674 results about "Common-mode interference" patented technology

An electronic proximity sensing apparatus has at least one signal pad. The signal pads are each connected to receive an electric voltage signal. At least two sensing conductors are routed in proximity to the signal pads, and a sensor is operable to detect the difference in voltage between two of the at least two sensing conductors. Differential sensing is further applied to other capacitive proximity sensing circuits to reduce common-mode interference.

A microphone assembly includes a microphone composed of a case having an open end and a printed circuit board. The printed circuit board is disposed in the open case end. The microphone assembly further includes a metal screen coupled to the case over the printed circuit board for shielding the microphone from electromagnetic interference. The metal screen includes several apertures.

Aspects of the present invention are directed to using surface acoustic wave (SAW) sensors mounted on a disc coupling component in a powertrain to measure the torque generated by an automobile engine. The sensor may be positioned and oriented on the disc coupling component so that the phase velocities of SAWs propagating through active elements of the SAW sensors are aligned with principal strain components due to torque in the disc coupling component. The torque may be calculated by determining the difference between resonant frequencies of the active elements to suppress common-mode interference factors. In addition, SAW resonant frequencies may be communicated in a non-contacting manner by utilizing rotary and stationary couplers employing radio frequency (RF) signals. Moreover, SAW sensors may be activated and interrogated by employing targeted RF pulses having different carrier frequencies at or near respective resonant frequencies of each resonator in a SAW sensor.

The invention provides a USB (Universal Serial Bus) interface circuit which comprises a USB connector, a power common mode filter module, a signal common mode filter module, a power differential mode filter module, a signal differential mode filter module and an electrostatic protection module. Common mode interference, differential mode interference, electrostatic interference and the like on a power line and a signal line in the circuit can be eliminated; particularly, the additionally arranged power common mode filter module can eliminate common mode interference between a power VBUS and a working ground GND; and the circuit is small in size, low in cost and high in practicability, has very good protection effects on electrostatic discharge (ESD) and electromagnetic interference (EMI), allows a USB signal to be free from distortion, and ensures that a product smoothly passes USB certification and EMC (Electromagnetic Compatibility) certification. In addition, a high-voltage protection module and a high-frequency filter module can eliminate high-voltage signal interference and high-frequency signal interference in the circuit, so that the interference resistance of the USB interface circuit is further improved, and the signal transmission performance of the USB interface circuit is improved.

The invention discloses a balanced radio frequency electrically tunable bandpass filter with constant relative bandwidth. The bandpass filter consists of an upper-layer microstrip structure, a middle-layer dielectric substrate, and a lower-layer grounded metal. The upper-layer microstrip structure is a balanced circuit, and comprises four half-wavelength resonators, two input feed networks, two output feed networks, two input ports and two output ports; the four half-wavelength resonators respectively consist of microstrip lines and variable capacitance diodes connected at two ends; the middle of the first half-wavelength resonator is connected with a capacitor and a microstrip line; the middle of the third half-wavelength resonator is connected with a capacitor; the second and fourth half-wavelength resonators are bent and symmetrical vertically; and the whole filter structure is in vertical mirror symmetry. The balanced radio frequency electrically tunable bandpass filter realizes constant relative bandwidth when a center frequency is tuned, can inhibit common-mode interference and can be used for a reconfigurable radio frequency front end for wireless communication.

A self-decoupling high-sensitivity resonant silicon micromechanical gyroscope mainly comprises an outer mass block, an inner mass block, a cantilever beam, a lever amplification mechanism, a DETF(double-ended tuning fork), a driving electrode, a detecting electrode, wherein the lever amplification mechanism, the fork, the driving electrode and the detecting electrode are arranged in the inner mass block. The structure of the micromechanical gyroscope is axially symmetric, and the inner and outer mass blocks are in Chinese character 'hui' shape, which is capable of making the component implement larger mass block in limited volume. The outer mass block and the inner mass block are separated by a folding beam for reducing effectively the coupling; a resonant beam is in the form of DETF, and both ends of the resonant beam are connected with the periphery through a fine neck structure, thereby reducing effectively the energy coupling of the resonant beam and the peripheral structure; two forks are arranged symmetrically for implementing difference output of resonant frequency, thereby reducing effectively the common-mode interference. The structural form of the invention improves sensitivity and resolution of the accelerometer, and reduces the coupling of the driving direction vibration to the detecting direction by using framework structure.

