US3786264A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High speed light detector amplifier
Assignee: General Electric Co
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Filing: 1973-01-02
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Granted: 1974-01-15
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Expires: 1993-01-02
Abstract
Abstract A light detector amplifier preferably fabricated as a monolithic integrated circuit has high speed of response (in the order of 1 microsecond) at low and high illumination levels, uses low quiescent power and supply voltage, and has an optional thyristor or power transistor output. A transistor preamplifier conducts in the quiescent state and reverse biases a photodiode. Upon illumination, current is diverted to the photodiode and a power amplifier is energized to produce an output which can also provide gating current for a thyristor output. Enhanced performance is obtained by the use of special components, and unique placement of components within the circuit. Voltage excursions are limited in the circuit at several points by current steering, pre-biasing and diode clamping techniques.
Inventors
- 👤 A Ferro
- 👤 J Harnden
- 👤 B Kurz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:00
CPC Classifications
H; H10; H10F; H10F39/00; H10F39/10; H10F39/103; H03; H03K; H03K17/00; H03K17/51; H03K17/78; H03K17/79
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
95 words
A light detector amplifier comprising a preamplifier circuit that is conducting in the quiescent state and has reduced conductivity in response to the sensing of incident light by a semiconductor photodiode, said semiconductor photodiode being connected to be reverse biased by said preamplifier circuit, current source and voltage clamping circuit means for supplying current to said preamplifier circuit that is diverted to said photodiode when illuminated by incident light, and a power amplifier circuit connected to be energized by the change of conductivity of said preamplifier circuit to produce an output indicative of sensed light.
Claim 2
Dependent Claim
95 words
A light detector amplifier comprising a preamplifier circuit that is conducting in the quiescent state and has reduced conductivity in response to the sensing of incident light by a semiconductor photodiode, said semiconductor photodiode being connected to be reverse biased by said preamplifier circuit, current source and voltage clamping circuit means for supplying current to said preamplifier circuit that is diverted to said photodiode when illuminated by incident light, and a power amplifier circuit connected to be energized by the change of conductivity of said preamplifier circuit to produce an output indicative of sensed light.
Claim 3
Dependent Claim
43 words
A light detector amplifier wherein the combination defined in claim 1 energized by a low voltage supply, and further comprising an output circuit including a power device energized by another higher voltage supply, said output circuit being controlled by said power amplifier circuit.
Claim 4
Dependent Claim
32 words
A light detector amplifier according to claim 1 further including a pulse generator that is controlled by said power amplifier circuit and includes a thyristor device for producing a higher power output.
Claim 5
Dependent Claim
54 words
A light detector amplifier according to claim 1 in which said current source and voltage clamping circuit means incudes a constant current source connected to said preamplifier circuit and one terminal of said photodiode, and further includes a series connected resistance element and diode element also connected to said preamplifier circuit and photodiode terminal.
Claim 6
Dependent Claim
64 words
A light detector amplifier according to claim 1 in which said preamplifier circuit is a transistor circuit and said reverse biased photodiode is connected between base and emitter terminals of said transistor circuit, said transistor circuit comprising at least first and second transistors of which said first transistor is operated in the linear region and said second transistor is operated in the saturated region.
Claim 7
Dependent Claim
82 words
A light detector amplifier according to claim 1 in which said preamplifier circuit is a transistor circuit and said reverse biased photodiode is connected between base anD emitter terminals of said transistor circuit, and said current source and voltage clamping circuit means includes a constant current source connected to said transistor circuit base terminal, and further includes a series connected resistance element and diode element also connected to said transistor circuit base terminal, and means for slightly forward biasing said diode element.
Claim 8
Dependent Claim
130 words
A high speed light detector amplifier comprising a transistor preamplifier circuit that is conducting in the quiescent state and has reduced conductivity in response to the sensing of incident light by a reverse biased semiconductor photodiode, said reverse biased semiconductor photodiode being connected between base and emitter terminals of said transistor preamplifier, said base terminal being a high impedance junction, current source and voltage clamping circuit means connected to said high impedance junction for supplying current to said preamplifier circuit that is diverted to said photodiode when illuminated by incident light, and for limiting voltage excursions of said high impedance junction, and a power amplifier circuit connected to be energized by current diverted when said preamplifier circuit changes conductivity to thereby produce a lower power output indicative of sensed light.
Claim 9
Dependent Claim
130 words
A high speed light detector amplifier comprising a transistor preamplifier circuit that is conducting in the quiescent state and has reduced conductivity in response to the sensing of incident light by a reverse biased semiconductor photodiode, said reverse biased semiconductor photodiode being connected between base and emitter terminals of said transistor preamplifier, said base terminal being a high impedance junction, current source and voltage clamping circuit means connected to said high impedance junction for supplying current to said preamplifier circuit that is diverted to said photodiode when illuminated by incident light, and for limiting voltage excursions of said high impedance junction, and a power amplifier circuit connected to be energized by current diverted when said preamplifier circuit changes conductivity to thereby produce a lower power output indicative of sensed light.
Claim 10
Dependent Claim
75 words
A light detector amplifier according to claim 7 in which said transistor preamplifier circuit comprises at least first and second transistors with the emitter of said first transistor connected to the base of said second transistor, said second transistor having a Schottky diode clamp between its base and collector to limit voltage excursions at said collector, said first transistor being operated in the linear region and said second transistor being operated in the saturated region.
Claim 11
Dependent Claim
41 words
A light detector amplifier according to claim 7 in which said reverse biased semiconductor photodiode has a low capacitance structure characterized by a patterned region of one conductivity type in the surface of a common layer of the opposite conductivity type.
Claim 12
Dependent Claim
27 words
A light detector amplifier according to claim 9 wherein said patterned region is the anode of said photodiode, said anode being connected to the lowest circuit potential.
Claim 13
Dependent Claim
71 words
A light detector amplifier according to claim 7 in which said current source and voltage clamping circuit means comprises a constant current source including a transistor connected to said high impedance junction, and further comprises a series connected resistor and diode element connected to said high impedance junction, and means for biasing said diode element to supply substantially greater current to said photodiode when illuminated than when not exposed to light.
Claim 14
Dependent Claim
34 words
A light detector amplifier according to claim 11 in which said constant current source transistor is a lateral split collector transistor with multiple, isolated collectors, one collector being connected to said high impedance junction.
Claim 15
Dependent Claim
32 words
A light detector amplifier according to claim 7 further including a pulse generator that is controlled by said power amplifier circuit and includes a thyristor device for producing a higher power output.
Claim 16
Dependent Claim
29 words
A light detector amplifier according to claim 13 in which said thyristor device is a lateral silicon controlled rectifier with a shorted cathode-gate structure for high dv/dt withstand capability.
Claim 17
Dependent Claim
33 words
A light detector amplifier according to claim 13 in which said power amplifier circuit comprises a high speed lateral transistor with a resistivity-graded base for generating a gating signal for said thyristor device.
Claim 18
Dependent Claim
43 words
A light detector amplifier according to claim 13 in which said power amplifier circuit comprises a plurality of transistors, and means for pre-biasing at least one of said transistors and limiting voltage excursions at the base of at least one of said transistors.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |