52results about How to "Realize constant current control" patented technology

The invention relates to a non-contact power supply primary circuit with a current expanding function. The non-contact power supply primary circuit comprises an inverter and a primary coil, wherein a primary compensating circuit is connected between the inverter and the primary coil. The primary compensating circuit comprises a first inductor, a first capacitor and a second inductor, wherein one end of the first inductor is connected with the output anode end of the inverter, the other end of the first inductor is connected with one end of the first capacitor and a first end of the second inductor, a second end of the second inductor is connected with one end of the compensating circuit through the primary coil, and the other end of the compensating circuit is connected with the other end of the first capacitor and the output cathode end of the inverter. The compensating circuit compensates inductance in the primary coil, and a resonance circuit is formed between the compensating circuit and the primary coil to enable the first inductor, the first capacitor and the second inductor to form the circuit with the current expanding function. The non-contact power supply primary circuit with the current expanding function can achieve constant control of currents of primary cables, has the current expanding function and is wide in application range and safe and reliable.

The invention discloses a back light source drive circuit directly driving a lamp strip circuit by using a primary half-bridge resonance circuit. The back light source drive circuit comprises a primary resonance circuit, a secondary lamp strip circuit and an optical isolating feedback circuit having an optical coupling feedback function, wherein the primary resonance circuit generates a driving pulse signal according to the received external voltage and a current signal fed back by the optical isolating feedback circuit, and provides needed work voltage for the secondary lamp strip circuit according to the driving pulse signal; and the optical isolating feedback circuit samples the loaded current in the secondary lamp strip circuit in real time, and feeds back the current signal to the primary resonance circuit. The back light source drive circuit directly lightens and controls the back light source by using the primary half-bridge resonance circuit; and optical coupling is used as the feedback control from the secondary level to the primary level. The drive circuit is simplified so as to eliminate a secondary side LED driving chip, and reduce device number of the whole system.

The invention discloses an LED (Light Emitting Diode) constant-current driving circuit. The LED constant-current driving circuit comprises a voltage reference unit which is used for generating the reference voltage, a peak current detection keeping unit, an error amplifier unit, a current comparator unit, a demagnetization detection unit and a self-adaptive unit. According to the LED constant-current driving circuit disclosed by the invention, the LED constant-current control can be realized, the service life of an LED can be prolonged, the problem of CTR (Current Transmission Rate) attenuation of an optical coupler is overcome as the circuit is free from an optical coupler device, the stability of the circuit is increased, the EMI (Electro Magnetic Interference) and the harmonic distortion can be greatly improved as the switching frequency of a power switching tube of the circuit is a variable frequency, an external circuit can be greatly simplified by adopting the circuit, and the using cost can be greatly reduced.

The invention provides an LED driving circuit applicable to a silicon controlled rectifier light modulator, and a control circuit thereof. The control circuit comprises a light modulation phase detection circuit, a phase filtering circuit connected with the light modulation phase detection circuit, a non-linear reference circuit connected with the phase filtering circuit, a zero cross detection circuit in direct or indirect coupling with an output end of the LED driving circuit, an output current simulation circuit connected with the zero cross detection circuit, an average current ring adjusting circuit connected with the non-linear reference circuit and the output current simulation circuit, a reset circuit connected with the average current ring adjusting circuit, an interrupted time-delay circuit connected with the phase filtering circuit, and a main driving circuit connected with the reset circuit, the interrupted time-delay circuit and the zero cross detection circuit. The control circuit can realize high power factor single-stage light modulation and has advantages of no scintillation and good compatibility.

The invention provides a driving control system with multiple LED (light emitting diode) loads for an automobile. The driving control system comprises a first power supply unit, a second power supply unit and a control unit, wherein the first power supply unit and the second power supply unit are both provided with a sampling unit and are used for providing load voltages to respective load based on the switching conditions of the respective controlled switch unit; and the control unit is used for outputting a balance signal for controlling a constant unit in the first power supply unit and a switch control signal for regulating and controlling the switching frequency of each controlled switch unit based on the sampling result of each sampling unit, wherein the constant unit is used for converting the direct current voltage output by the first power supply unit into a corresponding load voltage and regulating the corresponding load voltage based on the balance signal, so that the power supplied for each load is kept constant, and the sampling units are used for collecting the voltage signal of each controlled switch unit and the power supply signal of each load. According to the system, the voltage of each load can be kept stable.

