84 results about "Crossover distortion" patented technology

An integrated circuit provides a complete electronic ballast control with power factor correction for fluorescent lamps. The integrated circuit contains a simplified power factor correction (PFC) circuit to reduce component count and supply voltage requirements to reduce manufacturing costs while providing a robust control. The PFC circuit has a variable gain for fast response at high gain and optimized power factor control at low gain. An increased on time for the PFC switch when the input line voltage approaches zero dynamically reduces crossover distortion, thereby reducing total harmonic distortion. The integrated circuit incorporates a number of fault protections.

A system and method for power conversion synchronizes multiple phases at a desired phase angle difference. The power conversion involves variable frequency switching, fixed on-time and provides power factor correction. A relative measure of a phase angle difference between two phases permits each phase to be controlled to obtain the desired phase angle difference. The power conversion involves transition mode switching to help reduce switching losses. A phase angle difference detector may be provided for each phase. The various phases may have different inherent frequencies that vary with switching frequency, and are synchronized to an average frequency. Current measures can be taken with a single component, such as a resistor. A maximum frequency control limits period width to avoid high frequency switching. An added switch on time improves input voltage crossover distortion. One or more phases can be deactivated in light load conditions.

A system and method for power conversion synchronizes multiple phases at a desired phase angle difference. The power conversion involves variable frequency switching, fixed on-time and provides power factor correction. A relative measure of a phase angle difference between two phases permits each phase to be controlled to obtain the desired phase angle difference. The power conversion involves transition mode switching to help reduce switching losses. A phase angle difference detector may be provided for each phase. The various phases may have different inherent frequencies that vary with switching frequency, and are synchronized to an average frequency. Current measures can be taken with a single component, such as a resistor. A maximum frequency control limits period width to avoid high frequency switching. An added switch on time improves input voltage crossover distortion. One or more phases can be deactivated in light load conditions.

The invention is applicable to the field of LED lamps, and provides an LED driving circuit and an LED lamp. The LED driving circuit comprises a PFC control unit and a PWM control unit. In the embodiment of the invention, the PFC control unit of the LED driving circuit adopts a PFC control chip; and the PFC control chip comprises a highly linear multiplier and a THD optimal circuit for reducing alternating input current crossover distortion and can reduce the total harmonic distortion (THD) existing in the LED driving circuit so as to enhance the electromagnetic compatibility (EMC) of the LED driving circuit and improve the performance of the LED driving circuit.

A testing method or apparatus utilizes filter banks to measure time varying or dynamic harmonic distortion or intermodulation distortion. With a stairstep signal and filter banks, Nth order harmonic and or intermodulation distortion is measured via the filter banks at different offsets provided by an arbitrary low frequency signal. An amplifier with crossover distortion will show increased harmonic and or intermodulation distortion near the zero crossing while providing less distortion in other portions of the transfer curve of the amplifier.

A controller for reducing the harmonics contents in the AC-to-DC converter that is capable of minimizing THD due to crossover distortion. The controller can approximate the shape of the current running through boost inductor to the sinusoidal waveform of the rectified line input voltage and in the meantime to keep the valley of rectified sinusoidal waveform line voltage close to local ground value. The controller can be used in a transition mode power factor correction device suitable for a wide range of AC line input voltage and output loading application.

The invention provides a feedback shift (FBS) type compensating network which can be used in the audio power amplifier and any negative feedback amplifying circuit with emitter or source follower output stage and can replace the traditional miller capacitance to provide phase-lag compensation. As the feedback network forms a local negative feedback with current-voltage amplifying stage and output stage in the frequency range above dominant pole, the degradation of circuit performance in the middle and high frequency range generally caused by the decrease of big ring negative feedback is made up to a certain extent so that the breakthrough increase of the indexes related to the output stage such as crossover distortion in middle and high frequency range is realized, the dependency of the circuit on the bias current of the power tube is greatly reduced, and a class AB amplifier which only uses tens of milliamps bias current can realize the crossover distortion level of the class A power amplifier or even less. The invention is a structural improvement for the traditional negative feedback amplifying circuit, the method is easy and the compensating network can be used in most of power amplifiers and other negative feedback amplifying circuits.

