Abstract: A transimpedance amplifier is provided which includes a feedback path. The feedback path includes a feedback resistor and a voltage generator. The feedback resistor has a parasitic capacitance associated therewith. The feedback resistor also has a first node at a first voltage. The voltage generator can be capacitively coupled to the feedback resistor at a second node via the parasitic capacitance. The voltage generator is configured to generate a second voltage at the second node which is substantially equal to the first voltage. This prevents a current from flowing through the parasitic capacitance thereby reducing and/or eliminating the effect of the parasitic capacitance on the transimpedance amplifier.

Abstract: A photoreceptor amplifier circuit comprises a differential amplifier circuit, which includes a differential transistor pair constituted of two transistors and active loads corresponding to said differential transistor pair, said differential amplifier circuit outputting a voltage according to an output current of a photoreceptor. The photoreceptor amplifier circuit further comprises a correcting current generation circuit for generating a correcting current based on a current difference between said two transistors and supplying the correcting current to said differential amplifier circuit.

Abstract: A light receiving amplification circuit according to the present invention includes: a light receiving element; an amplification circuit which amplifies a photoelectric current generated by the light receiving element and outputs from an amplification stage for external output and a plurality of amplification stages for feedback; an operating current source set in each of the amplification stages which supplies an operating current to the corresponding amplification stages; a gain selection switch set in the respective plurality of amplification stages for feedback, which interrupts the operating current between the corresponding amplification stage and the operating current source; and a gain resistor set in the respective plurality of amplification stages for feedback and connected between the operating current side of the corresponding gain selection switch and an input of the amplification circuit.

Abstract: A filter comprising an off-chip capacitor is described. The off-chip capacitor may be coupled to a circuit bonding pad. The output terminal of an amplifier may be coupled to the circuit bonding pad by a plurality of conductors insulated from one another over at least a portion between the output terminal and the circuit bonding pad.

Abstract: A direct current (DC) offset canceling circuit of a trans-impedance amplifier and an automatic gain control trans-impedance amplifier is provided, including: a trans-impedance amplifier for receiving an input current and converting the input current into a first voltage signal, while the trans-impedance amplifier is provided with a plurality of inverters connected in series, wherein a sample node is defined between each inverter; a DC detector for retrieving and comparing the signals at any sample node, thereby generating a trigger signal according to the comparison; a DC eliminator for providing a path to the DC component of the input current in response to the triggering by the signal trigger, to eliminate the DC component; a reference voltage unit for outputting a reference voltage value; and a voltage output amplifier for comparing the reference voltage and the first voltage signal, to amplify the output of a second voltage signal.

Abstract: An integrated preamplifier circuit for detecting a signal current from a photodiode and converting the signal current into an output voltage is provided. The circuit includes a signal amplifier and a dummy amplifier, the dummy amplifier being matched to the signal amplifier. Each of these amplifiers includes an input transistor and an output transistor, the input transistor of the signal amplifier receiving an input signal derived from the signal current and the input transistor of the dummy amplifier receiving no input signal. The signal and dummy amplifiers provide the desired differential output signal. The input transistors of the signal and dummy amplifiers each have a biasing current source forced to follow a reference current source implemented within the integrated circuit.

Abstract: An assembly is provided that may be used in high data rate optical communications, such as free-space communication systems. The assembly may include a main optical receiver element and a lenslet array or other optical element disposed near the focal plane that collects an optical signal and focuses that signal as a series of optical signal portions onto a photodetector array, formed of a series of InGaAs photodiodes, for example. The electrical signals from the photodetectors may be amplified using high bandwidth transimpedance amplifiers connected to a summing amplifier or circuit that produces a summed electrical signal. Alternatively, the electrical signals may be summed initially and then amplified via a transimpedance amplifier. The assembly may be used in remote optical communication systems, including free-space laser communication environments, to convert optical signals up to or above 1 Gbit/s or higher data rates into electrical signals at 1 Gbit/s or higher data rates.

Abstract: Disclosed is an infrared remote control receiver comprising a photo diode for converting an optical signal to an electrical signal, a semiconductor signal processing device for receiving the electrical from the photo diode, eliminating noise components from the electrical signal output from the photo diode and generating a pulse signal corresponding to a remote control signal transmitted from a remote control transmission device, and a micro computer for receiving the pulse signal from the semiconductor signal processing device and performing a remote control operation instructed by a user of the remote control transmission device by decoding the received pulse signal, wherein the semiconductor signal processing device is fabricated using CMOS devices fabrication processes.

Abstract: An apparatus comprises a first substrate and a second substrate. The first substrate includes an optoelectronic device and a matching circuit. The second substrate includes a driver circuit. A frequency response of the optoelectronic device is changed by the matching circuits. The first substrate is coupled to the second substrate via respective bond pads from the first and second substrates such that the matching circuit is interposed between the optoelectronic device and the driver circuit.

Abstract: A current voltage converter circuit includes a light receiving element which receives a light output from a laser and generates a light current according to the light output, a current distributor circuit which distributes the light current from the light receiving element, the current distributor circuit being configured of a current mirror circuit which includes a transistor pair and a first operating amplifier. The current voltage converter circuit further includes a voltage converter circuit which converts a current distributed by the current distributor circuit into a voltage, the voltage converter circuit including a second operating amplifier.

Abstract: A receiver circuit having an optical reception device and having an amplifier connected to the reception device, the amplifier also having a circuit for setting the operating point of the amplifier and also at least one control terminal of the circuit, by which the operating point of the amplifier can be selectively changed between at least two values at the user end. The receiver circuit according to the invention enables a noise optimization of the amplifier by virtue of an adjustability of the operating point of the amplifier.

Abstract: A burst-mode optical receiver of a differential-output structure is disclosed.

Abstract: An Improved Signal Receiver Having Wide Band Amplification Capability is disclosed. Also disclosed is a receiver that is able to receive and reliably amplify infrared and/or other wireless signals having frequency bandwidths in excess of 40 MHz. The receiver of the present invention reduces the signal-to-noise ratio of the received signal to ?th of the prior systems. The preferred receiver eliminates both the shunting resistor and the feedback resistor on the input end by amplifing the signal in current form. Furthermore, the receiver includes transconductance amplification means for amplifying the current signal without the need for Cascode stages. Finally, the receiver includes staged amplification to amplify the current signal in stages prior to converting the signal into a voltage output.

Abstract: An amplifier circuit for converting the current signal from an optical receiving element into a voltage signal. The amplifier circuit includes a transimpedance amplifier having a differential amplifier and a feedback resistor, a first adjustable resistor which is connected in parallel with the feedback resistor and whose resistance value is defined by a first control signal, and a series circuit connected in parallel with the feedback resistor. The series circuit includes a first capacitor and a second adjustable resistor, whose resistance value is defined by a second control signal. The two adjustable resistors are preferably formed as MOS resistors and have the same control signal applied to them. The amplifier circuit permits the provision of a high dynamic range during the operation of a transimpedance amplifier.

Abstract: The invention relates to a feedback circuit for a transimpedance amplifier, which is typically used for converting an input current from a photodiode into an output voltage. The feedback circuit of the present invention linearizes the transconductance feedback, as the input current signal varies, by providing a constant current source for supplementing the DC feedback current through a bypass transistor, thereby reducing a variation in the low frequency cut off.

Abstract: An integrated circuit includes a first-stage amplifier circuit and a following-stage amplifier circuit connected in series, a common power source pad for supplying power to the amplifier circuits, and metal wires respectively connecting the common power source pad to the amplifier circuits. On the metal wire which connects the first-stage amplifier and the power source pad, an integrator is electrically connected. This arrangement decreases a coupling noise generated in the first-stage amplifier circuit, thereby stabilizing circuit operation of the following-stage amplifier circuit.

Abstract: In one embodiment, the linear gain region of a preamp is widened by performing the following actions within the preamp: converting a received input current to a first voltage; in accordance with one of a plurality of discrete gain states, amplifying the first voltage to produce a second voltage; in response to the received input current crossing one or more thresholds, switching the gain state used for amplifying the first voltage; and outputting an indication of the preamp's current gain state. Preamps for performing this and other methods are also disclosed.

