45results about How to "High dimming accuracy" patented technology

The invention discloses a pulse width modulation (PMW) modulation circuit which specifically comprises a first transmission door, a first current comparer, a first alternative selector, a reset set (RS) trigger, two input nor gates, a phase inverter, a first N-channel metal oxide semiconductor (NMOS) tube, an error accumulation capacitor and a comparer with the selection function. The PMW modulator circuit can certainly modulate external input PWM signals according to current actually flowing through a light-emitting diode (LED), the duty ratio is adjusted, the duty ratio of the PWM signals actually participating in dimming in the circuit can be dynamically and correspondingly modulated as actual current change of the LED, and a signal driving switch of the LED is controlled to enable the luminance of the LED in all digital pulse periods to be equal to a preset value to improve PME dimming accuracy.

The invention provides a PWM light modulation method and device. A plurality of PWM periods are combined into a control signal, so as to achieve the control of the brightness of illumination equipment. After the above design is employed, the light modulation precision cannot be affected while the frequency of a PWM signal is improve. Through the change of a combined scheme, more light modulation levels can be obtained, thereby achieving higher light modulation precision and a more smooth and flexible light modulation effect.

The invention discloses a dimming circuit and a dimming method for an LED light supplementing lamp. An input end of a reference voltage module in the dimming circuit is connected with a power source, an output end of the reference voltage module is connected with a voltage sampling circuit, an amplifier and a single chip microcomputer, an output end of the voltage sampling circuit is connected with the amplifier, an output end of the amplifier is connected with the single chip microcomputer, the single chip microcomputer is connected with a constant-current driving circuit, and the constant-current driving circuit is in drive connection with an LED. The dimming method includes steps of (1), acquiring a reference voltage source via the reference voltage module; (2), matching a potentiometer with a divider resistor to sample signals; (3), enabling an operational amplifier circuit to process the signals so as to remove interference signals; (4), enabling the single chip microcomputer to complete high-precision A/D (analog/digital) conversion to obtain digital signals; (5), processing the digital signals to obtain digital PWM (pulse-width modulation) signals; and (6), adjusting the constant-current driving circuit by the digital PWM signals to control brightness variation of the LED. According to the dimming scheme, the dimming circuit and the dimming method have the advantages of high dimming precision, accurate brightness control, few required peripheral devices and the like.

The invention relates to the technical field of automobile lamps, in particular to an MEMS intelligent illumination system for an automobile lamp, an automobile lamp assembly comprising the MEMS intelligent illumination system for the automobile lamp and an automobile comprising the automobile lamp assembly. The MEMS intelligent illumination system for the automobile lamp comprises a light source and an MEMS pixel array; light emitted by the light source is transmitted through the MEMS pixel array and then is emitted out; the MEMS pixel array comprises a plurality of supporting bases which are provided with light transmitting channels and are distributed in an array mode; and an MEMS micro-blocking piece and an MEMS micro-blocking piece driving circuit are movably arranged on each supporting base, wherein the MEMS micro-blocking pieces can open or close the light transmitting channels, and the MEMS micro-blocking piece driving circuits drive the MEMS micro-blocking pieces to move on the supporting bases. The MEMS intelligent illumination system, the automobile lamp assembly and the automobile have the advantages that each MEMS micro-blocking piece driving circuit independently controls the swinging frequency of the corresponding MEMS micro-blocking piece on a single pixel point, and therefore the gray level of the emitted light can be adjusted, the pixel is high, the dimming precision is high, the size is small, the operation reliability and stability are good, and the integration degree is high.

The invention discloses a dimming interface control circuit and method, and an LED driving system, chip and method, being characterized by: being able to be compatible with PWM dimming and analog dimming only by using one interface while two ports are not required and extra external filter capacitors are not required, thus being low in cost. The dimming interface control circuit and method, and the LED driving system, chip and method can process the received PWM signal or analog signal into a PWM signal, can perform chopping on the constant current reference voltage in a pulse width mode, is high in the dimming accuracy, is high in the dimming depth, and is preferable in the batch consistency.