The invention discloses a broadband piezoelectric vibration energy collection system. The system comprises a frequency collection circuit, a voltage stabilizing push-pull circuit and an operational amplifier circuit. The frequency collection circuit collects the frequency of the electric power signal collected by a broadband piezoelectric vibration energy collection system, the voltage stabilizingpush-pull circuit uses a frequency modulation circuit composed of a triode Q1, a capacitor C2 and a capacitor C4 to stabilize the signal frequency, simultaneously uses an operational amplifier AR1 and an operational amplifier AR2 to form a feedback voltage stabilizing circuit for voltage stabilization, and finally uses a triode Q4 to a triode Q7 to form the push-pull circuit to prevent the signalfrom crossover distortion; and the operational amplifier circuit uses an operational amplifier AR3 to perform in-phase amplification of the signal and simultaneously filters the signal by employing aRC filtering circuit composed of a resistor R20, a resistor R21, a capacitor C8 and a capacitor C9 to send the signal to the remote control terminal of the broadband piezoelectric vibration energy collection system through an emitter E1 so as to collect the electric energy power signal frequency collected by the broadband piezoelectric vibration energy collection system in real time, perform automatic calibration of the signal and prevent the data signal from distortion.

A push-pull amplifier having low output impedance and low crossover distortion is provided. A least one of a current through a sourcing current path of an output stage and a current through a sinking current path of the output stage is determinative of a quiescent current control signal produced for controlling a quiescent current of the amplifier. The quiescent current is controlled by symmetrically controlling a bias voltage applied to a sourcing active output device and a bias voltage applied to a sinking active output device in response to the quiescent current control signal. An output stage sourcing control signal for controlling the sourcing active output device is referenced directly to a shared terminal of the sourcing active output device, and an output stage sinking control signal for controlling the sinking active output device is referenced directly to a shared terminal of the sinking active output device.

The invention discloses an industrial equipment operation monitoring signal adjusting circuit. The circuit comprises a frequency acquisition circuit, a separation switch circuit and a push-pull outputcircuit. The frequency acquisition circuit acquires analog signal frequency received by the industrial equipment operation monitoring control terminal. According to the separation switch circuit, a triode Q5, a variable resistor RW1, a capacitor C4 and a capacitor C5 form a synchronous separation circuit to divide a signal into two paths of signals with the same frequency and different amplitudes; a capacitor C2, a capacitor C3, an inductor L4 and a triode Q1 are used in one parth to form a frequency modulation circuit to adjust the signal frequency; in the second path, a diode D1, a diode D2and a capacitor C6 form a noise reduction circuit to reduce the signal-to-noise ratio; and finally, the push-pull output circuit uses a triode Q7 and a triode Q8 to form a push-pull circuit to prevent signal crossover distortion, and the signal is output after being stabilized by a voltage stabilizing tube D3, i.e., a compensation signal of an analog signal received by the industrial equipment operation monitoring control terminal, so that high-frequency component attenuation is overcome.

The invention discloses a dead zone pre-compensation method for the TNPC bidirectional converter of an alternating current-direct current hybrid micro-grid. Real-time judgment of a current vector based on a two-phase synchronous rotation d-Q rectangular coordinate system is used. In different three-level space vector regions, the given instruction reference space voltage vector is decomposed to determine the equation of the dead zone pre-compensation correction space voltage vector. A dead zone compensation factor is used to adaptively adjust the compensation depth to realize dead zone compensation of a power switching device in the converter. The method is characterized in that the method is realized by programming; the compensation depth is adaptively adjusted; the algorithm is easily realized through calculation and programming, which helps to quickly and easily realize accurate dead zone compensation; crossover distortion is eliminated; the waveform quality is improved; and the input current harmonics of the alternating current-direct current hybrid micro-grid are suppressed.

A testing method or apparatus utilizes filter banks to measure time varying or dynamic harmonic distortion or intermodulation distortion from a device. With a stairstep or arbitrary signal and filter banks, Nth order harmonic and or intermodulation distortion is measured via the filter banks at different offsets provided by an arbitrary low frequency signal. An amplifier with crossover distortion will show increased harmonic and or intermodulation distortion near the zero crossing while providing less distortion in other portions of the transfer curve of the amplifier. One or more distortion signals from the device (e.g., audio device) may be measured for a phase and or frequency modulation effect.

