JPS5766324A - Light receiving circuit - Google Patents

Light receiving circuit

Info

Publication number
JPS5766324A
JPS5766324A JP14352380A JP14352380A JPS5766324A JP S5766324 A JPS5766324 A JP S5766324A JP 14352380 A JP14352380 A JP 14352380A JP 14352380 A JP14352380 A JP 14352380A JP S5766324 A JPS5766324 A JP S5766324A
Authority
JP
Japan
Prior art keywords
light
light receiving
current
dark current
receiving element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP14352380A
Other languages
Japanese (ja)
Other versions
JPS636820B2 (en
Inventor
Hiroaki Fukuda
Yukihisa Oda
Shigeharu Kita
Takeo Hara
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sharp Corp
Original Assignee
Sharp Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sharp Corp filed Critical Sharp Corp
Priority to JP14352380A priority Critical patent/JPS5766324A/en
Publication of JPS5766324A publication Critical patent/JPS5766324A/en
Publication of JPS636820B2 publication Critical patent/JPS636820B2/ja
Granted legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/10—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void
    • G01J1/16—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void using electric radiation detectors
    • G01J1/1626—Arrangements with two photodetectors, the signals of which are compared

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)

Abstract

PURPOSE:To constitute the simple light receiving circuit which is suitable for the operation at high temperatures and for sensing of very small amount of light by eliminating a dark current due to a light receiving element which does not receive the light from the current sensed by a light receiving element which actually receives the light. CONSTITUTION:The dark current of the light receiving element PT1, whic does not receive the light and which is used for cancelling the dark current, is the same as the dark current of the light receiving element PT2 which actually receives the light. The emitter currents ID and I3 of transistor Tr1 and Tr2 which are connected to both light receiving elements are adjusted to be equal, and a current mirror circuit is constituted. In said light receiving circuit, since the base current Ib=IPT2- I3 (where IPT2 is light current of PT2 + dark current) of Tr3 in the case the light from LED is inputted to PT2 is ID=I1 (comparison reference current)+IPT1 (dark current of PT1), Ib=(IPT2-IPT1)-I1 is obtaind. Therefore, the effect of the dark current is eliminated. Thus, the erroneous operation at high temperature can be eliminated, and the vary small amount of light can be sensed at a normal temperature.
JP14352380A 1980-10-13 1980-10-13 Light receiving circuit Granted JPS5766324A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP14352380A JPS5766324A (en) 1980-10-13 1980-10-13 Light receiving circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP14352380A JPS5766324A (en) 1980-10-13 1980-10-13 Light receiving circuit

Publications (2)

Publication Number Publication Date
JPS5766324A true JPS5766324A (en) 1982-04-22
JPS636820B2 JPS636820B2 (en) 1988-02-12

Family

ID=15340713

Family Applications (1)

Application Number Title Priority Date Filing Date
JP14352380A Granted JPS5766324A (en) 1980-10-13 1980-10-13 Light receiving circuit

Country Status (1)

Country Link
JP (1) JPS5766324A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60117663A (en) * 1983-11-29 1985-06-25 Mitsubishi Electric Corp Functional trimming process
EP0603899A2 (en) * 1992-12-25 1994-06-29 Canon Kabushiki Kaisha Driver circuit
EP0654945A1 (en) * 1993-11-23 1995-05-24 Thomson-Csf Injection circuit for thermal imaging

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60117663A (en) * 1983-11-29 1985-06-25 Mitsubishi Electric Corp Functional trimming process
EP0603899A2 (en) * 1992-12-25 1994-06-29 Canon Kabushiki Kaisha Driver circuit
EP0603899A3 (en) * 1992-12-25 1994-10-12 Canon Kk Driver circuit.
US5514989A (en) * 1992-12-25 1996-05-07 Canon Kabushiki Kaisha Semiconductor light emitting element driver circuit
EP0654945A1 (en) * 1993-11-23 1995-05-24 Thomson-Csf Injection circuit for thermal imaging
FR2713037A1 (en) * 1993-11-23 1995-06-02 Thomson Csf Injection circuit, in thermal imaging.

Also Published As

Publication number Publication date
JPS636820B2 (en) 1988-02-12

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