78 results about "Gain–bandwidth product" patented technology

An avalanche photo-detector (APD) is disclosed, which can reduce device capacitance, operating voltage, carrier transport time and dark current as well as increasing response speed and output power. Thus, an avalanche photo-detector (APD) with high saturation power, high gain-bandwidth product, low noise, fast response, low dark current is achieved. The APD includes an absorption layer with graded doping for converting an incident light into carriers, an undoped multiplication layer for multiplying current by means of receiving carriers, a doped field buffer layer sandwiched between the absorption layer and the multiplication layer for concentrating an electric field in the multiplication layer when a bias voltage is applied, and an undoped drift layer sandwiched between the absorption layer and the field buffer layer for capacitance reduction.

The invention provides an optical-receiver preamplifier for receiving analog or digital optical signals. The preamplifier comprises a high-gain amplifier A1, an input circuit, a negative-feedback impedor Zf, a low-gain amplifier A2 adjustable in gain and a feedback capacitor Cff, wherein the input circuit takes a photoelectric converter as a main component; the negative-feedback impedor Zf is connected with the reverse input end and the output end of the A1; the feedback capacitor Cff connects the output end of the A2 with the reverse input end of the A1; and the output end of the A1 can be directly connected with the input end of the A2 or can be connected with the input end of the A2 through a buffer. Output signals of the preamplifier are taken out from the output end of the A1 or the output end of the buffer, and can be directly subjected to subsequent signal processing or be further amplified and then subjected to subsequent signal processing.

The invention discloses a self-adapting current multiplication circuit and a low-dropout-voltage linear voltage regulator integrating the circuit. Firstly, constant bias voltage of an NMOS transistor and constant bias voltage of a PMOS transistor are generated through a constant bias voltage generating circuit, and then a lagging current comparator collects small part of load current which is compared with constant current; when a load is in a light load, the lagging current comparator shuts off a self-adapting current multiplication generating circuit, self-adapting current multiplication voltage VBPA rises, the bias current of an operational amplifier of the low-dropout-voltage linear voltage regulator lowers, in this way, stability is guaranteed, and quiescent dissipation is reduced; when the load is in a heavy load from a moderate load, the lagging current comparator turns on the self-adapting current multiplication generating circuit, the self-adapting current multiplication voltage VBPA lowers, the bias current of the operational amplifier increases to the specific times the bias current of the operational amplifier during the light load, the gain bandwidth product of the low-dropout-voltage linear voltage regulator increases, and transient response performance is enhanced.

The invention discloses a low power consumption high slew rate high gain bandwidth product fully differential operational amplifier. An operational amplifier circuit adopts an input stage current extraction structure and partially extracts currents inside a load pipe through an active current mirror to reduce the effective resistance of the operational amplifier; slew rate enhancing circuits are in parallel connection with bilateral sides of a main operational amplifier to enhance the slew rate of output signals; an output stage applies a Class-AB output structure. According to the low power consumption high slew rate high gain bandwidth product fully differential operational amplifier, the current mirror is connected to an input end load pipe in a parallel mode, the effect of transconductance reduction is achieved due to adjustment of the breadth length ratio of the current mirror, and accordingly the integral circuit keeps the gain bandwidth product and satisfies the integral modulator required level under the condition that the power consumption is reduced and a feedforward structure is connected to the operational amplifier in a parallel mode to inject compensating current for the load to increase the slew rate of the output signals when the operational amplifier is in a working state and transient state power consumption is not consumed excessively.

A source-measure unit (SMU) may be implemented with respective digital control loops for output voltage and output current. The output voltage and output current may be measured with dedicated ADCs (analog-to-digital converters). The readings obtained by the ADCs may be compared to a setpoint, which may be set in a digital loop controller. The digital loop controller may be used to produce an output to drive a DAC (digital-to-analog converter) until the output voltage and/or output current and/or a function thereof reach the respective desired levels. The digital loop controller may implement respective integrating functions for the respective digital control loops, and may also implement a compensation function featuring pole-zero pairs to stabilize the respective current/voltage outputs. Coefficients of the compensation function may be calculated based on user programmable parameters corresponding to the gain bandwidth product, compensation frequency, and ratio of the added pole-zero frequencies.

