Reference voltage circuit
AssigneeNEC Electronics Corporation
InventorHidetoshi Ozoe
Life of this patent
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Abstract
A reference voltage circuit includes three PMOS transistors and two NMOS transistors. The three PMOS transistors constitute a current mirror circuit and the two NMOS transistors constitute a load circuit. A dummy NMOS transistor is added to a load circuit so as to make three NMOS transistors correspond to the three PMOS transistors and a ratio of currents leaking through PN junctions of diffusion layers on the side of the current mirror circuit is set equal to a ratio of currents leaking through PN junctions of diffusion layers on the side of the load circuit. This allows the reference voltage circuit to output a reference voltage that does not change with temperature even at high temperatures.
Claims11
A reference voltage circuit comprising:
- first, second, third MOS transistors being of one conduction type and having drains respectively connected to first, second, third nodes and gates commonly connected to said second node in order to constitute a current mirror circuit;
- first, second MOS transistors being of the other conduction type and having drains respectively connected to said first and second nodes and gates commonly connected to said first node in order to constitute a load circuit;
- a source resistor having one end connected to a source of said second MOS transistor of the other conduction type and constituting said load circuit;
- and
- an output resistor having one end connected to said third node used to output a reference voltage and constituting said load circuit,
- said reference voltage circuit being further constructed such that a dummy diffusion layer of the other conduction type is connected to at least said third node in order to set a ratio of currents leaking, during operation of said reference voltage circuit, through PN junctions of diffusion layers connected to said first, second, third nodes and being of the other conduction type equal to a ratio of currents leaking, during operation of said reference voltage circuit, through PN junctions of diffusion layers connected to said first, second, third nodes and being of one conduction type.
Dependencies are inferred from the claim text.