An optical receiver includes an APD that converts an input optical signal into a current signal, a TIA that converts the current signal output from the APD into a voltage signal, an LIA that shapes a waveform of the voltage signal output from the TIA, an AOC having a time constant switching function, the AOC automatically compensating for an offset voltage between differential outputs from the TIA, and a convergence-state detection circuit that outputs, after detecting convergence completion of the automatic compensation in the AOC, to the AOC, a time constant switching control signal for switching a time constant from a high-speed time constant to a low-speed time constant.

Techniques and mechanisms for providing signal communication with a configurable transceiver circuit. In an embodiment, an integrated circuit comprises transceiver circuitry including an output stage and current mirror circuitry. The output stage is coupled to receive a differential signal pair and to provide at least one output signal based on the differential signal pair. In another embodiment, configuration logic is operable to select between a first mode and a second mode of the transceiver circuit. The first mode includes the current mirror circuitry being disabled from providing a current signal to the output stage, and a first circuit path being closed to provide voltage to the output stage. The second mode includes the first circuit path being open and the current mirror circuitry being enabled to provide a current signal to the output stage.

An optical sensor and a method having a high linearity digital controlling mechanism are provided. An optoelectronic component converts a light energy into a photocurrent. Then, the photocurrent flows to a current mirror and is amplified by a gain to form a charging current by the current mirror to charge a capacitor. A comparator compares a voltage of the capacitor with a reference voltage multiple times to generate a comparison signal. A counter determines a digital value capturing range according to the gain, and counts bit values that fall within the digital value capturing range from the comparison signal to output a counted signal. A noise cancellation processor reduces the digital value capturing range according to the gain, and removes one or more of the bit values that do not fall within the digital value capturing range from the counted signal to output a sensed signal.

In order to further develop a circuit arrangement (CR; CR′) for receiving optical signals (SI) from at least one optical guide (GU), said circuit arrangement (CR; CR′) comprising: at least one light-receiving component (PD) for converting the optical signals (SI) into electrical current signals (I.sub.PD), at least one transimpedance amplifier (TA), being provided with the electrical current signals (I.sub.PD) from the light-receiving component (PD), at least one automatic gain controller (AG) for controlling the gain or transimpedance (R) of the transimpedance amplifier (TA), at least one integrator (IN) in a feedback path (FP), said integrator (IN) generating a control signal (V.sub.int), at least one voltage-controlled current source (CS), being provided with the control signal (V.sub.int) from the integrator (IN), at least one limiter (LI) acting as a comparator and generating in its output a logic level for positive or negative voltages in its input,
and a corresponding method in such a way that a multilevel optical link can be provided, at least one second transimpedance amplifier (TA2) arranged in parallel to the transimpedance amplifier (TA), and at least one automatic offset controller (AO) for setting the voltage (V.sub.offset) for the second transimpedance amplifier (TA2)
are proposed.

In order to further develop a circuit arrangement (CR; CR′) for receiving optical signals (SI) from at least one optical guide (GU), said circuit arrangement (CR; CR′) comprising: at least one light-receiving component (PD) for converting the optical signals (SI) into electrical current signals (I.sub.PD), at least one transimpedance amplifier (TA), being provided with the electrical current signals (I.sub.PD) from the light-receiving component (PD), at least one automatic gain controller (AG) for controlling the gain or transimpedance (R) of the transimpedance amplifier (TA), at least one integrator (IN) in a feedback path (FP), said integrator (IN) generating a control signal (V.sub.int), at least one voltage-controlled current source (CS), being provided with the control signal (V.sub.int) from the integrator (IN), at least one limiter (LI) acting as a comparator and generating in its output a logic level for positive or negative voltages in its input,
and a corresponding method in such a way that a multilevel optical link can be provided, at least one second transimpedance amplifier (TA2) arranged in parallel to the transimpedance amplifier (TA), and at least one automatic offset controller (AO) for setting the voltage (V.sub.offset) for the second transimpedance amplifier (TA2)
are proposed.

A digitally-controlled transimpedance amplifier (TIA) circuit is provided in which a plurality of feedback loops are digitally controlled, including, but not limited to, the DC offset cancellation loop, the variable gain control loop, and the TIA feedback impedance adjustment loop. The digitally-controlled TIA circuit includes digital loop-control circuitry that consumes less area on the TIA IC chip than the analog circuitry traditionally used to perform the feedback loop control in the analog domain. In addition, because digital logic continues to shrink as IC processes continue to evolve, the size of the IC chip packages will further decrease over time, leading to a smaller footprint in systems in which they are employed. The digital loop control circuitry is also capable of independently varying the gains of multiple gain stages of the variable gain control circuit to provide better control over the gain stages and better overall performance of the TIA circuit.

A digitally-controlled transimpedance amplifier (TIA) circuit is provided in which a plurality of feedback loops are digitally controlled, including, but not limited to, the DC offset cancellation loop, the variable gain control loop, and the TIA feedback impedance adjustment loop. The digitally-controlled TIA circuit includes digital loop-control circuitry that consumes less area on the TIA IC chip than the analog circuitry traditionally used to perform the feedback loop control in the analog domain. In addition, because digital logic continues to shrink as IC processes continue to evolve, the size of the IC chip packages will further decrease over time, leading to a smaller footprint in systems in which they are employed. The digital loop control circuitry is also capable of independently varying the gains of multiple gain stages of the variable gain control circuit to provide better control over the gain stages and better overall performance of the TIA circuit.

A bio-sensing device (and method) calibrates a time period used to make bio-physical measurements. The device initiates a light source sense phase followed by a first ambient sense phase and a second ambient sense phase. In the light source sense phase, the device is configured to receive a digital value indicative of current through a photodetector while the light source circuit is enabled and in each of the first and second ambient sense phases, the device is configured to receive digital values while the light source circuit is disabled. The device iteratively varies the time period between the phases until the digital value received during the first ambient sense phase is within a threshold of the digital value received during the second ambient sense phase. It then applies the same time separation between the light source sense phase and the ambient phase thereby equalizing the magnitude of the ambient light in the two phases.

A receiver of a pulsed light signal comprises a photodiode adapted to generate an electric current in response to this light signal, having a parasitic capacitance C.sub.d as its characteristic; an electrical ground; and a transimpedance amplifier connected to the input of the photodiode by a linking capacitor C.sub.liaison. It includes an attenuation pad located between the photodiode and the transimpedance amplifier, consisting of a capacitor C.sub.p where C.sub.p=C.sub.d/(α−1), α being a predetermined attenuation, where α>1.

A receiver of a pulsed light signal comprises a photodiode adapted to generate an electric current in response to this light signal, having a parasitic capacitance C.sub.d as its characteristic; an electrical ground; and a transimpedance amplifier connected to the input of the photodiode by a linking capacitor C.sub.liaison. It includes an attenuation pad located between the photodiode and the transimpedance amplifier, consisting of a capacitor C.sub.p where C.sub.p=C.sub.d/(α−1), α being a predetermined attenuation, where α>1.