The invention discloses a preceding-stage EMI filtering protective circuit of a driving power source. The preceding-stage EMI filtering protective circuit of the driving power source comprises a fuse, a temperature-sensitive resistor, a surge protection circuit, a differential mode interference suppression circuit, a common mode interference suppression circuit and the like. According to the preceding-stage EMI filtering protective circuit of the driving power source, a multi-stage filtering structure is used for carrying out effective filtration and removal on electromagnetic interference signals entering from a power grid, three voltage dependent resistors with different discharge voltage values are used for carrying out discharge protection on surge voltage, and the fuse and the temperature-sensitive resistor are arranged close to a connection port, can carry out disconnection protection when the overcurrent occurs, and achieves the effect of soft start on the whole driving power source. The preceding-stage EMI filtering protective circuit of the driving power source has the advantages of being simple in circuit, small in size, low in cost, good in reliability, high in inserting loss and the like.

The invention relates to a bridgeless AC/DC power factor converter with low on-state loss and aims to provide a bridgeless power factor correction converter with single inductance and three levels. The converter comprises an input inductance, a Boost arm circuit, a clamping circuit and an output voltage-dividing capacitor, wherein the Boost arm circuit is formed by connecting two switch tubes and two diodes in series. The two diodes are arranged at the outside of the Boost arm circuit, and the two switch tubes are arranged at the inside. An anode of the diode DF1 is connected with a drain electrode of a switch S1, a source electrode of the switch S1 is connected with a drain electrode of a switch S2, and a source electrode of the switch S2 is connected with a cathode of the diode DF2. The switch tubes of the Boost arm circuit are opened and closed, and then the charging and discharging on the inductance and the power factor correction of the input end are realized. The invention only needs one input inductance to obtain two negative and positive DC buses, and has the advantages of low stress and high utilization rate of the device, low on-state loss, low common-mode interference and high conversion efficiency.

The invention discloses a fully differential increment sampling method of a successive approximation type analog-digital converter. According to amplitude characteristic analysis of a neural signal, it is determined that during a non-active period of the signal, most amplitude values of the signal fall into a window of 16LSB, and therefore, a judging window is arranged to shield high-order redundancy conversion of the SAR ADC during the non-active period of the signal. When the signal is active, the amplitude change of the signal exceeds 16LSB and the ADC performs conversion from the high-order bits, so that the problem that the input signal amplitude needs to be limited for an input-tracking SAR ADC structure is solved. The increment sampling SAR ADC provided by the invention is a fully differential structure. The fully differential increment sampling method could effectively restrain common mode interference and even-order harmonic, improve accuracy of ADC conversion and solve the problems that the common mode disturbance of a signal-end structure is large and the noise of the even-order harmonic is obvious. Simultaneously, compared with a single-ended increment sampling structure, the fully differential structure has a doubled signal conversion range, thereby effectively broadening the range of input signals.

An apparatus for monitoring battery voltage and temperature includes a host controller and acquisition boards, and every acquisition board for the battery includes a voltage acquisition module, a temperature acquisition module, a host control chip MCU, A/D convertor module, an opto-isolator module, a CAN bus communication module and two external connection ports CN1, CN2. The input end of the AD transformation module is connected with the output end of the voltage acquisition module and the temperature acquisition module, and the output end of the A/D convertor module is connected with the opto-isolator module via a SPI bus, and the I/O port of the SPI bus module in the main control chip MCU is connected with the opto-couple isolation module, and the host control chip MCU is connected with the CAN bus communication module of the host controller via the CAN bus communication module, and the acquisition boards are connected via a socket piece in turn. The present invention is simple in structure, convenient in operation, high in data precision and high in the consistency and interchangeability of each acquisition board. Furthermore, the present invention utilizes opto-isolator module to isolate the high-voltage battery with the host controller circuit, so as to avoid the problem of common mode interference.

