79results about "Amplifiers with multiple amplifying elements" patented technology

A cascode circuit with improved withstand voltage is provided. The cascode circuit includes three or more transistors, such as MOSFET transistors. Each transistor has a control terminal, such as a gate, and two conduction terminals, such as a drain and a source. The conduction terminals are coupled in series between two output terminals, such as where the drain of each transistor is coupled to the source of another transistor. A signal input is provided to the gate for the first transistor. Two or more control voltage sources, such as DC bias voltages, are provided to the gate of the remaining transistors. The DC bias voltages are selected so as to maintain the voltage across each transistor to a level below a breakdown voltage level.

A method and apparatus provides techniques for electrically isolating switching devices in a stacked RF power amplifier, which prevents the switching devices from being subjected to high breakdown voltages. The isolation provided allows the power amplifier to be implemented on an integrated circuit.

The invention is related to linear amplifier (LA), and high power pulse electrical source (HPPES). LA uses power unit IGBT as linear unit. HPPES uses LA. LA is composed of two operational amplifiers, one power unit IGBT, and a non-inductive resistance. HPPES consists of a main current source, two current sources I1 and I2, two controllable voltages, three capacitors, switch K, diode D, inductance L, and non-inductive current limiting resistance. Whole circuit forms controllable linear current source with good tracking performance, and characteristic of constant current source. Using variable supply power, HPPES lowers wastage of power unit so as to raise efficiency of system.

An ultra-low power high-speed current sampling circuit belongs to the technical field of power management circuits. The current sampling circuit comprises a sampling module and an auxiliary clamping module, wherein the sampling module comprises an operational amplifier and a first NMOS transistor, the gate of the first NMOS transistor is connected to the gate of a power tube, the drain thereof is connected to the drain of the power tube and connected to the power supply voltage, and the source thereof is connected to the negative input terminal of the operational amplifier; the positive input terminal of the operational amplifier is connected to the source of the power tube, and the voltage of the output terminal of the operational amplifier returns to the negative input terminal of the operational amplifier through a feedback loop; the auxiliary clamp module sets upper and lower limits for the output voltage of the operational amplifier, the voltage clamp is used to accelerate the transient process from the disabled state to the enabled state, and an ultra-low power current sampling circuit with fast response speed is realized combined with the wide bandwidth. The invention also proposes an operational amplifier with a wide bandwidth to further accelerate the transient response of the current sampling circuit.

A capacitive gain amplifier circuit amplifies an input signal by a pair of differential amplifier circuits couples in series. The first differential amplifier circuit is reset during an autozero phase while disconnected from the second differential amplifier circuit, and the first and second differential amplifier circuits are connected together in series during a chop phase. A set of feedback capacitors is selectively switched in between respective outputs of the second differential amplifier circuit and respective inputs of the first differential amplifier circuit during the chop phase.

A small signal amplifier with a large signal output boost stage are connected between first and second supply rails. The small signal amplifier receives first and second input signals and provides an output signal at an output node which drives a load. Under small signal conditions, the output signal varies approximately linearly with the difference voltage. However, under large signal conditions, a rail-to-rail large signal output boost stage connected to the output node is arranged to drive the output node close to the first or second supply rail as needed to provide the current demanded by the load. The large signal output boost stage is off in small signal conditions, but comes on rapidly and transfers maximum charge to the load under large signal conditions.

A Hall signal amplify circuit includes a Hall sensor module connected to a power supply, first amplifier, second amplifier, third amplifier, compensation module, a first output of the Hall sensor module is connected to a non-inverting input of the first amplifier, a second output of the Hall sensor module is connected to an inverting input of the first amplifier, the non-inverting output terminalof the first amplifier is respectively connected with the non-inverting output terminal of the second amplifier and the non-inverting input terminal of the third amplifier. The inverting output terminal of the first amplifier is respectively connected with the inverting output terminal of the second amplifier and the inverting input terminal of the third amplifier, the first output terminal of thecompensation module is connected with the non-inverting input terminal of the second amplifier, and the second output terminal of the compensation module is connected with the inverting input terminal of the second amplifier. The invention generates the equivalent input offset voltage related to the thermal voltage through the compensation module, and has good temperature compensation function while eliminating the operational amplifier offset voltage.

