Abstract: An infrared ray receiving circuit includes a band pass filter including two variable transconductance amplifiers, a detector including a differential switch, and a wave-form shaping circuit including a hysteresis comparator. In the infrared ray receiving circuit, the hysteresis width of the hysteresis comparator can be adjusted, so that generation of hair peaks in the output signal of the hysteresis comparator can be avoided. In addition, the generation of an output signal having a pulse width which is shorter than a prescribed pulse width can be avoided.

Abstract: A transistor is connected to form a diode and connected with another transistor so that the base and the emitter is connected to the base and the emitter of the other transistor, respectively, thereby to constitute a partial current mirror. A plurality of the partial current mirrors thus constituted are serially connected between an input terminal and a reference terminal, and an output terminal is connected to the collector of a partial current mirror which is directly connected to the reference terminal. Transistors of the same polarity are used to obtain an output current larger than an input current. On the contrary, to obtain an output current smaller than an input current, the transistors constituting the partial current mirror directly connected to the reference terminal are made to have the opposite polarity to the transistors constituting other partial current mirrors.

Abstract: The comparator has a differential amplifier receiving first and second inputs and producing an output, a first current source adding a first current to the differential amplifier in response to one potential level of said output, and a second current source adding a second current to the differential amplifier in response to the other potential level of said output. The differential amplifier comprises two input transistors having emitters connected in common and a current mirror as a load having an input section connected to the collector of one of the input transistors and an output section connected to the collector of the other input transistor. The first and second current are fed to the input and output sections of the current mirror, respectively.

Abstract: A semiconductor integrated circuit device is designed to prevent capacitive coupling between a wiring layer and respective circuit elements in the integrated circuit device. A plurality of island regions are provided along one major surface of a semiconductor substrate, and an insulating film is formed on the one major surface of the substrate. A first wiring layer on the insulating film is connected at a first contact section to an impurity region of one conductivity type within one island region among the plurality of island regions. A second wiring layer on the insulating film is connected at a second contact section to a first impurity region of opposite conductivity type within the one island region. A third wiring layer on the insulating film is connected to another island region among the plurality of island regions and extends over the portion of the one island region between the first contact section and the first impurity region of opposite conductivity type.