(19)
(11) EP 0 426 150 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
02.10.1991 Bulletin 1991/40

(43) Date of publication A2:
08.05.1991 Bulletin 1991/19

(21) Application number: 90120902.3

(22) Date of filing: 31.10.1990
(51) International Patent Classification (IPC)5: G05F 3/20, G05F 3/22, G05F 3/30
(84) Designated Contracting States:
DE FR GB

(30) Priority: 02.11.1989 JP 284976/89

(71) Applicant: KABUSHIKI KAISHA TOSHIBA
Kawasaki-shi, Kanagawa-ken 210 (JP)

(72) Inventor:
  • Yoshida, Yoshihiro, c/o Intellectual Property Div.
    Minato-ku, Tokyo 105 (JP)

(74) Representative: Lehn, Werner, Dipl.-Ing. et al
Hoffmann, Eitle & Partner, Patentanwälte, Postfach 81 04 20
81904 München
81904 München (DE)


(56) References cited: : 
   
       


    (54) Constant voltage circuit


    (57) In a constant voltage circuit, when a second resistor element (13) is inserted between the base and collector of a first transistor (14) and between the other terminal of a first resistor element (11) and the base of a second transistor (16), a basic equation for calculating a bandgap voltage reference can be calcu­lated free from a base-emitter voltage of the third transistor (17). Therefore, since a change in base-­emitter voltage on the basis of a change in current flowing through the third transistor (17) does not appear as an output voltage, the output voltage can be stabilized.







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