Reference voltage generating circuit of generating a plurality of reference voltages
AssigneeNEC Corporation
InventorKazuki Ohno
Life of this patent
Estimating the term…
Abstract
A reference voltage generating circuit comprises a differential amplifier having a first input connected to receive a constant voltage and a second input connected through a voltage feedback path to an output of the differential amplifier so as to receive a voltage in proportion to an a first reference voltage outputted from the differential amplifier. A voltage divider composed of series-connected resistors is connected to the output of the differential amplifier so as to form a current path independent of the voltage feedback path, so that the voltage divider generates a second reference voltage different from the first reference voltage. Thus, a single reference voltage generating circuit generates a plurality of reference voltages.
Claims2
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.
Dependencies are inferred from the claim text.