Abstract: Signal transmission in opto-electronic devices by moving the quiescent component of a differential signal. Exemplary circuits and techniques are disclosed for moving the quiescent component of the differential output signal of a preamplifier amplifying the output of a photodiode to provide an indication of the received signal strength. The quiescent component is moved in response to the average diode current, either symmetrically by imposing the same change on the differential outputs of the preamplifer, or unsymmetrically such as by imposing a change on one of the differential outputs only, and either linearly or nonlinearly with the average diode current. Detection in a postamplifier may be by open circuit techniques, such as by comparing the quiescent output of the preamplifier with a fixed reference, or by using feedback techniques that can cancel or alter the imposed quiescent component. Also exemplary embodiments for use in conjunction with opto-electronic transmitters are disclosed.

Abstract: Power supply noise affects the performance of many amplifier circuits. Power supply noise rejection circuits are typically used in conjunction with amplifier circuits to reduce the effects of the noise. Unfortunately, the main issue with a transimpedance amplifier (TIA) is that it has a single input port and a single output port, and the output ports are often required to be of a differential type in order to interface with a differential input post amplifier circuit. As a result, the conversion from single input port operation to a dual input port configuration for differential operation is often the cause of poor power supply noise rejection. A circuit is thus provided that overcomes the limitations in the prior art by providing a differential TIA for use with a filter circuit and differential amplifier that overcomes the limitations of the prior art.

Abstract: Disclosed herein is a PhotoDiode Integrated Circuit (PDIC) having multiple gain states. The PDIC includes a current-voltage conversion unit, an input amplification stage circuit, a reference resistance unit, a feedback resistance unit, and a switching unit. The current-voltage conversion unit converts a current signal into a voltage signal. The input amplification stage circuit is connected to the current-voltage conversion unit to receive and amplify the voltage signal. The reference resistance unit is connected to the second input terminal of the input amplification stage circuit. The output amplification stage circuit is connected to the output terminal of the input amplification stage circuit. The feedback resistance unit is connected in parallel between the second input terminal and the output terminal of the output amplification stage circuit, and is configured to have a plurality of resistance elements. The switching unit selectively connects the plurality of resistance elements.

Abstract: Among the embodiments of the present invention is an apparatus that includes a transistor, a servo device, and a current source. The servo device is operable to provide a common base mode of operation of the transistor by maintaining an approximately constant voltage level at the transistor base. The current source is operable to provide a bias current to the transistor. A first device provides an input signal to an electrical node positioned between the emitter of the transistor and the current source. A second device receives an output signal from the collector of the transistor.

Abstract: A photoelectric apparatus has a phototransistor which receives a light signal and in which a collector current thereof varies according to intensity of the received light signal, and a transistor in which a collector current thereof varies according to a base voltage thereof. The phototransistor and the transistor constitute a differential amplification circuit. At least one of the phototransistor and the transistor outputs an electric signal.

Abstract: An approach is provided for detecting EM waves using a photodetector coupled to an amplifier stage. The amplifier stage uses capacitive feedback to reduce or cancel intrinsic capacitance of the photodetector. A variety of capacitance structures may be used to provide the capacitive feedback such as shielded capacitors and capacitor arrays. The amplifier stage may be either single-ended or fully differential, depending upon the requirements of a particular application. Noise cancellation circuitry may also be included to reduce noise and offset sources present in the amplifier stage. The approach is applicable to a variety of contexts and applications. Example applications include, without limitation, detection of both brightness and Time of Flight (TOF) in 3D sensing applications. The approach may also be used to detect EM wave intensity in 2D sensing systems and, in general, for any application requiring simultaneously high speed and high sensitivity EM detection.

Abstract: An amplifier circuit amplifies the difference between an output voltage from a current voltage conversion circuit and a bias voltage. The current voltage conversion circuit converts a photocurrent of a photodiode which detect incoming light into a voltage. A gm-amp charges or discharges a capacity by a current corresponding to the difference between the output voltage from the amplifier circuit and a reference voltage. A field effect transistor supplies a drain current, which is controlled by voltages at the respective terminals of the capacity, to the photodiode, in order to prevent the output voltage of the amplifier circuit from being varied due to the influence of a DC photocurrent flowing in the photodiode. The gate of a field effect transistor, which is connected in parallel to a current voltage conversion resistor, has an identical voltage with the gate of the field effect transistor.

