Patent ID: 7005839

Claim:
A reference power supply circuit comprising: a first PN junction configured to connect an N type semiconductor area to a first potential; a second PN junction configured to connect an N type semiconductor area to the first potential and having a size different from that of the first PN junction; a first current supply configured to be connected between a second potential and a P type semiconductor area of the first PN junction, the first current supply supplying a current only to the first PN junction; a first resistive element configured to have one end connected to a P type semiconductor area of the second PN junction; a second resistive element configured to be connected in parallel with the first resistive element and second PN junction; a second current supply configured to be inserted between the other end of the first resistive element and the second potential; a third current supply configured to be connected between the second potential and an output terminal; and a differential amplifier configured to have an inverting input terminal and a non-inverting input terminal and to receive, at the inverting input terminal, a potential on a first connection point between the first current supply and the first PN junction and, at the non-inverting input terminal, a potential on a second connection point between the second current supply and the first resistive element and to control the first, second and third current supplies by a difference between a potential of the inverting input terminal and a potential of the non-inverting input terminal.