31results about How to "Stable dimming" patented technology

The present invention discloses an HUD brightness automatic regulation device and method in the automatic control technology field. The device comprises: a horizontal light sensor and a vertical light sensor, wherein the installation directions of the horizontal light sensor and the vertical light sensor are mutually perpendicular and the measuring ranges of the horizontal light sensor and the vertical light sensor are the same, and the vertical light sensor is provided with a light filter membrane; a microprocessor, wherein the microprocessor comprises an A/D processing module, a data processing module and a PWM module, the horizontal light sensor and the vertical light sensor are configured to convert the detected light brightness signals to digital signals through the A/D processing module and then transmit the digital signals to the data processing module, and the data processing module performs processing and calculation to obtain PWM digital quantity applied to the PWM module; the LED module, wherein the LED module comprises a LED driver and a LED lighting chain, and the PWM module controls the brightness of the LED lighting chain through the LED driver; an external rotary knob configured to transmit the brightness regulation signals to the A/D module for manual regulation of the brightness. The light regulation range is wide, and the light regulation is more smooth.

To provide a lighting device for a semiconductor light-emitting element adapted to allow stable achieve dimmed lighting ranging from a very minute optical output to rated lighting to be achieved by use of a switching power source operating in a discontinuous mode. [Means for Settlement] A device for dimmed lighting of a semiconductor light-emitting element 4 by use of a DC-DC converter 3 operating in the discontinuous mode includes a burst dimming control part for intermittently stopping an ON/OFF operation of a switching element Q1, thereby adjusting a current flowing to the semiconductor light-emitting element 4, output detecting parts 5a, 5b for detecting at least one of the current flowing to the semiconductor light-emitting element 4 or a voltage applied to the semiconductor light-emitting element 4, and a feedback control part 6 for adjusting an ON period or a burst dimming control period of the switching element Q1 during the ON/OFF operation so that a detected value of the output detecting parts 5a, 5b approaches a target value. In the vicinity of a dimming control lower limit, power supply to the feedback control part 6 may be stopped.

A PWM generating section (32) for black insertion lighting control outputs a black insertion PWM pulse VBL for driving a fluorescent lamp (43) such that a black insertion period for unlighting the fluorescent lamp (43) and a period for lighting the fluorescent lamp (43) are provided in one vertical period, a PWM generating section (31) for luminance lighting control outputs a lighting control PWM pulse Vpwm1 for PWM driving the fluorescent lamp (43) so as to repeat lighting and unlighting in the lighting period, an AND circuit (33) outputs an inverter drive signal Vout1 where the lighting control PWM pulse Vpwm1 and the black insertion PWM pulse VBL are superposed, and an inverter (42) drives the fluorescent lamp (43) by applying a voltage corresponding to the inverter drive signal Vout1 to the fluorescent lamp (43).

The invention provides an AC LED light adjustment method which is characterized in that PWM signals are adopted to directly modulate the AC supply voltage for working of an AC LED, the AC voltage envelope wave form and the AC voltage peak value are kept constant, the AC voltage effective value is adjusted by PWM duty cycle, the light adjustment range of the AC LED is enlarged to be 1-100%, and the light adjustment is stable. The invention further provides an inductive light adjustment controller for realizing the AC LED light adjustment method. The adopted method or inductive light adjustment controller provided by the invention can be widely applied to AC LED lamps, light adjustment and inductive intelligent automatic light adjustment can be realized, the purpose of dynamic secondary energy conservation is achieved, and the energy conservation effect is obvious.

The invention provides a load driving circuit and a driving method. The load driving circuit comprises a voltage conversion circuit and a cascaded linear constant current circuit, the voltage conversion circuit is used for converting an input voltage into a first working voltage based on a feedback signal of the linear constant current circuit, and the linear constant current circuit is used as a post-stage circuit to be coupled with the voltage conversion circuit. The circuit is used for providing a driving voltage and a driving current for a load and generating a feedback signal based on a load voltage signal to control the voltage conversion circuit. According to the invention, the pre-stage boost circuit is combined with the feedback of the post-stage linear constant-current circuit so that the self-adaptive adjustment of the output voltage is realized, the overall efficiency of the system is improved, and a stable dimming and color modulation function of an LED can be realized.