The invention relates to a multiphase parallel LED (Light-Emitting Diode) driving power supply and a dimming method thereof. The driving power supply comprises an input rectifier, a PFC (Power Factor Correction) circuit, a switch parallel network, an LCL-T type resonant network, an output rectifier filter and the like. The switch parallel network consists of n parallel inversion modules; and when a high-power output is ensured, a current stress of a power device in each parallel module is reduced. Each parallel inversion module comprises two dimming modules with phase shifting and dimming functions; an output current of the driving power supply is changed by regulating a phase shifting angle of a half-bridge arm in each dimming module; and a dimming range is expanded and the whole-range dimming is implemented by phase shifting combination of two dimming modules of each parallel inversion module.

The invention discloses an LED dimming drive circuit and a switching power supply. The LED dimming drive circuit comprises a power switch tube cut-off time control circuit, a power switch tube conduction time control circuit and a power switch tube drive circuit. When a dimming voltage of the dimmer is higher, it indicates that the brightness of an LED load needing to be adjusted is larger, that is, the value of the current output to the LED load by the switching power supply is larger, the working frequency corresponding to a critical conduction mode can meet the LED dimming brightness requirement at the moment, so the LED dimming drive circuit works in the critical conduction mode when the dimming voltage is larger. When the dimming voltage is lower and a deep dimming mode is required, the working frequency corresponding to the critical conduction mode cannot meet the LED dimming brightness requirement at the moment, so the LED dimming drive circuit works in an intermittent working mode capable of further reducing the working frequency, the current value of the LED load is further reduced, the dimming depth of the LED load is increased, and the dimming precision of the LED load is improved.

The invention relates to the technical field of automatic adjustment of automobile headlamp low beams and discloses an automobile lamplight automatic adjusting method and system. The automobile lamplight automatic adjusting method includes the following steps that a light adjustment control unit acquires and analyzes axial accelerated speed and angular speed data obtained by a G sensor installed in the light adjustment control unit; the light adjustment control unit obtains automobile information through an automobile body bus and recognizes the state of an automobile; the light adjustment control unit calculates the current automobile head inclination angle of the automobile according to the axial accelerated speed data; and according to the state of the automobile, the light adjustment control unit controls a light adjustment execution mechanism to adjust the irradiation distance of headlamps according to the automobile head inclination angle and selectively according to the angularspeed data. Light adjustment accuracy is high, no external equipment is needed, the cost of the whole system is reduced, the risk that the whole system fails due to the severe use environment of an automobile chassis is avoided, and the maintenance problem of a height sensor is solved.

The invention discloses a control circuit for controlling a power transistor, a driving circuit, an LED lamp system and a control method. The control circuit receives an adjusting signal, and the control circuit is used for adjusting the amplitude of a current flowing through the power transistor based on the adjusting signal when a characterization value of the adjusting signal is greater than afirst threshold value; the control circuit is used for adjusting the current flowing time of the power transistor based on the adjusting signal when the characterization value of the adjusting signalis less than a second threshold value, wherein the second threshold is less than or equal to the first threshold. According to the invention, the control precision and efficiency can be improved. Whenthe characterization value (such as the duty ratio) of the adjusting signal (such as the PWM signal) is a smaller value, the control precision is improved; meanwhile, the drive circuit is small in loss and high in efficiency. The invention is applied to an LED drive scheme, so the dimming precision of an LED drive circuit is improved.

The invention relates to a driving control circuit structure for realizing a dimming function. The driving control circuit structure comprises: a duty ratio detection module used for sampling and calculating an input pulse wave through a high-speed clock signal to obtain a group of digital output signals; a coding circuit module which is used for generating a two-bit control signal through the digital output signal; a first digital-to-analog conversion circuit module which is used for generating a non-linear change current and a fixed current, and further adjusting an output current through a frequency modulation mode; a frequency modulation circuit module; a second digital-to-analog conversion circuit module which is used for outputting voltage and further changing output current by changing peak voltage; a peak current detection circuit module; and a logic control circuit module. By adopting the driving control circuit structure for realizing the dimming function, the dimming precision and the dimming depth are effectively improved, and when the driving control circuit structure is applied to dimming and color modulation occasions, light felt by human eyes can achieve relatively soft changes in brightness and hue, and the brightness of a lamp can be adjusted to be darker at night.

