44results about How to "Control duty cycle" patented technology

The invention discloses a temperature control system, which comprises a lower computer and an upper computer, wherein the lower computer consists of an automatic voltage regulation (AVR) single chip microcomputer, a temperature sensor, a light-emitting diode (LED) display, a temperature setting circuit and a temperature heating circuit; and the upper computer consists of a personal computer (PC) and interactive software. According to the system, temperature and time for keeping the temperature can be input to the upper computer according to a temperature curve required by a user, the lower computer controls the gradience of the temperature and the system can meet requirements of users on different temperatures at different moments, responds sensitively and has higher accuracy.

A tunable, low power clock generator employs a voltage regulator, one or current generators and a variable resistor bank that, together, produce a control voltage for trimming a VCO. The control voltage is arranged to also compensate, at least, for the variables of temperature, supply voltage and fabrication processes as they affect the VCO output frequency. The current generator is well characterized over the variables discussed and the resistor bank is a flexible series / parallel array of resistors made from differing materials exhibiting different temperature coefficients. The resistor bank provides for various overlapping resistance values simultaneously with various overlapping temperature coefficients wherein the temperature coefficient profile of the clock generator over frequency and temperature is controlled.

The invention discloses a backlight module, a display device and a drive method of the display device, and belongs to the technical field of displaying. The technical problem that the color crack phenomenon exists in an existing FSC liquid crystal displayer is solved. The backlight module comprises a controller and a plurality of partition backlights. Each partition backlight comprises at least two light sources with different colors, wherein the two light sources are independently driven. The controller controls the turning-on time of the light sources with different colors in all partition backlights. The backlight module can be used for liquid crystal display televisions, liquid crystal displays, mobile phones, tablet personal computers and other display devices.

The invention provides a driving method of a liquid crystal display. The driving method of the liquid crystal display comprises steps that a time schedule controller is used to output a source electrode enabling signal to a source electrode driver, and is used to output grid electrode enabling signal to a grid electrode driver; the source electrode driver is used to receive the source electrode enabling signal, and a duty ratio of a source electrode driving signal output to a source electrode line is reduced based on the source electrode enabling signal; the grid electrode driver is used to receive the grid electrode enabling signal, and a duty ratio of a grid electrode driving signal output to a grid electrode line is reduced based on the grid electrode enabling signal. The invention also provides the liquid crystal display and an electronic device. The liquid crystal display can be provided with a four-domain structure, and a quantity of electronic components is reduced based on improvement of color cast, and then an aperture ratio of a pixel is improved.

The invention relates to a mutual inductor magnetic balance method of a multi-state switch circuit. The mutual inductor magnetic balance method comprises the steps of S1, sampling a difference mode current of a mutual inductor; S2, comparing the difference mode current with a reference signal; and S3, controlling duty cycle of a main switching tube of a bridge arm of the multi-state switch circuit according to a comparison result so as to acquire magnetic balance of the mutual inductor. By implementing the mutual inductor magnetic balance method and device of the multi-state switch circuit, the difference mode current of the mutual inductor is sampled, the duty cycle of the main switching tube of the bridge arm of the multi-state switch circuit is controlled, and thus, the magnetic balance of the mutual inductor can be further acquired.

The present invention relates to the technical field of electronics, in particular to a clock system used in an electronic system. The clock system comprises: a host computer, connected to a PCI bus and used for setting a frequency of a clock that needs to be output and choosing a corresponding channel, wherein the host computer is provided with an upper-layer software module that is connected to the PCI bus and that is used for calculating a value of a control register of a dedicated clock chip according to the frequency, set by the host computer, of the clock that needs to be output; CPLD, connected to the PCI bus and used for acquiring the value of the control register and sending the value of the control register to the dedicated clock chip; and the dedicated clock chip, used for generating a corresponding clock signal according to the value of the control register and outputting the corresponding clock signal. According to the above technical scheme of the present invention, the output clock frequency can be set by the host computer, the clock output range is super wide, and the resolution is high. According to the present invention, a duty cycle of the output clock can also be controlled, thereby meeting system requirements on the duty cycle.

