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940 results about "Transimpedance amplifier" patented technology
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In electronics, a transimpedance amplifier, (TIA) is a current to voltage converter, almost exclusively implemented with one or more operational amplifiers. The TIA can be used to amplify the current output of Geiger–Müller tubes, photo multiplier tubes, accelerometers, photo detectors and other types of sensors to a usable voltage. Current to voltage converters are used with sensors that have a current response that is more linear than the voltage response. This is the case with photodiodes where it is not uncommon for the current response to have better than 1% nonlinearity over a wide range of light input. The transimpedance amplifier presents a low impedance to the photodiode and isolates it from the output voltage of the operational amplifier. In its simplest form a transimpedance amplifier has just a large valued feedback resistor, Rf. The gain of the amplifier is set by this resistor and because the amplifier is in an inverting configuration, has a value of -Rf. There are several different configurations of transimpedance amplifiers, each suited to a particular application. The one factor they all have in common is the requirement to convert the low-level current of a sensor to a voltage. The gain, bandwidth, as well as current and voltage offsets change with different types of sensors, requiring different configurations of transimpedance amplifiers.
A pulse monitoringplethysmographsystem for establishing a history of the pulses of the user over an extended period of time, comprises a housing, a piezoelectric sensing element mounted within said housing, and fixed to the housing, a force transmitting member positioned to cause said piezoelectric sensing element to flex in response to an external force and to generate a current, and a transimpedance amplifier. The transimpedance amplifier converts the current generated by the flexing of the piezoelectric element into a voltagesignal and an analog to digital converter converts the voltagesignal into digital data. A digital memory storing member is provided for storing the digital data and establishing a history of data over an extended period of time.
The invention concerns a conditioning circuit (10) for an external signal (IN) representative of a physiological quantity, arranged between an optical sensor (11) and a processing unit (12), the received external signal (IN) being broken down into a useful component and an ambient component, characterized in that the conditioning circuit includes a first stage (13) including a transimpedance amplifier with an incorporated high pass filter (15) using a feedback loop to subtract the ambient signal component from the received external signal, and to deliver at output an amplified useful signal (IN1), a second stage (16) including a blocker sampler circuit (17) for demodulating the amplified useful signal and delivering at output a demodulated useful signal (IN2), and a third stage (18) including a bandpass filter (19) for filtering the demodulated useful signal in the frequency band of the physiological quantity to be detected and for transmitting a conditioned signal (OUT) to the processing unit.
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.
An inductive proximity sensor is disclosed. The proximity sensor includes a resonator with a bifurcated inductance coupled to a plurality of transimpedance amplifiers. A portion of the resonator is configured to generate eddy currents in a target containing metal. In various embodiments, the transimpedance amplifiers provide signals associated with eddy currents to a synchronous detector. Apparatus and methods for operating the inductive proximity sensor are disclosed.
A signal processor and processing method are provided for measuring current received from a photo-detector. Generally, the processor includes a transimpedance amplifier (TIA) to integrate a current received from a photo-detector in the optical navigationsystem to generate a voltagesignal having a slope that is proportional to the received current, and a comparator having a first input coupled to an output of the TIA to receive the voltagesignal, and a second, inverting, input coupled to a threshold voltage. The comparator is configured to compare the voltage signal to the threshold voltage and to generate an output pulse having a predetermined voltage and a duration or width that is a function of the received current.
The embodiment of the invention discloses an overcurrent protection circuit, and the circuit comprises a level converter and a substrate array line drive (GOA) circuit in electrical connection with the level converter. The circuit also comprises a current detection circuit, a current-voltage converter, a voltagecomparator, a timercontrol register, and a logic gate circuit. The GOA circuit is connected with the current detection circuit, and the current detection circuit is connected with the current-voltage converter. The current-voltage converter is connected with the in-phase input end of the voltage comparator, and the inverted-phase input end of the voltage comparator is connected with a reference voltage. The output end of the voltage comparator is connected with the input end of the timercontrol register and the first input end of the logic gate circuit. The output end of the timercontrol register is connected with the second input end of the logic gate circuit. The output end of the logic gate circuit is connected with the level converter. According to the embodiment of the invention, the circuit can prevent the wrong triggering of an overcurrent protection operation. The invention also provides a liquid crystal display comprising the circuit.
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.
A nested transimpedance amplifier (TIA) circuit includes a zero-order TIA having an input and an output. A first operational amplifier (opamp) has an input that communicates with the output of the zero-order TIA and an output. A first feedback resistance has one end that communicates with the input of the zero-order TIA and an opposite end that communicates with the output of the first opamp. A first feedback capacitance has a first end that communicates with the input of the zero-order TIA and a second end that communicates with the output of the zero-order TIA. A capacitor has one end that communicates with the input of the zero-order TIA.
