701 results about "Hysteresis comparator" patented technology

High-efficiency envelope tracking (ET) methods and apparatus for dynamically controlling power supplied to radio frequency power amplifiers (RFPAs). An exemplary ET circuit includes a switch-mode converter coupled in parallel with a split-path linear regulator. The switch-mode converter is configured to generally track an input envelope signal Venv and supply the current needs of a load (e.g., an RFPA). The split-path linear regulator compensates for inaccurate envelope tracking by sourcing or sinking current to the load via a main current path. A current sense path connected in parallel with the main current path includes a current sense resistor used by a hysteresis comparator to control the switching of the switch-mode converter. The split-path linear regulator is configured so that current flowing in the current sense path is a lower, scaled version of the current flowing in the main current path.

A digital switching power amplifier with Multivariable Enhanced Cascade Controlled (MECC) includes a modulator, a switching power stage and a low pass filter. In the first preferred embodiment an enhanced cascade control structure local to the switching power stage is added, characterised by having a single local feedback path A (7) with a lowpass characteristic and local forward blocks B1 or B (3, 4). The leads to a much improved system with a very low sensitivity to errors in the switching power stage. In the second preferred embodiment of the invention the control structure is extended with a global structure composed of a single feed-back path C (8) and forward paths blocks D1 or D (1, 2). This provides further improvements and a very low sensitivity to load variations and filter errors. Both MECC embodiments are characterised by being simple in implementation, stable and extendible by adding / removing simple local (3) or global (1) forward path blocks. A third embodiment of the invention is a controlled self-oscillating pulse modulator, characterised by first a non-hysteresis comparator as modulator and second by a higher order oscillating loop realized in both forward path B1 and feedback path A to determine stable self-oscillating conditions. An implemented 250W example MECC digital power amplifier has proven superior performance in terms of audio performance (0.005% distortion, 115 dB dynamic range) and efficiency (92%).

A switching regulator includes a switching transistor, an inductor, a feedback voltage generator, a hysteresis comparator circuit, and a feedback loop circuit. The switching transistor alternately switches on and off. The inductor charges when the switching transistor is on. The feedback voltage generator generates a first feedback voltage by dividing an output voltage. The hysteresis comparator circuit has a voltage comparator to compare the first feedback voltage against a reference voltage to output a comparator output signal as a result of the comparison. The feedback loop circuit feeds the comparator output signal back to the feedback voltage generator to generate a second feedback voltage. The first feedback voltage has an alternating current component substantially dependent on the second feedback voltage varying with the comparator output signal.

An on-chip temperature control system includes a temperature sensor, which monitors a temperature of a chip, and a hysteresis comparator which checks whether the temperature is in an acceptable range. A reference adjustment circuit is responsive to the hysteresis comparator to adjust an on-chip voltage to control the temperature locally by adjusting a local supply voltage, if the temperature is out of range.

A power converting device includes a single-phase multiplex converter used as an active filter and a control device. The single-phase multiplex converter includes multiple single-phase inverters connected in series at AC output sides. Each of the single-phase inverters converts DC power fed from a DC power supply into AC power. The control device includes hysteresis comparators and controls output voltage of the single-phase multiplex converter by gradational output voltage control, based on the sum of selectively combined output voltages of the multiple single-phase inverters. The control device controls the single-phase multiplex converter so that an output current follows a harmonic compensation reference currents, canceling harmonics leaking from a load to which the power converting device is connected.

In a control circuit which turns on / off the switching device elements included in a synchronous rectifier step-down switching regulator, a hysteresis comparator compares the detection voltage that corresponds to the output voltage of the step-down switching regulator with a first threshold voltage and a second threshold voltage. A light-load detection circuit detects whether or not a load is in the light-load state. A driver circuit turns on / off the switching device elements according to the pulse signal output from the hysteresis comparator. Upon the light-load detection circuit detecting the light-load state, the hysteresis comparator shifts the second threshold voltage toward the higher-voltage side by a predetermined voltage difference.