The invention discloses a four-group parallel inverter welding power supply control method and circuit. The four-group parallel inverter welding power supply comprises a main controller, a PWM controller and four groups of inverter sub-power supplies connected in parallel, wherein each inverter sub-power supply comprises a three-phase rectification circuit, a filter circuit, an IGBT full-bridge inverter circuit, a transformation and rectification circuit and a current detection circuit which are connected in sequence; the PWM controller outputs four groups of independent PWM control signals to the four groups of IGBT full-bridge inverter circuits respectively; rising edges of the four paths of PWM control signals are synchronous; output current of each inverter sub-power supply is detected; the output current of each inverter sub-power supply is compared with a current set value; the output currents of the inverter sub-power supplies are compared; and the turn-off time of the falling edge of each PWM signal is controlled, the duty ratio of the PWM signal of the inverter sub-power supply with large output current is reduced, the duty ratio of the PWM signal of the inverter sub-power supply with small output current is increased, the output currents of the inverter sub-power supplies are equal, and the reliability of the welding power supply is improved.

The invention discloses a temperature control system, which comprises a lower computer and an upper computer, wherein the lower computer consists of an automatic voltage regulation (AVR) single chip microcomputer, a temperature sensor, a light-emitting diode (LED) display, a temperature setting circuit and a temperature heating circuit; and the upper computer consists of a personal computer (PC) and interactive software. According to the system, temperature and time for keeping the temperature can be input to the upper computer according to a temperature curve required by a user, the lower computer controls the gradience of the temperature and the system can meet requirements of users on different temperatures at different moments, responds sensitively and has higher accuracy.

The invention provides a capacitor voltage balance control method of a cascade reactive power compensation device, belonging to the technical field of reactive power compensation control, and aiming at solving the problem that the existing method for balancing the capacitor voltage of a power unit is complex in process and unstable in control status. The method comprises the following steps of: firstly, acquiring the alternating current-side voltage u and the alternating current-side voltage i of each power unit in the cascade reactive power compensation device to obtain the instantaneous power polarity of each power unit; sampling the instantaneous capacitor voltage of a power unit by the frequency which is same as that of the carrier of the reactive power compensation device to obtain a voltage adjusting value of the power unit to be taken as a modification value of the carrier; confirming the modification value of the carrier and the overlapping mode of the carrier, and obtaining the adjusted carrier; and comparing the adjusted carrier with the sinusoidal modulation wave to obtain a modulating signal of the power unit, and controlling the power unit of the reactive power compensation device by the modulating signal to realize the capacitor voltage balance control of the compensation device. The capacitor voltage balance control method is used for balancing the capacitor voltage of the reactive compensation device.

The invention relates to a step-down DC-DC conversion circuit for an electric vehicle. The step-down DC-DC conversion circuit comprises an output voltage value control circuit, the pulse width modulation signal output end of a CPU of the output voltage value control circuit is connected with the input end of an optocoupler, the output end of the optocoupler is connected with the control pulse input end of a drive module, and the drive pulse output end of the drive module is connected with grids of IGBTs. The collector of each IGBT is connected with the positive electrode of the power battery,and the load is connected between the emitter of each IGBT and the negative electrode of the power battery; and a plurality of load fly-wheel diodes which are connected in parallel are connected between the emitting electrode of each IGBT and the negative electrode of the power battery. A +5V power supply is generated by the power battery through the DC-DC converter to be used by the CPU, and a +15V power supply is generated to be used by the driving module. The circuit is further provided with an input voltage value display circuit, an output voltage setting and display circuit and an actualoutput voltage value display circuit. A low-voltage storage battery does not need to be installed, the installation space of the automobile is saved, the purchasing and battery replacing cost is saved, and operation is reliable.

