63results about How to "Control current" patented technology

The present invention relates to displays that use LED strings for backlighting. A lead string is provided with continuous drive voltage and the non-lead strings are provided with pulsed drive pulses. The string having the highest forward voltage is selected as the lead string. Feedback information indicative of the currents flowing through the non-lead strings is used to determine the duty cycles of the voltage pulses provided to drive the non-lead strings. The non-lead strings are controlled using pulsed drive voltages to minimize power dissipation in the circuit.

The invention relates to an LED constant current driving circuit which comprises a rectifying circuit (100), a decompression voltage stabilization circuit (200) connecting with a DC output end of the rectifying circuit (100), a constant current circuit (300) including a control module U2, a control circuit (400) using software to change and control the current output by the constant current circuit (300), and an LED load circuit (500); wherein the control circuit (400) comprises a singlechip U1 and a control switch S2; a current detection end of the control module U2 in the constant current circuit (300) is connected with a load, and a regulation end thereof is connected with the control circuit (400), so that constant current control can be provided for an LED. When differential pressure between input and output of the LED constant current driving circuit is high, stable and reliable current still can be output, and the output current can be controlled by the software, so that the LED constant current driving circuit is applicable to multiple application requirements, and has the advantages of simple circuit, higher electrical efficiency, and being beneficial to energy conservation and environmental protection.

A motor starter system comprises solid state switches for connection between an AC line and motor terminals for controlling application of AC power to the motor. A voltage sensor senses AC line voltage and the motor terminal voltage. Current sensors sense motor current. A control circuit controls operation of the solid state switches. The control circuit limits switch current during a start mode and detects a stall condition responsive to sensed AC line voltage and motor terminal voltage and selectively boosts motor current during the start mode if a stall condition is detected.

The invention relates to a low dropout regulator. The low dropout regulator comprises a feedback circuit, a reference voltage unit which is connected with the cathode of an error amplifier. A control end of a first on-element in the feedback circuit is connected with an output end of the error amplifier. An input end of the first on-element and an output end of the first on-element are respectively connected with a power supply and an output end of the regulator. A resistor branch and a circumscribed capacitor branch are connected between the output end of the regulator and ground in parallel. The resistor branch is provided with a first resistor and a second resistor. The first resistor and the second resistor are in series. The anode of the error amplifier is connected with the first resistor and the second resistor. The first resistor and the second resistor feed back signals. An output end of a second on-element is connected with the ground through a third resistor. An input end of the second on-element is connected with the output end of the regulator, and a control end of the second on-element is connected with the output end of the error amplifier. The problems that transmission voltage fluctuation is too large and stable time is too long caused by load current saltus step of the low dropout regulator are solved, static power consumption increase is reduced to a maximized degree, the circuit structure is simple, transient response speed and precision of low dropout regulator (LDO) circuits are greatly improved.

The embodiment of the invention discloses a charging control method applied to a terminal. The terminal comprises a body and a back cover. A rechargeable power supply is embedded in the body. The backcover is covered by an electrochromic film. The electrochromic film is electrically connected with the rechargeable power supply. The method comprises the steps that whether the electric capacity ofthe rechargeable power supply reaches a preset value is determined; if the electric capacity of the rechargeable power supply reaches the preset value, the rechargeable power supply is controlled to output preset current to the electrochromic film; and the electrochromic film adjusts the color of the electrochromic film according to the preset current. The invention further provides a terminal anda computer-readable storage medium. By implementing the scheme, on the basis that the rechargeable power supply efficiently uses the solar power, the safety of the power supply is fully ensured.

The present disclosure relates to a WDM-PON (wavelength division multiplexed-passive optical network) optical transmitter; and, more particularly, to a system for controlling driving current of the WDM-PON optical transmitter. The present disclosure provides a driving current control method of the optical transmitter for in use in the WDM-PON, including: setting an attenuation value of a variable optical attenuator to X; detecting an optical power Px received by a monitoring photo diode of the optical transmitter; setting an attenuation value of the variable optical attenuator to Y; detecting an optical power Py received by the monitoring photo diode of the optical transmitter; calculating an optical power Pout of an optical signal outputted from a common terminal of a 1×N optical multiplexer/demultiplexer based on the detected optical power Px and Py; and controlling a driving current based on the calculated optical power Pout.