A fast-settling digital automatic gain control circuit comprises first and second gain-controllable amplifiers in series. Each amplifier can be digitally switched between minimum and maximum gains by control logic that receives inputs from a multi-level voltage comparator. A peak detector connected to the output of the first gain-controlled amplifier is used to set the overall operating ranges for several threshold detectors. Four reference voltages are generated from the peak detector. The highest reference voltage is used to clock and reset the gain control logic with a hysteresis comparator to the instantaneous input signal from the first gain-controlled amplifier. The three other lower reference voltages are used to provide three-bits of digital input data to the gain control logic. Two digital controls are output, a min / max gain bit for the first gain-controlled amplifier, and a similar min / max gain bit for the second gain-controlled amplifier.

The invention discloses a three-level three-phase four-wire active power filter and a control method thereof. The filter comprises two capacitors, a three-level inverter bridge, a previous LC (inductance and capacitance) output filter, a posterior LC output filter and a grid-connected switch, middle points of the two capacitors are directly connected with a neutral wire of a power grid, the two capacitors are connected with three bridge arms of the three-level inverter bridge in parallel after being serially connected with each other, the three-level inverter bridge is a three-level diode-clamped type three-level inverter bridge, and an output end of the three-level inverter bridge is connected into a three-phase power source in a three-phase four-wire power source by the previous LC output filter, the posterior LC output filter and the grid-connected switch sequentially. The control method includes controlling the three-level three-phase four-wire active power filter by the aid of control of three control loops and a hysteresis comparator.

The invention discloses a rectification control circuit for a bidirectional CLLLC resonant converter. Both the primary side and the secondary side of the transformer in the bidirectional CLLLC resonant converter are connected to a current transformer, and the current on the power receiving side of the transformer is sampled, and It is converted into a voltage signal through a unit resistance, and connected to the inverting input terminals of two hysteresis comparators through a voltage sensor. The output signals of the two hysteresis comparators respectively drive the leading switch and the lagging switch on the power receiving side to realize MOSFET rectification. Since the on-resistance of the MOSFET is very small, the rectification control circuit for the bidirectional CLLLC resonant converter of the present invention reduces the rectification loss and improves the overall efficiency of the converter compared with diode rectification.

Various embodiments of the invention provide for single and dual phase charge pump, two stage DC / DC buck-boost converters having fast line and load transient control irrespective of load conditions. In certain embodiments of the invention, this is accomplished by controlling a desired output voltage with an error amplifier that controls a plurality of hysteresis comparators. A dual phase charge pump architecture eliminates ripple currents and mode transitions and increases efficiency by splitting the total current between two paths. Certain embodiments allow to use low voltage semiconductor devices, which significantly reduces switching losses and further increases efficiency.

In the motor drive apparatus, a Hall element outputs a first sinusoidal signal and a second sinusoidal signal, of mutually opposite phases, in accordance with rotor position. A hysteresis comparator compares the first sinusoidal signal and the second sinusoidal signal outputted from the Hall element, and outputs a rectangular wave signal. A pulse width modulation signal generation circuit detects timing at which phase switches, based on the first sinusoidal signal and the second sinusoidal signal outputted from the Hall element, and outputs a pulse width modulation signal in which duty ratio gradually changes, in a predetermined time-period in which the phase switches. A drive circuit combines the rectangular wave signal and the pulse width modulation signal by a logical operation, and drives the fan motor.

The present invention relates to the field of the driving circuit technology that is a power MOSFET driving circuit. The power MOSFET driving circuit includes a hysteresis comparator, a switch driving stage, an over-current protection circuit module, and the hysteresis comparator compares the externally controlled signals with the reference power level to determine the control signal obtaining the switch drive, and the switch drive stage circuit makes a drive output to the power MOSFET and the drain terminal voltage when the power MOSFET is conductive is induced into the input end of the over-current protection circuit to realize the over-current protection comparing to the standard. The input signal Vin is compared with the standard current Vref through the hysteresis comparator to judges and obtains the logically controlled signal Vol which controls the switch power stage together with the over-current signal Vx to realize over-current protection, and when Vx is a low level and the output level logic of the switch power level is identical to that of the Vol signal. The present invention is adapted to the integrated circuits such as the integrated switch power supply and the control circuit thereof.

