89results about How to "High precision constant current" patented technology

The invention relates to a light-dimmer driving circuit. The light-dimmer driving circuit comprises a power supply input module, a transformer, a current output driving module, a pulse width modulation (PWM) module, an input voltage sampling module, an output voltage sampling module and a control center, wherein the power supply input module is mainly used for rectification and filtering of an input voltage signal, the transformer is used for voltage reduction of the voltage signal output by the power supply input module, the current output driving module is used for driving of current output according to the voltage signal which is transformed, the PWM module is used for adjusting output power of the current output driving module according to a control signal in the control center, the input voltage sampling module is used for sampling of the input voltage signal and transmitting the input voltage signal to the control center, the output voltage sampling module is used for sampling of output voltage and transmitting the output voltage to the control center, and the control center is used for controlling a PWM signal according to an input voltage sampling signal, an output voltage sampling signal and an input current signal. According to the light-dimmer driving circuit, due to the fact that the control center is used for controlling the PWM signal according to the input voltage sampling signal, the output voltage sampling signal and the input current signal, the output power of the current output driving module is enabled to change evenly, flicker-free light adjusting is achieved, constant current output is achieved, and range of the light adjusting is wide.

The invention discloses a constant current source system for average current mode control, and a control method thereof. The constant current source system comprises an inductor L1 and a sampling resistor RCS which are connected in series with an external connection load, a freewheeling diode D1 which is connected in parallel with the load, the inductor L1 and the sampling resistor RCS, and a power switch which is used for controlling charging and discharging states of the inductor. The constant current source system further comprises an error amplifier, a loop compensation unit, a first voltage current converter, an oscillator, a PWM modulation unit, a latch trigger unit, a driving unit, a first resistor R1 which is connected with the positive input end of the error amplifier and a reference source, and a second resistor R2 which is connected with the negative input end of the error amplifier and one end of the sampling circuit. According to the constant current source system for the average current mode control, and the control method thereof, brought forward by the invention, the output current precision of a constant current source system can be improved, at the same time, the work frequency is fixed, and the design of the constant current source system can be simplified.

The invention relates to an LED (light-emitting diode) multi-lamp distributed group drive system. The system comprises a front-end high-power isolated constant voltage source and a plurality of back-end low-power non-isolated constant current sources. The front-end high-power isolated constant voltage source comprises an input rectifying and filtering circuit, a power supply management chip, a primary clamping circuit of a transformer, a high-frequency transformer, an output rectifying and filtering circuit and an output voltage sampling, comparing and feedback circuit. The input end of each back-end low-power non-isolated constant current source is connected with the output end of the front-end high-power isolated constant voltage source, and stable direct current voltage output from the front end is transformed to required direct current through a constant current circuit so as to realize the single-lamp constant current drive of a small LED lamp. The LED multi-lamp distributed group drive system disclosed by the invention has the advantages of simple structure, small volume, high constant current precision, high reliability, high power factor, high efficiency and the like.

The invention relates to a primary edge current reference generating circuit and a primary edge current reference generating method for a high power factor constant-current switch power supply. The conventional primary edge current reference generating circuit is complicated. An input end of a first multiplier is used as an input end of the primary edge current reference generating circuit; an input end of a conduction angle detection circuit is used as another input end of the primary edge current reference generating circuit, and the output end of the conduction angle detection circuit is connected with another input end of the first multiplier; the output end of the first multiplier is used as an input end of a current loop; another input end of the current loop is used as the other input end of the primary edge current reference generating circuit; the output end of the current loop is connected with an input end of a second multiplier; another input end of the second multiplier is connected with the input end of the conduction angle detection circuit; and the output end of the second multiplier is used as the output end of the primary edge current reference generating circuit. Sampling hold is not required, so that the error caused by sample hold is eliminated, and the constant-current precision of the output current is improved.

The invention discloses a constant current control system for a continuous current mode (CCM) and a discontinuous conduct mode (DCM) of a primary-side feedback flyback power supply. The control system comprises a current detection module, an output feedback module, a current computation module, an error computation module, a PID module, a PWM module and a drive module; the control system is connected with a controlled switch power supply to form a closed loop; the current detection module and the output feedback module collect basic parameters for achieving a constant current algorithm; the current computation module computes an average current of a primary-side inductor at a switch-on stage of the switch, computes an average current of secondary output currents according to a turns ratio relation between input and output, and works out an output current by averaging integrals of the current on time, the output value executes a compensation algorithm in the digital PID module, a compensation value is transmitted to a PWM module, an appropriate duty ratio is output by the drive module, and thus high precision constant current of the digital power supply is controlled.