The invention belongs to the technical field of LED illumination, and discloses an LED lamp driving circuit, a control method and electronic equipment. The circuit comprises: a first anti-interference circuit which receives alternating current and filters the alternating current to obtain power supply voltage; a power correction circuit which performs power factor correction according to the power supply voltage to obtain a power correction voltage, and outputs the power correction voltage to the analog dimming circuit; a pulse modulation circuit which generates a pulse width modulation signal according to the dimming control voltage signal; and an analog dimming circuit which generates a constant-current power supply voltage corresponding to the dimming control voltage signal according to the power correction voltage and the pulse width modulation signal, and supplies power to the LED through the constant-current power supply voltage. Through the circuit, electromagnetic interference is reduced, power factor correction is carried out, a pulse width modulation signal is generated through dimming, a stable constant-current power supply is provided, dimming of an LED lamp is more stable, and the phenomena of lamp flashing and the like are prevented.

The invention provides an energy-saving lamp lighting system used for endoscope, comprising a microscope, an upper light source, a lower light source, a power supply, a power switch or the like, wherein the upper light source, fixed by an inner and outer bracket, is composed of LED of the upper light source; the lower light source, composed of LED of the lower light source, is fixed on the bottom of the microscope.

The invention relates to an LED silicon controlled rectifier dimming circuit. The LED silicon controlled rectifier dimming circuit comprises a silicon controlled rectifier dimmer, an EMI filtering circuit, a rectifying bridge, a leakage circuit, a power supply management circuit and a transformer, wherein the output end of the silicon controlled rectifier dimmer is connected with the first input end of the EMI filtering circuit; the EMI filtering circuit is connected with the rectifying bridge; the rectifying bridge is connected with the leakage circuit; two voltage input ends of the leakage circuit are connected with the first end and the second end of a primary winding of the transformer respectively, and the second output end of the rectifying bridge is grounded; the input end of the power supply management circuit is connected with the first end of the primary winding; the power supply end of the power supply management circuit is connected with the first end of an auxiliary winding of the transformer; the second end of the auxiliary winding of the transformer is grounded; and a secondary winding of the transformer is used for being connected with an LED light source. The LED silicon controlled rectifier dimming circuit can be used for high-power LED silicon controlled rectifier dimming illumination equipment; and meanwhile, the LED illumination light-emitting efficiency can be ensured while a condition that the silicon controlled rectifier dimming illumination equipment does not flicker at low luminance can be satisfied.

The present invention provides a power supply device and a lighting device, which can dim a light-emitting element stably. The power supply device includes a control circuit and a detection circuit.The control circuit switches between a current control mode and a voltage control mode according to an inputted dimming signal and thus dims the light-emitting element. In the current control mode the control circuit controls an output current supplied to the light-emitting element to a target current, and in the voltage control mode the control circuit controls an output voltage supplied to the light-emitting element to a target voltage. The detection circuit detects the output current and the output voltage, and the control circuit sets the target voltage switched between the current control mode and the voltage control mode as a first voltage.

The invention provides a distributed intelligent tunnel lighting system which comprises a lighting centralized control device, lighting terminal dimming control devices, an outer-tunnel light intensity detection device, an in-tunnel lighting quality monitoring device, a traffic flow detection device, a lighting device, a communication device and a control platform. The lighting centralized control device is used for carrying out data acquisition on the lighting terminal dimming control devices distributed in the tunnel and issuing a control command, wherein the control command is obtained by comparing data acquired by the outer-tunnel light intensity detection device, thein-tunnel lighting quality monitoring device and the traffic flow detection device with an illumination dimming strategy set in the lighting centralized control device, so that the on or off of the lighting device in the tunnel and the lighting brightness are controlled. The system has the advantages of being high in controllability, not high in construction environment requirement and basically not limited by construction conditions.

The invention relates to an LED lamp voltage stabilizing method and circuit adapted to fluctuation of an input voltage automatically. The method is based on a circuit composed of a field effect transistor or triode and an LED lamp; an adaptive voltage stabilizing module electrically connected to the gate electrode of the field effect transistor or the base electrode of the triode is arranged, andis electrically connected with an input power supply; the adaptive voltage stabilizing module includes charging and discharging current channels; when a voltage difference during fluctuation of the input power supply causes discharging of the adaptive voltage stabilizing module, the adaptive voltage stabilizing module can carry out rapid discharging via the discharging channel, and the absolute value of the voltage of the adaptive voltage stabilizing module is reduced rapidly; and when the voltage difference during fluctuation of the input power supply causes that the input power supply charges the adaptive voltage stabilizing module, the adaptive voltage stabilizing module carries out charging via the charging channel, and the absolute value of the voltage of the adaptive voltage stabilizing module is increased. The LED lamp voltage stabilizing method and circuit have the advantages of simple circuit structure, low cost, stable light modulation and safe and reliable performance.