106 results about "Chopper amplifier" patented technology

The invention discloses a signal conditioning circuit, a conditioning method thereof and a double sampling retaining circuit. The signal conditioning circuit comprises a first chopping switch, a programmable gain amplifier, a second chopping switch, a double sampling retaining circuit, an analog-to-digital converter, and a digital reduction sampling filter which are connected in sequence. The double sampling retaining circuit samples outputs of the programmable gain amplifier in two-phase positions of a chopping clock, and the results of two samplings are added. and an added output voltage is transmitted to and processed by the analog-to-digital converter, and the digital reduction sampling filter. Since the double sampling retaining circuit is added, the invention avoids the residual and off-tune problem in a chopping amplifier. Meanwhile, the invention facilitates the integration of a single chip, without the need of external filtering capacitor. Furthermore, a novel sequential control reduces the consumption of a digital signal conditioning circuit based on a chopping amplifier.

A capacitance difference detecting circuit has timing generator that outputs a current switching pulse signal for controlling a switching operation of a current switching circuit, outputs a gate pulse signal for controlling a chopper amplifier so that the chopper amplifier detects the first charging voltage when a first variable capacitor is charged by a first charging voltage and detects a second charging voltage when a second variable capacitor is charged by a second charging voltage, outputs a first sample pulse signal for controlling a first sampling and holding circuit so that the first sampling and holding circuit samples and holds the output signal of the chopper amplifier when the first charging voltage is detected, and outputs a second sample pulse signal for controlling the second sampling and holding circuit so that the second sampling and holding circuit samples and holds the output signal of the chopper amplifier when the second charging voltage is detected.

The invention discloses a ripple elimination loop for a capacitance coupled chopper amplifier. An output voltage ripple of a chopper amplifier is converted to an AC signal, the AC signal is modulated to a DC signal, the DC signal is integrated by an integral module to obtain an integral voltage, and the integral voltage is converted to a compensating current through a transconductance module to compensate the offset voltage of the chopper amplifier and suppress the output voltage ripple of the chopper amplifier. In addition, according to the ripple elimination loop disclosed by the invention, the offset voltage of the integral module can be greatly suppressed by using the combination of a high-frequency chopping technology and a Ping-Pong self-zeroing technology in the ripple elimination loop, and thus the accurate integral voltage can be obtained, the accurate compensating current can be formed to suppress the offset current of a main amplifier in the chopper amplifier, and a good effect of suppressing the output voltage ripple of the chopper amplifier can be achieved.

In a chopper amplifier circuit operable at a low voltage utilizing a switched operational amplifier, a chopper modulator chopper-modulates an input signal according to a predetermined control signal, and outputs a chopper-modulated signal. An amplifier circuit constituted by the switched operational amplifier amplifies the chopper-modulated signal outputted from the chopper modulator, and outputs an amplified chopper-modulated signal. A chopper-demodulator of the switched operational amplifier chopper-demodulates the amplified chopper-modulated signal outputted from the amplifier circuit according to the control signal, and outputs a demodulated output signal as a chopper-amplified output signal from an output terminal. A chopper modulator chopper-modulates a demodulated signal outputted from the chopper demodulator according to the control signal, and outputs a chopper-modulated signal to an input terminal of the amplifier circuit.

The invention provides a method for eliminating chopping waves and ripple waves and an analogue-digital conversion circuit for realizing the method. The method comprises the following steps of: carrying out two times of sampling on signals in a chopping wave period at an interval which is one half of time of the chopping wave period; and carrying out integration and summation on two times of sampling values so as to keep useful signals and eliminate residual ripple wave signals in the chopping waves. The signal amplification and analogue-digital conversion circuit comprises a chopping wave amplifier and a sigma-delta analogue-digital converter which is cascaded behind the chopping wave amplifier. A switching structure which is embedded into the sigma-delta analogue-digital converter is adopted and an analogue addition function of a first-grade integrator in the analogue-digital converter can be used for carrying out first-order reshaping (voltage summation) on the residual ripple waves of output signals of the chopping wave amplifier, so that the ripple wave amplitude is reduced and influences on the conversion precision of the analogue-digital converter is weakened. The circuit does not need an analogue low-pass filter between the chopping wave amplifier and the analogue-digital converter, so that the power consumption and the area are saved and the design of the circuit is simplified.

Novel circuitry and methodology are provided for correcting the offset associated with a voltage-controlled current source. An offset correction circuit is coupled to the current source to prevent the output current produced by the current source from deviating from a desired level. The current source may include a transconductance amplifier or a chopper amplifier, and may be configured to produce a zero or non-zero value of the output current.

Novel circuitry and methodology are provided for correcting the offset associated with a voltage-controlled current source. An offset correction circuit is coupled to the current source to prevent the output current produced by the current source from deviating from a desired level. The current source may include a transconductance amplifier or a chopper amplifier, and may be configured to produce a zero or non-zero value of the output current.

A temperature and process-stable magnetic field sensor bias current source provides improved performance in Hall effect sensor circuits. A switched-capacitor sensing element is used to sense either a reference current or the bias current directly. A current mirror may be used to generate the bias current from the reference current, and may include multiple current source transistors coupled through corresponding control transistors that are switched using a barrel shifter to reduce variations in the bias current due to process variation. The current mirror control may be provided via a chopper amplifier to reduce flicker noise and the current mirror control voltage may be held using a track/hold circuit during transitions of the chopper amplifier to further reduce noise due to the chopping action.

Various apparatuses and methods are described where a signal is amplified using a chopper amplifier arrangement, and ripples caused by said chopper amplifier arrangement are reduced. In some cases, this reduction of ripples is performed by controlling a voltage offset of an amplifier of said chopper amplifier arrangement. In other embodiments, a detection of ripples or a chopping of the chopper amplifier arrangement is at least temporarily disabled.