The invention discloses a constant current control system for the output current of a primary-side feedback flyback power supply converter. Based on the conventional constant current control strategy, Ts compensation, Tr compensation, and primary-side peak current compensation are added, constant current processing of digital PI compensation is also combined, and two modes of PWM and PFM are employed for control. Without considering some compensation, under the PWM mode, the switch-on time is reduced with the reduction of a load, and the deviation of the output current from the rated current is larger and larger with the reduction of the load; under the PFM mode, the switch-on time is maintained unchanged, and the deviation of the output current from the rated current is maintained unchanged. According to the system, the constant current precision can finally reach +/-2%, and the constant current characteristic of the flyback converter is improved.

The invention belongs to the technical field of constant current driving, and provides an LED lighting device, an LED driving circuit and a switch power source driving chip of the LED driving circuit. The switch power source driving chip comprises a switch device, a logic control module, a first voltage comparison module and a degaussing detection module. The input end of the first voltage comparison module is connected with the input end of an output stage circuit, the output end of the first voltage comparison module is connected with the first input end of the logic control module, the first input end of the degaussing detection module is connected with the voltage output end of an output circuit, the second input end of the degaussing detection module is connected with the output end of the logic control module, the output end of the degaussing detection module is connected with the second input end of the logic control module, and the switching frequency of the switch device is adjusted by the logic control module according to control signals output by the first voltage comparison module and the degaussing detection module. Compared with the prior art, the LED lighting device, the LED driving circuit and the switch power source driving chip are high in constant current accuracy, simple in circuit structure and low in manufacturing cost.

The invention discloses a constant current control device for a switching power supply. A gradient detection module is used for detecting the gradient of voltage on a current sampling resistor of a power supply circuit and converting the gradient into corresponding gradient voltage; voltage compensation module is used for adding the gradient voltage with the voltage of the Vref0 pin of the voltage compensation module to obtain the voltage of the Vref pin of the voltage compensation module; the voltage of the Vref pin of the voltage compensation module is taken as the threshold voltage of a turn-off comparator; the other end of the turn-off comparator is connected with voltage Vcs on the sampling resistor; and the threshold voltage is compared with the voltage Vcs on the sampling resistor, and a control signal is output to a reset signal of an R-S trigger to trigger a driving circuit and turn off a switch tube. Due to the adoption of the constant current control device, the size of a circuit system can be reduced, and the reliability of the system is improved. Constant output during input of different line voltages is ensured, and the constant current can be ensured to output during variation of a transformer Lp of the circuit.

The invention discloses an LED constant-current driving circuit of multi-path self-adaptive loads. The LED constant-current driving circuit comprises a booster circuit providing positive electrode driving voltage for LED string lamps, a control circuit, a closed loop constant-current mirror driving circuit and a sampling circuit. The closed loop constant-current mirror driving circuit comprises an operational amplifier, power MOS transistors and current limiting resistors R1. The output end of the booster circuit is connected with the positive electrodes of each path of LED string lamps, the negative electrodes of each path of LED string lamps are connected with a drain electrode of one corresponding power MOS transistor, the gate electrode of each power MOS transistor is connected with the output end of the operational amplifier, the source electrode of each power MOS transistor is grounded through one current limiting resistor R1, and one end, connected with the corresponding power MOS transistor, of each current limiting resistor R1 is connected with the reverse input end of the operational amplifier. The output end of the closed loop constant-current mirror driving circuit is connected with the sampling circuit, the control circuit is respectively connected with the sampling circuit and the booster circuit, and the control circuits controls the output voltage of the booster circuit according to the voltage value acquired by the sampling circuit. The LED constant-current driving circuit is high in constant-current precision and capable of automatically regulating the driving voltage and driving multiple paths of LED string lamps at the same time.