Provided is an induction type wireless power supply system double-closed-loop constant output current control method. The method comprises outer-loop controlling and inner-loop controlling. The outer-loop controlling comprises the steps that based on a short time fourier transformation method, real-time processing is carried out on output voltage and output current signals of a primary side high-frequency inverter, an equivalent impedance of a resonance circuit is calculated, it is judged whether an impedance phase-angle is in a threshold value range or not, if the impedance phase-angle exceeds a threshold value, an automatic frequency adjusting module is started, calculation is repeated, and the equivalent impedance of the primary side resonance circuit is judged until a system works in a resonance state. The inner-loop control comprises the steps that an input voltage theoretical value of the high-frequency inverter is calculated and corrected, and is used as an input voltage reference value of the inner-loop controlling. According to deviation of the input voltage reference value and a measuring value (actual input voltage of the high-frequency inverter), real-time calculation is carried out, a duty ratio of a switch signal of the deviation is removed, and a corresponding switch pulse signal is output. According to double-closed-loop constant output current controlling, energy output of an induction type wireless power supply system can be effectively controlled, and the wireless electric energy transmission quality is improved.

The invention relates to a compensation circuit for stabilizing the output current of a phase shift resonance soft switching inverter. In the scheme, a Hall sensor or current diverter is eliminated, the control circuit is simplified, the interference introduced by the traditional sampling circuit is eliminated, the system response time is reduced, and the output constant-current characteristic ofthe inverter is improved. The compensation circuit mainly comprises a leading leg pulse generating and regulating circuit, the pulse output terminal of the leading leg pulse generating and regulatingcircuit is respectively connected with a driving pulse sampling circuit, a lagging leg pulse generating and regulating circuit and an amplifying and isolating circuit, the driving pulse sampling circuit is connected with a compensating circuit, the compensating circuit is connected with a current given filtering circuit, and the compensating circuit is connected with an input current given signalVg; and the current given filtering circuit is respectively connected with the leading leg pulse generating and regulating circuit and the lagging leg pulse generating and regulating circuit, and thelagging leg pulse generating and regulating circuit is also respectively connected with the driving pulse sampling circuit, the current given filtering circuit and the amplifying and isolating circuit.

The invention relates to a high power factor non-electrolytic capacitance LED driving power supply and a control method thereof. The high power factor non-electrolytic capacitance LED driving power supply comprises a rectifier circuit, a two-circuit interleaved parallel-connected Boost circuit, an auxiliary circuit and an LED load; the two-circuit interleaved parallel-connected Boost circuit worksin a current discontinuous mode to realize a power factor correction function and constant current control; the auxiliary circuit is used for balancing the difference between the alternating currentinput instantaneous power and the direct current output instantaneous power, then use of large capacity electrolytic capacitance is avoided, film capacitance can be used instead of the electrolytic capacitance, and the non-electrolytic capacitance LED driving power supply is realized; and through coordination control of the interleaved parallel-connected Boost circuit and the auxiliary circuit, low ripple output and constant current control of the LED load can be realized.

The invention provides a constant current control device, method and system for electromagnetic valve. The device comprises a control chip, a driving module, a current sampling module and a current conversion module, wherein the control chip is an original data processing chip of equipment of a to-be-controlled electromagnetic valve, and the current sampling module and the current conversion module are used for representing a digital current signal of an actual current value passing through the to-be-controlled electromagnetic valve and transmitting the digital current signal to the control chip; the control chip is used for generating a corresponding target PWM control signal according to a preset target current value and the digital current signal, generating a driving signal according to the target PWM control signal and transmitting the driving signal to the driving module; and the driving module is used for transmitting a current with the corresponding output current value to theto-be-controlled electromagnetic valve according to the driving signal from the control chip, wherein a difference value between the output current value and the target current value is within a preset target current error range. According to the scheme, the cost for constant current control of the electromagnetic valve can be lowered.

