overdischarge determination signal;
- an overcharge detection circuit for comparing the voltage of the cell with a predetermined charge reference voltage, determining whether the secondary battery is in an overcharged state, and generating an overcharge determination signal;
- a discharge control switch connected to the overdischarge detection circuit and deactivated in the overdischarged state based on the overdischarge determination signal;
- a first charge control switch deactivated in the overdischarged state based on the overdischarge determination signal and the overcharge determination signal;
- a second charge control switch activated in the overdischarged state based on the overdischarge determination signal and the overcharge determination signal;
- and
- a current-limiting circuit connected in series with the second charge control switch for limiting a charging current when charging is performed.
Dependencies are inferred from the claim text.