A chopper stabilized amplifier with synchronous switched capacitor noise filtering is disclosed. In an exemplary embodiment, an apparatus includes a chopper amplifier having an input that receives an input signal and an output that outputs an amplified signal. The chopper amplifier includes an input chopping circuit and an output chopping circuit, where the input and output chopping circuits operate in response to a chop clock. The apparatus also includes a switched capacitor filter having an input that receives the amplified signal and an output that outputs a filtered signal. The switched capacitor filter operates in response to a filter clock. The apparatus also includes a filter timing adjuster that receives a reference voltage and adjusts a phase of the filter clock with respect to the chop clock to reduce chopper noise on that reference voltage.

A chopper amplifier includes a chopper modulator to modulate a certain detection signal and a bias voltage by a certain control signal and output a chopper modulation signal, a first differential amplifier to differentially amplify the chopper modulation signal from the chopper modulator and output a differential modulation signal, a chopper demodulator to demodulate the differential modulation signal from the first differential amplifier by the control signal and output a demodulation signal, a second differential amplifier to extract a detection signal component from the demodulation signal, and a plurality of filters connected at an input terminal of the second differential amplifier and having different cutoff frequencies from each other relative to the demodulation signal.

Disclosed is a digital-to-analog converter, a display panel driver containing the same as well as a method for converting digital-to-analog. The digital-to-analog converter outputting an analog data voltage corresponding to n-bit data, includes a chopping amplification unit adapted to receive an upper bit voltage corresponding to upper x bits of the n-bit data and a lower bit voltage corresponding to lower y bits of the n-bit data and to output the analog data voltage. The chopping amplification unit may include a sample and hold capacitor adapted to be charged with the upper bit voltage in a non-inverting mode, and a chopping amplifier adapted to supply the upper bit voltage to the sample and hold capacitor in the non-inverting mode and adapted to output a voltage corresponding to the sum of the upper bit voltage and the lower bit voltage as the analog data voltage in an inverting mode.

An RF power detector having a wide dynamic range may comprise a chopping amplifier and is configured to detect pulsed high frequency RF signals. The chopping amplifier controlled by a bias current regulator amplifies and chops an RF signal by periodically enabling and disabling the amplifier according to a system clock. The chopped high frequency RF signal feeds a Schottky diode biased to operate in the square law region for weak signals. The Schottky diode voltage is tapped and high pass filtered. The voltage drives a logarithmic and linear converter. The converter outputs are summed to produce an output voltage that is a repeatable and stable monotonically increasing function of the RF power.

Apparatus and methods for multi-channel autozero and chopper amplifiers are provided herein. In certain configurations, an amplifier includes at least three channels that operate using multiple phases, including at least a non-inverting chop phase, an inverting chop phase, and an autozero phase. The amplifier further includes an autozero and chopping timing control circuit, which at least partially interleaves or staggers timing of the channels' phases. For example, in certain configurations, when one or more of the channels are being autozeroed at a certain time instance, at least some of the remaining channels operate in the non-inverting chop phase or the inverting chop phase.

The invention provides a chopping amplifier circuit coupled with a sensor. Without an additional offset voltage regulating circuit and an additional offset temperature characteristic regulating circuit, the reduction of the offset voltage of the sensor and the influence of the temperature characteristic of the offset voltage are realized, and also low frequency noise of the sensor is effectively reduced. A Wheatstone bridge composed of one sensor and three dark units is also provided, and electrical signals are adjusted to high frequency by controlling a clock signal CLK. The offset voltage and the low frequency noise of the signals are filtered with a filter, and the signals are demodulated back to low frequency with a multiplier. The chopping amplifier circuit not only is simpler than conventional circuits, but also has a higher signal-to-noise ratio than the conventional circuits do.

A sensor device is provided with a voltage detection type sensor unit for converting a physical quantity into a voltage value and outputting a voltage signal indicating the voltage value; a chopper amplifier unit for generating a modulation signal by chopping the voltage signal output from the sensor unit with a predetermined chopping frequency, amplifying the modulation signal into an amplification signal, then demodulating the amplification signal and outputting it as an output signal; an integration unit including an operational amplifier, an input resistor connected to the inverting input terminal of the operational amplifier and a capacitor connected between the inverting input terminal and an output terminal of the operational amplifier; and a digital conversion unit for converting the output signal integrated by the integration unit into a digital signal.

A chopper stabilized amplifier that utilizes a multi-frequency chopping signal to reduce chopping artifacts. By utilizing a multi-frequency chopping signal, the amplifier DC offset and flicker noise are translated to the higher chopping frequencies but are also smeared, or spread out in frequency and consequently lowered in amplitude. This lower amplitude signal allows for less stringent filtering requirements.

The invention discloses a reference adjustable programmable linear hall sensor chip comprising a hall plate, a chopping amplifier, a reference voltage control circuit, an adjustable gain amplifier and a static output control circuit. The hall plate induces a magnetic field signal and converts the magnetic field signal into a hall voltage signal which enters the adjustable gain amplifier through detuning elimination by the chopping amplifier. The reference voltage of the chopping amplifier is controlled by the reference voltage control circuit, the gain of the adjustable gain amplifier is controlled by a gain adjusting circuit, and zero output of the static output control circuit is controlled and adjusted by a zero adjusting circuit. The advantages of the reference adjustable programmable linear hall sensor chip are that 1, internal reference output can be realized, and external reference input is allowed so that the static output voltage is enabled to follow the external reference voltage; 2, the consistency of the static output voltage can be realized so that the problem of different output voltage caused by manufacturing technology error can be solved; and 3, the size of the gain can be accurately controlled.