The invention provides an amplifier and a class AB amplifier. The amplifier comprises a first input transistor, a first impedance unit, a current source, a first push-pull output circuit and a first level shifting unit. The first input transistor receives a first input voltage. The impedance unit is coupled to the first input transistor. The current source is coupled to the first input transistor. The push-pull output circuit comprises a first PMOS transistor and a first NMOS transistor which are connected in series to output a first output voltage. The first input transistor is coupled to a control terminal of the first NMOS transistor. The level shifting unit is used for shifting a voltage of the first input transistor and providing a first shifted voltage to the PMOS transistor. The inventive amplifier and class AB amplifier are capable of amplifying an input signal in full wave to keep high power efficiency while eliminating crossover distortion.

The invention discloses a camera signal calibration system. The camera signal calibration system comprises a frequency acquisition circuit, a separation feedback circuit and a wave-limiting output circuit. The frequency acquisition circuit acquires the modulated analog signal frequency in the controller; according to the separation feedback circuit, a triode Q4, a variable resistor RW1, a capacitor C4 and a capacitor C5 form a synchronous separation circuit to divide a signal into two paths of signals with the same frequency and different amplitudes, one path of the signal is input into a noise reduction circuit consisting of an operational amplifier AR1, a diode D1 and a diode D2 to reduce the signal-to-noise ratio, and in the second path, a triode Q1 and a triode Q2 form a push-pull circuit to prevent signal crossover distortion; a triode Q3 is used for detecting the potential difference of the two paths of signals; finally, an operational amplifier AR2, a resistor R8 and a resistorR9 form a differential circuit to carry out differential processing on the signal; the wave-limiting output circuit uses resistors R11-R13 and a triode Q6 to form a wave-limiting circuit to limit a signal waveform and then inputs the signal waveform into a modulated analog signal in the controller, and the output signal is a compensation signal after the controller received the modulated analog signal.

A push-pull amplifier having low output impedance and low crossover distortion is provided. A least one of a current through a sourcing current path of an output stage and a current through a sinking current path of the output stage is determinative of a quiescent current control signal produced for controlling a quiescent current of the amplifier. The quiescent current is controlled by symmetrically controlling a bias voltage applied to a sourcing active output device and a bias voltage applied to a sinking active output device in response to the quiescent current control signal. An output stage sourcing control signal for controlling the sourcing active output device is referenced directly to a shared terminal of the sourcing active output device, and an output stage sinking control signal for controlling the sinking active output device is referenced directly to a shared terminal of the sinking active output device.

The invention discloses an intelligent reminding effective aerosol inhalation device for internal medicine nursing. The device comprises a frequency acquisition circuit, a feedback comparison circuitand a filtering emission circuit. The frequency acquisition circuit is used for acquiring analog signal frequency of a controller in the internal medicine nursing intelligent reminding effective aerosol inhalation device. The feedback comparison circuit uses a triode Q1 and a triode Q2 to form a push-pull circuit to prevent signal crossover distortion. Meanwhile, an operational amplifier AR1, a diode D2 and a diode D3 are used for forming a mean value detection circuit to extract mean value signals in signal waveforms, an operational amplifier AR4, a capacitor C4, a capacitor C5 and a capacitor C9 are used for forming a frequency selection circuit to limit the signals, and a capacitor C7, a capacitor C8 and resistors R16-R16 are used for the filtering transmitting circuit. And a resistor R18 forms a filter circuit to filter signal clutters, and the signal clutters are sent to a remote monitoring platform of the aerosol inhalation device through a signal emitter E1, so that the performance of the internal medicine nursing intelligent reminding effective aerosol inhalation device is guaranteed.

The invention discloses a current waveform method of a single-phase direct current-alternating current (DC-AC) inverter, which is realized on the basis of a closed loop control system of the single-phase DC-AC inverter. A compensation frame is arranged at the output end of a current loop regulator PI2, and the sum of the compensation frame and the output ultra-long range (ULR) of the regulator PI2 is used as the input of the next level. By the method for controlling the current waveforms, the crossover distortion of the current waveforms of the single-phase DC-AC inverter caused by dead time can be effectively restrained, so that the sine degree of output current waveform of the single-phase DC-AC inverter is improved, and the total harmonic distortion degree (THD) is reduced. The inverter can work in grid and off-grid and is suitable for converting various DC voltages into AC voltages.

