SEMICONDUCTOR DEVICE AND POWER SUPPLY VOLTAGE CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor device that causes no malfunction in its internal circuit even when relations of a plurality of power supply voltages are inverted due to momentary failure or momentary interruption or the like. SOLUTION: The semiconductor device of this invention is provided with a VDD detection circuit 1 that detects a level of a power supply voltage VDD, a VCC detection circuit 2 that detects a level of a power supply voltage VCC, a level comparator circuit 3 that discriminates whether the power supply voltage VCC is higher than the power supply voltage VDD, a level comparator circuit 4 that discriminates whether or not the power supply voltage VDD is higher than 1/3 of the power supply voltage VCC, and a control circuit 7 that controls whether or not the power supply voltages VDD, VCC are to be supplied to an internal power supply generating circuit and an internal circuit 6. On the occurrence of a momentary failure or momentary interruption, when the level relation between the power supply voltages VDD, VCC is inverted or the power supply voltages VDD, VCC are lowered according to the operating voltage of transistors, since the control circuit 7 initializes the internal circuit 6 by surely stopping the operation of the internal power supply generating circuit 5, the occurrence of an accidental junction leak or malfunction of the internal circuit 6 or the like can be prevented.