165results about How to "Improve EMI performance" patented technology

The invention discloses a mixed format signal optical fiber transmission device. The mixed format signal optical fiber transmission device comprises a sending end, a fiber channel and a receiving end, wherein the sending end converts input camera link format video image signals and multi-channel universal serial signals into optical signals, the optical signals are sent to the receiving end through the fiber channel, and the receiving end receives the optical signals and restores the optical signals to original video image signals and multi-channel universal serial data signals. The mixed format signal optical fiber transmission device is suitable for optical fiber transmission of the camera link video image signals and the multi-channel universal serial signals in all configuration modes, the transmission of mixed format signals in a single-fiber channel at different rates can be achieved through multiplexing of a transmission bus, and consumption of extra fiber channels and devices is reduced. According to the mixed format signal optical fiber transmission device, electrical signal conversion processing and transmission control are achieved through a field programmable gate array (FPGA) device, the requirement for actual functions is met, meanwhile, the usage of application-specific integrated circuits is reduced, the advantage of high integration and universalization degrees can be achieved, and supports can be provided for further function extension and performance upgrading.

A magnetic interface circuit for a LAN, such as an Ethernet network, includes a transformer having a first winding connected to the line side of the LAN and a second winding connected to the circuit side of the LAN. Each of the first and second windings has two output ports and one of the windings has a center tap port A 3-wire common mode choke having a center winding and two outer windings, the center winding of a 3-wire common mode choke is connected to the center tap of the one winding and the outer windings of the 3-wire common mode choke are respectively connected to the output ports of the one winding.

An electrical connector assembly having shielded cage assembly with at least one port for receiving modules, and methods of manufacture and use thereof. In one embodiment, the modules comprise SFP-type (small form-factor pluggable) modules, and the shielded cage assembly comprises an EMI shield member that is disposed at a port opening for the electrical connector assembly. In one variant, the EMI shield member can be disposed on the electrical connector cage assembly without the need for secondary processing techniques such as soldering, or resistance welding. This is accomplished via for example the utilization of mechanical snap features.

An electrical connector assembly having shielded cage assembly with a plurality of ports for receiving modules. In one embodiment, the modules comprise SFP (small form-factor pluggable) modules, and the electrical connector assembly is adapted for low-profile applications, thereby optimizing the amount of area and volume occupied by the SFP assembly. In one variant, the SFP modules are pluggable into individual ports, whereby two modules are interconnected to a single header connector interconnected to a motherboard. Methods of manufacturing the connector assembly are also disclosed.

A bridgeless PFC power converter comprises a first inductor and a second inductor coupled from a first input-terminal and a second input-terminal to a first transistor and a second transistor. A first diode and a second diode are coupled from the first transistor and the second transistor to an output capacitor. A first capacitor and a second capacitor are coupled from the input-terminals to the ground terminal through a third transistor and a fourth transistor. A control circuit generates a first-switching signal and a second-switching signal to control the first transistor and the second transistor. The second-switching signal will turn on the second transistor when the first-switching signal switches the first transistor. The first-switching signal will turn on the first transistor when the second-switching signal switches the second transistor. The control circuit turns off the third transistor and the fourth transistor during the light-load of the PFC power converter.

A new type of the passive non-dissipative snubber with a single saturable reactor improves the performance of the boost converter used as a front-end active Power Factor Correction (PFC) in two critical areas: excess voltage stresses caused by high voltage spikes on input high voltage switching transistor of the boost converter is eliminated and EMI noise is much reduced. The high voltage spike energy instead of being dissipated as in a dissipative snubber circuits is recovered resulting in increased conversion efficiency. High voltage spike elimination also allows use of lower voltage rated devices with lower ON resistance, hence further increasing the efficiency of the PFC boost converter.

The invention discloses a super-junction device. A charge flowing region comprises a super-junction structure consisting of a plurality of alternately arranged N-type columns and P-type columns; the N-type columns have two or more widths; backward voltages required for completely exhausting the N-type columns with different widths are different, so that backward voltages corresponding to capacitance minimum values of super-junction units consisting of the N-type columns with different widths are different; and the number of the widths of the N-type columns is set to be two or more, so that the backward voltages corresponding to the capacitance minimum values of the super-junction units are mutually staggered, the super-junction units with the capacitance values greater than the capacitance minimum values always exist under any backward voltage, and the integral capacitance minimum value of the super-junction structure of the charge flowing region is increased and greater than the superposition of the capacitance minimum values of the super-junction units. The invention furthermore discloses a manufacturing method for the super-junction device. According to the super-junction device and the manufacturing method, the capacitance minimum value of the super-junction structure can be increased, the strong voltage change in a switch can be reduced, electromagnetic interference performances of a circuit and a system can be improved, so that the device is easy to use.

