Patent EP0678982A2 successfully refreshed from Google Patents.
EP0678982A2
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EP
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Semiconductor light emitting element driving circuit
Assignee: Canon Inc
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Filing: 1995-04-13
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Granted: —
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Expires: 2015-04-13
Abstract
Abstract A semiconductor light emitting element driving circuit for driving a light emitting element (4), comprises a bipolar transistor (1), a base of which is applied with a control signal for driving the light emitting element (4), and which, in response to the control signal, drives the light emitting element (4) by flowing a current between an emitter and a collector, and a gate insulated transistor (3) which operates as a constant current source connected to the bipolar transistor (1).
Inventors
- 👤 Hiroyuki C/O Canon K.K. Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 10:24
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/10; G; G11; G11B; G11B7/00; G11B7/12; G11B7/125; G11B7/126; H03; H03K; H03K17/00; H03K17/04; H03K17/041; H03K17/04113; H03K17/16; H03K17/161; H03K17/162; H03K17/51; H03K17/56; H03K17/567
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
73 words
A semiconductor light emitting element driving circuit for driving a light emitting element, comprising: a bipolar transistor, a base of which is applied with a control signal for driving said light emitting element, and which, in response to the control signal, drives said light emitting element by flowing a current between an emitter and a collector; and a gate insulated transistor which operates as a constant current source connected to said bipolar transistor.
Claim 2
Dependent Claim
49 words
A circuit according to claim 1, wherein a series circuit consisting of a resistor and a capacitor is inserted into a line between said bipolar transistor and said light emitting element, and said bipolar transistor, said constant current source, and said series circuit are integrated into a single chip.
Claim 3
Dependent Claim
18 words
A circuit according to claim 1, wherein a plurality of said gate insulated transistors are connected in parallel.
Claim 4
Dependent Claim
78 words
A circuit according to claim 1, wherein said semiconductor light emitting element driving circuit is a semiconductor integrated circuit in which differentially connected bipolar transistors and a MOS transistor are formed on the same substrate, and has a semiconductor light emitting element connected to and driven by collectors of said differentially connected bipolar transistors, and emitters of said differentially connected bipolar transistors are connected to a drain of said MOS transistor which operates as a constant current source.
Claim 5
Dependent Claim
17 words
A circuit according to claim 4, wherein a plurality of said MOS transistors are connected in parallel.
Claim 6
Dependent Claim
46 words
A circuit according to claim 4 or 5, wherein a time constant circuit consisting of a resistor and a capacitor and formed in the same integrated circuit as said MOS transistor used as a constant current source is connected to a gate of said MOS transistor.
Claim 7
Dependent Claim
22 words
A circuit according to any one of claims 4 to 6, wherein bases of said bipolar transistors are driven by complementary signals.
Claim 8
Dependent Claim
113 words
A circuit according to claim 1, wherein said semiconductor light emitting element driving circuit comprises two differentially connected bipolar transistors formed in an integrated circuit, a constant current source connected to a common emitter of said bipolar transistors, and a semiconductor light emitting element connected to a collector of one of said bipolar transistors, and drives said semiconductor light emitting element by applying complementary pulse signals to bases of said bipolar transistors, and a series circuit consisting of a resistor and a capacitor is formed in said integrated circuit, in which said bipolar transistors are formed, and connected between the collectors of said bipolar transistors and a power supply or a substrate potential.
Claim 9
Dependent Claim
87 words
A circuit according to claim 8, wherein by properly selecting a resistance of said resistor and a capacitance of said capacitor in relation to a parasitic inductance occurring outside said integrated circuit, a current flowing through said semiconductor light emitting element when the complementary pulse signals are applied to the bases of said bipolar transistors is set in a critical state which is between a state in which the current varies in an oscillating manner and a state in which the current varies in an unoscillating manner.
Claim 10
Dependent Claim
20 words
A drive circuit for a light emitting device having a drive transistor coupled to an insulated gate transistor current source.
Claim 11
Dependent Claim
24 words
A switching circuit comprising a drive transistor, which may form one of a differential pair, coupled to and integrated with a series RC circuit.
References Cited (Backward Citations)
No citation records indexed.
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