The invention belongs to the field of MEMS (Micro-Electro-Mechanical Systems) inertia devices, and particularly relates to a capacitance type micro-accelerometer digital output fully differential digital micro-accelerometer interface circuit system. The system comprises a drive signal generating part, a fully differential charge integrator, a fully differential post-amplifier, a fully differential pre-distorter, a relative dual-sampling and sampling retaining circuit, a fully electric integrator, a dynamic comparator, a D/A (Digital/Audio) converter and an electrostatic force feedback device. The system improves the linearity of an accelerometer system, effectively lowers the quantization noise of D/A conversion, restrains zero shift, reduces common mode interference generated by switching charge injection and a substrate noise, improves power supply rejection ration (PSRR), and reduces harmonic distortion.

The invention discloses a multichannel human body skin potential acquiring system which comprises a power supply module, a multichannel selection module, a pre-amplification module, a shield module, a filter module, a 50Hz trap module, a post-amplification module, an AD conversion module, an SD (Serial Digital) card storage module and a main control module, wherein an acquisition electrode and a reference electrode are accessed into the multichannel selection module, and then accessed into the pre-amplification module for amplification after being subjected to strobing through the multichannel selection module, interference signals are filtered by using the filter module, and common-mode interference of an input stage is inhibited by using the shield module; filtered signals enter the post-amplification module after passing through the 50Hz trap module, the output of the post-amplification module is connected with the AD conversion module and written into the SD card storage module according to a certain format by the main control module; and the main control module controls the working process of the whole acquiring system. The invention provides a system for acquiring electric signals excited by all organs and tissues on the skin of a human body so as to replace an acquiring instrument being only suitable for electrocardio in the prior art.

A non-contact electrocardiogram (ECG) sensor having an ECG electrode and guard electrode coupled to an electronic circuit that actively gain-corrects the electrocardiogram signal based on fringe capacitance signal and filters the gain-corrected signal based on a static charge reference signal. The compensation system first makes a gain correction for the preamplifier to address ECG electrode-to-subject motion and then removes any additive static common mode interference from motion-induced static charge generation.

The invention discloses a balanced type radio frequency voltage tunable bandpass filter with constant absolute bandwidth. The bandpass filter comprises a micro-band structure at an upper layer, a medium substrate at a middle layer and grounding metal at a lower layer. The micro-band structure at the upper layer adopts a balanced circuit and comprises four semi-wavelength resonators, two input feed networks, two output feed networks, two input ports and two output ports; each of the four semi-wavelength resonators comprises a micro-band line and a variable capacitance diode with two connected ends; capacitors are loaded at the middles of the first semi-wavelength resonator and the third semi-wavelength resonator; the second semi-wavelength resonator and the fourth semi-wavelength resonator are bent and arranged symmetrically; and the whole filter structure is in mirror symmetry. The balanced type radio frequency voltage tunable bandpass filter provided by the invention realizes constant absolute bandwidth during centre frequency tuning and can restrain common mode interference and can be used for a reconstructed radio frequency front end of wireless communication.

Class-D amplifiers have evolved from using binary pulse-width modulation (PWM) modulators to three-level PWM modulators. Three-level PWM drivers for audio applications offer the benefits of eliminating costly elements at the output of an audio system. However, they also introduce increased common-mode interference. Three-level PWM generates three states, but one state has two interchangeable representations which can be scrambled in order to shape the common-mode output spectrum.

The invention provides a method and transformer for reducing common-mode interference in a sandwich winding transformer. In the invention, a shield winding is respectively arranged between a secondary winding and adjacent windings to ensure that parasitic capacitance between a primary winding and the secondary winding can be reduced and a new path is provided for a common-mode current and the common-mode current is guided into ground (GND), therefore, the common-mode interference caused by the common-mode current can be reduced.

The invention discloses a direct frequency output vibratory gyroscope structure, the aim is to design and manufacture a frequency modulation output vibratory gyroscope based on the plane manufacturing technology, so that the output signal anti-interference capability of the vibratory gyroscope is improved. The design of the vibratory gyroscope is characterized in that: (1) by adopting frequency local modulation means, the signal loss is greatly reduced, and the weak Coriolis effect localized frequency modulation is achieved; (2) by adopting a frame mass block supporting structure, the transverse Coriolis acceleration is correspondingly and significantly enlarged, which is effectively imposed on the axial direction of a resonator beam; (3) two resonator beams adopt a differential resonant structure, and a plurality types of the common-mode interferences can be inhibited, such as temperature stress; and (4) the plane project design is easy to adapt to the related technology of wire cutting machining or MEMS, and is easy to be miniaturized.

