45results about How to "Good constant current effect" patented technology

The invention discloses a control circuit and a control method of a primary side feedback constant current of a constant current actuator of an alternating current-direct current (AC-DC) light-emitting diode (LED). The control circuit comprises a power switch tube, a secondary current sampling circuit, an error amplifier, an integrator and a pulse width modulator, wherein the power switch tube controls the work of primary inductance in a discontinuous working mode, the secondary current sampling circuit takes samples of demagnetizing time of a secondary winding and the current peak value of the primary inductance through a primary side auxiliary winding and generates feedback signals corresponding to the average value of a secondary current in each switching period based on the demagnetizing time and the current peak value, the error amplifier amplifies the errors between reference voltage and the feedback signals of a sampling circuit of the secondary current, the integrator carries out integration on the value amplified by the error amplifier, and the pulse width modulator generates pulse width modulation signals to control the power switch tube to work based on the signals output by the integrator. The control circuit and the control method of the primary side feedback constant current improve a constant current effect of output currents, and achieves high-precision constant current control with high power factor control.

The invention relates to a light-emitting diode (LED) dimming driving system with a silicon controlled bypass dimming circuit. The LED dimming driving system with the silicon controlled bypass dimming circuit comprises an alternating current / direct current (AC / DC) LED constant current actuator and a LED light string, wherein the input end of the AC / DC LED constant current actuator is electrically connected with an alternating current electric supply, the output end of the AC / DC LED constant current actuator is connected with the LED light string, the silicon controlled bypass dimming circuit is arranged, the input end of the silicon controlled bypass dimming circuit is connected with the alternating current (AC) electric supply, and the output end of the silicon controlled bypass dimming circuit is connected with a dimming interface of the AC / DC LED constant current actuator. The AC / DC LED constant current actuator obtains energy from the AC electric supply, and outputs a constant current value to drive the LED light string. The AC / DC LED constant current actuator is provided with an analog dimming interface which is used for adjusting an output current value according to an analog voltage amplitude value of an input dimming signal so as to change luminance of the LED light string. According to the silicon controlled bypass dimming circuit, the input end of the silicon controlled bypass dimming circuit is connected with the AC electric supply, and the output end of the silicon controlled bypass dimming circuit generates a smooth direct current analog voltage signal to serve as a dimming signal which is input into the analog dimming interface of the AC / DC LED constant current actuator. The value of amplitude of the dimming signal output by the silicon controlled bypass dimming circuit can be adjusted by adjusting an adjustable knob of the silicon controlled bypass dimming circuit, and thus a current value and the luminance of the LED light string can be adjusted.

The invention relates to a high-efficiency LED constant current driving circuit. The circuit comprises an input rectification filter circuit, a switch power supply management chip, an isolation switch transformer, a primary clamping circuit of the transformer, an output rectification filter circuit, an output current sampling circuit, a reference voltage generation circuit, a comparison circuit and a photoelectrical coupling circuit, wherein the input end of the input rectification filter circuit is connected with commercial AC electricity, while the output end is connected with a primary winding of the isolation switch transformer through the switch power supply management chip; the primary clamping circuit of the transformer is connected in parallel with the primary winding of the isolation switch transformer; the input end of the output rectification filter circuit is connected with the primary winding of the isolation switch transformer, while the output end is connected with LED load; an output current sampling circuit is connected in series with the LED load; the input end of the reference voltage generation circuit is connected with the LED load; and the input end of the comparison circuit is connected with the output current sampling circuit and the reference voltage generation circuit, while the output end is connected with the switch power supply management chip through the photoelectrical coupling circuit. The circuit improves the circuit integration degree, the reliability, the constant current precision and the circuit conversion efficiency.

The invention discloses a constant current DC (Direct Current)-DC converter utilizing digital PWM (Pulse-Width Modulation) control and a constant current LED (Light Emitting Diode) drive DC-DC converter. The constant current DC-DC converter utilizing digital PWM control comprises a power level and a digital PWM control level which are electrically connected, as well as a constant current control level electrically connected with the power level and the digital PWM control level respectively. The constant current DC-DC converter utilizing digital PWM control and the constant current LED drive DC-DC converter disclosed by the invention can overcome defects in the prior art, such as complex structure, high cost, large power consumption and low conversion efficiency, so as to realize the advantages of simple structure, low cost, small power consumption, good constant current effect and high conversion efficiency.