The invention discloses a pressure regulating type arc robot additive forming system. The system adopts an arc pressure control method to achieve a controlled arc additive forming process through electric arc control, the structure of a welding gun is mainly improved, the appearance of the improved welding gun is roughly similar to that of a plasma arc welding gun. According to the additive forming system, a pressure regulating control type welding gun is arranged so that the pressure regulation can be achieved through the distance between a welding wire and a workpiece in the additive formingprocess, in addition, the diameter of the through hole of the welding gun in the system can be increased and reduced through feedback of voltage in real time, so that the shape of the output electricarc is controlled, then the transition form and the transition frequency of molten drops are adjusted, and finally the process control of the additive forming part is realized.

A digital to RF-conversion device that combines the D/A conversion function and the upconversion function by a RF-carrier or IF-signal. The device comprises a plurality of parallel unit cells, each of which is a mixer cell type converter having a differential data switch section connected in series to a differential LO-switch pair. The differential LO-switch is further connected in series to a current source. Each unit cell is adapted to receive a control voltage indicative of a data signal value.

A method and apparatus for controlling the speed of a DC electric motor receives a periodic commutation signal having a fixed duration on cycle and an off cycle. The commutation signal then is modified to form a periodic modified commutation signal having substantially the same period duration as the commutation signal. The modified commutation signal has a single on cycle per period. The method and apparatus then determine a desired speed of the motor, and vary the duration of the on cycle of the commutation signal to form the on cycle of the modified commutation signal. The on cycle of the modified commutation signal has a duration that is less than the fixed duration. By varying in this manner, the rotor rotates at substantially the desired speed.

Provided herein is an MV DRAM device capable of storing multiple value levels using an SET device. The device includes one or more word lines; one or more bitlines; a DRAM cell connected to intersections of the word lines and the bitlines; a current source transistor having a source connected to a power supply voltage and a gate and a drain connected to the bitlines; an SET (single electron transistor) device having a gate connected to the bitlines and a source connected to the ground voltage; and a transistor connected between the bitlines and the drain of the SET device, wherein the gate of the transistor is connected to the ground voltage. According to the MV DRAM device of the present invention, since two or more multiple value data are stored in a cell, it is possible to increase the storage density of the device. In addition, since the MV DRAM device only needs to enable the word lines in order to rewrite the data, thereby requiring only a small amount of current flow, it is suitable for a low-power application.

The invention discloses a constant current control method and a circuit of a multipath paralleled LED power supply. The method comprises the following steps: S100: presetting a current threshold and an MOS (Metal Oxide Semiconductor) voltage drop threshold; S110: opening an MOS tube; S200: detecting the current of each LED lamp bank, judging whether a current value is less than the threshold exists or not, if so, executing S300; and otherwise, executing S400; S300: controlling an AC-DC module to boost the LED lamp banks by using an optical coupling feedback control circuit to ensure that current values of all LED lamp banks are greater than the set current threshold; S400: carrying out current drop processing on the LED lamp banks the current values of which are greater than the set threshold by using a control module to ensure that the current value of each LED lamp bank is equal to the preset current threshold; and S500: carrying out voltage drop detection on the MOS tube of each LED lamp bank by using the control module, controlling the AC-DC module to reduce the direct current output voltage of the MOS tube the voltage drop of which is greater than the threshold and then executing the S200. By adopting the invention, the problems of the light equation and the light decay can be effectively solved and the efficiency of the circuit can be greatly improved.

The invention discloses an electromagnetic brake control circuit and an electromagnetic brake controller. The electromagnetic brake control circuit comprises an excitation coil, a control circuit and a switch circuit, wherein the control circuit outputs a brake turning-on signal or a brake keeping signal; the switch circuit receives the brake turning-on signal or the brake keeping signal, performs turning on or turning off, and controls the magnitude of currents passing the excitation coil; the excitation coil controls the armature of a brake to loosen a brake disc when the control circuit outputs the brake turning-on signal; the excitation coil controls the armature of the brake to be separated from the brake disc when the control circuit outputs the brake keeping signal. The electromagnetic brake control circuit has the advantages that the heat generation quantity of the electromagnetic brake is reduced by using the current control manner, and the service life of the brake is prolonged.

The invention discloses an SOC-based automobile electric power steering system assisting characteristic curve design method. Considering the battery SOC condition, the SOC is divided into three kinds,namely, SOC is smaller than 40%, SOC is larger than 40% and smaller than 70%, and SOC is larger than 70%; for the condition that SOC is smaller than 40%, segment treatment is performed correspondingto a curve assisting characteristic curve; for the condition that SOC is larger than 40% and smaller than 70%, secondary exponential smoothing is performed; for the condition that SOC is larger than 70%, primary exponential smoothing is performed. On the basis of considering electric power automobile battery energy management, the assisting characteristic curve is reasonably designed, the power-assisted steering performance can be remarkably improved, the phenomena that power supply of an assisted motor is not continuous due to the fact that torque of the hand changes rapidly or the hand torque operation is large, and then steering is difficult are avoided, it is ensured that a battery can generate stable electric energy output in various electric quantity stages so that steering assistance calculated by the assisting characteristic curve is stable, the assistance performance is improved to the maximum extent while assisting stability and safety are ensured, and energy is saved.

