Patent ID: 6147549
Filing Date: 2000-11-14
Classification: G05F

Abstract:
A reference voltage generating circuit comprising a differential amplifier having a first input connected to a constant voltage input terminal and an output connected to a first reference voltage output terminal for supplying a first reference voltage, a first resistor having one end connected to said output of said differential amplifier and the other end connected to a second input of said differential amplifier, a second resistor having one end connected to the other end of said first resistor and the other end connected a power supply terminal, a third resistor having one end connected to said first reference voltage output terminal and the other end connected to a second reference voltage output terminal for supplying a second reference voltage different from the first reference voltage, a fourth resistor connected having one end connected to said second reference voltage output terminal and the other end connected to a third reference voltage output terminal, and a fifth resistor having one end connected to said third reference voltage output terminal and the other end connected to said power supply terminal;said reference voltage generating circuit further including a switch connected between said second reference voltage output terminal and the other end of said third resistor, said switch being put in an OFF condition in response to a test signal, and a test voltage supplying circuit having a voltage output connected to said second reference voltage output terminal and activated in response to said test signal so as to supply a test voltage to said second reference voltage output terminal.