Patent US4498001A successfully refreshed from Google Patents.
US4498001A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transimpedance amplifier for optical receivers
Assignee: Nokia Bell Labs
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Filing: 1982-07-26
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Granted: 1985-02-05
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Expires: 2002-07-26
Abstract
Abstract An improved transimpedance amplifier allows an optical transmitter and receiver to be in close proximity to each other without fear of overloading the receiver. The improvement increases the dynamic range of the transimpedance amplifier and thereby the operating range of the receiver. A peak detector (22) at the output of an inverting amplifier (11) within the transimpedance amplifier turns on a field effect transistor (FET) circuit (23) when an AC component of an electrical signal becomes so large that the inverting amplifier would otherwise go into saturation. The FET circuit (23) acts as an AC shunt impedance at the input of the inverting amplifier and diverts the excess AC current to ground (30). Also, the FET circuit (23) acts as a DC resistance in concert with sense and sink current mirrors (21) and (24) to effectively divert an excessive DC component of the electrical signal away from the input of the inverting amplifier (11). Although the dynamic range of the transimpedance amplifier is increased, the optical sensitivity and the performance of the receiver remain unchanged.
Inventors
- 👤 Lanny S. Smoot
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:46
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3084; H03F; H03F3/00; H03F3/04; H03F3/08; H03F3/087; H04; H04B; H04B10/00; H04B10/60; H04B10/66; H04B10/69; H04B10/691
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
153 words
A transimpedance amplifier for converting an optical signal to an electrical signal comprising: an amplifying means with an input and output, means for receiving the optical signal and converting it to a current with AC and DC components, the optical receiving means being connected to the input of the amplifying means, means for comparing a voltage at the output of the amplifying means to a preset reference voltage, means responsive to the comparing means for providing an impedance between the input of the amplifying means and a ground reference level, means comprising a current mirror for sensing the DC component of the current, means comprising a current mirror responsive to the sensing means for diverting the DC component of the current away from the input of the amplifying means, through the impedance means, and the impedance means being responsive to the comparing means to divert the AC component of the current to ground.
Claim 2
Dependent Claim
153 words
A transimpedance amplifier for converting an optical signal to an electrical signal comprising: an amplifying means with an input and output, means for receiving the optical signal and converting it to a current with AC and DC components, the optical receiving means being connected to the input of the amplifying means, means for comparing a voltage at the output of the amplifying means to a preset reference voltage, means responsive to the comparing means for providing an impedance between the input of the amplifying means and a ground reference level, means comprising a current mirror for sensing the DC component of the current, means comprising a current mirror responsive to the sensing means for diverting the DC component of the current away from the input of the amplifying means, through the impedance means, and the impedance means being responsive to the comparing means to divert the AC component of the current to ground.
Claim 3
Dependent Claim
31 words
The transimpedance amplifier of claim 1 in which the amplifying means comprises: an inverting amplifier with an input and an output, resistance means being connected in feedback relationship with the amplifier.
Claim 4
Dependent Claim
17 words
The transimpedance amplifier of claim 1 or 2, in which the optical receiving means is a photodiode.
Claim 5
Dependent Claim
18 words
The transimpedance amplifier of claim 1 in which the impedance means is a field effect transistor circuit (FET).
Claim 6
Dependent Claim
45 words
The transimpedance amplifier of claim 4 in which the FET circuit comprises: field effect transistor, a capacitor means, one end being connected to the FET and the other end being connected to ground for blocking the DC component and passing the AC component of current.
Claim 7
Dependent Claim
15 words
The transimpedance amplifier of claim 4 in which the comparing means is a peak detector.
Claim 8
Dependent Claim
134 words
A transimpedance amplifier for converting an optical signal to an electrical signal comprising: an amplifying means with an input and output, means for receiving the optical signal and converting it to a current with AC and DC components, the optical receiving means being connected to the input of the amplifying means, means for comparing a voltage at the output of the amplifying means to a preset reference voltage, means responsive to the comparing means for providing an impedance between the input of the amplifying means and a ground reference level, means comprising a current mirror for sensing the DC component of the current, and means comprising a current mirror responsive to the sensing means for diverting the DC component of the current away from the input of the amplifying means, through the impedance means.
