DETECTING CIRCUIT OF FLUCTUATION OF EXTERNAL POWER SUPPLY VOLTAGE FOR SEMICONDUCTOR DEVICE

摘要

PURPOSE:To simplify the construction of a circuit and to enable the incorporation thereof in a semiconductor element, by constructing the same of a reference voltage forming circuit composed of diodes and a resistor, a voltage divider circuit composed of two resistors and a comparator circuit constructed of a differential amplifier. CONSTITUTION:A detecting circuit is constructed by providing a reference voltage forming circuit 9 constructed of diodes 6 and 7 and a resistor 8, connected to an external power supply and outputting a reference voltage VR to a common of the diodes 6 and 7 and the resistor 8, a voltage divider circuit 12 constructed of a series circuit of two resistors 10 and 11, connected to the external power supply and outputting a divided voltage VD obtained by dividing an external supply voltage VCC to a common node of the two resistors 10 and 11, and a comparator circuit 14 constructed of a differential amplifier 13 and comparing the reference voltage VR with the divided voltage VD. According to this constitution, the fluctuation of the external voltage can be detected by a simple circuit construction, and the circuit can be incorporated easily in a semiconductor element such as a SRAM element without complicating manufacturing processes. When a circuit element is constructed of MOS FET, mounting of the circuit on MOS IC such as SRAM. is facilitated.