A class AB folded-cascode amplifier having improved gain-bandwidth product, comprises a differential input circuit including a differential transistor pair coupled to a source of tail current and responsive to a differential input signal for conducting a first current, a cascode circuit coupled to the differential input circuit for supplying a second current thereto, and a class AB output stage. A compensation circuit is configured for feeding back mutually complementary compensation signals from an output node to the differential input circuit. Another compensation circuit is configured for feeding back a signal from the output of the output stage to the input of the output stage.

Provided herein are multi-stage broadband amplifier configured to achieve a high gain-bandwidth product in a non-distributed architecture and methods for designing the same. The broadband amplifier can include an input stage having a broadband matching unit and an input buffer unit, a gain stage having an RLC network and a amplifier unit and an output stage having a common collector amplifier and an RC compensation unit.

The invention discloses a broadband programmable gain amplifier based on an operational amplifier. By designing an operational amplifier with two poles and a zero point and using a zero point compensated secondary pole realized by a feedforward structure, the amplifier expands running bandwidth when ensuring 60dB low-frequency gain and obtains 10MHz cut-off bandwidth and the gain bandwidth product of 4.5GHz. The whole programmable gain amplifier realizes the regulation of 10MHz bandwidth and 50dB gain. The invention has negative feedback structure, stable performance and higher linearity, and the gain depends on the ratio of feedback resistance and input resistance; and the end-to-end input and output can be realized, and a signal dynamic range is wide.

The invention discloses a cascode transimpedance amplifier with high gain, low noise and optimal bias adjustment, which includes: a main amplifier and an auxiliary amplifier, and also includes: a connection between the output terminal of the auxiliary amplifier and the gate of the main amplifier In between, a bias circuit with a high-pass filter structure is added to isolate the DC bias of the main amplifier and the auxiliary amplifier, so that both work in the best bias state; a cascode amplifier is used to replace the DC bias in the auxiliary amplifier Common-source stage amplifier, providing higher gain-bandwidth product; series inductor L at the input ₁ , the series inductor L between the common-source and common-gate devices of the cascode amplifier ₂ , the two inductances, the photodetector capacitance at the input end and the parasitic capacitance of the MOS tube form two π-type matching networks respectively. On the premise of ensuring that the overall bandwidth of the transimpedance amplifier is not reduced, the present invention improves the circuit gain and reduces noise, and finally realizes the RGC transimpedance amplifier with high gain and low noise.

A class AB folded-cascode amplifier having improved gain-bandwidth product, comprises a differential input circuit including a differential transistor pair coupled to a source of tail current and responsive to a differential input signal for conducting a first current, a cascode circuit coupled to the differential input circuit for supplying a second current thereto, and a class AB output stage. A compensation circuit is configured for feeding back mutually complementary compensation signals from an output node to the differential input circuit.

An active RC filter has an op-amp and a biasing circuit arranged to bias the op-amp to set a gain bandwidth product of the op-amp according to a desired pole frequency of the filter. The biasing circuit is operable according to an output of an RC calibration circuit. The op-amp can be an OTA transconductance amplifier, and the biasing circuit can be arranged to maintain a constant product of R and transconductance at an input of the transconductance amplifier. This biasing can help to set the pole frequency more accurately and can thus reduce the need for bandwidth margin to be provided to allow for manufacturing process variations.

The present disclosure relates to a capacitively-coupled distributed amplifier (DA) having an input line and an output line that are coupled to one another through a broadband interface network and DA segments. The input line receives an input signal and the output line provides an output signal based on amplifying the input signal. The broadband interface network includes a group of capacitive elements coupled between the input line and the DA segments to extend a gain-bandwidth product of the DA. The broadband interface network further includes a resistor divider network coupled between the input line and the DA segments to extend a lower end of an operating bandwidth of the DA. As such, the operating bandwidth of the DA may extend from baseband frequencies to microwave frequencies.

The invention discloses a low-power consumption three-level operational amplifier for driving a large-load capacitor. The amplifier is composed of fifteen MOS transistors, two capacitors and a resistor Ra, wherein the fifteen MOS transistors comprise the first PMOS transistor M10, the second PMOS transistor M11, the third PMOS transistor M13, the fourth PMOS transistor M17, the fifth PMOS transistor M18, the sixth PMOS transistor M21, the seventh PMOS transistor M24, the eighth PMOS transistor M31, the first NMOS transistor M13, the second NMOS transistor M14, the third NMOS transistor M15, the fourth NMOS transistor M16, the fifth NMOS transistor M22, the sixth NMOS transistor M23 and the seventh NMOS transistor M30; the two capacitors comprise the first compensation capacitor Cm and the second compensation capacitor Ca. Compared with the prior art, the three-level operational amplifier can drive the large-load capacitor (hundreds of pF) under the low-voltage low-power consumption (microW) condition, and has a large gain bandwidth product and a better swing rate.