Claim 9
Dependent Claim
134 words
A transimpedance amplifier for converting an optical signal to an electrical signal comprising: an amplifying means with an input and output, means for receiving the optical signal and converting it to a current with AC and DC components, the optical receiving means being connected to the input of the amplifying means, means for comparing a voltage at the output of the amplifying means to a preset reference voltage, means responsive to the comparing means for providing an impedance between the input of the amplifying means and a ground reference level, means comprising a current mirror for sensing the DC component of the current, and means comprising a current mirror responsive to the sensing means for diverting the DC component of the current away from the input of the amplifying means, through the impedance means.
Claim 10
Dependent Claim
130 words
An improved transimpedance amplifier for converting an incoming optical signal to a corresponding electrical signal comprising: a photodetector for receiving the optical signal and generating a corresponding electrical current with AC and DC components, an amplifier with an input connected to said photodetector and an output, means comprising a current mirror connected to the photodetector for sensing and sinking the DC component, means connected to the output of the amplifier for sensing the AC component, an impedance means which simultaneously provides an AC path responsive to the AC sensing means to divert the AC component away from the input of the amplifier and a DC path responsive to the DC sensing and sinking means to divert the DC component of the input current away from the input of the amplifier.
Claim 11
Dependent Claim
130 words
An improved transimpedance amplifier for converting an incoming optical signal to a corresponding electrical signal comprising: a photodetector for receiving the optical signal and generating a corresponding electrical current with AC and DC components, an amplifier with an input connected to said photodetector and an output, means comprising a current mirror connected to the photodetector for sensing and sinking the DC component, means connected to the output of the amplifier for sensing the AC component, an impedance means which simultaneously provides an AC path responsive to the AC sensing means to divert the AC component away from the input of the amplifier and a DC path responsive to the DC sensing and sinking means to divert the DC component of the input current away from the input of the amplifier.
Claim 12
Dependent Claim
193 words
A transimpedance amplifier for converting an optical signal to an electrical signal at high frequencies comprising: an amplifying means with an input and output, a photodiode means coupled to the input of said amplifier means for receiving the optical signal and converting it to a current with AC and DC components, a peak detecting means for comparing a voltage at the output of the amplifying means to a preset reference voltage, a field effect transistor circuit means responsive to the detecting means for providing an AC impedance and DC resistance between the input of the amplifying means and a ground reference level, a current sense mirror means for sensing the DC component of the current, a current sink mirror means for diverting the DC component of the current away from the input of the amplifying means, through the field effect transistor circuit, the field effect transistor circuit being responsive to the peak detecting means when the voltage at the output of the amplifying means is approximately equal to the preset voltage thereby causing the field transistor circuit to become a variable AC impedance and diverting the AC component of the current to ground.
Claim 13
Dependent Claim
193 words
A transimpedance amplifier for converting an optical signal to an electrical signal at high frequencies comprising: an amplifying means with an input and output, a photodiode means coupled to the input of said amplifier means for receiving the optical signal and converting it to a current with AC and DC components, a peak detecting means for comparing a voltage at the output of the amplifying means to a preset reference voltage, a field effect transistor circuit means responsive to the detecting means for providing an AC impedance and DC resistance between the input of the amplifying means and a ground reference level, a current sense mirror means for sensing the DC component of the current, a current sink mirror means for diverting the DC component of the current away from the input of the amplifying means, through the field effect transistor circuit, the field effect transistor circuit being responsive to the peak detecting means when the voltage at the output of the amplifying means is approximately equal to the preset voltage thereby causing the field transistor circuit to become a variable AC impedance and diverting the AC component of the current to ground.
Claim 14
Dependent Claim
30 words
The transimpedance amplifier of claim 9 in which the amplifying means comprises: an inverting amplifier with an input and an output, resistance means connected in feedback relationship with the amplifier.
Claim 15
Dependent Claim
17 words
The transimpedance amplifier of claim 10 in which the photodiode is a P-type, Intrinsic, N-type (PIN) photodiode.
Claim 16
Dependent Claim
50 words
The transimpedance amplifier of claim 11 in which said field effect transistor circuit means comprises: a field effect transistor (FET), a capacitor means one end being connected to the FET and the other end being connected to ground for blocking the DC component and passing the AC component of current.
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) | 1988-02-05 | 1988-08-06 | 1989-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-05 | 1992-08-06 | 1993-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-05 | 1996-08-06 | 1997-02-05 | $7700.00 | Window Closed / Lapsed |