The invention discloses a bridgeless electrolytic-capacitor-free low-ripple-wave high-power constant-current power supply of an LED lamp. The bridgeless electrolytic-capacitor-free low-ripple-wave high-power constant-current power supply of the LED lamp comprises an alternating-current power supply circuit, a control circuit, a coupling-out circuit and a ripple wave restraining circuit. The alternating-current power supply circuit comprises a constant-current drive chip U1, a constant-current drive chip U2, an alternating-current positive half-wave current loop and an alternating-current negative half-wave current loop, wherein the constant-current drive chip U1 and the constant-current drive chip U2 are controlled by the positive half-wave and the negative half-wave of an alternating-current power supply Uin. The current of the alternating-current positive half-wave current loop and the current of the alternating-current negative half-wave current loop both flow through a primary winding N11 and a primary winding N12 of a magnetic integration transformer TR so that an induced voltage can be generated on a secondary winding NV1 and a secondary winding NV2, and then the working voltage of the constant-current drive chip U1 and the working voltage of the constant-current drive chip U2 are provided through the control circuit. An induced secondary current is generated on a center post secondary winding N2 and is output to the loaded LED lamp through the coupling-out circuit. The ripple wave restraining circuit restrains current ripple waves. According to the bridgeless electrolytic-capacitor-free low-ripple-wave high-power constant-current power supply of the LED lamp, a bridge rectifier and an electrolytic capacitor are not adopted, so that the electric power is increased, the reliability is improved, the drive capability of the chips is improved through expanded current, the working temperature of the chips is lowered, the service life of the chips is prolonged, the constant-current precision is high, the current ripple waves are small, the LED lamp does not flicker, and the circuits meet the environmental-friendliness principle.

The invention discloses a transformer secondary winding zero current detecting circuit used for an LED driving power source. The zero current detecting circuit comprises a transformer auxiliary winding unit, a resistor voltage divider unit, a negative edge detecting unit, a current sampling unit, a constant-current control unit and a logic and driving unit. The transformer auxiliary winding unit is used for sampling voltages of the two ends of a transformer secondary winding, the resistor voltage divider unit is used for dividing the sampled voltages and inputting the sampled voltages into a control chip, and the negative edge detecting unit is used for performing negative edge detecting on the waveform of the input voltage and generating a zero current detecting signal. The current sampling unit is used for sampling peak value currents of a transformer primary winding, the constant-current control unit is used for performing constant-current control over output currents output by the LED driving power source, and the logic and driving unit is used for performing logic control over output signals of the constant-current control unit, then driving a power switch tube and controlling the negative edge detecting unit. The LED driving power source has a very good effect of outputting constant currents, and meanwhile an ideal load regulation and linear regulation can be achieved.

The invention discloses a bidirectional cuk circuit-based electrolytic capacitance-free LED driving power supply and a switching method thereof. Circuit topology includes a bridge rectifier circuit, The input side of the bridge rectifier circuit is an AC input. The output side of the bridge rectifier circuit is a flyback transformer T connected in series with a first switching transistor Q1, a bidirectional cuk circuit connected in parallel with the output side of the flyback transformer T, an output filter inductor Lo, an output filter capacitor Co and an LED load. The invention has the advantages of high power factor and high constant current precision. By using bidirectional circuit to deal with the pulsating power difference between input and output power, non-electrolytic capacitor can be used instead of electrolytic capacitor, which prolongs the service life of the whole driving power supply and improves the stability of the system.

The invention discloses a high-accuracy laser remote-sensing numerically-controlled power supply system and a control method. The system comprises a BOOST PFC (power factor correction) module, a chip-isolating power supply module, an MOS (metal oxide semiconductor) driving module, a main circuit voltage reducing module and a control module. The BOOST PFC module is connected with the chip-isolatingpower supply module and the main circuit voltage reducing module. The chip-isolating power supply module is connected with the MOS driving module. The main circuit voltage reducing module is connected with the control module. The control module is connected with the MOS driving module. The MOS driving module is connected with the main circuit voltage reducing module. The high-accuracy laser remote-sensing numerically-controlled power supply system and the control method have the advantages that the problems of low digitization of the laser power sources of semiconductor pumps and low constantcurrent accuracy of low voltage and high currents are solved; the structures of conventional two-stage series circuits are improved, and accordingly, high-accuracy working currents can be provided tolaser remote-sensing semiconductor laser devices; the control method capable of achieving rapid algorithm filtering, high-accuracy control and high-robustness control is provided.

