Abstract: According to an embodiment, a voltage detecting device includes: a first operational amplifier having an inversion input terminal to which first detection voltage is supplied and a non-inversion input terminal to which voltage of an external output terminal is supplied; a first transistor provided between the external output terminal and a reference voltage terminal and having a gate to which an output voltage of the first operational amplifier is applied; a second operational amplifier having an inversion input terminal to which second detection voltage is supplied and a non-inversion input terminal to which the voltage of the external output terminal is supplied; and a second transistor provided between the external output terminal and the reference voltage terminal and having a gate to which output voltage of the second operational amplifier is applied.

Abstract: A waveform generating circuit includes a constant current circuit that supplies a constant current through a power source; a current mirror circuit that flows an output current that is n times an input current; and a switching circuit that switches a flowing direction of the current in the constant current circuit between the current mirror circuit and the output terminal according to the logical level of the rectangle input signal. The waveform generating circuit generates a triangle wave having a falling slope waveform that is n times the rising slope. On the other hand, the waveform generating circuit that receives an inverted signal of the signal generates a triangle wave and its voltage is compared with another in the comparator to generate an output signal.

Abstract: A waveform generating circuit includes a constant current circuit that supplies a constant current through a power source; a current mirror circuit that flows an output current that is n times an input current; and a switching circuit that switches a flowing direction of the current in the constant current circuit between the current mirror circuit and the output terminal according to the logical level of the rectangle input signal. The waveform generating circuit generates a triangle wave having a falling slope waveform that is n times the rising slope. On the other hand, the waveform generating circuit that receives an inverted signal of the signal generates a triangle wave and its voltage is compared with another in the comparator to generate an output signal.

Abstract: A band-gap type constant voltage generating circuit is produced in a semiconductor chip, and has a first potential terminal and a second potential terminal. A band-gap circuit includes first and second transistors having respective bases connected to each other, a first resistor connected between emitters of the first and second transistors, and a second resistor connected between the emitter of the second transistor and the first potential terminal. A constant voltage production circuit is provided between the first and second potential terminals to produce and output a constant voltage based on a base-emitter voltage of the second transistor of the band-gap circuit, and the constant voltage is fed as a feedback signal to the base of the second transistor of the band-gap circuit. A driver circuit is provided between the first and second potential terminals and connected to collectors of the first and second transistors to drive the band-gap circuit.

Abstract: A band-gap type constant voltage generating circuit is produced in a semiconductor chip, and has a first potential terminal and a second potential terminal. A band-gap circuit includes first and second transistors having respective bases connected to each other, a first resistor connected between emitters of the first and second transistors, and a second resistor connected between the emitter of the second transistor and the first potential terminal. A constant voltage production circuit is provided between the first and second potential terminals to produce and output a constant voltage based on a base-emitter voltage of the second transistor of the band-gap circuit, and the constant voltage is fed as a feedback signal to the base of the second transistor of the band-gap circuit. A driver circuit is provided between the first and second potential terminals and connected to collectors of the first and second transistors to drive the band-gap circuit.