The invention discloses a data signal distortion adjusting circuit. The circuit comprises a frequency acquisition circuit, a feedback calibration circuit and a voltage stabilization output circuit, wherein the frequency acquisition circuit acquires a low-frequency data signal received by a controller in the computer equipment; the feedback calibration circuit uses an operational amplifier AR1 anda capacitor C2 to form a noise reduction circuit, low frequency signal noise is filtered, one path of an output signal of the noise reduction circuit uses an operational amplifier AR2, a diode D2 anda diode D3 to form a detection circuit to filter a disturbance signal in the signal; in the second path, a triode Q4 and a triode Q5 form a push-pull circuit to prevent signal crossover distortion; and finally, the operational amplifier AR3 adds the two paths of signals and inputs the signals into the voltage stabilization output circuit. The voltage stabilization output circuit uses an operational amplifier AR4, an operational amplifier AR5, a capacitor C4 and a capacitor C5 to form a filter circuit to further stabilize signal potential output, and error correction can be carried out on low-frequency data signals received by a single-chip microcomputer port in a controller in computer equipment.

The invention discloses a water quality monitoring real-time early-warning system. The system includes a frequency collection circuit, a frequency modulation feedback circuit and a filter transmittingcircuit. The frequency collection circuit uses a frequency collector J1, of which a model is SJ-ADC, to detect water resource environment measurement data signal frequency received by a ground center. The frequency modulation feedback circuit receives output signals of the frequency collection circuit from two paths, a first path uses a triode Q1 and a triode Q 2 to form a push-pull circuit to prevent signal crossover distortion, a second path sues resistors R2- R4 and capacitors C2-C4 to form a frequency selection circuit to screen out single frequency signals, finally, a frequency modulation circuit formed by a triode Z3, a triode Z4 and resistors R8-R10 receives signals of the two paths and carries out frequency modulation, the filter transmitting circuit uses an inductor L2, a capacitor C7 and a capacitor C8 to form a filter circuit to filter out signal clutters. The water resource environment measurement data signal frequency received by the ground center can be detected in realtime, and converted into a water environment monitoring platform early-warning correction triggering signal.

The invention provides a loudspeaker box power amplification circuit, and belongs to the technical field of loudspeaker box power amplification. The loudspeaker box power amplification circuit has the advantages that the cost is low, the transmitted signals are not easy to distort, and the power can be amplified at multiple levels. The power amplification circuit comprises a signal input module, a voltage amplification module, an over-current protection module, a current amplification module, a signal output module and an over-load reminding module. The main components of the power amplification circuit are triodes; the conducting voltage of each triode at a low frequency band is relatively low, so that generated crossover distortion can be decreased to the lowest; and the triodes used in the current are easier to match, so that the circuit cost is reduced.

An electronically-enhanced cable of known characteristic impedance that is used to interconnect low level signals between the generating source and a pre-amplifier or amplifier with minimal noise-pick-up or cross-over distortion. The electronic enhancement means being integral with the cable and such that the voltage gain of the source signals is maintained at unity while the signal current is amplified 1000 or more times.

The invention discloses a low-voltage series fault arc detection system. The system comprises a voltage detection circuit, a signal conditioning circuit and an operational amplifier transmitting circuit, the voltage detection circuit collects low-voltage series fault arc voltage; the signal conditioning circuit uses an operational amplifier AR1, a diode D1 and a diode D2 to form a mean value circuit to screen out mean value signals. Meanwhile, a triode Q2 and a triode Q3 are used for forming a push-pull circuit to prevent signal crossover distortion; an input operational amplifier AR3 is arranged in the in-phase input end; an absolute value circuit is formed by an operational amplifier AR2, a diode D3, a diode D4 and an operational amplifier AR5; after being detected by a detection circuitconsisting of a silicon controlled rectifier VTL1 and a voltage stabilizing tube D5, the signal is input into an inverting input end of an operational amplifier AR3; and finally, an operational amplifier transmitting circuit uses an operational amplifier AR4 to amplify the signal in the same phase, the signal is transmitted to the arc detection system control terminal through a signal transmitterE1, and the signal is converted into series fault arc state detection through voltage change and directly transmitted to the arc detection system control terminal.

