PROTECTION CIRCUIT, CHARGE CONTROL CIRCUIT, AND REVERSE CURRENT PREVENTION METHOD EMPLOYING CHARGE CONTROL CIRCUIT
First Claim
Patent Images
1. A protection circuit comprising:
- a current limitation element, to connect between an external reference terminal and an internal reference potential to limit the amount of current flowing from the external reference terminal to a power source terminal, when a reversed polarity voltage s applied at the power source terminal; and
a conducting element, to connect between the power source terminal and the internal reference potential to adjust the internal reference potential to the potential at the power source terminal, when the reversed polarity voltage is applied.
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Abstract
A protection circuit to protect from a reverse current, including a current limitation element to connect between an external reference terminal and an internal reference potential to limit the amount of current flowing from the external reference terminal to a power source terminal, when a reversed polarity voltage is applied at the power source terminal; and a conducting element to connect between the power source terminal and the internal reference potential to adjust the internal reference potential to the voltage at the power source terminal, when the reversed polarity voltage is applied.
13 Citations
14 Claims
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1. A protection circuit comprising:
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a current limitation element, to connect between an external reference terminal and an internal reference potential to limit the amount of current flowing from the external reference terminal to a power source terminal, when a reversed polarity voltage s applied at the power source terminal; and a conducting element, to connect between the power source terminal and the internal reference potential to adjust the internal reference potential to the potential at the power source terminal, when the reversed polarity voltage is applied. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A charge control circuit comprising:
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a power source terminal to which a power source voltage is applied from an external power source; an output terminal to output a current based on the power source voltage; an external reference terminal connected to an external reference potential; a driver transistor connected to the power source terminal, the output terminal, and an internal reference potential; and a protection circuit to prevent a reverse current owing from the output terminal to the power source terminal, the protection circuit comprising; a current limitation element, to connect between the external reference terminal and the internal reference potential to limit the amount of current flowing from the external reference terminal to the power source terminal, when a reversed polarity voltage is applied at the power source terminal; and a conducting element, to connect between the power source terminal and the internal reference potential, to adjust the internal reference potential to the potential at the power source terminal to stop parasitic operation of the driver transistor, when the reversed polarity voltage is applied. - View Dependent Claims (11, 12)
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13. A reverse current prevention method employing a charge control circuit that has a power source terminal to which a power source voltage is applied from an external power source;
- an output terminal to output a current based on the power source voltage;
an external reference terminal connected to an external reference potential; and
a driver transistor connected between the power source terminal, the output terminal, and an internal reference potential,the method comprising the steps of; applying a reverse polarity voltage, whose potential is lower than a potential at the external reference terminal, at the power source terminal; limiting the amount of current flowing from the external reference terminal to the power source terminal; detecting that the reversed polarity voltage is applied; connecting the internal reference potential with the power source terminal; decreasing the internal reference potential to the potential at the power source terminal; stopping parasitic operation of the driver transistor; and preventing a reverse current from flowing from the output terminal to the power supply terminal through the driver transistor. - View Dependent Claims (14)
- an output terminal to output a current based on the power source voltage;
Specification