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US 7,583,904 B2Granted
Transimpedance (TIA) circuit usable for burst mode communications
AssigneeBroadlight Ltd.
InventorsRaviv Weber, Moshe Levy, Rafi Dvir
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Abstract
A transimpedance amplifier (TIA) circuit usable for burst mode communications is provided. The TIA circuit includes a TIA stage, a limiter-amplifier, and a DC restoration loop. The invention overcomes problems of the prior art relating to burst communications, such as a DC level in the output signal which can change from burst to burst and a duty-cycle distortion in large signals. This is achieved by using a DC restoration loop that ensures achieving zero DC potential within variable acquisition periods.
Claims32
A burst-mode transimpedance amplifier (TIA) circuit, comprising:
- a TIA stage;
- a limiter-amplifier having a first input coupled to said TIA stage, a second input coupled to a direct current (DC) restoration loon and two differential outputs coupled to said direct current (DC) restoration loop, wherein said differential outputs are also outputs of said burst-mode TIA circuit;
- and
- a DC restoration loop coupled between the differential outputs and the second input of said limiter-amplifier and being configured to perform DC cancellation within variable acquisition periods, wherein the DC cancellation ensures substantially zero DC potential difference between said differential outputs;
- wherein said DC restoration loop comprises:
- an integrator having inverting and non-inverting inputs coupled to said differential outputs and an output port;
- a resistor coupled to the output port of said integrator;
- a switch switchably coupled across said resistor;
- and
- a capacitor having a first end coupled to a common junction of said switch and said resistor and having a second end connected to ground.
7 more elements
A burst-mode transimpedance amplifier (TIA) circuit, comprising:
- a TIA stage;
- a limiter-amplifier having a first input coupled to said TIA stage and a second input coupled to a first reference voltage;
- a DC restoration loop having two differential outputs coupled to respective outputs of said limiter-amplifier and two inputs connected to said limiter-amplifier, wherein said DC restoration loop is capable of performing at least DC cancellation within variable acquisition periods, wherein the DC cancellation ensures substantially zero DC potential difference between said differential outputs;
- wherein said DC restoration loop, comprises:
- a first integrator having an inverting input coupled to a second reference voltage and a positive input port coupled to said limiter-amplifier;
- a second integrator having a non-inverting input coupled to a feedback net and a negative input port coupled to said limiter-amplifier;
- a third integrator having a non-inverting input coupled to an output of said first integrator and an inverting input coupled to an output of said second integrator;
- a resistor coupled to the output of said third integrator and to a first end of a capacitor coupled at opposite end to GND;
- and
- a switch switchably coupled across said resistor;
- wherein said capacitor, said switch and said resistor form said feedback net.
8 more elements
A burst-mode transimpedance amplifier (TIA) circuit, comprising:
- a TIA stage;
- a limiter-amplifier having a first input coupled to said TIA stage, a second input coupled to a first reference voltage and two differential outputs connected to a direct current (DC) restoration loop, wherein the differential outputs are also outputs of said burst-mode TIA circuit;
- and
- a DC restoration loop coupled to said differential outputs and being configured to perform DC cancellation within variable acquisition periods, wherein performing said DC cancellation ensures substantially zero DC potential difference between said differential outputs;
- wherein said DC restoration loop comprises:
- an integrator having an inverting input and a non-inverting output coupled to a first feedback loop and a non-inverting input and invert output coupled to a second feedback loop, wherein the integrator is further coupled to a second reference voltage;
- a first feedback loop including a first resistor coupled between the non-inverting output and a first one of the differential outputs, a second resistor coupled between the inverting input and the first differential output, a first switch switchably coupled across said second resistor and a first capacitor connected between the inverting input and the non-inverting output;
- and
- a second feedback loop including a third resistor coupled between the inverting output and a second one of the differential outputs, a fourth resistor coupled between the non-inverting input and the second differential output, a second switch switchably coupled across said fourth resistor and a second capacitor connected between the non-inverting input and the inverting output.
6 more elements
Dependencies are inferred from the claim text.