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 including a first plurality of switches and a second plurality of switches, the first plurality of switches turning on or off based on a first signal for turning on the switches for a first period, the second plurality of switches turning on or off based on a second signal for turning on the switches for a second period, the second period being different from the first period,the first switch circuit switching 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 to reverse polarity of voltage inputted to the voltage divider circuit;
whereinin the first period, the first plurality of switches of 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, andin the second period, the second plurality of switches of 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, andthe voltage detection circuit detects a difference between the first input voltage and the second input voltage, based on the voltages output from the voltage divider circuit.
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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.
15 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 including a first plurality of switches and a second plurality of switches, the first plurality of switches turning on or off based on a first signal for turning on the switches for a first period, the second plurality of switches turning on or off based on a second signal for turning on the switches for a second period, the second period being different from the first period, the first switch circuit switching 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 to reverse polarity of voltage inputted to the voltage divider circuit;
whereinin the first period, the first plurality of switches of 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 second plurality of switches of 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, and the voltage detection circuit detects a difference between the first input voltage and the second input voltage, based on the voltages output from the voltage divider circuit. - 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 including a first plurality of switches and a second plurality of switches, the first plurality of switches turning on or off based on a first signal for turning on the switches for a first period, the second plurality of switches turning on or off based on a second signal for turning on the switches for a second period, the second period being different from the first period, wherein the voltage detection method comprises; switching 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 by the first switch circuit to reverse polarity of voltage inputted to the voltage divider circuit; and detecting a difference between the first input voltage and the second input voltage, based on the voltages output from the voltage divider circuit; wherein the switching step comprises; in the first period, by the first plurality of switches, 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, by the second plurality of switches, 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