A testing method or apparatus utilizes a filter or modifier to measure time varying or dynamic harmonic, intermodulation, cross modulation, and or N-Beat or triple distortion from a device. With a stairstep or arbitrary signal and another signal, Nth order harmonic, cross modulation, triple beat, N-Beat, and or intermodulation distortion is measured via the filter or modifier at different offsets or time provided by an arbitrary low frequency signal. For example, an amplifier with crossover distortion will show increased (e.g., time varying) harmonic, cross modulation, triple beat, and or intermodulation distortion near the zero crossing while providing less distortion in other portions of the transfer curve of the amplifier. One or more distortion signals from the device (e.g., audio device) may be measured for a phase and or frequency modulation effect.

The invention discloses a power amplifier circuit powered by a single power supply based on an MOS transistor. The circuit comprises a power amplification circuit and an intermediate amplifier. The power amplification circuit is electrically connected with the intermediate amplifier, the power amplification circuit comprises a positive half-cycle power amplification circuit, a negative half-cyclepower amplification circuit and an impedance matching output transformer, and a class B single-power-supply transformer coupling push-pull power analog linear amplification circuit is formed by connecting power MOS single tubes or multiple tubes with the same characteristics in parallel; the intermediate amplifier comprises an output feedback detection circuit, a proportional integral differentiating circuit, a positive and negative half-cycle balance and crossover distortion correction circuit and a protected positive and negative half-cycle voltage follower circuit. The power amplifier circuit is directly installed in a power amplifier, a voltage type MOS tube is adopted as a power tube, a front end circuit is simple and reliable, universality is large, the size is small, reliability ishigh, power matching is simple, and the power amplifier circuit is particularly suitable for a broadcast power amplifier machine requiring alternating current and direct current, and full-power outputthe same as that of alternating current power supply is kept during direct current power supply.

A power device(s) is biased and operates in Class-AB. A purpose of the disclosed embodiments is to minimize crossover distortion over a broad range of operating conditions, not only for a nominal case. The bias current of a power transistor is automatically adjusted in response to process and temperature variations. Preferably, the adjustment is performed using an error-feedback arrangement. An exemplary ‘rule’ for bias adjustment involves satisfying a proportionality relationship between the small-signal device transconductance at the operating point, and a maximum device transconductance. The disclosed adaptive bias scheme utilizes a dual replica master-slave control architecture. A self-adapting circuit is provided to change the bias current (or voltage) so that the value is always the optimum value, irrespective of operating temperature and / or process variations. Self-biasing is introduced wherein no manual adjustment is necessary, thereby saving production or lab time. Amplifier robustness to process and temperature variations is improved, increasing yield.

The invention belongs to the technical field of electronics and audio amplification, and relates to a hearing-aid made of a TDA2822 (Tunnel Diode Amplifier). The hearing-aid comprises a direct current (DC) power supply, a power supply filter circuit, a constant current source and pickup circuit, an emitter follower, an audio signal regulating circuit and an integrated power amplification circuit. The hearing-aid is characterized in that the constant current source and pickup circuit is used as a power supply of a capacitor microphone (MIC), the emitter follower is used as a high-resistance amplification circuit, and the type of the integrated power amplification circuit (IC1) in a BTL (Bridge-Tied-load) mode application circuit is TDA2822M. The hearing-aid provided by the invention is formed by combining discrete components and the integrated power amplification circuit. The hearing-aid has the characteristics of simple circuit structure, fewer peripheral elements, little cross distortion, good tone quality, wide working voltage range, less static current and electricity consumption, output power capable of meeting the requirements on people with poor hearing, and the like, and is a hearing-aid attractive in price and quality, thereby solving or overcoming the problems of partial defects existing in some hearing-aids on the market, and the like.

The invention discloses an output amplifier comprising transistors and a field-effect transistor. A base of a first transistor serves as a signal output end, and a drain electrode and a source electrode of the field-effect transistor form a signal output end. The first transistor and a second transistor form a differential input electrode and a third transistor forms a high-gain intermediate amplifier to prevent signals from generating crossover distortion so as to influence output signal power. Negative feedback is utilized to increase gain, output power is large and application is convenient.