The invention discloses a single-input hysteresis comparator circuit, comprising threshold voltage generating loop to generate threshold voltage and positive feedback branch to generate hysteresis voltage, where the positive feedback branch is composed of current source I3 and switch SW connected in series; the threshold voltage generating loop comprises PMOS tubes P1 and P2, NMOS tubes N3 and N4, and current sources I1 and I2; grid of the PMOS tube P1 is used as input end, drain of the PMOS tube P1 is earthed and source of the PMOS tube P1 is connected with source of the NMOS tube N3 and connected to the switch SW and the other end of the switch SW is connected with input end of the current source I3; grid and drain of the NMOS tube N3 are interconnected to grid of the NMOS tube N4 and output end of the current source I1; drain of the NMOS tube N4 is connected with output end of the current source I2, and source of the NMOS tube N4 is connected with that of the PMOS tube P2; grid and drain of the PMOS tube P2 are earthed; input ends of the current sources I1, I2 and I3 are all connected with power supply VDD. And it is designed to detect whether some voltage in a chip is overlow, and it has only one input end to input a voltage to be detected.

The invention relates to a temperature compensation method of a Hall switch based on a CMOS (complementary metal oxide semiconductor) technology and a circuit thereof. The method comprises the following steps: carrying out voltage stabilization and voltage offset on a power supply; and converting Hall voltage signals into single-terminal voltages and eliminating offset voltages as well as comparing processed voltage signals with a set threshold voltage in hysteresis, wherein temperature coefficients of the set threshold voltage are same as temperature coefficients of Hall mobility of a Hall chip. By using the method, temperature coefficients of a threshold voltage of a hysteresis comparator are same as temperature coefficients of electron mobility of a material which is used by the Hall chip, so that the temperature coefficients of the Hall mobility can be offset, thus the Hall switch can work in the temperature range of -40 to 150 DEG C. Compared with the prior art, based on the CMOS technology, fewer components are used in the method, thus the Hall switch can work normally in the wider temperature range.

The invention discloses an active thermal optimization control method and device of an electromobile driving system. The method comprises the following steps of calculating total loss of an inverter according to real-time data of the inverter; obtaining a first junction temperature value and a second junction temperature value of an inverter equivalent thermal resistance network according to the total loss and an inverter thermal resistance model; obtaining a first switching frequency according to the first junction temperature value, a first safe temperature limit value and a hysteresis comparator; simultaneously obtaining a second switching frequency according to the second junction temperature value, a second safe temperature limit value and the hysteresis comparator; and selecting the smaller one of the first switching frequency and the second switching frequency as the switching frequency of the electromobile driving system. According to the method, a current-type quasi-Z source inverter is adopted, and the problem of active thermal optimization control of the inverter on an actual heat constraint condition is solved by adjusting the shoot-through duty ratio of the inverter, the switching frequency and a control signal output from a space vector pulse width modulator.

The invention discloses a rotor-position sensor doubly salient motor system and a control method thereof, belonging to the field of doubly salient motor systems and the control method thereof. The system consists of a doubly salient motor, an excitation winding, a main power circuit and a control circuit, wherein, the main power circuit comprises a power supply and an IPM; and the control circuit comprises an isolation circuit, a failure detection circuit, a three-phase current sampling circuit, an excitation current sampling circuit, a PWM control circuit, an over-current and over-voltage protection circuit, an ADC module, a position detecting circuit, a rotation speed calculation circuit, a logic control circuit, a capture unit, a speed loop, a current loop, a hysteresis comparator and a PI regulator. The control method indirectly controls the current of the doubly salient motor by adopting a dual-loop control type of internal loop for current and external loop for rotation speed and comparing the given rotation speed for reference with the fed practical rotation speed. The method has simple system, firmer structure, reliable operation and high efficiency.