The invention discloses a self-excited oscillation driving circuit which comprises a filtering device, a driving device, a switching device, a sampling device connected with the switching device, and a transformer. The transformer at least comprises a self-excited driving winding. The driving device controls on/off of the switching device. The driving device, the self-excited driving winding, the switching device and the sampling device form a loop. The self-excited oscillation driving circuit is characterized in that the self-excited oscillation driving circuit further comprises a current control device connected into the loop formed by the driving device, the self-excited driving winding, the switching device and the sampling device to further control the switching device.

A primary side feedback switching power supply control chip includes a reference voltage unit, a comparator unit, a voltage monitoring unit, a driving unit, a switch unit and a rectifying unit, the switch power supply control chip omits a self-powered time generator, the self-supply time within a single cycle is determined by the voltage at the voltage feedback pin of the switching power supply control chip. In addition, an energy storage module for supplying power to the switching power supply control chip is connected between a power supply pin and a voltage feedback pin of the switching power supply control chip, so that whether the control system operates in the self-powered mode or the non-self-powered mode, The current is passed through the voltage sampling module, so that the peak current expression of the energy storage transformer module is the same, so that the performance of the control system is not affected in the self-powered mode, the minimum load capacity is strong in the constant voltage mode, the constant current precision is high and the linear adjustment rate is good in the constant current mode.

The invention discloses an LED (light-emitting diode) display screen constant-current driving circuit with an optional mirror image ratio. The constant-current driving circuit comprises a reference voltage source circuit, a constant-current adjusting circuit, a voltage sampling circuit, a current mirror image ratio self-adjusting circuit, a current mirror circuit and a display frame data processing circuit, wherein the reference voltage source circuit comprises a seven-loop oscillator and bandgap reference circuit; the constant-current adjusting circuit comprises a comparator, a current offset tube and an external ground resistance; the voltage sampling circuit comprises a differential comparator and a logic processing circuit; the current mirror image ratio self-adjusting circuit comprises a plurality of logic and time sequence circuits; the current mirror circuit comprises a plurality of current mirror image tubes; the display frame data processing circuit comprises a plurality of display frame data processing units; and the output drive channel port of the circuit is provided with a 13V withstand voltage circuit which comprises two NMOS (N-channel metal oxide semiconductor) transistors. The driving circuit provided by the invention has the advantages of increasing the gray levels of the LED display screen, increasing the brightness contrast and solving the withstand problemof the output drive channel port with low cost.

The invention provides an automatic sterilization lamp. The automatic sterilization lamp comprises an ultraviolet sterilization lamp, an illuminating lamp and a control device, wherein the ultraviolet sterilization lamp and the illuminating lamp are respectively connected with the control device. The automatic sterilization lamp is characterized in that the control device comprises a power supply circuit, a main control circuit, a human body sensing circuit, a sterilization lamp drive circuit and an illuminating lamp drive circuit, the sterilization lamp drive circuit and the illuminating lamp drive circuit are respectively connected with the power supply circuit, one end of the main control circuit is connected with the power supply circuit, the other end of the main control circuit is respectively connected with the human body sensing circuit and the illuminating lamp drive circuit, the human body sensing circuit is connected with the sterilization lamp drive circuit, the sterilization lamp drive circuit is connected with the ultraviolet sterilization lamp, and the illuminating lamp drive circuit is connected with the illuminating lamp. The automatic sterilization lamp combines the illuminating lamp and the ultraviolet sterilization lamp together, not only can not injure a human body, but also achieves full automatic control, and furthermore is low in energy consumption, low in cost, and easy to popularize and use.

An LED constant current power source circuit comprises an input protection circuit module, an EMI filtering circuit module, a rectification filtering circuit module, a power conversion circuit module, a direct current output circuit, a voltage stabilization constant current circuit module, a feedback circuit module, a PWM control circuit module, a PFC circuit module and a sampling circuit module, wherein the current sampling circuit module, the feedback circuit module and the PWM control circuit module are combined together, and the functions of overvoltage/ overcurrent protection and output short-circuit protection are achieved. When the voltage or the currents of an output end is detected to be abnormal, the signal is fed back to the PWM control circuit module through the feedback circuit module, and an IC in the PWM control circuit module outputs a corresponding signal to enable the power source circuit to stop output work, so that an LED lamp connected with the power source circuit for use is protected. Meanwhile, the LED constant current power source circuit has the advantages of being high in constant current accuracy, high in reliability, simple in circuit structure, low in cost and the like.