Abstract: There is provided a feedback amplifier capable of easily controlling its dynamic range without a separate gain control signal generation circuit. The feedback amplifier includes an input terminal detecting an input voltage from input current, a feedback amplification unit amplifying the input voltage to generate an output signal, and an output terminal outputting a signal amplified by the feedback amplification unit. The feedback amplification unit includes a feedback circuit unit including a feedback resistor located between the input terminal and the output terminal, and a feedback transistor connected in parallel to the feedback resistor; and a bias circuit unit supplying a predetermined bias voltage to the feedback transistor of the feedback circuit unit and merged in the feedback amplification unit.

Abstract: A high frequency amplifier comprising a first trans-impedance amplifier, a second trans-impedance amplifier, a third amplifier, and a variant current source is provided. The first trans-impedance amplifier receives an input current and outputs a first output voltage accordingly. The second trans-impedance outputs a second voltage. The third amplifier receives the first and the second voltage. The variant current source is connected between the input terminal of the second trans-impedance and a ground terminal or a power supply source. The variant current source delivers a variant current to change the second voltage such that the second voltage may follow the first voltage. The input current flows into the first trans-impedance amplifier, while the variant current flows into the second trans-impedance amplifier. The input current flows out the first trans-impedance amplifier, while the variant current flows out the second trans-impedance amplifier.

Abstract: A system and method for emitting and detecting light uses a light emitting device, e.g., a light emitting diode, to emit light and to detect incident light. As an example, the system and method may be used in a digital camera, a camera phone or an illuminated device, such as a liquid crystal display device.

Abstract: A transimpedance amplifier, which is useful as an optical fiber preamplifier, is disclosed. The illustrative embodiment exhibits four characteristics. First, it minimizes the equivalent input noise current. Second, it has a wide bandwidth. Third, it has a reasonably large output voltage, and fourth, it is stable over wide temperature and voltage ranges. The illustrative embodiment comprises a transimpedance stage and a gain stage. Both stages employ a pure NMOS design which contributes to the above four advantages. Bandwidth is further increased over the prior art by the use of inductive loads. The inductive loads of the illustrative embodiment are not physical inductors, but transistor-based “active” inductors: the combination of a resistor connected in series with the gate of an NMOS transistor.

Abstract: An amplifier includes an amplification path and multiple offset-compensation feedback paths. The amplification path has multiple amplifier stages, and the feedback paths are coupled to the amplification path. By including multiple feedback paths, such an amplifier can maintain its output DC-offset voltage at a desired level over a full range of amplitudes, i.e., power, of the input signal.

Abstract: In one embodiment, the present invention includes a differential traveling wave amplifier having a lumped differential preamplifier stage and a distributed differential amplifier stage coupled by a differential end termination interface. In certain embodiments, the distributed differential amplifier stage may include transverse electromagnetic transmission lines coupled between its input and output.

Abstract: This preamplification circuit comprises a first circuit section, second circuit section the input signal of which is the output signal of the first circuit section, and third circuit section which is connected with the input section of the first circuit section and consumes a part of the current to be inputted to a connection point with the input section of the first circuit section and has the capacitance value of the third circuit section set at a value for suppressing a gain peaking of gain frequency characteristics which occurs in the preamplification circuit.

Abstract: A method and apparatus to provide automatic gain control and offset correction in a transimpedance amplifier.

Abstract: A system reduces unwanted oscillations in a multiple gigabit per second, high gain amplifier portion. The system includes a power source portion having a plurality of power sources and a bias current portion having a plurality of bias current devices. The system also includes an amplification portion having a plurality of amplifiers. A first group of the plurality of amplifiers is coupled to the power source portion and the bias current portion, such that feedback voltage is substantially eliminated to substantially eliminate oscillations in the amplification portion.