The invention relates to a pulse controller with six PWM (pulse width modulation), which belongs to the technical field of power electronics and automatic control. The PWM pulse controller is composed of a voltage comparator, an inertia link or an integrating link, a hysteresis comparator and the like. The PWM controller, a control object, feedback transformation and the like form a PWM pulse control system, the controlled variable of the control object outputs feedback variable through a feedback transformation link and outputs a pulse signal with control giving through the comparator, a triangle waveform signal is generated through the inertia link or the integrating link, and a PWM pulse control signal is generated through the hysteresis comparator and is acted on the control object to adjust the output variable. When conditions are changed or output pulse acts continuously to enable the feedback variable to deviate from a given target, the PWM controller outputs a pulse control signal, which enables the output of the control object to trace the given target. The PWM controller has simple and reliable structure, low cost, rapid system response, high efficiency and wide application value.

An input voltage is applied to an inverting input terminal of a comparator having no hysteresis. A first constant voltage is divided by resistors to create a reference voltage. The reference voltage is applied to a non-inverting input terminal of the comparator through a resistor. Only while an output voltage of the comparator is a low level, a predetermined constant current is supplied to a supply point of the reference voltage and a constant current of the same magnitude is absorbed from the non-inverting input terminal of the comparator.

In the motor drive apparatus, a Hall element outputs a first sinusoidal signal and a second sinusoidal signal, of mutually opposite phases, in accordance with rotor position. A hysteresis comparator compares the first sinusoidal signal and the second sinusoidal signal outputted from the Hall element, and outputs a rectangular wave signal. A pulse width modulation signal generation circuit detects timing at which phase switches, based on the first sinusoidal signal and the second sinusoidal signal outputted from the Hall element, and outputs a pulse width modulation signal in which duty ratio gradually changes, in a predetermined time-period in which the phase switches. A drive circuit combines the rectangular wave signal and the pulse width modulation signal by a logical operation, and drives the fan motor.

The invention discloses a parallel combined converter with multi-module input and serial output as well as a soft start control method thereof, belonging to the field of converter control. A circuit of the converter is formed by adding a current peak value suppression and input voltage-sharing control circuit and a switching pipe drive circuit on the basis of an original combined converter; the sampling voltage of output current is compared with a threshold value of a hysteresis comparator determined by given reference voltage and output to a logical OR-gate through a phase inverter; an inputvoltage sampling value is compared with a threshold level determined by the given reference voltage and then output to the logical OR-gate; when the output of the logical OR-gate is a high level, theswitching pipe is controlled to discharge a soft start capacitor of a drive chip so as to stop outputting drive signals and turn off modules; when the output of the logical OR-gate is a low level, theswitching pipe is controlled to be closed, and the soft start capacitor of the drive chip is charged so as to generate the drive signals and turn on the modules. The invention realizes current peak limiting and module input voltage-sharing, improves the reliability of the converter and reduces the cost.

The invention relates to a Hall switch circuit with temperature compensation, comprising a voltage stabilizer, a Hall induction sheet, a Hall voltage difference amplifier, a hysteresis comparator and an output unit, wherein the Hall induction sheet is connected between the output and an earth wire of the voltage stabilizer; two input ends of the Hall voltage difference amplifier are respectively connected with the Hall induction sheet; the hysteresis comparator is connected with the output end of the Hall voltage difference amplifier; and the output unit is connected with the input end of the hysteresis comparator. The Hall switch circuit is characterized in that the Hall voltage difference amplifier comprises a difference input pair, a current source and a load resistor, wherein the difference input pair consists of two transistors; the current source offsets the difference input pair and is directly proportional to absolute temperature; and the load resistor is respectively in series connected with the transistors of the difference input pair and is made from materials the same as that of the Hall induction sheet. The Hall switch circuit can eliminate the influence of microhenry temperature coefficient without special requirement for a process and is well controlled.

