67results about How to "Improve EMI characteristics" patented technology

The invention relates to a control method which can be applied to an active-clamp flyback miniature photovoltaic grid-connected inverter device. The active-clamp flyback miniature photovoltaic grid-connected inverter device comprises a flyback converter and a power frequency polarity conversion circuit. In the device, a current reference is used for controlling a flyback primary-side current peak value so that the device can output a half-wave sinusoidal current, and the output voltage is clamped by a grid voltage. When the instantaneous power is lower, a constant frequency current discontinuous mode in combined with a variable frequency current critical continuous mode is adopted in the flyback control method. When the flyback converter works in a variable frequency current critical discontinuous mode, an auxiliary switching tube can be conducted for a period of time when the secondary-side current of the flyback converter reaches zero, the conduction time can be accurately controlled by a digital chip, thus realizing the leakage inductance energy feedback and the soft switch of a master switching tube under the condition of wide-range output voltages and different instantaneous powers and greatly improving the efficiency under the condition of full loads.

The invention relates to an inverter circuit used for solar energy photovoltaic grid connection, comprising first, second, third and fourth controlled switches used for converting direct current (DC)of solar cells to alternating current (AC) suitable for grid connection. The four controlled switches are connected in a full-bridge manner. The connection point of the first controlled switch and thesecond controlled switch is a first AC output point. The connection point of the third controlled switch and the fourth controlled switch is a second AC output point. The inverter circuit also comprises a first afterflow module which is connected between the first AC output point and the second AC output point when on the positive semi-cycle of the AC output voltage, and a second afterflow modulewhich is connected between the first AC output point and the second AC output point when on the negative semi-cycle of the AC output voltage. The inverter circuit and a device thereof have the effects of low cost, light weight and high conversion efficiency.

A connector has a board with a plurality of contact pads electrically connected to a plurality of signal lines on one side. The connector also has a modularized structural unit on the other side. The structural unit includes a plurality of spring contacts as the mate to which the contact pads are electrically connected. The connector further has a shaft provided near the central part of the board and perpendicular to the board and a roller provided on the structural unit. To combine the contact pads and the contacts, the shaft is rotated to cause the rollers to engage with a projecting part provided at the tip of the shaft. The roller is provided higher in position than the circuit board on which the connector is to be mounted.

The invention aims at disclosing a flyback photovoltaic grid-connected inverter adopting an interleaving parallel-connection active clamping technology. Two flyback circuits are in in-out parallel connection with each other, one auxiliary switch tube is respectively added to each flyback circuit, and drains of the two auxiliary switch tubes are connected with each other, are in series connection with a public clamping capacitor to form a clamping circuit and are respectively in parallel connection with two corresponding ends of a transformer primary side winding. An opening signal of one of the flyback circuit auxiliary switch tubes aligns with a closing signal of the other flyback circuit auxiliary switch tube, the alignment method guarantees that the duty ratio of the two flyback circuits is substantially maintained consistent, and the active clamping technology is achieved easily. The communicating time of the auxiliary switch tube of each flyback circuit can be calculated through a digital control circuit according to output voltage values at current moment and accurately controlled, and is suitable for wide-range output voltage occasions. The flyback photovoltaic grid-connected inverter reduces output current ripple, achieves leakage-inductance energy absorption and effective utilization, enhances circuit efficiency and improves electro-magnetic interference (EMI) characteristics of a high-frequency circuit.

A signal transmission device for transmitting touch data and a display device using the same are disclosed. The signal transmission device includes a plurality of integrated circuits driving touch sensors and outputting touch data obtained from the touch sensors, a controller controlling the integrated circuits and determining a touch input on the basis of the touch data received from the integrated circuits; and a plurality of lines connecting the controller and the integrated circuits in a multi-point manner. The controller and the integrated circuits communicate with each other in both directions via the lines. A data packet of differential signal transmitted between the controller and the integrated circuits includes a header interval, a register address interval, and a data interval allocated between a start dummy clock and an end dummy clock.