A connector module for receiving a signal converter and electrically connecting the signal converter to a printed circuit board mounted within an electronic system. The connector module includes a conductive cage having a plurality of press-fit type pins and a shielding lid. The connector module further defines a top opening and a cavity with an opening on a bottom portion of the conductive cage for receiving the connector which electrically connecting with the signal converter. The shielding lid covers on the top opening. The connector comprises a plurality of contacts each having a press-fit end, said press-fit ends extending toward the printed circuit board and mounting therein.

A stacked pluggable cage (100) in accordance with the present invention is adapted for receiving two transceivers (200). The stacked pluggable cage includes a shielding shroud (11) defining a receiving space (13), and a first and a second intermediate walls (12) inserted in the shielding shroud. The first and second intermediate walls are disposed adjacent to each other to divide the receiving space into a first and a second receiving subspaces (13a, 13b) for receiving the transceivers respectively. Each intermediate wall has a body portion (121), and a number of flexible fingers (124) extending rearwardly from the body portion and tilting toward corresponding receiving subspace for grounding corresponding transceiver to thereby improve EMI performance.

An adapter using an electrically-conductive wall within the adapter to channel EMI emissions to ground. In a preferred embodiment, the adapter comprises: (a) an elongated housing having a first and second end and defining a first passageway extending axially from the first end toward the second end, and a second passageway extending axially from the second end toward the first end, each passageway configured to receive an optical connector plug; (b) an electrically-conductive wall traversing the adapter between the first and second passageways, the wall being sized to cover a substantial portion of the opening when the adapter is mounted to the chassis; and (c) at least one portion of the wall extending outside of the housing to electrically couple with the chassis of the computer system when the adapter is mounted to the chassis forming an electrically-conductive path between a point on the wall and the chassis.

The invention provides a quasi-resonant device for switching power supplies. The quasi-resonant device comprises a sampling module used for sampling a transformer secondary degaussing time Tds according to a feedback signal Vsen of voltage output of a switching power supply after a switching tube of a quasi-resonant module in the switching power supply is closed, a valley bottom sampling module used for sampling a resonant valley bottom signal of the quasi-resonant module according to the Vsen, a fixed-proportion time generation module connected with the sampling module and used for generating time T at a preset proportion through Tds processing, and a logic processing module respectively connected with the valley bottom sampling module and fixed-proportion time generation module and used for acquiring the first valley bottom signal after the time T and using the first valley bottom signal as a switching signal to open the switching tube. According to the device, the efficiency can be increased, electromagnetic interference can be improved, the cost can be reduced, and switching loss and noise can be avoided. The invention further provides a quasi-resonant system for switching power supplies and a quasi-resonant control method for switching power supplies.

The invention discloses a flyback switching power supply. On the basis of a common three-winding absorption flyback converter, the dotted terminal of NP1 in a transformer B is connected to a power supply, the dotted terminal of NP2 of a second primary side winding is grounded, double-wire winding of NP1 and NP2 is guaranteed, one capacitor C1 is added, one end of C1 is connected with the heteronymous terminal of NP1, and the other end of C1 is connected with the heteronymous terminal of NP2, so that NP1 and NP2 are excited when Q1 is conducted in a saturated manner, energy is output from secondary side NS when Q1 is disconnected, and energy of leakage inductance is losslessly adsorbed through D1; the flyback switching power supply is suitable for working under low voltage, and the utilization rate and current density of primary side winding are improved, so that the power density is large, relatively large leakage inductance between primary side and secondary side is permitted, and the conversion efficiency is high.

The invention discloses a three-phase alternating direct current voltage boost-buck conversion circuit and a control method thereof, A three-phase alternating-current step-up / step-down converter include an input switch tube set, a rectifier switch unit and an energy storage freewheeling unit, the input switch tube group comprising first to third switch tubes, the rectifier switch unit comprising first to sixth diodes, fourth to sixth switch tubes, the energy storage freewheeling unit comprising seventh diodes, eighth diodes, seventh switch tubes, first to second freewheeling inductors and capacitors. The conversion circuit of the invention has a simple structure and a relatively simple control method, so that the advantages are obvious when the output voltage range of small and medium power is wide and high efficiency and high power density are required.

The invention discloses a forward switching power supply. On the basis of a common three-winding absorption forward switching converter, the like terminal of a first primary winding NP1 in a transformer B is connected with a power supply, the like terminal of a second primary winding NP2 in a transformer B is grounded, and NP1 and NP2 are wound in a bifilar manner. A capacitor C1 is added, one end of C1 is connected with the unlike terminal of NP1, and the other end of C1 is connected with the unlike terminal of NP2, so in case of saturation conduction of Q1, both NP1 and NP2 are excited magnetically, and a secondary winding outputs energy; in case of turn-off of Q1, the energy of primary exciting current is losslessly absorbed by NP2 through D1. The forward switching power supply is suitable for working under a low voltage, and the utilization rate and the current density of the primary windings are improved, so the power density is large, large leakage inductance between primary and secondary sides is allowed, and the conversion efficiency is high.

