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Patent US5343034A successfully refreshed from Google Patents.
US5343034A
Expired / Lapsed
US
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Bias circuit for photodiode having level shift circuitry
Assignee: Canon Inc
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Filing: 1993-04-08
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Granted: 1994-08-30
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Expires: 2013-04-08
Abstract
Abstract In order to reduce a change in reverse bias to a photodiode due to drift of a power supply caused by, e.g., noise, and to suppress generation of a wrong photoelectric current detection signal, a bias circuit includes a load element (4), a transistor (Q1) for receiving a current from the load element (4) at its collector, a transistor (Q2) constituting a current mirror circuit together with the transistor (Q1), a level shift circuit connected between the base of an output transistor (Q3) of the current mirror circuit and the collector of the transistor (Q1), and constituted by transistors (Q4-Q7) and load elements (R1-R4), and a photodiode (1) connected to a desired potential node of the level shift circuit.
Inventors
- 👤 Toshiaki Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:53
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/60; H04B10/66; H04B10/69; H04B10/691; H04B10/6911; G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/22; G05F3/222; G05F3/227; G05F3/26; G05F3/265
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
123 words
A bias circuit for a photodiode, comprising: a first load element; a first transistor for receiving a current generated by said first load element at a collector thereof; a second transistor, a base of which is commonly connected to a base of said first transistor to constitute a current mirror circuit; and a level shift circuit connected between the base of an output transistor of said current mirror circuit and the collector of said first transistor, and constituted by a transistor or a combination of a constant voltage element with a transistor, and a second load element different from said first load element, wherein an anode or cathode of said photodiode is connected to a desired potential node of said level shift circuit.
Claim 2
Dependent Claim
123 words
A bias circuit for a photodiode, comprising: a first load element; a first transistor for receiving a current generated by said first load element at a collector thereof; a second transistor, a base of which is commonly connected to a base of said first transistor to constitute a current mirror circuit; and a level shift circuit connected between the base of an output transistor of said current mirror circuit and the collector of said first transistor, and constituted by a transistor or a combination of a constant voltage element with a transistor, and a second load element different from said first load element, wherein an anode or cathode of said photodiode is connected to a desired potential node of said level shift circuit.
Claim 3
Dependent Claim
18 words
A circuit according to claim 1, wherein said first load element comprises a resistor element or a circuit.
Claim 4
Dependent Claim
19 words
A circuit according to claim 1, wherein said transistor constituting said level shift circuit includes a plurality of transistors.
Claim 5
Dependent Claim
44 words
A circuit according to claim 3, wherein a collector of each of said plurality of transistors is connected to a reference voltage source, and an emitter thereof is connected to a base of another of said plurality of transistors and said second load element.
Claim 6
Dependent Claim
21 words
A circuit according to claim 1, wherein said second load element is connected to emitters of said first and second transistors.
Claim 7
Dependent Claim
20 words
A circuit according to claim 1, wherein a collector of said output transistor is connected to a reference voltage source.
Claim 8
Dependent Claim
41 words
A circuit according to claim 1, wherein said level shift circuit comprises a transistor, and a collector of said transistor, a collector of said output transistor, and one electrode of said first load element are connected to a reference voltage source.
Claim 9
Dependent Claim
14 words
A circuit according to claim 1, wherein said constant voltage element comprises a diode.
Claim 10
Dependent Claim
15 words
A circuit according to claim 1, wherein said second load element has a resistor element.
Claim 11
Dependent Claim
91 words
A bias circuit for a photodiode, comprising: a first load element; a first transistor for receiving a current generated by said first load element at a collector thereof; and a level shift circuit connected between a base and the collector of said first transistor, and constituted by a transistor or a combination of a constant voltage element with a transistor, and a second load element different from said first load element, wherein an anode or cathode of said photodiode is connected to a desired potential node of said level shift circuit.
Claim 12
Dependent Claim
91 words
A bias circuit for a photodiode, comprising: a first load element; a first transistor for receiving a current generated by said first load element at a collector thereof; and a level shift circuit connected between a base and the collector of said first transistor, and constituted by a transistor or a combination of a constant voltage element with a transistor, and a second load element different from said first load element, wherein an anode or cathode of said photodiode is connected to a desired potential node of said level shift circuit.