The invention provides a wireless charging device for an electric vehicle and an output control method thereof. The wireless charging device comprises a transmitting end and a receiving end, wherein the transmitting end is connected with a work frequency power supply and consists of a work frequency rectifying unit, a power factor correction unit, an inversion unit, a transmitting coil unit, a first communication unit and a first control unit; and the receiving end is connected with a battery system of the electric vehicle and consists of a receiving coil unit, a load compensation unit, a high frequency rectifying and filtering unit, a BOOST transformation unit, a second communication unit and a second control unit. The output control method comprises the following steps of: carrying out power-on and power-off control on the output power by the transmitting end, and carrying out continuous closed-loop control on output voltage or current by the receiving end according to the requirements of a battery system. The transmitting coil unit and the receiving coil unit are mutually coupled to carry out wireless energy transmission, and the first communication unit and the second communication unit are communicated in a wireless way.

The invention relates to a power supply device for an RF transmitter (5), that comprises at least one battery (2) and a capacitor (3) electrically connected in parallel between the battery (2) and the RF transmitter (5), and a voltage elevator (4') for charging the capacitor (3) to a storage voltage (Vc) higher than the voltage supplied by the battery during a first charging period, wherein the voltage elevator (4') includes an inductor (L) and a diode (D) in series as well as a switch (40') capable of periodically controlling, during the charging phase, the energy build-up in the inductor (L) followed by a transfer of the accumulated energy in the capacitor (3). According to the invention, the control signal (Sc) of the switch is predetermined and has a variable period so as to control, for each period: the closing of the switch (40') for a fixed calculated period so that the current in the inductor (L) may increase from a value equal to zero up to a predetermined limit value; the opening of the switch (40') for a duration that varies as a function of the voltage (Vc) of the capacitor (3), defined so that the current in the inductor (L) may decrease from said predetermined limit value down to a value equal to zero.

The invention discloses manufacturing equipment of an elevator guide rail support. The manufacturing equipment structurally comprises a left main support, a cooling device, a base, a discharging support, a first machining wheel box, a second machining wheel box, a machining conveying pipe, a right control main machine box, a back connecting support, a working state display lamp and a guide rail discharging opening; the base is arranged at the lower portion of the left main support, the left main support and the base are of an integrated structure, the interior of the base is of a solid structure, and the left main support and the base are of a C-shaped structure, and the working stability of equipment can be effectively improved; and when the water temperature is improved, the water amountand the air amount are improved, the equipment cooling power is improved, the water temperature falls, and the working reliability of the equipment is effectively improved.

The invention discloses a voltage regulator. The voltage regulator comprises an error amplifier, a first switch, a driving tube, an offset maintenance circuit and a feedback circuit; a first input endof the error amplifier receives reference voltage; the first switch is closed or disconnected under the control of a first control signal; a first end of the first switch is coupled with an output end of the error amplifier; a control end of the driving tube is coupled with a second end of the first switch; an output end of the driving tube outputs regulation voltage; an input end of the drivingtube is coupled with a power supply; a first end of the offset maintenance circuit is coupled with the input end of the driving tube; a second end of the offset maintenance circuit is coupled with thecontrol end of the driving tube; when the first switch is controlled to be closed, the offset maintenance circuit is charged/discharged by the error amplifier; when the first switch is controlled tobe disconnected, the offset maintenance circuit is suitable for providing offset voltage for the driving tube; the feedback circuit is coupled with the output end of the driving tube and is suitable for carrying out voltage division on the regulation voltage so as to output a feedback signal at a feedback node; and the feedback signal is transmitted to a second input end of the error amplifier. The voltage regulator is capable of greatly reducing the circuit power consumption, is simple in circuit and is capable of saving the layout area.