The invention discloses a flyback switching power circuit. A valley filling circuit is adopted in a filter circuit of the flyback switching power circuit. The work voltage of a capacitor C1 and the work voltage of a capacitor C2 in the valley filling circuit are reduced by a half, -40 DEG C electrolytic capacitor can be adopted, and a third capacitor C3 is in parallel connection to a charging diode D3 in an existing valley filling circuit, so that the withstand voltage of the third capacitor C3 is half of a peak value of input pulse direct current, and high-frequency ripple current of a back switching power 300 can be fully and effectively absorbed. A varistor RV1 and a varistor RV2 are arranged before and behind a rectifier bridge 101, and a thermistor NTC, a safety capacitor X1 and an inductor L form a multi-level two-way filter and protection circuit. The flyback switching power circuit has the advantages that the power factor is high and not affected by a value of the C3, the topological structure of the circuit is simple, the absorption effect on surging voltages is good, cost is low, the size is small, and the difference mode conduction interference degree of the flyback switching power circuit reaches the CLASS B in GB9254.

A conducted EMI noise reduction effect close to that achieved by using an optimal modulating waveform as a modulating wave is achieved when employing a frequency spreading technique as a measure against noise when a conducted EMI standard is extended to a low-frequency range. A triangular wave / Hershey's Kiss approximation signal generating unit and a triangular wave generation control unit generate a fundamental triangular wave by a transistor charging a capacitor with a current and a transistor discharging the current from the capacitor. A slope switching signal generating unit generates signals expressing the start and end of a charge period and the start and end of a discharge period. An additional charge or additional discharge is carried out in response to the signals turning a transistor on, and the slope of the triangular wave temporarily increases in that period only.

The invention discloses a wide-range input efficient direct current-direct current converter, which comprises a boost interleaved boosted circuit, a resonance half-bridge transformation circuit, a synchronous rectification and filter circuit and a DSP (digital signal processor) digital control circuit, wherein the boost interleaved boosted circuit consists of two boost circuits; the resonance half-bridge transformation circuit consists of two resonance circuits, and input ends of the two resonance circuits are connected in series, and are connected with the output end of the boost interleaved boosted circuit; the synchronous rectification and filter circuit consists of two synchronous rectification networks arranged in parallel, and the input end of each synchronous rectification network is connected with the output end of the corresponding resonance circuit; the DSP digital control circuit is respectively connected with the boost interleaved boosted circuit, the resonance half-bridge transformation circuit and the synchronous rectification and filter circuit. According to the wide-range input efficient direct current-direct current converter disclosed by the invention, the disadvantages of high switching loss and brought EMI (electro-magnetic interference) characteristic worsening of a direct current-direct current converter are solved.

The present invention provides a single-segment linear constant-power LED (light-emitting diode) driving circuit and a method. The circuit includes a voltage input module, an LED load, a power switching tube, a sampling resistor, an overvoltage control module which is used for detecting the drain-end voltage of the power switching tube, a current control module which is used for limiting the peak current of the LED load, and a comparison module. According to the single-segment linear constant-power LED (light-emitting diode) driving circuit and the method, when input voltage is larger than the conduction voltage of the LED load, the current control module limits the peak current, so that a current average value in different input voltage periods can be constant; when the input voltage is larger than a set value, current flowing through the LED load is turned off, and therefore, power consumption can be decreased; and when the input voltage is smaller than the conduction voltage of the LED load, the LED load is turned off. According to the single-segment linear constant-power LED (light-emitting diode) driving circuit and the method of the invention, the control of average current in alternating current periods is realized by using a compensation capacitor, the peak current is limited, and therefore, constant power output in a wide input voltage range is realized; and the turn-off voltage and turn-off slope of the LED are adjusted through an external resistor, and therefore, the high efficiency of the system can be realized, and the electromagnetic interference performance of the system can be optimized.

The present invention provides a modularized connector for a computer, including a housing forming at least three receptacle chambers and having an end face forming a notch and an opposite end face forming wire retention sections respectively communicating the receptacle chambers, and also forming mounting sections close to the wire retention sections; a first connector received in one of the receptacle chambers and having conductive connection wires extending through the respective wire retention section, the first connector being encased by a metal casing; second connectors respectively received in the remaining ones of the receptacle chambers and each having conductive connection wires extending through the respective wire retention section, each second connector being encased by a metal casing that has an end wall forming at least one resilient tab; and a conductor block arranged in the notch and having opposite side faces in physical engagement with the metal casings of the first and second connectors that juxtapose each other. The modularized connector features easy mounting / dismounting and enhanced EMI performance.

The lift control cabinet includes one main circuit unit and one control circuit unit set separately in two magnetically isolated rooms inside the lift control cabinet. The said configuration can minimize the electromagnetic interference of the main circuit unit on the control circuit unit, so as to reduce error detection rate of the control signal and malfunctions. In addition, the lift control cabinet has all the electric elements single-side mounted and thus easy overhaul and lowered maintenance cost, and the surface of the lift control cabinet is covered with plated conductive material, rather than insulating material, and thus has excellent shield effect.