Claim 13
Dependent Claim
31 words
A circuit according to claim 10, further comprising a second transistor, a base of which is commonly connected to a base of said first transistor to constitute a current mirror circuit.
Claim 14
Dependent Claim
56 words
A circuit according to claim 10, wherein said transistor constituting said level shift circuit includes a plurality of transistors, a collector of each of said plurality of transistors is connected to a reference voltage source, and an emitter thereof is connected to a base of another of said plurality of transistors and said second load element.
Claim 15
Dependent Claim
18 words
A circuit according to claim 10, wherein said first load element comprises a resistor element or a circuit.
Claim 16
Dependent Claim
21 words
A circuit according to claim 10, wherein one electrode of said first load element is connected to a reference voltage source.
Claim 17
Dependent Claim
15 words
A circuit according to claim 10, wherein said second load element has a resistor element.
Claim 18
Dependent Claim
20 words
A circuit according to claim 10, wherein said second load element is connected to an emitter of said first transistor.
Claim 19
Dependent Claim
49 words
A circuit according to claim 16, further comprising a second transistor, a base of which is commonly connected to a base of said first transistor to constitute a current mirror circuit, and wherein the emitter of said first transistor is electrically connected to an emitter of said second transistor.
Claim 20
Dependent Claim
64 words
A circuit according to claim 10, further comprising a second transistor, a base of which is commonly connected to a base of said first transistor to constitute a current mirror circuit, and wherein a collector of said transistor of said level shift circuit, a collector of said second transistor, and one electrode of said first load element are connected to a reference voltage source.
Claim 21
Dependent Claim
14 words
A circuit according to claim 10, wherein said constant voltage element comprises a diode.
Claim 22
Dependent Claim
24 words
A circuit according to claim 10, wherein an emitter of said transistor of said level shift circuit is connected to said constant voltage element.
Claim 23
Dependent Claim
83 words
A bias circuit for a photodiode, comprising: a transistor, a collector of which is connected to a reference voltage source, and an emitter of which is connected to a load element having a resistance, and a first transistor, an emitter of which is held at a potential lower than a potential supplied from said reference voltage source, wherein a cathode or anode of said photodiode is connected to the emitter of said transistor, the emitter of which is connected to said load element.
Claim 24
Dependent Claim
83 words
A bias circuit for a photodiode, comprising: a transistor, a collector of which is connected to a reference voltage source, and an emitter of which is connected to a load element having a resistance, and a first transistor, an emitter of which is held at a potential lower than a potential supplied from said reference voltage source, wherein a cathode or anode of said photodiode is connected to the emitter of said transistor, the emitter of which is connected to said load element.
Claim 25
Dependent Claim
171 words
A circuit according to claim 21, further comprising a second transistor, a base of which is electrically connected to a base of said first transistor, an emitter of which is electrically connected to the emitter of said first transistor, and a collector of which is connected to said reference voltage source, and wherein one electrode of said load element is electrically connected to the bases of said first and second transistors, the other electrode of said load element is electrically connected to the emitters of said first and second transistors, the collector of said second transistor is connected to said reference voltage source, and a base of a transistor, an emitter of which is connected to said load element via another load element, and the collector of said first transistor are connected to said reference voltage source, said another load element being different from said load element, having a resistor element or circuit, and generating a base voltage of said transistor, the emitter of which is connected to said load element.
Claim 26
Dependent Claim
32 words
A circuit according to claim 22, further comprising a constant voltage element between the emitter of said transistor, the emitter of which is connected to said load element, and said load element.
Claim 27
Dependent Claim
14 words
A circuit according to claim 23, wherein said constant voltage element comprises a diode.
References Cited (Backward Citations)
US3828241A
Cited
US3911268A
Cited
US4467192A
Cited
US4759081A
Cited
US4730128A
Cited
JPS62159534A
Cited
US4797546A
Cited
US4945227A
Cited
JPH01254080A
Cited
US5270533A
Cited
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