38results about "Switched capacitors control" patented technology

A low noise amplifier including a variable gain amplifier stage configured to accept an input signal and to provide a load driving signal; a tunable bandpass filter connected as a load to the variable gain amplifier stage, wherein the bandpass filter includes a cross-coupled transistor pair, and at least one cross-coupled compensation transistor pair biased in a subthreshold region configured to add a transconductance component when the load driving signal is of a magnitude large enough to decreases a transconductance of the cross-coupled transistor pair; and, a controller circuit configured to tune the bandpass filter. The filter can be tuned in respect to the frequency and the quality factor Q.

A variable matching circuit includes a transformer which is disposed between first and second transistor circuits. A primary inductor device and a secondary inductor device are magnetically coupled in the transformer. The primary inductor device is connected between an output terminal of the first transistor circuit and a bias circuit for the first transistor circuit. The secondary inductor device is connected between an input terminal of the second transistor circuit and a bias circuit for the second transistor circuit. Connection points between the primary inductor device and the bias circuit for the first transistor circuit and between the secondary inductor device and the bias circuit for the second transistor circuit are connected to first and second capacitive elements, respectively. At least one of inductance values of the respective primary and secondary inductor devices and capacitance values of the respective first and second capacitive elements is variable.

One embodiment of the invention may include a programmable gain amplifier comprising an input multiplexer (14) operative to sequentially select input signals (12) for amplification. The input signals may be chosen from a plurality of input signals based on a selection signal. The programmable gain amplifier (18) may include at least one amplifier gain stage operative to apply a variable gain amount to a selected input signal. The programmable gain amplifier may further include a gain mapping component that controls the variable gain amount for each of the selected input signals.

An impedance matching network for a radio frequency (RF) amplifier includes multiple stages connected to each other in a first to last order. A first stage produces an RE output signal, and a last stage receives an RF input signal. Each stage includes a first inductor connected to produce an output signal, a second inductor connected to receive an input signal from a next stage, a capacitor connected between the first and second inductors and a ground. In addition, each stage other than the first stage further includes a first switch to by-pass the first and second inductors, a second switch connected between the first and second inductors and the ground, and a controller for controlling, the first and second switches to select a particular power level of a set of power levels.

An apparatus includes an input terminal to receive a radio frequency (RF) signal and to communicate the RF signal to a low noise amplifier (LNA) via an input signal path, and a capacitor attenuator coupled to the input terminal to attenuate the RF signal by a controllable amount and having a first portion controllable to include a used part configured on the input signal path and an unused part coupled between the input signal path and an AC reference node, and a second portion coupled between the LNA and the AC reference node.

Provided is a current-voltage conversion amplifier circuit including: a plurality of light receiving devices generating a current signal proportional to an amount of light by receiving the light; multipliers amplifying the current signal, converting the amplified current signal into a first voltage signal, outputting the amplified current signal, or outputting the converted first voltage signal; multi input amplifiers outputting first and second output voltage pairs through a process for receiving output values of multipliers and an offset voltage and amplifying the received output values and offset voltage; a multiplexing unit selecting and outputting one first and second output voltage pair among the first and second output voltage pairs outputted from multi input amplifiers; and a signal conversion unit converting a difference value between first and second output voltages outputted from the multiplexing unit and outputting the converted digital signal.

The invention provides a switched capacitor adjustable gain amplifier with high gain and low noise. The switched capacitor adjustable gain amplifier comprises an external signal source, a square wavegenerator, a switched capacitor integrator and a feedback circuit with a signal amplification function, wherein the external signal source and the square wave generator are connected to the switched capacitor integrator, the switched capacitor integrator outputs through the feedback circuit, the switched capacitor integrator comprises seven COMS switching tubes opened by forward pulses, a samplingcapacitor, an adjustable feedback capacitor and an integrating capacitor, and the feedback circuit comprises an operational amplifier. According to the switched capacitor adjustable gain amplifier, the time-reduced integrated frequency of the feedback capacitor is equivalent to the reduction of the capacitance value of the feedback capacitor; the noise of the PGA is reduced while the high gain isrealized; meanwhile, the layout area of the circuit is not increased, the power consumption and the cost are reduced, the detection precision and the detection efficiency of the circuit are improved,and the switched capacitor adjustable gain amplifier is suitable for various sensor interfaces, signal conditioning chips and signal links and has a great market development prospect in automotive electronics, white household appliances, industrial automation and the Internet-of-things.

The present invention relates to an interface circuit for a capacitive accelerometer sensor for measuring an acceleration value sensed by the sensor. The interface circuit comprises a plurality of electrical switches and three programmable capacitors. Two of the programmable capacitors are arranged to implement gain trimming of the interface circuit, while one of the programmable capacitors is arranged to implement acceleration range selection.