An apparatus comprising a first amplifier circuit, a detect circuit, a control circuit and a second amplifier circuit. The first amplifier circuit may be configured to generate an amplified signal in response to an input signal. The detect circuit may be configured to generate a feed-forward signal in response to the amplified signal. The control circuit may be configured to generate a dynamic control signal in response to the feed-forward signal. The second amplifier circuit may be configured to generate an output signal in response to (i) the amplified signal and (ii) the dynamic control signal. The control circuit may be configured to control a gain of the second amplifier circuit by adjusting a magnitude of the dynamic control signal.
A transimpedance amplifier, which is useful as an optical fiberpreamplifier, is disclosed. The illustrative embodiment exhibits four characteristics. First, it minimizes the equivalent inputnoise 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.
A sequential wavefront sensor includes a light source, a beam deflecting element, a position sensing detector configured to output a plurality of output signals and a plurality of composite transimpedance amplifiers each coupled to receive an output signal. The output of each composite transimpedance amplifier is phase-locked to a light source drive signal and a beam deflecting element drive signal.
An energy-efficient photoreceptor apparatus and a transimpedance amplifier apparatus having high energy-efficiency and low power consumption of which are achieved through multiple distributed gain amplification stages, adaptive loop gain control circuitry and unilateralization, thereby enabling fast and precise performance over a wide range of input-current levels. The high-energy efficiency, robust feedback stability and performance of the present invention can be utilized to achieve sub-milliwatt pulse oximeters and may be employed in other current-to-voltage amplification and conversion applications. The use of analog processing on the outputs of the photoreceptor apparatus also helps lower the overall power of pulse oximeters.
A gain switching determination circuit (250) compares / determines a comparative input voltage (Vc) from an inter-stage buffer (230) with a first hysteresis characteristic, and outputs a gainswitching signal (SEL) based on the comparison / determination result to first and second transimpedance amplifier core circuits (210, 220), thereby switching the gains of the core circuits. This obviates holding a comparison input voltage with long response time in a level holding circuit for gain switching determination, which allows instantaneous gain switching determination and instantaneous response corresponding to burst data.
A transimpedance amplifier (TIA) circuit according to the present invention includes a first opamp having an input and an output. A second opamp has an input that communicates with the first opamp and an output. A first feedback path communicates with the input and the output of the first opamp and includes a first resistance. A second feedback path communicates with the input and the output of the second opamp and includes a second resistance. A third feedback path communicates with the input of the first opamp and the output of the second opamp.
Disclosed is a front end circuit involving a transimpedance amplifier that drives a resistor, thereby lowering the input impedance of the circuit by dividing the feedback resistance by the gain of the amplifier. In the front end circuit of the present invention, a first transistor is coupled in series with a resistor, where the received signal is input to a base or gate of the first transistor and the amplified received signal is recovered from a collector or drain of the first transistor such that the first transistor and resistor provide the gain of the front end circuit. A second transistor has an emitter or source coupled to the base or gate of the first transistor. A base or gate of the second transistor is coupled to the collector or drain of the first transistor and a collector or drain of the second transistor is coupled to a power supply rail. The second transistor thus provides the feedback path for the transimpedance amplifier thereby reducing the input impedance of the circuit.
A system for a feedback transimpedance amplifier with sub-40 khz low-frequency cutoff is disclosed and may include amplifying electrical signals received via coupling capacitors utilizing a transimpedance amplifier (TIA) having feedback paths comprising source followers and feedback resistors. The feedback paths may be coupled prior to the coupling capacitors at inputs of the TIA. Voltages may be level shifted prior to the coupling capacitors to ensure stable bias conditions for the TIA. The TIA may be integrated in a CMOSchip and the source followers may comprise CMOS transistors. The TIA may receive current-mode logic or voltage signals. The electrical signals may be received from a photodetector, which may comprise a silicongermaniumphotodiode and may be differentially coupled to the TIA. The chip may comprise a CMOSphotonicschip where optical signals for the photodetector in the CMOS photonics chip may be received via one or more optical fibers.
A receiver optical subassembly (ROSA) includes a photodetector array and a transimpedance amplifier (TIA) array. In each data channel, the photodetector is wire bonded to a corresponding input pad of the TIA array. A ground pad is disposed between adjacent input pads and connected to a ground plane via an isolated bonding strip on the photodetector array in order to alleviate crosstalk between the channels. The output data channels of the TIA are tightly spaced at the output pads of the TIA and are fanned out on the ceramic to increase the spacing of the data channels as they extend from the TIA. The ROSA includes the use of embedded capacitance to reduce crosstalk and noise by decoupling reference planes formed within the multilayer ceramic substrate. Input and output ground planes of the TIA are separated in the vicinity of the TIA and coupled on a ceramic layer spaced farther from the TIA, to alleviate crosstalk.
A nested transimpedance amplifier (TIA) circuit comprises a zero-order TIA having an input and an output. A first transconductanceamplifier has an input that communicates with said output of said zero-order TIA and an output. A first feedback resistance has one end that communicates with said input of said zero-order TIA and an opposite end that communicates with said output of said first transconductanceamplifier. A first feedback capacitance has a first end that communicates with said input of said zero-order TIA and a second end that communicates with said output of said zero-order TIA. A capacitance has one end that communicates with said input of said zero-order TIA.