A method for controlling dissipation in a video amplifier for a display signal. The method comprises the steps of setting a first current for establishing a first gain bandwidth product in the video amplifier. Generating a control signal in accordance with a slew rate of the display signal. Modifying the first current responsive to the control signal such that the video amplifier gain bandwidth product is controlled in accordance with the slew rate of said display signal.

The invention discloses a noise coefficient test method based on a vector network analyzer and a noise source, and belongs to the technical field of test. The method can be used to overcome the problem of a matching error between a tested piece and an instrument, is especially suitable for the condition that the tested piece is not matched well, and can be used to improve the test accuracy. The method is used in combination with a noise receiver of the vector network analyzer, the dynamic test range is widened, and both low and high noise coefficients can be measured accurately via the method;the vector network analyzer is used to measure the gain of the test piece; the vector network analyzer calibrates an error item via a port to obtain the most accurate gain of the test piece; the noise source is used to represent the receiver; and the noise source represents a gain bandwidth product of the receiver, the gain bandwidth product is measured accurately via formulas in cold and hot states, and the noise source can be traced back.

The invention discloses a novel variable gain amplifier circuit in a current mode. The variable gain amplifier circuit comprises a variable gain circuit, a functional digital control logic circuit and a direct current offset calibration circuit, wherein the variable gain circuit comprises four full balanced digital programmable current amplifiers; the functional digital control logic circuit is used for coding a control signal into a binary signal and then controlling gain decibels of the variable gain circuit; and the direct current offset calibration circuit feeds a low-frequency signal output by the variable gain circuit back to an input end of the variable gain circuit to form a negative feedback loop. In the amplifier circuit in the current mode, signal input is low resistance, signal output is high resistance, and a circulating signal is a current signal and is not influenced by the magnitude of voltage. A variable gain amplifier in the current mode is in a Class-AB output structure, so that the power consumption of the circuit is greatly reduced. The current amplifier is free from limitation of a gain bandwidth product, so that the bandwidth is not limited on any gain almost.

The invention relates to large-scale integrated circuits, and aims to boost input transconductance and output resistance of an amplifier, further improve direct current gain of the amplifier and finally realize boost of direct current gain and gain bandwidth product of the amplifier under the condition of same chip area. Therefore, the technical scheme of the invention is a gain-boosted operational amplifier applicable to a TFT-LCD drive circuit. The gain-boosted operational amplifier applicable to the TFT-LCD drive circuit is composed of a Recycling folded cascade amplification stage, an output resistance boosting loop, a transconductance boosting loop and a high swing output stage; differential mode signals Vin- and Vin+ are input through the Recycling folded cascade amplification stage, then, the signals are subjected to the cross positive feedback effect of the output resistance boosting loop stage and the transconductance boosting loop stage and further subjected to current multiplication of a cascade current mirror, and finally, the signals are output to an output end through the high swing output stage. The gain-boosted operational amplifier applicable to the TFT-LCD drive circuit is mainly applied to the large-scale integrated circuits.

The invention relates to a double-second-order active RC filter circuit and a compensation method thereof. The circuit comprises an Akerberg-Mossberg double-second-order unit and a resistor R5, wherein one end of the resistor R5 is connected with the inverted input end of an operational amplifier A1 of the Akerberg-Mossberg double-second-order unit, and the other end of the resistor R5 is connected with the output end of an operational amplifier A3 of the Akerberg-Mossberg double-second-order unit. According to the double-second-order active RC filter circuit and the compensation method thereof, the double-second-order active filter circuit with a high Q value is built by using the operational amplifiers with low gain bandwidth products, sensitiveness to the gain bandwidth products of the operational amplifiers of the Q value is minimized, and power consumption of a filter is reduced. An active feedback network is built by means of an existing reverse buffer, leading phase quantity matched with the gain bandwidth products of the operational amplifiers is provided, and the best phase compensation is conducted on consumption of two integrators of a feed-forward network in a frequency range of a filter transmission band.