US 11,362,629 B2Granted

Transimpedance amplifier circuit

AssigneeSumitomo Electric Industries, Ltd.

InventorsNaoki Itabashi, Keiji Tanaka

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Abstract

A transimpedance amplifier (TIA) circuit disclosed includes an input terminal, a first TIA circuit, a second TIA circuit, a field effect transistor (FET), and a gain control circuit. The first TIA circuit outputs a voltage signal from a first output in accordance with an input current received at a first input electrically connected to the input terminal. The second TIA circuit outputs a reference signal from a second output. The FET varies a resistance between a first current terminal and a second current terminal in accordance with a control signal applied to a control terminal. The first current terminal is electrically connected to the input terminal. The second current terminal is electrically connected to the second output of the second TIA circuit. The gain control circuit detects an amplitude of the voltage signal and generates the control signal according to a detection result of the amplitude.

Claims9

Dependent claims

A transimpedance amplifier (TIA) circuit comprising:

an input terminal configured to receive a current signal from an external photodetector;
a first TIA circuit having a first input and a first output, the first input being configured to receive an input current, the first TIA circuit being configured to convert the input current to a voltage signal, the first output being configured to output the voltage signal, the first input being electrically connected to the input terminal;
a second TIA circuit having a second input and a second output, the second input being left open, the second output being configured to output a reference signal;
a field effect transistor (FET) having a control terminal, a first current terminal, and a second current terminal, the first current terminal being electrically connected to the input terminal, the second current terminal being electrically connected to the second output of the second TIA circuit, the FET being configured to vary a resistance between the first current terminal and the second current terminal in accordance with a control signal applied to the control terminal;
and
a gain control circuit configured to detect an amplitude of the voltage signal and generate the control signal according to a detection result of the amplitude,
wherein the second TIA circuit has same circuit configuration as the first TIA circuit.

4 more elements

A transimpedance amplifier (TIA) circuit comprising:

an input terminal configured to receive a current signal from an external photodetector;
a first TIA circuit having a first input and a first output, the first input being configured to receive an input current, the first TIA circuit being configured to convert the input current to a voltage signal, the first output being configured to output the voltage signal, the first input being electrically connected to the input terminal;
a second TIA circuit having a second input and a second output, the second input being left open, the second output being configured to output a reference signal;
a field effect transistor (FET) having a control terminal, a first current terminal, and a second current terminal, the first current terminal being electrically connected to the input terminal, the second current terminal being electrically connected to the second output of the second TIA circuit, the FET being configured to vary a resistance between the first current terminal and the second current terminal in accordance with a control signal applied to the control terminal;
a variable gain amplifier configured to generate a differential signal based on the voltage signal and the reference signal, the variable gain amplifier having a variable gain set by the control signal;
and
a gain control circuit configured to detect an amplitude of the differential signal and to generate the control signal according to a detection result of the amplitude,
wherein the second TIA circuit has a same circuit configuration as the first TIA circuit.

5 more elements

Dependencies are inferred from the claim text.