Abstract: A variable decision threshold apparatus includes a comparator for receiving the electrical signal and for comparing it to a threshold level. A signal strength monitor monitors the strength of the electrical signal and a scaler scales the decision threshold level to the measured amplitude of the electrical signal so that the percentage set as the threshold level is maintained.

Abstract: A semiconductor photosensor device which outputs a detection result when a trigger signal is inputted, comprises: a photodiode current arithmetic circuit which is in an operating state regardless of whether before or after the input of the trigger signal, and which outputs a photocurrent generated by light irradiation; a first amplifier which is in an operating state regardless of whether before or after the input of the trigger signal, and which amplifier and outputs the output of the photodiode current arithmetic circuit; and a second amplifier which is in a non-operating state before the input of the trigger signal, wherein the second amplifier shifts to an operating state upon receiving the trigger signal, and amplifies and outputs the output of the first amplifier.

Abstract: A current-voltage transforming circuit used with a photo detector integrated circuit includes a photo detector to detect a photo signal (laser beam signal) to generate a photo current, an amplifier to amplify the photo current, which corresponds to the photo signal, an emitter follower to receive an output of the amplifier, an output buffer to receive an output of the emitter follower, a current detecting limiter unit having an input terminal and an output terminal and turned on to generate a limiter current when the detected current outputted from the amplifier is greater than a predetermined current, and a feedback resistor connected between the photo detector and an output terminal of the output buffer.

Abstract: In a photocurrent-to-voltage conversion apparatus for converting a photocurrent flowing through a light receiving element into a detection voltage, an amplifier, a feedback resistor and a clamping MOS transistor are provided. The amplifier has an input connected to the light receiving element and an output for generating the detection voltage, and includes (2n+1) inverter stages connected in series where n is 1, 2 . . . . The feedback resistor and the clamping transistor are connected between the output and input of the amplifier. The clamping MOS transistor is controlled by an output voltage of a non-final inverter one of the inverter stages.

Abstract: In an amplifier circuit, a main amplification section includes an amplifier for amplifying an input signal and a reference voltage generation circuit for generating a reference voltage from an output signal of the amplifier. Other main amplification sections each including the same internal structure are cascade-connected. A switch is provided for selecting any of amplifier outputs of these main amplification sections. A frequency component lower than that of an input signal to the amplifier circuit is removed by a filter circuit, and thereafter, the presence/absence of an input signal is detected by an amplitude detection circuit and a comparator. With such a structure, even if the input signal abruptly changes, e.g., immediately after the start of communication or immediately after the end of communication, an optical signal input is correctly detected and reproduced.

Abstract: Circuits for converting an input current to an output voltage that employs a uniquely biased common-gate or common-base stage as a current buffer and a direct drive of the current buffer output into an impedance to convert the current signal to a voltage signal.

Abstract: An optical component, such as an optical receiver, is provided that includes a detector configured to receive a signal from an optical fiber and to communicate with a translationl module of the optical component. A transimpedance amplifier of the optical component is configured to receive an electrical signal from the detector and to transmit an amplified signal to the translation module. The transimpedance amplifier is configured for a controlled low cutoff frequency as optical power to the transimpedance amplifier increases, so that the optical sensitivity of the transimpedance amplifier is not traded for optical overload.

Abstract: A transimpedance amplification apparatus includes a signal source for generating a current signal, a source follower stage, a common source stage and a shunt feedback resistor. The source follower stage having a source follower structure receives the current signal to reduce an impedance of the signal source. The common source stage, following the source follower stage, driven by the reduced signal source impedance, amplifies the current signal to extend a frequency bandwidth of the current signal and buffers the amplified signal with the extended frequency bandwidth thereof maintained, wherein the reduced signal source impedance serves to extend a frequency bandwidth of the common source stage. The shunt feedback resistor, which is installed between the source follower stage and the common source stage, adjusts an input DC bias of the source follower stage and increasing a transimpedance gain of the common source stage.

Abstract: An optical input preamplifier includes a photodiode for converting an input optical signal into a photocurrent as an output current, pre-amplifying circuit for pre-amplifying the output current from the photodiode wherein the output current is pre-amplified to form a pre-amplifying current, and an output circuit device converting the pre-amplifying current into an output signal. Therefore, the output current from the photodiode passes through the pre-amplifying circuit and the output circuit unit to substantially enhance the sensitivity of the optical input preamplifier.

