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US 5,646,573 AGranted
Automatic gain-control transimpedence amplifier
AssigneeAnadigics, Inc.
InventorsRobert J. Bayruns, Timothy M. Laverick
Life of this patent
Estimating the term…
Abstract
Automatic Gain Transimpedance Amplifiers for analog applications having high bandwidth, wide dynamic range, and ultra-high linearity. The transimpedance amplifiers includes an operational amplifier and a variable feedback resistance means connected between the input and the output of the amplifier. The variable feedback resistance means may include a single feedback PIN diode, two serially connected feedback PIN didoes, a PIN diode connected to a feedback resistor in parallel, or two serially connected PIN diodes connected to a feedback resistor in parallel. Ultra-high linearity is achieved because the dynamic resistance of the PIN diode under forward bias is substantially linearly dependent on the inverse of the current that passes the diode.
Claims28
An automatic gain control transimpedance amplifier comprising:
- an operational amplifier having input and output nodes;
- a photodiode having one end operatively coupled to the input node of said operational amplifier, said photodiode receiving input optical signal and providing corresponding current signal;
- and
- feedback means operatively coupled between the input and output nodes of said operational amplifier, said feedback means comprising a feedback PIN diode forward biased by a DC supply voltage inductively coupled to said output node of said voltage amplifier,
- said feedback means providing a feedback resistance that is substantially linearly dependent on the inverse of a DC component of said current signal,
- whereby increasing the amplitude of said optical signal increases said DC component, thereby reducing said feedback resistance.
3 more elements
An automatic gain control transimpedance amplifier comprising:
- an operational amplifier having input and output nodes;
- a photodiode having one end operatively coupled to the input node of said operational amplifier, said photodiode receiving input optical signal and providing corresponding current signal;
- and
- feedback means operatively coupled between the input and output nodes of said operational amplifier,
- said feedback means comprising two feedback PIN diodes connected in series, each of said PIN diodes being forward biased, said feedback PIN diodes being forward biased by a DC supply voltage inductively coupled to said output node of said operational amplifier,
- said feedback means providing a feedback resistance that is substantially linearly dependent on the inverse of a DC component of said current signal,
- whereby increasing the amplitude of said optical signal increases said DC component, thereby reducing said feedback resistance.
4 more elements
An automatic gain control transimpedance amplifier comprising:
- an operational amplifier having input and output nodes;
- a photodiode having one end operatively coupled to the input node of said operation amplifier, said photodiode receiving input optical signal and providing a corresponding current signal;
- and
- a feedback branch operatively coupled between the input and output nodes of said operational amplifier,
- said feedback branch comprising a feedback resistive means connected in parallel to a forward biased feedback PIN diode having a dynamic resistance substantially linearly dependent on the inverse of a DC component of the current passing said PIN diode, said feedback PIN diode being forward biased by a DC supply voltage inductively coupled to said output node of said voltage amplifier,
- whereby increasing the amplitude of said optical signal increases the amplitudes of the DC component, thereby reducing the dynamic resistance of said feedback PIN diode, and thereby reducing an effective feedback resistance of said feedback branch.
3 more elements
An automatic gain control transimpedance amplifier comprising:
- an operational amplifier having input and output nodes;
- a photodiode having one end operatively coupled to said input node of said operation amplifier, said photodiode receiving input optical input signal and producing corresponding current signal;
- and
- a feedback branch coupled between said input and output nodes of said operational amplifier,
- said feedback branch comprising a feedback resistive means connected in parallel to serially connected, forward biased first and second feedback PIN diodes, said feedback PIN diodes being forward biased by a DC supply voltage inductively coupled to said output node of said voltage amplifier,
- whereby increasing the amplitude of said input optical signal increases the amplitude of a DC component of the current passing said PIN diodes, thereby reducing the dynamic resistance of said feedback PIN diodes and the feedback resistance of said feedback branch.
3 more elements
A transimpedance amplifier comprising:
- an operational amplifier having input and output nodes;
- and
- feedback means operatively coupled between the input and output nodes of said operational amplifier, said feedback means comprising a feedback PIN diode forward biased by a DC supply voltage inductively coupled to the output node of said amplifier,
- said operational amplifier comprising a single-stage inverting voltage amplifier, said single-stage inverting voltage amplifier comprising first and second field effect transistors (FETs) serially connected along their drain-to-source paths with the drain terminal of said second FET operatively connected to the source terminal of said first FET,
- the drain terminal of said first FET being operatively connected to said output node of said operational amplifier,
- the gate terminal of said second FET being connected to said input node of said operational amplifier,
- the gate terminal of said first FET being resistively coupled to the source terminal of said second FET through a first resistive means, and
- the source terminal of said second transistor being resistively coupled to a ground potential through a second resistive means.
5 more elements
A transimpedance amplifier comprising:
- an operational amplifier having input and output nodes;
- and
- feedback means operatively coupled between the input and output nodes of said operational amplifier,
- said feedback means comprising two feedback PIN diodes connected in series, said feedback PIN diodes being forward biased by a DC supply voltage inductively coupled to said output node of said operational amplifier,
- said operational amplifier comprising a single-stage inverting voltage amplifier, said single-stage inverting voltage amplifier comprising first and second field effect transistors (FETs) serially connected along their drain-to-source paths with the drain terminal of said second FET operatively connected to the source terminal of said first FET,
- the drain terminal of said first FET being operatively connected to said output node of said operational amplifier,
- the gate terminal of said second FET being connected to said input node of said operational amplifier,
- the gate terminal of said first FET being resistively coupled to the source terminal of said second FET through a first resistive means, and
- the source terminal of said second transistor being resistively coupled to a ground potential through a second resistive means.
6 more elements
Dependencies are inferred from the claim text.