Voltage detection circuit, overcurrent detection circuit, charging current control system, and voltage detection method
First Claim
Patent Images
1. A voltage detection circuit, comprising:
- a first input terminal that inputs a first input voltage;
a second input terminal that inputs a second input voltage;
a third input terminal to provide a ground potential;
a voltage divider circuit having a first serial resistor and a second serial resistor, the first serial resister having a plurality of resistors connected in series and a first voltage dividing terminal at the intermediate connecting point of the plurality of resistors, the second serial resistor having a plurality of resistors connected in series and a second voltage dividing terminal at the intermediate connecting point of the plurality of resistors; and
a first switch circuit which inputs a signal having a first period and a second period to switch the state of connection of each of the input terminals to the first serial resistor and the second serial resistor in the first period and the second period;
wherein in the first period, the first switch circuit connects the first input terminal to one end of the first serial resistor, connects the second input terminal to one end of the second serial resistor, and connects the third input terminal to the other end of the first serial resistor and the other end of the second serial resistor, and in the second period, the first switch circuit connects the third input terminal to one end of the first serial resistor and one end of the second serial resistor, connects the first input-terminal to the other end of the first serial resistor, and connects the second input terminal to the other end of the second serial resistor.
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Abstract
A voltage detection circuit detects an input voltage in first and second periods to average by using a switch circuit and a sampling circuit. At this time, the input voltage of the second period is added to the input voltage of the first period so that a polarity of variations is opposite, the variations being in relative errors of a plurality of resistors for dividing the input voltage, in input offset voltages of a voltage amplifier for amplifying an inputted minute voltage, and in input offset voltages of a comparator for comparing an amplified voltage value with a certain level.
17 Citations
22 Claims
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1. A voltage detection circuit, comprising:
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a first input terminal that inputs a first input voltage;
a second input terminal that inputs a second input voltage;
a third input terminal to provide a ground potential;
a voltage divider circuit having a first serial resistor and a second serial resistor, the first serial resister having a plurality of resistors connected in series and a first voltage dividing terminal at the intermediate connecting point of the plurality of resistors, the second serial resistor having a plurality of resistors connected in series and a second voltage dividing terminal at the intermediate connecting point of the plurality of resistors; and
a first switch circuit which inputs a signal having a first period and a second period to switch the state of connection of each of the input terminals to the first serial resistor and the second serial resistor in the first period and the second period;
whereinin the first period, the first switch circuit connects the first input terminal to one end of the first serial resistor, connects the second input terminal to one end of the second serial resistor, and connects the third input terminal to the other end of the first serial resistor and the other end of the second serial resistor, and in the second period, the first switch circuit connects the third input terminal to one end of the first serial resistor and one end of the second serial resistor, connects the first input-terminal to the other end of the first serial resistor, and connects the second input terminal to the other end of the second serial resistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A voltage detection method by use of a voltage detection circuit comprising:
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a first input terminal that inputs a first input voltage;
a second input terminal that inputs a second input voltage;
a third input terminal to provide a ground potential;
a voltage divider circuit having a first serial resistor and a second serial resistor, the first serial resistor having a plurality of resistors connected in series and a first voltage dividing terminal at the intermediate connecting point of the plurality of resistors, the second serial resistor having a plurality of resistors connected in series and a second voltage dividing terminal at the intermediate connecting point of the plurality of resistors; and
a first switch circuit which inputs a signal having a first period and a second period to switch the state of connection of each of the input terminals to the first serial resistor and the second serial resistor in the first period and the second period, wherein the voltage detection method comprises;
in the first period, connecting the first input terminal to one end of the first serial resistor, connecting the second input terminal to one end of the second serial resistor, and connecting the third input terminal to the other end of the first serial resistor and the other end of the second serial resistor; and
in the second period, connecting the third input terminal to one end of the first serial resistor and one end of the second serial resistor, connecting the first input terminal to the other end of the first serial resistor, and connecting the second input terminal to the other end of the second serial resistor. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification