Abstract: A modulator includes an integrator, an input chopping switch, and output chopping switch, and a control circuit. The integrator has a differential amplifier, a first switch and a series circuit. The first switch is connected between input and output terminals of the differential amplifier. The series circuit is connected between the input and output terminals of the differential amplifier. The series circuit has a second switch, an input capacitance chopping switch, an integration capacitor and an output capacitance chopping switch. The control circuit controls the input chopping switch and the output chopping switch to execute chopping being at a chopping frequency identical to the input capacitance chopping switch and the output capacitance chopping switch. The chopping frequency of the input and output capacitance chopping switches is lower than a switching frequency of the first switch.

Abstract: An amplifier circuit includes: an amplifier; a first switched resistor unit configured by connecting in series a first resistance element having one or more resistors and a first switch, and having one end connected to an input terminal of the amplifier; a second resistance element unit connected between an other end of the first switched resistor unit and an output terminal of the amplifier and including one or more resistors; a second switch connected between a common connection point of the first switched resistor unit and the second resistance element unit and a reset potential point; and a control circuit for exclusively turning on and off the first switch and the second switch, respectively.

Abstract: A current sensor includes a current detection unit, a relay, a relay control unit, and a resistance value correction circuit. The current detection unit detects a detection target current based on a terminal voltage of a shunt resistor located in series with a path through which the detection target current flows and a detection resistance value for current detection corresponding to a resistance value of the shunt resistor. The relay is located in series with the path through which the detection target current flows. The relay control unit controls the relay to be turned on or off. The resistance value correction circuit calculates the resistance value of the shunt resistor as a calculated resistance value and corrects the detection resistance value based on the calculated resistance value.

Abstract: A current sensor for a detection target current using a shunt resistor includes: a resistance value correction circuit having a correction resistor; a signal application unit that applies an alternating current signal to a series circuit of the shunt resistor and the correction resistor; a voltage detection unit that detects terminal voltages of the shunt resistor and the correction resistor; and a correction unit that calculates a resistance value of the shunt resistor and corrects the resistance value for detection; and a power supply circuit having a first power supply generation unit that generates a first power supply of the signal application unit from an input power supply of an outside; and a second power supply generation unit that generates a second power supply of the voltage detection unit.

Abstract: A delta-sigma modulator includes a capacitively-coupled amplifier, a first integrator, a second integrator, a quantizer, a first switch, a second switch, and a control circuit. The first switch is connected between an input of the capacitively-coupled amplifier and a sampling capacitor of the capacitively-coupled amplifier to execute a chopping operation. The second switch is connected between an output of the capacitively-coupled amplifier and an input of the first integrator to execute a chopping operation. The control circuit executes modulation through the first switch at the input of the capacitively-coupled amplifier, executes demodulation through the second switch at the output of the capacitively-coupled amplifier, and imports an output signal of the capacitively-coupled amplifier into the first integrator after the demodulation.

Abstract: A clock signal generation circuit for a switched capacitor circuit with a chopping function unit includes: first and second synchronous clock circuits that generate first and second synchronous clock signals, respectively; an edge signal generation circuit that generates one or more rise and fall edge signals by delaying the first synchronous clock signal; a first clock generator that generate a first clock signal group for driving the switched capacitor circuit; and a second clock generator that generates a second clock signal group for driving the chopping function unit. Frequencies of the first and second clock signal groups are respectively defined by the first and second synchronous clock circuits. Rise and fall edges of the first and second clock signal groups are defined by the edge signal generation circuit.

Abstract: A current sensor for detecting a current based on a terminal voltage and a resistance value of a shunt resistor, includes: a resistance value correction circuit having: correction resistors; a signal application unit; a voltage detection unit that detects terminal voltages of the shunt resistor and a part of the correction resistors in a first period, and terminal voltages of all of the correction resistors in a second period; and a correction unit that corrects the resistance value for current detection based on a calculated resistance value of the shunt resistor. Resistance values and resistance accuracies of the correction resistors are higher as the plurality of correction resistors are disposed farther from the shunt resistor.

Abstract: A current sensor of a detection target current using a shunt resistor includes: a resistance value correction circuit having: a correction resistor; a signal application unit that applies an alternating current signal to a series circuit of the shunt resistor and the correction resistor; a first voltage detection unit that detects the terminal voltage of the shunt resistor; a second voltage detection unit that detects a terminal voltage of the correction resistor; and a correction unit that calculates the resistance value of the shunt resistor based on a first voltage detection value by the first voltage detection unit and a second voltage detection value by the second voltage detection unit, and corrects the resistance value for current detection based on a calculated resistance value of the shunt resistor.

Abstract: A clock signal generation circuit for a switched capacitor circuit with a chopping function unit includes: first and second synchronous clock circuits that generate first and second synchronous clock signals, respectively; an edge signal generation circuit that generates one or more rise and fall edge signals by delaying the first synchronous clock signal; a first clock generator that generate a first clock signal group for driving the switched capacitor circuit; and a second clock generator that generates a second clock signal group for driving the chopping function unit. Frequencies of the first and second clock signal groups are respectively defined by the first and second synchronous clock circuits. Rise and fall edges of the first and second clock signal groups are defined by the edge signal generation circuit.

Abstract: A current sensor for a detection target current using a shunt resistor includes: a resistance value correction circuit having a correction resistor; a signal application unit that applies an alternating current signal to a series circuit of the shunt resistor and the correction resistor; a voltage detection unit that detects terminal voltages of the shunt resistor and the correction resistor; and a correction unit that calculates a resistance value of the shunt resistor and corrects the resistance value for detection; and a power supply circuit having a first power supply generation unit that generates a first power supply of the signal application unit from an input power supply of an outside; and a second power supply generation unit that generates a second power supply of the voltage detection unit.

Abstract: A current sensor for detecting a current based on a terminal voltage and a resistance value of a shunt resistor, includes: a resistance value correction circuit having: correction resistors; a signal application unit; a voltage detection unit that detects terminal voltages of the shunt resistor and a part of the correction resistors in a first period, and terminal voltages of all of the correction resistors in a second period; and a correction unit that corrects the resistance value for current detection based on a calculated resistance value of the shunt resistor. Resistance values and resistance accuracies of the correction resistors are higher as the plurality of correction resistors are disposed farther from the shunt resistor.

Abstract: A current sensor of a detection target current using a shunt resistor includes: a resistance value correction circuit having: a correction resistor; a signal application unit that applies an alternating current signal to a series circuit of the shunt resistor and the correction resistor; a first voltage detection unit that detects the terminal voltage of the shunt resistor; a second voltage detection unit that detects a terminal voltage of the correction resistor; and a correction unit that calculates the resistance value of the shunt resistor based on a first voltage detection value by the first voltage detection unit and a second voltage detection value by the second voltage detection unit, and corrects the resistance value for current detection based on a calculated resistance value of the shunt resistor.