The invention discloses a high-performance rectifier diode replaced circuit which comprises a capacitor, a low-voltage clock generator, a charge pump circuit, a band-gap reference circuit, a hysteresis comparator, a driving amplifier and a power metal oxide semiconductor (MOS) pipe and is characterized in that the low-voltage clock generator detects voltages at two ends of a diode pipe and generates clock signals to drive the charge pump circuit; the charge pump circuit detects the voltages at two ends of the diode pipe and stores the charges in the capacitor after the charges are amplified; the voltage stored on the capacitor and the standard voltage output by the band-gap reference circuit are respectively output to the hysteresis comparator for comparison; and when the voltage stored in the capacitor is larger than the standard voltage output by the band-gap reference circuit, the hysteresis comparator outputs starting signals which are amplified by the driving amplifier and then output to the power MOS pipe to drive the power MOS pipe to be conducted. The high-performance rectifier diode replaced circuit can achieve equivalent diode working characteristics through a pulse working mode and can totally replace original selective beacon radar (SBR) devices in performance and dimension.

The invention relates to a device and a method for direct torque control of a permanent magnet synchronous motor, belonging to the technical field of alternating current motor transmission. The device comprises the permanent magnet synchronous motor, a signal detecting circuit, a processor and an inverter. A current signal and a direct current bus voltage signal of the permanent magnet synchronous motor are respectively output to the signal detecting circuit which transmits the signals to the processor for processing so as to obtain a switch signal which is transmitted to the inverter for controlling the motor. According to a stator flux linkage amplitude error and an electromagnetic torque error, the device and the method respectively estimate a reference voltage vector in a stator rotating coordinate system, then convert the reference voltage vector into a stator biphase static coordinate system, and finally utilize a space vector modulation method to generate the switch signal for the inverter so as to control the permanent magnet synchronous motor. The device and the method adopt the space vector modulation method and substitute a proportional controller for a conventional hysteresis comparator so as to effectively reduce the pulsating movement of flux linkage and torque. The method adopted for voltage vector estimation is simple so that the structure of the control system can be simplified and easily realized.

The invention belongs to electronic technology, is applied to the technical field of aviation electronics, and particularly relates to a frequency signal acquisition circuit with an adaptive threshold. The acquisition circuit comprises a clamping circuit, a filtering circuit, a comparison circuit, a threshold generation circuit and a digital shaping circuit, one branch of an inputted engine rotating speed signal of an input is insulated and clamped and then connected to a negative input end of the comparison circuit, the other branch is connected on the threshold generation circuit, and an output of the threshold generation circuit is connected at a positive input end of the comparison circuit. The acquisition circuit has the advantages that an acquisition circuit of a traditional engine rotating speed signal acquires, restrains and interferes signals through a hysteresis comparator, and the acquisition circuit solves the problems of fixed threshold of the acquisition circuit of the traditional engine rotating speed signal and poor interference resistance. The acquisition circuit can automatically change a comparison threshold of the hysteresis comparator according to change of an amplitude of the engine rotating speed signal of the input, and the interference resistance of an interface circuit is improved.

The invention discloses a direct torque control method for a brushless direct current motor. By speed and torque double closed loop control, a rotating speed loop is used as an outer loop, and a torque loop is used as an inner loop; motor speed is calculated according to an output signal of a Hall sensor of the brushless direct current motor, and the motor speed is compared with reference speed to obtain speed error; an output value obtained after fuzzy self-adaptation adjustment is used as a torque expectation value; torque error is obtained by subtracting actual torque from expectation torque, wherein the actual torque is calculated by multiplying back-EMF (Electromotive Force) and phase current; the torque error is inputted into a hysteresis comparator; the hysteresis comparator outputs a position signal of a rotor; and an appropriate voltage vector is selected from a formulated switch list to control an inverter bridge connected with a DC power supply so as to make the brushless direct current motor output stable torque. By the method, the defect that current hysteresis control has a poor effect of inhibiting electromagnetic torque is avoided, and the problem that a traditional PID control method has low precision and poor anti-jamming capability in control of BLDCM is overcome.