Abstract: An analog-to-digital converter includes a first switch circuit, a first integrator, a second switch circuit, a second integrator, a quantizer and a digital-to-analog converter. The first switch circuit receives an external analog signal, outputs the analog signal in reverse phase, and outputs the analog signal in positive phase. The first integrator receives and integrates the analog signal with cross-coupling. The second switch circuit outputs an output of the first integrator and a common mode output potential of the first integrator. The second integrator samples and integrates an output of the second switch circuit. The quantizer single-bit-quantizes an output of the second integrator to provide the output as a digital signal output. The digital-to-analog converter receives an output of the quantizer and provides the output as an analog signal output. Each of the first and second integrators receives and integrates an output of the digital-to-analog converter with cross-coupling.

Abstract: A power-supply-voltage detecting circuit in an embodiment includes a compensation circuit and a switching element which controls ON-and-OFF of the signal output of the signal circuit. The compensation circuit has a positive temperature coefficient to balance out the negative temperature coefficient that the switching element has.

Abstract: An optical receiver circuit and an optical coupling device, which includes: a light-receiving element; TIA operable to output a first voltage signal in response to input of the current signal; a voltage source operable to supply a second voltage signal serving as a reference voltage for determining pulse switching; a voltage source operable to supply a third voltage signal serving as a reference voltage for generating a shift control signal; a level shift circuit operable to output a voltage signal generated by subtracting a level shift voltage from the first voltage signal; a comparator operable to convert the first voltage signal to a pulse, and a controller operable to output the shift control signal outputting the first voltage signal shifted to a low-level side when the first voltage signal exceeds the third voltage signal, and outputting the first voltage signal without shifting after the output of the level shift circuit is lowered below the second voltage signal, are provided.

Abstract: A photocoupler includes a light emitting device, a drive circuit; a clamp circuit and a light receiving section. For an input voltage to the input terminal being within a range between a first voltage and a second voltage, the photocoupler is allowed to enter an operation mode in which the drive circuit, in response to the digital signal inputted thereto, drives the light emitting device to convert the digital signal to the optical signal, and the electrical signal is externally outputted from the light receiving section. For an input voltage to the input terminal being outside the range between the first voltage and the second voltage, the photocoupler is allowed to enter an inspection mode in which the drive circuit stops driving the light emitting device, the first transistor of the clamp circuit is turned on, and a current generally equal or proportional to a clamp current of the clamp circuit is supplied to the light emitting device so that characteristics of the light emitting device can be measured.

Abstract: An analog-to-digital converter includes a first switch circuit, a first integrator, a second switch circuit, a second integrator, a quantizer and a digital-to-analog converter. The first switch circuit receives an external analog signal, outputs the analog signal in reverse phase, and outputs the analog signal in positive phase. The first integrator receives and integrates the analog signal with cross-coupling. The second switch circuit outputs an output of the first integrator and a common mode output potential of the first integrator. The second integrator samples and integrates an output of the second switch circuit. The quantizer single-bit-quantizes an output of the second integrator to provide the output as a digital signal output. The digital-to-analog converter receives an output of the quantizer and provides the output as an analog signal output. Each of the first and second integrators receives and integrates an output of the digital-to-analog converter with cross-coupling.

Abstract: An optical receiver circuit and an optical coupling device, which includes: a light-receiving element; TIA operable to output a first voltage signal in response to input of the current signal; a voltage source operable to supply a second voltage signal serving as a reference voltage for determining pulse switching; a voltage source operable to supply a third voltage signal serving as a reference voltage for generating a shift control signal; a level shift circuit operable to output a voltage signal generated by subtracting a level shift voltage from the first voltage signal; a comparator operable to convert the first voltage signal to a pulse, and a controller operable to output the shift control signal outputting the first voltage signal shifted to a low-level side when the first voltage signal exceeds the third voltage signal, and outputting the first voltage signal without shifting after the output of the level shift circuit is lowered below the second voltage signal, are provided.

Abstract: According to an aspect of the present invention, there is provided a signal coupler including, a first coil being formed over a semiconductor substrate, the first coil including a first pad-pair and a first metal wiring, the first pad-pair including two first pads, the first metal wiring being perpendicularly configured as a half-loop over the semiconductor substrate, both ends of the first metal wiring being bonded to each of the first pad, respectively, an input circuit being configured in the semiconductor substrate and providing electrical current corresponding to an input signal to the first metal wiring, a second coil being opposed to the first coil and formed over the semiconductor substrate, the second coil including a second pad-pair and a second metal wiring, the second pad-pair including two second pads, the second metal wiring being perpendicularly configured as the half-loop over the semiconductor substrate, both ends of the second metal wiring being bonded to each of the second pad, respectively

Abstract: A photocoupler includes a light emitting device, a drive circuit; a clamp circuit and a light receiving section. For an input voltage to the input terminal being within a range between a first voltage and a second voltage, the photocoupler is allowed to enter an operation mode in which the drive circuit, in response to the digital signal inputted thereto, drives the light emitting device to convert the digital signal to the optical signal, and the electrical signal is externally outputted from the light receiving section. For an input voltage to the input terminal being outside the range between the first voltage and the second voltage, the photocoupler is allowed to enter an inspection mode in which the drive circuit stops driving the light emitting device, the first transistor of the clamp circuit is turned on, and a current generally equal or proportional to a clamp current of the clamp circuit is supplied to the light emitting device so that characteristics of the light emitting device can be measured.