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JPS5548706A - Light emitting element driving circuit - Google Patents

Light emitting element driving circuit

Info

Publication number
JPS5548706A
JPS5548706A JP12133878A JP12133878A JPS5548706A JP S5548706 A JPS5548706 A JP S5548706A JP 12133878 A JP12133878 A JP 12133878A JP 12133878 A JP12133878 A JP 12133878A JP S5548706 A JPS5548706 A JP S5548706A
Authority
JP
Japan
Prior art keywords
voltage
amplifier
light emitting
emitting element
input
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.)
Pending
Application number
JP12133878A
Other languages
Japanese (ja)
Inventor
Ryuji Tokuda
Masahiko Ogawa
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.)
Canon Inc
Original Assignee
Canon Inc
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 Canon Inc filed Critical Canon Inc
Priority to JP12133878A priority Critical patent/JPS5548706A/en
Publication of JPS5548706A publication Critical patent/JPS5548706A/en
Pending legal-status Critical Current

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Abstract

PURPOSE: To obtain the light emitting element driving circuit of high efficiency and high accuracy by letting the control signal exciting a light emitting element be the modulated wave signal by pulses, etc. and keeping the input level to an amplifier always within an active input voltage range.
CONSTITUTION: Output of a modulating transistor TR 11 is being applied to the inversion input terminal of an operational amplifier 2 together with a reference voltage 1. Power source is being supplied from the common terminal 9. The output potential of the amplifier 2 can be only the low voltage for the voltage between emitter and base of a driving TR 4 even when current flows in a light emitting element 3. This makes operation possible until the supply voltage becomes the value adding the collector-emitter saturated voltage of the TR 4 to the forward voltage of the element 3. In addition, since the control signal such as pulses, etc. is being applied to the input of the amplifier 2, the amplifier 2 may be controlled always in the active region without interrupting the feedback loop. This enables the element driving of high efficiency and high accuracy to be performed.
COPYRIGHT: (C)1980,JPO&Japio
JP12133878A 1978-10-02 1978-10-02 Light emitting element driving circuit Pending JPS5548706A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP12133878A JPS5548706A (en) 1978-10-02 1978-10-02 Light emitting element driving circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12133878A JPS5548706A (en) 1978-10-02 1978-10-02 Light emitting element driving circuit

Publications (1)

Publication Number Publication Date
JPS5548706A true JPS5548706A (en) 1980-04-08

Family

ID=14808774

Family Applications (1)

Application Number Title Priority Date Filing Date
JP12133878A Pending JPS5548706A (en) 1978-10-02 1978-10-02 Light emitting element driving circuit

Country Status (1)

Country Link
JP (1) JPS5548706A (en)

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