An amplification circuit, which may be in a receive path of a communication device, includes an amplifier including at least a first amplification device and a switchable attenuation circuit. The switchable attenuation circuit includes one or more switches and a plurality of attenuation devices and is operable to provide different levels of attenuation to an input signal prior to input to the amplifier depending on the status of the one or more switches. The attenuation devices may be capacitors, wherein the capacitors may be arranged to form a capacitive divider with a level of attenuation dependent on the status of the switches. The switchable attenuation circuit may be a switched capacitive attenuation ladder of n stages, n being any integer, each ladder stage including a capacitive divider. The amplification circuit may also include a switch, which when closed provides an unattenuated path for the input signal to the amplifier input.

This disclosure provides a method for gain control in a wireless receiver. The wireless receiver comprises a first receiver chain adapted to receive a first signal in a first frequency range, a second receiver chain adapted to receive a second signal in a second frequency range, and a common amplifier module operatively connected to the first receiver chain and the second receiver chain. The method comprises determining a first target gain level for a first path comprising the common amplifier module and the first receiver chain, and determining a second target gain level for a second path comprising the common amplifier module and the second receiver chain. The method comprises setting a gain GA of the common amplifier module and a gain GRx1 in the first receiver chain and a gain GRx2 in the second receiver chain based on the first target gain level and the second target gain level.

An analog front-end circuit for a portable health monitoring device is characterized by comprising a capacitive coupling instrumentation amplifier, a gain programmable amplifier and a band-pass filter. A pre-charging loop composed of a first buffer and a second chopping switch is adopted, a positive feedback loop is composed of a first adjustable capacitor, a second adjustable capacitor and a third chopping switch, and the pre-charging loop and the positive feedback loop are used for impedance enhancement and work in the circuit at the same time, so that the input impedance is greatly improved. The self-calibration module is used for preventing the problem of circuit oscillation possibly caused by impedance improvement; meanwhile, the gain of the programmable gain amplifier is calibrated by using the same calibration logic, and the gain precision of the analog front-end circuit is improved.

A scalable dynamic range analog-to-digital converter. In one instance, a method of scaling a dynamic range of an analog-to-digital converter is provided. The method includes operating the analog-to-digital converter at a first dynamic range. The method also includes receiving a radio frequency signal and detecting an on-channel signal level of the radio frequency signal. The method also includes when the on-channel signal level is above an on-channel threshold, operating the analog-to-digital converter at a second dynamic range. The method also includes when the on-channel signal level is below the on-channel threshold, operating the analog-to-digital converter at the first dynamic range.

The invention discloses a variable gain amplification circuit for pressure-sensitive touch. The circuit comprises an operational amplification module, a gain configuration module and a clock control module; the clock control module is used for generating a control clock; the gain configuration module is used for configuring gain and output bias voltage according to the control signal, so that an input signal is amplified through reverse operation, superposed with fixed bias voltage and then output; according to the invention, the gain of the amplification circuit is adjusted by adjusting the capacitance value ratio of the input end of an operational amplifier to a feedback branch; the fixed bias amount of the output voltage is changed by adjusting the capacitance value ratio of the input of the operational amplifier to a reference voltage branch; the output signal is only related to the reference voltage, the gain and the input, accurate amplification is obtained when the voltage of the input signal is close to zero, and the problem in amplification when the input signal is close to zero (ground) during light touch in a pressure-resistance change-voltage sensing-based touch schemeis solved.

The invention belongs to the field of sensors, the invention relates to a method for controlling a variable gain amplifier in an infrared receiving chip. The chip area can be greatly saved; reducing cost, improving stability of current values, the circuit comprises a current source, a capacitor and a variable gain method device, one end of the current source is connected with VCC, and the other end is connected with the input end of the switch. The output end of the switch is connected with the upper pole plate of the capacitor and the voltage control end of the variable gain method device; the control end of the switch is connected with the output end of the oscillator; the current value of the current source is set to be I; wherein the capacitance value of the capacitor is C, the periodof the output signal of the oscillator is T, the duty ratio is A, the gain of the variable gain amplifier is V * g, V is the gain control voltage, g is the gain constant, and the gain G of the variable gain amplifier in one period T is expressed as G = V * g = [(I * T * A)/C] * g; the gain change rate of the variable gain amplifier is controlled by adjusting the duty ratio of the output signal ofthe oscillator.

The embodiment of the present invention relates to the field of electronic technology, and discloses an I-V conversion module. In the embodiment of the present invention, the I-V conversion module includes: a current output sensor, a pre-integration circuit, a charge transfer auxiliary circuit, and an I-V conversion circuit including an inverting amplifier; the current output sensor passes through the pre-integration circuit connected to the input end of the I-V conversion circuit; the charge transfer auxiliary circuit is connected in parallel with the inverting amplifier; wherein, when both the pre-integration circuit and the charge transfer auxiliary circuit are open, the pre-integration The integrating circuit pre-integrates the induced current output by the current output sensor to store the pre-integrated charge; when both the pre-integrated circuit and the charge transfer auxiliary circuit are connected, the pre-integrated charge is transferred to the I ‑V conversion circuit. The embodiment of the present invention reduces the time required for the establishment of the I-V conversion module and reduces power consumption.