The invention discloses a power supply circuit and a display device. The power supply circuit comprises a power source, a charging and discharging module and a detection module, wherein the detection module is used for detecting a detection parameter on a power supply path; according to the detected detection parameter, a corresponding mode signal is fed back to the power source by the detection module; preset working voltage is output to a load by the detection module; the power source is used for receiving the mode signal fed by the detection module; according to the mode signal, the power supply voltage corresponding to the mode signal is output by the power source; when the mode signal is a low-power signal, the charging and discharging module is charged by the power source; the charging and discharging module is used for discharging to the detection module when the power source outputs the power supply voltage corresponding to a high-power signal; and when the power source outputs the power supply voltage corresponding to the lower-power signal, charging is carried out by the power source. According to the scheme, the phenomenon that the power consumption of the power source is drastically fluctuated along with the change of the power consumption of the load can be effectively avoided, the power source can stably work, so that the service life of the power source is prolonged, and the EMI (electro-magnetic interference) characteristic of the product is improved.

The invention discloses a high-frequency high-saturation-flux-density ferrite, a preparation method, an inductor and a transformer. The ferrite contains main components and auxiliary components in parts by mole: the main components contain 55-57 mol% of Fe2O3, 0-3.5 mol% of ZnO, and the balance MnO; the auxiliary components contain 0.01-0.03 wt% of Nb2O5, 0.02-0.10 wt% of CaCO3, 0.01-0.04 wt% of V2O5, 0-0.01 wt% of SiO2, 0-0.05 wt% of Ta2O5, 0-0.05 wt% of TiO2 and 0.10-0.25 wt% of Co2O3. The ferrite provided by the invention has high saturation magnetic flux density and can be suitable for inductors and transformers. Moreover, the inductor prepared from the high-frequency ultrahigh-saturation magnetic flux density manganese-zinc ferrite material has the advantages of small size and is capable of meeting the requirement for miniaturization of devices.

The invention provides a BUCK converter and a frequency locking control circuit thereof. The frequency locking control circuit includes: a frequency-discriminating phase-discriminating logic circuit which generates first and second control logic signals having frequency error information according to a duty ratio signal of the BUCK converter and a frequency error signal of a reference signal; a charge pump connected with the frequency-discriminating phase-discriminating logic circuit and which controls on and off of fan-out current and fan-in current according to the first and second control logic signals and which outputs a voltage signal containing the frequency error information to an adaptive-on time generation circuit; a current source which generates the fan-out current and the fan-in current. The frequency locking control circuit is introduced herein such that the BUCK converter based on ACOT(adaptive continuous on time) structure enables the problem to be well solved that wide0input wide-output in actual application has switching frequency fluctuations, and EMI (electromagnetic interference) characteristic of a system is also greatly improved.

A display apparatus includes a display part, a signal control part, data driving parts, and first and second wiring pairs. The display part includes pixels. The signal control part includes a transmission part that converts an image signal into a multi-level signal. The data driving parts receive the multi-level signal from the transmission part, convert the multi-level signal into a reproduced image signal and provide the pixels with the reproduced image signal. The first and second wiring pairs connect the transmission part and at least one data driving part of the data driving parts. The multi-level signal includes serial data of the image signal and an embedding clock embedded in the serial data. A voltage level of the serial data in the multi-level signal is different from a voltage level of the embedding clock in the multi-level signal.

The invention relates to an adjusting circuit for switching power supply constant voltage output, and the adjusting circuit comprises a first comparator, a first RS latch, a sampling and holding unit,a first resistor, a second resistor, a third resistor, a fourth resistor, a first operation amplifier and low-pass filtering unit, a second comparator, a second RS latch, a driving module, a power transistor and a constant voltage output adjusting circuit, wherein the constant voltage output adjusting circuit comprises a current compensating module, a frequency adjusting module and a sampling compensation module. When alternating current input voltage is relatively low and output power is relatively high and/or a switching power supply works in a continuous current mode, switching frequency and/or sampling moment of voltage on an output voltage feedback management pin and/or the voltage on the output voltage feedback pin are adjusted to vary with variation of the voltage on input capacitance, ripple wave generated by the output voltage varying with variation of the voltage on the input capacitance is restrained, variation of the switching frequency is adjusted, and switching frequencyspectrum is expanded.