A receiver for high-speed data communications, which receives a differential signal through a pair of signal lines. The receiver includes a common-mode choke, which has first and second signal windings, which are respectively coupled in series to the pair of signal lines so as to attenuate common-mode interference in the differential signal. The choke also has a sampling winding, which is inductively coupled to the signal windings so as to generate a sampled signal responsive to current flowing in the signal windings. Signal processing circuitry is coupled to receive the sampled signal from the sampling winding and to receive the differential signal from the signal windings and to process the differential signal responsive to the sampled signal.

A planar transformer arrangement and method provide isolation between an input signal and an output signal. The planar transformer arrangement includes a planar medium having a first layer, a second layer, and a dielectric interlayer arranged between the first and second layers; at least one meandering primary winding arranged on the first layer of the planar medium, a current flow being induced within the primary winding in accordance with the input signal; at least one meandering secondary winding arranged on the second layer of the planar medium, the primary and secondary windings forming a planar transformer, whereby a voltage is induced across the secondary winding in accordance with the current flow within the primary winding; and a mode elimination arrangement configured to produce a compensated voltage by compensating for a common mode interference on the voltage induced across the secondary winding, the mode elimination arrangement being further configured to generate the output signal in accordance with the compensated voltage; wherein the dielectric interlayer of the planar medium provides a voltage isolation between the primary and secondary windings.

The invention relates to the electric power electronic technical field, and discloses a DC-DC converting circuit which comprises N unit converting circuits, M inductance units, a circuit input positive terminal, a circuit input negative terminal, a circuit output positive terminal and a circuit output negative terminal. The input positive terminal of the first unit converting circuit is in connection with the circuit input positive terminal through an inductance unit, and is directly in connection with the circuit input positive terminal; the input negative terminal of a Kth unit converting circuit is in connection with the input positive terminal of a (K+1)th unit converting circuit through the inductance unit or is directly in connection with the input positive terminal of a (K+1)th unit converting circuit; K, M and N are all natural numbers, KN, and 1=M=(N+1). The input negative terminal of an Nth unit converting circuit is in connection with the circuit input negative terminal through the inductance unit or is directly in connection with the circuit input negative terminal; the outputs of the N unit converting circuits are in parallel connection or in series connection, and are in connection with the circuit output positive terminal and the circuit output negative terminal. The DC-DC converting circuit reduces the cost, eliminates or reduces common mode interference, realizes interleaving control, decrease input and output current ripples, and is in favor of reducing filters and implementation difficulty.

The invention belongs to the vehicle charging technology field and discloses an electric vehicle charging system. The system comprises a phase-shifting rectifier transformer connected to an external power grid. A backward stage of the phase-shifting rectifier transformer is connected to a concentration rectifier unit. A backward stage of the concentration rectifier unit is connected to a direct current bus unit and a backward stage of the direct current bus unit is connected to a DC/DC conversion circuit. In the invention, a concentration-type multiple pulse wave rectifier is used to replace multiple groups of modular parallel PWM-type high frequency PWM rectification circuits. An input terminal of the circuit is the phase-shifting rectifier transformer. Through transformer rectification, a high power factor and a low current harmonic wave are realized. Simultaneously, a concentration-type power factor rectification circuit shares a transformer whose an input high voltage is converted into a low voltage; the transformer is reconstructed into the phase-shifting rectifier transformer so that cost is greatly reduced. A rectifying element works in a power frequency work state, there is no high frequency switch losses and no common mode interferences caused by a high speed switch, efficiency is increased, reliability is improved and cost is reduced.

The invention discloses a current detection circuit which can be used for detecting a load current of an H bridge circuit. According to the current detection circuit, a positive voltage and a negative voltage of two ends of a detection resistor can be alternately and respectively detected through controlling two amplifiers, the other amplifier works at a zeroing state when one amplifier works in a signal amplification state, a problem of common-mode interference in the prior art can avoided when bidirectional current detection is carried out, and a precise detection current signal can be provided.