The invention discloses a single-tube-driven electromagnetic heating circuit in the field of electromagnetic heating. The single-tube-driven electromagnetic heating circuit comprises a filter capacitor C1, a magnet exciting coil L1, a resonance capacitor C2, an IGBT switch tube Q1, a sampling circuit, a single chip microcomputer circuit and a pushing circuit, wherein a negative electrode of the filter capacitor C1, a negative electrode of the resonance capacitor C2 and an emitting electrode E of the IGBT switch tube Q1 are connected and in ground connection; a positive electrode of the filter capacitor C1 is connected with a direct-current positive electrode, the magnet exciting coil L1 is in serial connection between a positive electrode of the filter capacitor C1 and a positive electrode of the resonance capacitor C2; the positive electrode of the resonance capacitor C2 is connected with a collector electrode C of the IGBT switch tube Q1, a grid electrode G of the IGBT switch tube Q1 is connected with the output end of the pushing circuit U1 through a current limiting resistor, the input end of the pushing circuit is connected with the output end of the single chip microcomputer U2, and the pushing circuit U1 can drive the IGBT switch tube to move. According to the single-tube-driven electromagnetic heating circuit disclosed by the invention, the resonance capacitor is in parallel connection with the collector electrode and the emitting electrode of the IGBT switch tube, so that voltage borne by the IGBT switch tube is effectively reduced when the IGBT switch tube is stopped in a work process; temperature control is easy to achieved, and the single-tube-driven electromagnetic heating circuit can be applied to varieties of electromagnetic heating equipment.

The invention discloses a control method for a three-level power amplifier. The power amplifier comprises a power switching bridge circuit with an upper bridge switching tube and a lower bridge switching tube, and an electromagnetic bearing coil Lm connected between the two switching tubes. The control method is characterized by comprising the following steps: (1) during charging, switching on/off the upper bridge switching tube under the control of a corresponding driving signal, and keeping the lower bridge switching tube in a switch-on state; and (2) during discharging, switching on/off the lower bridge switching tube under the control of a corresponding driving signal, and keeping the upper bridge switching tube in a switch-off state. According to the method, control over the current of the electromagnetic bearing coil is realized through adoption of different ways for adjusting the upper bridge switching tube and the lower bridge switching tube, so that a conventional way of controlling the upper and lower switching tubes with a phase inverter is changed, and the control way is simpler.

The invention provides a capacitor and a switch power supply AC-DC circuit , which are applied to a high voltage-resistant circuit. The capacitor comprises a silicon substrate, a first insulation layer, a metal conductive layer and a base plate of an arbitrary lead frame in the high-voltage resistant circuit, wherein one surface of the silicon substrate covers the fist insulation layer, the metal conductive layer covers the first insulation layer, the other surface of the silicon substrate is connected with the base plate, and the thickness of the first insulation layer is determined according to a voltage-resistant impact value of the capacitor and the dielectric strength of the first insulation layer. With the capacitor provided by the embodiment of the invention, the miniature requirement of the circuit can be met.

The invention discloses a power saving device of a water heater. The power saving device of the water heater comprises a controller, a power saving device body and the water heater. The controller is located below the power saving device body and electrically connected with the power saving device body. The controller is internally provided with a variable-frequency input unit, a relay and a variable-frequency output unit which are electrically connected. More than one external power line is arranged on the variable-frequency input unit. The water heater is located on the right side of the controller and comprises a cold water inlet, a heating ring and a hot water outlet, wherein the cold water inlet is formed in the lower portion of the water heater; a ceramic tube is arranged outside the heating ring; an electromagnetic coil is arranged outside the ceramic tube; the hot water outlet is located in the upper portion of the water heater. The power saving device of the water heater has the advantages that water is heated rapidly, power consumption is reduced and electric leakage is avoided.

The invention relates to an ignition circuit of a separately-excited arc lighter. The ignition circuit comprises a direct-current power supply, a square wave generating circuit, a first driving and voltage boosting circuit and a first discharging needle, wherein the first driving and voltage boosting circuit comprises a power switch tube and a high-voltage transformer, a winding of the high-voltage transformer consists of a low-voltage winding and a high-voltage winding, and the power switch tube and the low-voltage winding in the high-voltage transformer are connected in series and then are connected to the two ends of the direct-current power supply; the first discharging needle is connected with the output end of the high-voltage winding, and a first driving branch is connected between the output end of the square wave generating circuit and the control end of the power switch tube; the power switch tube is disconnected and connected under the control of the output of the square wave generating circuit through the first driving branch, so that the current on the low-voltage winding is controlled. Due to the adoption of the separately excited driving mode, the ignition circuit is stable in work frequency, low in noise, large in instant starting power, easy to realize arc striking and reliable in work. Besides, the winding of the high-voltage transformer only consists of the low-voltage winding and the high-voltage winding, so that the production cost and the defective rate of the high-voltage transformer are reduced, and massive production is facilitated.