The invention provides an SOI lateral constant current diode and a manufacturing method thereof, belonging to the technical field of semiconductor power devices. The SOI lateral constant current diode is formed by interdigitated connection of multiple cells with the same structure, and the cells include a substrate, a buried oxide layer, an N-type lightly doped silicon, a P-type heavily doped region, and an N-type heavily impurity region, oxide dielectric layer, metal cathode, metal anode, P-type doped region; the P-type heavily doped region is located between the N-type heavily doped region and the P-type doped region, and the P-type heavily doped region and the N-type The heavily doped region is in ohmic contact with the metal cathode, the P-type doped region is in ohmic contact with the metal anode, and the N-type lightly doped silicon between the P-type heavily doped region and the N-type heavily doped region passes through the oxide dielectric layer and the metal cathode isolation. The invention adopts SOI technology, which can effectively prevent the adverse effects brought by the substrate leakage current in the integrated system; at the same time, it adopts double-carrier conduction, which increases the current density of the device, makes the linear region of the device steeper, and the pinch-off voltage is in the Within 5V.

The invention discloses a novel LED constant-current drive circuit. The novel LED constant-current drive circuit comprises an alternating current input end, a rectifier module, a filtering module with the power factor correction function, a current amplifying module and an output module, wherein the alternating current input end, the rectifier module, the filtering module, the current amplifying module and the output module are connected with one another in sequence. The current amplifying module comprises a current-limiting resistor and two triodes, wherein the current-limiting resistor and the two diodes are sequentially connected between the two electrodes of the current amplifying module. A constant-current control module is further arranged on the drive circuit. The constant-current control module comprises a field-effect tube. A source electrode of the field-effect tube is connected with base electrodes of the two triodes. A control grid electrode of the field-effect tube is connected between the current-limiting resistor and the two triodes. The LED constant-current drive circuit has the function of automatically conducting feedback and control according to changes of an output current, the output current can be automatically adjusted through feedback and control, a current which is outputted to flow through an LED can be constant, the constant-current effect is good, the long service life of an LED lamp can be ensured, and the LED constant-current drive circuit is economical and good in use effect.

The present invention provides a constant current diode, comprising: a substrate; an epitaxial layer formed on the substrate; a first doped region formed between the substrate and the epitaxial layer; formed on the epitaxial layer The second doped region, the third doped region and the fourth doped region; the first positive electrode formed on the surface of the third doped region and the first positive electrode formed on the surface of the second doped region and the fourth doped region The second positive electrode on the surface of the impurity region; the negative electrode formed on the back of the substrate; wherein, there are several first doped regions arranged side by side in the first direction between the third doped region and the fourth doped region. Two doped regions; the first doped region is in contact with the second doped region. The invention also provides a manufacturing method of the constant current diode. In the constant current diode and its manufacturing method provided by the present invention, a constant current diode with side gate plus bottom gate JFET structure is formed, its constant current value mainly depends on the distance between the second doped regions, and its constant current performance is good.

The invention discloses an LED light supplement control circuit used for a roller-shutter-type shutter exposure camera. The circuit comprises a light supplement lamp source, a power supply circuit portion and a control circuit portion. The power supply circuit portion comprises a rectifier B, a flyback switch conversion circuit K and an output filtering energy storage capacitor C13 which are successively connected. The control circuit portion comprises a flyback switch conversion control circuit DL1, a low voltage conversion direct current circuit DL2, an output voltage control circuit DL3, a power control circuit DL4, a MAX485 conversion circuit DL5, a single chip microcomputer control circuit DL6 and a trigger logic circuit DL7. The circuit has advantages that a trigger response speed is rapid; a constant current effect of a LED light source is good; and constant bright power of an LED light supplement lamp source and high light power during a light supplement process can be set.

This invention discloses a uniform and constant current method for parallel democratic bus, which compares current signals of constant branches with bus mean value and suppresses the branches with current exceeding the mean value, and carries out constant control to the general current by the constant current branches to reach the aim of mean distribution of the branches and constant general current, at the same time, the branches have their independent protection circuit and common indication to fault.

The invention discloses a novel scheme of electronic circuit design and application. The invention has the core contents that a common three-end adjustable voltage stabilizing device is applied to a constant-current circuit of an automobile ignition module and the obtained product is matched with a small amount of passive devices to replace a conventional automobile ignition module constant-current circuit so as to enable the circuit to be more simple and reliable; in the working process, the constant-current performance is more stable and the temperature characteristic is better. The scheme can be used for various types of ignition module constant-current control circuits and also can be suitable for ignition module circuits of which the output levels adopt power tubes (darlington tubes or IGBT ((Insulated Gate Bipolar Transistor)) with different characteristics.