The invention discloses a valley-switching digital control circuit of a switch power source, and belongs to the technical field of switch power source circuit design. The valley-switching digital control circuit comprises a voltage feedback detection module, a current feedback detection module, an arithmetic unit, a valley-switching digital control module, a and gate device and a PWM generating module, wherein the voltage feedback detection module is used for collecting switch power source voltage feedback signals, the current feedback detection module is used for collecting drive switch tube currents, the arithmetic unit is used for obtaining drive switch tube breakover signals according to voltage feedback detection module output signals and current feedback detection module output signals, the valley-switching digital control module is used for obtaining valley-switching signals according to the voltage feedback detection module output signals, the and gate device is used for conducting and operation on the drive switch tube breakover signals and the valley-switching signals, and the PWM generating module is used for generating actual duty ratio signals according to the operation result of the and gate device. By means of the valley-switching digital control circuit, the switch loss is effectively reduced while accurate valley switching is achieved, the valley-switching mode is switched into the real-time breakover mode when the resonant period is abnormal, and the valley-switching digital control circuit is suitable for discontinuous-mode switch power source chips in the PWM mode and PFM mode.

The invention discloses a novel wide-range high-frequency direct-current conversion device. The direct-current conversion device comprises a Buck module M1, a first coupling inductor L1, a second coupling inductor L2, a first three-level Boost module M2, a second three-level Boost module M3, a first supporting capacitor C1 and a second supporting capacitor C2. According to the Boost circuit, an interleaved three-level control strategy is adopted, the inductive current frequency is increased to four times of the switching frequency, soft switching of a switching device and a diode can be achieved through coupling inductance leakage inductance, the device loss is reduced, and the EMI characteristic is improved. Besides, the front-stage Buck circuit and the rear-stage Boost circuit are cascaded so that the application range of the input and output voltage can be broadened and short-circuit current-limiting operation of the output side can be realized. Meanwhile, the pre-stage Buck circuitcan realize a soft power-on function, an additional soft power-on circuit is not needed, and the power density of the device is further improved.

The invention discloses a wireless smoke controller for simultaneously connecting a fire fighting system and an intelligent building system. The wireless smoke controller is characterized in that the wireless smoke controller comprises a control module, a photoelectric smoke sensing module, a power supply module and a wireless transmission module, the photoelectric smoke sensing module and the wireless transmission module are connected to the control module, the control module is also connected to the fire fighting system and the intelligent building system, the fire fighting system and the control system are connected by a fire fighting bus, the intelligent building system and the control system are connected by a wireless module, the power supply module supplies power to the control module and the wireless transmission module, and the photoelectric smoke sensing module provides detection signals for the fire fighting module and the control module. The wireless smoke controller can be used for the fire fighting system and the intelligent building system at the same time and has the advantages of convenient installation, low cost and high practicability.

EMI properties are improved in an electrical connector for flat cables (1) and in a shield member (30) used therein. The electrical connector for flat cables (1) is constituted by: contacts (4), for contacting a shielding surface of a flat cable (100), which is inserted into the connector (1); an insulative housing (2), for holding the contacts (4), which is mounted on a circuit board (80) having a grounding portion (82); and the shield member (30), which is mounted on the insulative housing (2) so as to cover the outer surfaces thereof. The shielding surface of the flat cable (100) and the grounding portion (82) of the circuit board (80) are electrically connected when the shield member (30) is mounted on the insulative housing (2).

The embodiment of the invention discloses a control method of a switching power supply and the switching power supply. The control method comprises the steps that after the switching power supply is started, the control module obtains a voltage waveform of a connection point between the first switching tube and the filter inductor; when the voltage waveform of the connection point does not realize zero voltage switching, the control module adjusts the cut-off current of the second switching tube until the voltage waveform of the connection point is exactly increased; and when the voltage waveform of the connection point is exactly increased, the control module controls the first switch tube to be switched on so as to realize zero-voltage switching-on of the first switch tube. According to the embodiment of the invention, on the premise of not increasing the hardware cost of the switching power supply, the switching loss of the switching power supply is reduced, and the EMI characteristic of the switching power supply is effectively improved.