The invention discloses a driving circuit with high speed and large output swing. The driving circuit comprises a first-stage emitter follower circuit used for level displacement and impedance matching, and a second-stage differential structure grounded emitter amplifier circuit used for amplifying an input signal and providing a sufficient bandwidth, wherein the first-stage emitter follower circuit comprises an emitter follower formed by Q1 and Q2, a bias current source, an impedance matching resistor R1 and an impedance matching resistor R2; the bias current source is of a parallel structureof M1 and M4 which adopt a diode connection mode and M2 and M3 which are crossly coupled; the second-stage differential structure grounded emitter amplifier circuit comprises a main amplifier tube Q3and a main amplifier tube Q4 of a grounded emitter amplifier of the differential structure, and a large-resistance driving source electrode follower which is formed by R3/M5 and R4/M6 and has an inductance characteristic. The MOS tubes adopting the diode connection mode and the MOS tubes which are crossly coupled are connected in parallel, and an MOS device whose grid electrode has large resistance forms an active inductor, the formed driving circuit has the advantages of high speed and large output swing, the gain is improved, the linearity is improved, the circuit bandwidth is expanded, thechip area is saved, and the cost is reduced.

The invention discloses a reading device for a current type touch panel. The reading device comprises a current-to-voltage conversion unit, a voltage gain unit and an analog-digital converter, wherein the current-to-voltage conversion unit converts the sensing current of the current type touch panel into sensing voltage; an input end of the voltage gain unit is coupled to an output end of the current-to-voltage conversion unit so as to receive the sensing voltage; and an input end of the analog-digital converter is coupled to an output end of the voltage gain unit, and an output end of the analog-digital converter generates digital codes.

Provided is a weak-light-signal multistage amplifying circuit. The circuit is characterized in that the circuit comprises a photoelectric detector, a prefixed amplifying circuit, a three-stage operation amplifying circuit and a one-stage amplifying detection circuit; the photoelectric detector is connected with the prefixed amplifying circuit, and the prefixed amplifying circuit is connected to the three-stage operation amplifying circuit and the one-stage amplifying detection circuit; after the photoelectric detector receives light signals, electric currents are generated, voltage signals are output after the electric currents go through the prefixed amplifying circuit, and the voltage signals are output to two operational amplifying circuits at the same time, wherein in one circuit, the voltage signals go through the one-stage amplifying detection circuit and output direct-current signals for detecting the direct-current magnitude of light signals, and in the other circuit, the voltage signals go through the three-stage operation amplifying circuit and output voltage pulse signals for detecting light-intensity changes. The weak-light-signal multistage amplifying circuit achieves the accurate measurement of micron-level matter, and can effectively suppress disturbance, improve the signal-to-noise ratio and obtain effective light signals.

The invention discloses a radio frequency ultra wide band-driven amplifier chip which comprises two input resistors, two feedback resistors and an operational amplifier. The operational amplifier comprises three amplifiers including a first-stage amplifier, a second-stage amplifier and a third-stage amplifier, the two common-mode feedback circuits comprise a first-stage common-mode feedback circuit and a second-stage common-mode feedback circuit; wherein the first-stage amplifier and the second-stage amplifier are in direct-current coupling, the input end of the third-stage amplifier is connected with the input end of the first-stage amplifier, and the output end of the third-stage amplifier is connected with the output end of the second-stage amplifier to form a feedforward structure; according to the invention, high bandwidth and linearity can be realized, and compared with a traditional two-stage or three-stage amplifier with a compensation capacitor Cc, the amplifier provided by the invention is more suitable for a resistance feedback structure and can realize better performance.

Various embodiments of the present technology may provide methods and apparatus for an amplifier integrated circuit. The amplifier integrated circuit may provide a low gain bandwidth product to amplify at a higher speed and a high gain bandwidth product to amplify at a lower speed. The amplifier integrated circuit may achieve the low and high gain bandwidth product by generating a first current and a second current through a plurality of sets of series-connected transistors and operating a plurality of switches.

The invention relates to an operational amplifier controlled animation display conductivity test instrument, belonging to the demonstration field of teaching instruments. The animation display conductivity test instrument is composed of a test rod, a test clamp, tester jacks, a first-stage amplification unit, a second-stage operational amplification unit, an oscillation unit, a sound unit, a pushing unit, a zeroing unit, a light color display unit, an image effect unit and a quick-break protection adjustable power supply. A power supply for starting quick-break protection during overvoltage is arranged to protect stability of test instrument. When a tested electronic element is inserted into the tester jacks, according to the characteristics of object conductivity, the tested electronic element is amplified by the first-stage amplification unit and then enters an in-phase input end of a comparison amplifier in the second-stage operational amplifier unit, output is generated on the basis of the intensity of input signals, the sound unit is started to emit sound and also the pushing unit is excited to act, the light color display unit generates light display, animation images are formed, and then visual animation display and a voice effect are achieved. The operational amplifier controlled animation display conductivity test instrument is quite interesting, and can arouse the interest of teenagers to increase the love for science.