The invention discloses a compensating chain realizing a stable current output of a power supply of an inverter welder, which includes a pulse width modulator U1, wherein a pulse output terminal of the pulse width modulator U1 is connected with a drive pulse filter circuit; the drive pulse filter circuit is connected with the compensating chain; the compensating chain is connected with a current given filter circuit; the current given filter circuit is connected with an incoming current given signal Vg; meanwhile, the compensating chain is connected with a controlling end of the pulse width modulator U1. The compensating chain realizing a stable current output of a power supply of an inverter welder is characterized in that a Hall sensor or a shunt is saved; a controlling circuit is simplified; interruptions caused by a traditional sample circuit are eliminated; system responding time is accelerated; power supply output constant current characteristic is improved.

The invention discloses a current control circuit, which acquires current information on the output side of a bidirectional converter by means of a current sampling circuit, uses the outputs of a first voltage regulating circuit and a second voltage regulating circuit as the input of an error amplifier, regards the output of the error amplifier as the input of an optocoupler feedback circuit, feeds back a current signal on the output side into a PWM circuit through conversion processing by means of various levels of circuits, controls a duty ratio of a switching tube on the input side of a main power circuit by means of a control circuit, and realizes constant current of on the output side. The current control circuit can ensure that the bidirectional converter has no current oscillation and current spike when the bidirectional converter switches an operating direction, can realize the constant current on the output side of the bidirectional converter when only using one forward bandgap voltage reference source, and is simple in circuit.

The invention relates to the technical field of semiconductor detection equipment, in particular to a narrow-pulse high-current constant-current source and a control method thereof. A logic controllerFPGA is arranged to drive NMOS of a short-circuit branch through push-pull driving to improve the slope of pulse rising and falling edges, an SPI interface is connected with a digital-to-analog converter DA to control the output voltage, a current signal is output through operational amplifiers of a mirror current source, an MOSFET driver is controlled through multiple IO ports to connect or disconnect the short-circuit branch, meanwhile, the short-circuit branch is provided with a clamping circuit in a matched manner, so that the impact on the mirror current source is reduced, the overshootof narrow pulses is reduced, and finally, the current is output to a tested component through multi-path parallel connection. According to the invention, the load current is dispersed to more components through parallel branches, so that the heating value of an MOSFET can be effectively reduced; and by arranging the short-circuit branch, the limitation of the slew rates of the operational amplifiers on the narrow pulse transition process is eliminated, and by arranging multiple paths of parallel circuits and a clamping circuit, narrow pulse large-current constant-current control of an approximate ideal waveform is realized.

The invention relates to the technical field of constant current detection and control, in particular to a BUCK type DCDC output constant current detection and control circuit and method, comprising an input voltage compensation network, an output voltage dividing network, an input current sampling network, a loop control circuit and a step-down type circuit. The input voltage compensation networkis connected with an output voltage dividing network, the output voltage dividing network and the input current sampling network are connected with a loop control circuit, the step-down type circuitis connected with an input current sampling network and a loop control circuit, As that input current is detect and the input voltage compensation network is introduced at the same time, the output constant current control is realized, the input voltage and the output voltage are compensated, the influence of the offset factors such as the inductance value, the sample-and-hold, the capacitance, the charge injection and the buffered operational amplifier and the like is not exist, the structure is simple, additional control logic and the sample-and-hold circuit are not provided, and the precision is high.

The invention provides a primary side constant current controlled quasi single-stage high power factor circuit and device. The circuit comprises a rectifier bridge, an input capacitor, an inductor, a bus capacitor, a first diode, a switching tube, a second diode, a sampling resistor and a transformer, wherein the first end of the inductor is connected with the first end of the input capacitor, and the first end of the bus capacitor is connected with the second end of the inductor; the anode of the first diode is connected with the second end of the bus capacitor, and the cathode of the first diode is connected with the negative output end of the rectifier bridge; the first power end of the switching tube is connected with the second end of the inductor, and the control end of the switching tube receives the external driving signals; the anode of the second diode is connected with the second power end of the switching tube, and the cathode of the second diode is connected with the negative output end of the rectifier bridge; the first end of the sampling resistor is connected with the second power end of the switching tube, and the dotted terminal of the primary side winding of the transformer is connected with the second end of the sampling resistor; and the non-dotted terminal of the primary side winding of the transformer is connected with the second end of the bus capacitor, and the transformer is coupled with a load. The circuit provided by the invention has the advantage of lower cost compared with the traditional two-stage circuit, and has the advantage of reduction in ripple current of the load compared with the traditional single-stage circuit.

