Charge and discharge control circuit having low voltage detecting means for preventing charging of an abnormal cell
First Claim
1. A charge and discharge control circuit comprising:
- circuitry for monitoring whether the voltage of at least one secondary cell is above or below the threshold voltage of a MOS transistor and outputting a signal depending upon the monitored voltage for controlling the charging of the at least one secondary cell based upon the signal.
2 Assignments
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Accused Products
Abstract
A charge/discharge control circuit cuts off a current path to stop charging of an abnormal secondary cell when the voltage of the secondary cell is less than the threshold voltage of a MOS transistor. The charge/discharge control circuit includes a charge and discharge control circuit for monitoring the voltage of a secondary cell and outputting a signal for controlling the charging and discharging of the secondary cell, a switch circuit for receiving the output signal of the charge and discharge control circuit to stop the charging of the secondary cell in an overcharged or overdischarged state, and a low voltage detecting circuit for receiving the output signal of the charge and discharge control circuit, detecting whether the voltage of the secondary cell is below a predetermined voltage, which is below the overdischarge voltage and which is equal to the threshold voltage of a MOS transistor, and for controlling the switch circuit to prevent charging of the secondary cell if the voltage thereof is below the predetermined voltage.
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Citations
12 Claims
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1. A charge and discharge control circuit comprising:
- circuitry for monitoring whether the voltage of at least one secondary cell is above or below the threshold voltage of a MOS transistor and outputting a signal depending upon the monitored voltage for controlling the charging of the at least one secondary cell based upon the signal.
- View Dependent Claims (2, 3)
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4. A charge and discharge control circuit comprising:
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a charge and discharge control circuit for monitoring the voltage of at least one secondary cell and outputting a signal used for controlling the charge and discharge of the at least one secondary cell; a switch circuit for receiving the output signal of the charge and discharge control circuit for preventing charge or discharge of the at least one secondary cell when the at least one secondary cell is in one of and overcharged and an overdischarged state; and a low voltage detecting circuit for receiving the output signal of the charge and discharge control circuit, for detecting whether the voltage of at least one secondary cell is below a predetermined value at which charging of the secondary cell is to be prevented, the predetermined value being less than the voltage associated with an overdischarged state, and for controlling the switch circuit to prevent charging of the secondary cell. - View Dependent Claims (5)
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6. A charge and discharge control circuit for monitoring the voltage of a secondary cell, comprising:
- a first circuit for detecting whether the voltage of the secondary cell is in an overcharged or overdischarged state, generating a first signal when the secondary cell is in an overcharged state and generating a second signal when the secondary cell is in an overdischarged state; and
a second circuit for detecting whether the voltage of the secondary cell is below the threshold voltage of a MOS transistor and generating a third signal used for controlling the charging of the secondary cell. - View Dependent Claims (7, 8, 9, 10, 11, 12)
- a first circuit for detecting whether the voltage of the secondary cell is in an overcharged or overdischarged state, generating a first signal when the secondary cell is in an overcharged state and generating a second signal when the secondary cell is in an overdischarged state; and
Specification