The invention belongs to the field of compound eye micro-lenses and discloses a compound eye micro-lens array and a preparation method thereof, the preparation method comprises the following steps: preparing a compound eye substrate micro-lens array on a clean substrate; then dissolving the polymer in a volatile solvent to prepare a polymer solution, pouring the polymer solution on a substrate with a compound eye substrate microlens array, and forming a layer of uniform polymer film through spin coating; and placing the substrate in a closed container and standing for a period of time, obtaining a three-dimensional honeycomb-shaped ordered porous structure on the surface of the compound eye substrate microlens array after the solvent is completely volatilized, and preparing the compound eye microlens and further to make the compound eye microlens array. According to the invention, rapid and low-cost preparation of the compound eye microlens array can be achieved, and the high controllability of the shape, the diameter and the crown height of the bionic compound eye can be met.

The invention relates to a large-current constant-current ultraviolet light control circuit, which has a power processing circuit, a constant-current controller, a drive circuit, a constant-current circuit and an LED load sequentially connected; the input end of the constant-current circuit is also connected with a sampling circuit, The output terminals of the DC driving power supply circuit are connected; the output terminals of the sampling circuit are connected with the input terminals of the constant current controller; the output terminals of the sampling circuit are connected with the input terminals of the PI regulation circuit; the output terminals of the PI regulation circuit It is connected with the input terminal of the constant current controller; the constant current circuit includes a BUCK step-down topology circuit. The invention can stably output a large current of 25A, reduce the loss of the current, simplify the design of the driving circuit and save the cost.

The invention, which relates to the technical field of the illumination control system, discloses an intelligent controller for illumination. The controller comprises an upper computer remote controller, a PLC controller, a workshop overall illumination system, a workshop station illumination system, an office intelligent light control system and a visitor illumination system. The workshop overall illumination system comprises an infrared sensor, a sound sensor, a camera, a first control module and a first illumination device, and the infrared sensor, the sound sensor, the camera and the first illumination device are all connected with the first control module. Under the effect of a plurality of distributed systems, illumination devices are automatically turned on and turned off, illumination devices at stations are turned on and turned off according to the attendance checking conditions of employees, the light intensity is automatically adjusted, a visitor illumination system is additionally arranged, the systems can be matched and used mutually, and the controller is high in practicality, and achieves the intelligent and multi-functional effects.

The invention provides a driving method of a liquid crystal display. The driving method of the liquid crystal display comprises steps that a time schedule controller is used to output a source electrode enabling signal to a source electrode driver, and is used to output grid electrode enabling signal to a grid electrode driver; the source electrode driver is used to receive the source electrode enabling signal, and a duty ratio of a source electrode driving signal output to a source electrode line is reduced based on the source electrode enabling signal; the grid electrode driver is used to receive the grid electrode enabling signal, and a duty ratio of a grid electrode driving signal output to a grid electrode line is reduced based on the grid electrode enabling signal. The invention also provides the liquid crystal display and an electronic device. The liquid crystal display can be provided with a four-domain structure, and a quantity of electronic components is reduced based on improvement of color cast, and then an aperture ratio of a pixel is improved.

The invention relates to an intelligent bath heater for a shower room. The intelligent bath heater for the shower room comprises a shell; a warm air channel is arranged inside the shell; the air outlet end of the warm air channel is arranged on the lower surface of the shell and communicates with the outer side; an electric heating wire is arranged inside the warm air channel; an air blowing device is arranged on the inner side of the warm air channel and blows heat generated by the electric heating wire out of the air outlet end of the warm air channel; the intelligent bath heater further comprises a controller, a temperature sensor and a power chopper circuit; the controller comprises an MCU; an analog-digital conversion module, a storage module, a judgment module and a PWM wave output module are arranged inside the MCU; a reasonable temperature threshold value T is stored inside the storage module and corresponds to a preset duty ratio D; the output end of the temperature sensor isconnected with the input end of the analog-digital conversion module in the MCU; the output end of the PWM wave output module is connected with the first input end of the power chopper circuit; the second input end of the power chopper circuit is connected with the mains supply; and the output end of the power chopper circuit is connected with the voltage input end of the electric heating wire.