The invention discloses a constant current control circuit of an LED constant current driving system. The constant current control circuit includes a voltage control circuit used for selecting a reference voltage and a feedback voltage from a firsts reference voltage, a second reference voltage and load sampling feedback voltages according to control of a PWM control signal and a clock signal, and modulating the reference voltage and feedback voltage to output a regulating voltage signal; a driving signal generating circuit used for comparing the regulating voltage signal and a sawtooth wave signal of a fixed frequency to obtain a driving signal with a varying duty ratio, and the voltage of a load is controlled through the driving signal, so that the current of the load is kept constant. The constant current control circuit provided by the invention overcomes the problem that traditional PWM diming is limited by frequency, also solves the problem of low analog dimming precision, the load sampling feedback voltages are direct voltage signals, variation of PWM dimming signals are embodied through variation of voltage values of the load sampling feedback voltages, the regulation range is relatively wide, and the dimming precision is high.

The invention provides an LED drive circuit capable of realizing multiple output mode setting via a code dialing board. The LED drive circuit comprises an emergency driven LED circuit and a mains supply driven LED circuit, wherein the emergency driven LED circuit is powered via batteries, existence of alternating mains supply is detected via a one-chip microcomputer, and condition of the emergency driven LED circuit and condition of the mains supply driven LED circuit are controlled via on-off of a bidirectional silicon controlled rectifier; an LED output current, or LED output power or battery capacity and battery discharge time are set via a BCD code dialing board by the emergency driven LED circuit; codes of the BCD code dialing board correspond to a set output current, or a set output power value or set battery capacity and set battery discharge time; the corresponding codes are sent to the one-chip microcomputer via the BCD code dialing board, the one-chip microcomputer outputs modulated pulses of different duty ratios according to the codes of the BCD code dialing board and sends the same to a DC-DC direct current conversion circuit, and an aim of LED lamp multistage light modulation can be achieved.

The invention discloses a table lamp applying an adjustable light controller. The table lamp comprises a control base, a lamp pole and a bulb, wherein an LED light source is mounted in the bulb; the lamp pole is made from a metal material; the light controller is mounted in the control base; a TP connecting interface is arranged in the lamp pole; the light controller comprises a power supply circuit and a regulating circuit, and the signal input end of the regulating circuit is connected with the TP connecting interface, so that a person can realize the brightness regulation of the table lampby touching the lamp pole, signal input equipment, such as a TP touch screen, does not need to be additionally arranged for the table lamp, and the production cost of the table lamp is reduced; the table lamp adopts a PWM dimming mode, so that the table lamp cannot have LED chromatographic offset phenomena and has high dimming precision; and besides, the table lamp has various infinite dimming modes, intelligent dimming can be realized, power consumption is reduced, energy is saved, and the environment is protected.

The invention discloses a cascaded bus dimming driver. The cascaded bus dimming driver comprises a microprocessor, a cascaded bus data receiving module, a cascaded bus transmitting module, an input filtering module, a voltage conversion module, a constant current driving module, an output current adjustment module, a dimming module and an output voltage monitoring module; the input end of the cascaded bus data receiving module is connected with the input end of the cascaded bus transmitting module and the input end of the input filtering module; the cascaded bus data receiving module and the cascaded bus transmitting module are connected with the microprocessor separately; the output end of the input filtering module is connected with the input end of the voltage conversion module and theinput end of the constant current driving module; the output end of the voltage conversion module is connected with the power supply input end of the microprocessor; the input end of the output current adjustment module is connected with the output end of the microprocessor; the output end of the output current adjustment module is connected with the input end of the constant current driving module; the input end of the dimming module is connected with the output end of the microprocessor; and the output end of the dimming module is connected with the input end of the constant current drivingmodule.