The invention provides a direct-current solid-state circuit breaker. The direct-current solid-state circuit breaker comprises a switching circuit, a freewheeling inductor and a freewheeling capacitor;the switching circuit comprises an IGBT, two first switching diodes and two second switching diodes; one end of the freewheeling inductor is connected with the first end of the switching circuit; theother end of the freewheeling inductor is connected to the anode of the direct-current bus end of the direct-current solid-state circuit breaker; one end of the freewheeling capacitor is connected tothe anode of the direct-current bus end; the other end of the freewheeling capacitor is connected to the cathode of the direct-current bus end and the cathode of an energy source end. Therefore, a freewheeling circuit can maintain an approximately stable current value at the direct-current bus end, and realizes the constant current control of the direct-current bus end; and the controller can monitor the state of a direct-current circuit where the direct-current bus is located according to the current and/or voltage of the direct-current bus end, determine whether the direct-current circuit where the direct-current bus is located is in a fault state all the time, and determine whether to control an IGBT to be in an off state all the time so as to achieve a selective protection function.

The invention relates to the technical field of a welding machine, particularly a PWM pulse width type constant current charging type capacitor energy storage welding charging control system. The charging control system comprises a three-phase charging transformer, a single-phase charging transformer, a rectifying circuit, a DC-LINK filtering circuit, a PWM charging control part, a charging current detection part, a welding transformer, a discharging circuit, a discharging switch-off circuit, a discharging current detection part, a discharging control part and a capacitor bank; no matter the input power supply is in single phase or three phases, the input power supply can be controlled by the same controller; by adoption of the PWM pulse width modulation mode the precision can be improvedby 10 times or more (counted by 1,000HZ) compared with an SCR adjustment mode; by adoption of a hall current sensor, the charging current can be sampled in real time, and then the PWM pulse width is adjusted, thereby realizing constant current control; and charging and discharging are both realized by adopting the welding transformer, and the charging current direction and the discharging currentdirection are opposite, so that magnetization of the transformer can be prevented effectively.

The invention provides a resistance torque real-time adjusting method. The method comprises a test link and an application link. In the test link, the control module obtains, establishes and stores a corresponding relation table of the rotating speed, the current and the torque; in the application link, the control module receives a target torque instruction, and the target torque instruction comprises a target resistance torque; monitoring the real-time rotating speed of the resistance wheel; according to the corresponding relation table, the target torque instruction and the real-time rotating speed, a regulation and control current is calculated; regulation and control current is input into the electromagnet, and real-time adjustment of resistance torque is achieved. And when the rotating speed of the resistance wheel changes, the control module can recalculate the regulation and control current to keep the target resistance torque constant. Therefore, the resistance torque can be accurately adjusted in real time, the method is suitable for various electromagnetic control resistance wheel products, each electromagnetic control resistance wheel product has an independent product characteristic table (a corresponding relation table of rotating speed, current and torque), and the resistance torque does not need to be adjusted by adopting average data of a plurality of electromagnetic control resistance wheel products.

The invention relates to the technical field of LED drivers, in particular to a driving circuit based on a flyback conversion power supply. The technical problem that a driving circuit in the prior art is greatly influenced by temperature variation is solved. The driving circuit mainly comprises an LED set circuit, an error amplifying circuit, a supply voltage control circuit, a reference voltage source and a closed loop connection circuit. The LED set circuit comprises an LED lamp bead assembly and a heat conducting rod, the LED lamp bead assembly is installed on the outer wall of the heat conducting rod, and heat conductors are installed at one or two ends of the heat conducting rod.