Abstract: Disclosed is a transimpendance amplifier comprising a single ended input terminal to receive an input signal from a photodiode and differential output terminals. A circuit coupled between the single ended input terminal and a differential output terminal may vary the gain of the transimpedance amplifier in response to a DC current component of the input signal.

Abstract: A transimpedance amplifier includes a first amplifier, a first MOS resistor device and a first voltage divider circuit. The source terminal of the first MOS resistor device is coupled to the first amplifier inverting input. The voltage divider circuit is coupled between the first amplifier output and the non-inverting input. The output of the first voltage divider is coupled to the first MOS resistor drain terminal. A second amplifier, second MOS resistor device and a second voltage divider circuit is also provided. The output of the second amplifier is coupled to the gate terminal of the first MOS resistor device. The gate terminal of the second MOS resistor device is coupled to the second amplifier output. The drain terminal of the second MOS resistor device is coupled to the second amplifier non-inverting input.

Abstract: A sensor includes a gain stage with a differential amplifier with an adjustable gain. The differential amplifier may change its gain in response to the magnitude of a signal readout from the pixel array. The differential amplifier includes an input transistor with an adjustable transconductance. A transconductance controller can change the bias currents supplied to one or more sets of parallel transistors in the input transistor and consequently change the transconductance, and power consumption, of the input transistor. The transconductance controller can select a transconductance setting that is associated with a selected gain setting in order to more efficiently match the power consumption of the amplifier to its gain.

Abstract: Current-mode preamplifiers are provided. In accordance with an embodiment, a current-mode preamplifier includes a transistor, that acts as an input stage for the preamplifier, and a pair of current mirrors. The transistor includes a gate connected to the input of the preamplifier, a source connected to a first voltage supply rail, and a drain. The first current mirror, which is connected to a second voltage supply rail, includes an input connected to the drain of the first transistor, and an output. The second current mirror, which is connected to the first voltage supply rail, includes an input connected to the output of the first current mirror, a first output connected to the input of the preamplifier, and a second output connected to the output of the preamplifier.

Abstract: A pre-amplifier amplifies an output current of a photodetector that converts a burst optical signal into an electrical signal, and outputs an electric voltage signal. A gain switching circuit is connected with a serial circuit comprising a resistor and a switch and a serial circuit comprising a resistor and a switch, in parallel with a feedback resistor. The gain switching circuit includes an arrangement to receive the electric voltage signal output from the pre-amplifier, close the switch at a specific bit position, close the switch at the other specific bit position, upon occurrence of a situation that the switch is to be closed, provided that the switch is closed.

Abstract: A transimpedance amplifier with controllable noise reduction in which DC offsets due to the input signal are tolerated during reception of low input signals by reducing, e.g., terminating, a compensation current to remove a dominant source of thermal noise, but compensated during reception of higher input signals where the effects of DC offsets are more dominant.

Abstract: A system reduces unwanted oscillations in a multiple gigabit per second, high gain amplifier portion. The system includes a power source portion having a plurality of power sources and a bias current portion having a plurality of bias current devices. The system also includes an amplification portion having a plurality of amplifiers. A first group of the plurality of amplifiers is coupled to the power source portion and the bias current portion, such that feedback voltage is substantially eliminated to substantially eliminate oscillations in the amplification portion.

Abstract: The invention concerns an amplifier circuit for receiving an optical signal. The circuit comprises a light sensitive member (301) which delivers an electric signal in response to an optical signal. Furthermore, the amplifier circuit comprises an amplifier unit (302) with a first input (304) which receives an electric signal from the light sensitive member (301). The amplifier unit (302) is of the kind which does not have any special input intended for controlling the amplification. A filter unit (310) prevents a possible direct current from the light sensitive member (301) from reaching the first input (304). A control unit (314) is connected to the first input (304) for controlling the amplification of the circuit. The invention also concerns an optical communication system comprising an amplifier circuit of the above-described kind. The invention also concerns a method of controlling the amplification in an optical input stage.