423results about How to "High input impedance" patented technology

A bio-electrode for detecting heart signals and the like comprises a dry electode surface having an elevated resistivity to reduce the effect of polarization noise. The electrode is combined with a circuit having an external discharge resistor across which an output signal is obtained wherein the discharge resistor has a value which reduces the time constant of polarization noise to less than one second.

An integrated circuit, configured to process microphone signals, where the integrated circuit comprises: a preamplifier (306) with an amplifier section (301) which has a first input (φ) and a second input (φ*) and an output (φ), and with a feedback filter network (Z1; Z1, Z1*, Z2) coupled between the output (φ; φ, φ*) and the second input (φ′); where the first input (φ) to the amplifier section (301) has an input impedance which by means of the input impedance of the amplifier section is substantially isolated from the feedback network with respect to input impedance; and where the preamplifier has a frequency-gain transfer function which suppress low frequencies; and an analogue-to-digital converter coupled to receive an anti-aliasing filtered input signal and providing a digital output signal (Do).

A sensor arrangement (10) comprises an amplifier (11) having a signal input (12) to receive an input signal (SIN) and a signal output (13) to provide an amplified sensor signal (SOUT) that is an inverted signal with respect to the input signal (SIN). Furthermore, the sensor arrangement (10) comprises a feedback path connecting the signal output (13) to the signal input (12), wherein the feedback path comprises a series connection of a capacitive sensor (14) and a feedback capacitor (15). A voltage source arrangement (19) of the sensor arrangement (10) is connected to a feedback node (18) between the capacitive sensor (14) and the feedback capacitor (15).

A basic unit of lithium-ion battery, including: at least two series-connected lithium-ion cells; at least one lithium-ion cell for balance; controllable switches with the same number as the lithium-ion cells; a drive module for the controllable switches; a voltage detection module for detecting a voltage at two ends of the lithium-ion cells; and a controller. The lithium-ion cell for balance is connected in parallel to the lithium-ion cells. The controllable switches control the turn on / off of the connection in parallel between the lithium-ion cell for balance and each of the lithium-ion cells independently. The drive module for the controllable switches and the voltage detection module are connected to the controller. A battery pack including the basic unit of lithium-ion battery and a method for real-time charge / discharge equalizing of the basic unit of lithium-ion battery are also provided.

The invention provides methods and apparatus for improving the direct current (DC) offset performance of an oversampling analog-to-digital (A / D) converter, including A / D converters that include an oversampling quantizer such as a single or multi-bit Δ-Σ modulator, successive approximation quantizer, flash quantizer, pipelined quantizer or other suitable oversampling quantizer. A customized buffer / amplifier may be inserted between an analog chopper and a signal processing chain. The customized buffer / amplifier is optimized for input noise and the signal chain compensates for poor DC performance. The result is a buffered analog-to-digital converter with both low input noise and very good DC accuracy.

The invention relates to a universal data acquisition unit and a data acquisition method thereof, belonging to the technical field of data acquisition; the universal data acquisition unit comprises amicroprocessor; a multi-path discrete signal input interface is connected with the input end of a counter by a photoelectric isolating circuit, and a multi-path continuous signal input interface is connected with the input end of an A / D converter, and a microprocessor is connected with the input ends of the A / D converter and the counter. The data acquisition method comprises that: system initialization is carried out; continuous and discrete signal interrupt vector is set; interrupt latency is carried out, if the discrete signal is interrupted, the discrete signal is acquired; if the continuous signal is interrupted, the continuous signal is acquired; if a watchdog is interrupted, a system is restarted; if hibernation is interrupted, system setting data is stored, and then a hibernation state is carried out; and then, interrupt latency awaken operation is carried out, if awakening is interrupted, the system is started, and the setting is restored before interruption; if the continuoussignal and the discrete signal are acquired, interrupt latency is continuously carried out after data is transmitted to an upper computer; if not, interrupt latency is carried out directly.

The present invention belongs to the technical field of power electronics, in particular to an IGBT drive and protection circuit which can effectively realize power-down protection and can not be switched on by mistake. The IGBT drive and protection circuit comprises a common-emitter amplifying circuit, and a push-pull drive circuit and IGBT, wherein the common-emitter amplifying circuit is provided with a PWM signal input terminal for amplifying PWM signals, and the push-pull drive circuit is provided with a VDD power supply input terminal for receiving power from a VDD power supply. An NPN triode is connected between the common-emitter amplifying circuit and the PWM signal input terminal. The PWM signal input terminal is led out from the emitter; a base electrode of the terminal is provided with a VCC power supply input terminal through a resistor for receiving power from a VCC power supply; and a collecting electrode of the terminal is connected with the VDD power supply input terminal through a resistor. The IGBT drive and protection circuit has functions of power-down protection, gate protection and overvoltage protection for collecting electrodes, and is stable and reliable.

The invention discloses a high-linearity broadband stacking low noise amplifier based on a gain compensation technology. The high-linearity broadband stacking low noise amplifier comprises a two-stacking low noise amplification network, an interstage matching network and a two-stacking gain expansion amplification network which are connected in sequence; and a first power supply bias network and a second power supply bias network which are connected with the two-stacking low noise amplification network and the two-stacking gain expansion amplification network. According to the high-linearity broadband stacking low noise amplifier, a serial stacking structure is realized through adoption of two transistors with different sizes and ultra wide band noise and impedance matching are realized through combination of an RLC feedback network; through utilization of the gain compression compensation technology, the gain compression property of the two-stacking low noise amplification network is cancelled within a certain bias range through the two-stacking gain expansion amplification network and a linearity index of the amplifier is improved, so the whole low noise amplifier has good broadband, linearity, low power consumption and low noise amplification capability; and moreover, the low breakdown voltage property of an integrated circuit technology is avoided and the stability and reliability of a circuit are improved.

A light transmission module has a light transmitting unit having a light emitting portion for outputting an optical signal corresponding to a data signal input as an electrical signal, and a first power supply controller for controlling a drive power supply of the light emitting portion, a light transmission path for transmitting the optical signal introduced from the light transmitting unit, a light receiving unit having a light receiving portion for receiving the optical signal output from the light transmission path and outputting an electrical signal corresponding to the optical signal, and a second power supply controller for controlling a drive power supply of the light receiving portion, and at least one electrical transmission path, connecting the light transmitting unit and the light receiving unit, for transmitting a control signal for controlling power supply to the light emitting portion and the light receiving portion to the first power supply controller and the second power supply controller. The first power supply controller and the second power supply controller control the power supply to the light emitting portion and the light receiving portion based on the control signal input via the electrical transmission path.

A combined seat heater and capacitive occupancy sensor comprises a heater network and a capacitive sensing network. The heater network includes a heating element (10) connected between a first node (21) and a second node (22) to dissipate heat. The capacitive sensing network is connected to the heating element to apply an oscillating current thereto and to derive a capacitive load of the heating element from the voltage resulting on the heating element. The heater network comprises a common mode choke (16) connecting the first and the second node to a third (23) and a fourth (24) node, respectively. The capacitive sensing network further comprises means to sustain the oscillating current in or to drive the oscillating current into the heating element as well as a high-impedance amplifier (32) having an input node operatively connected to the heating element to probe the resulting voltage, and an output node (44) to provide an output signal indicative of the voltage.

The invention relates to a solution to a working power supply and the power of a two-wire-system electronic switch, relating to the field of illuminating electronic switches. The two-wire-system electronic switch comprises an off-state electrification circuit, a switch executive circuit, an on-state electrification circuit, and the like, wherein when loads are closed, the off-state electrification circuit supplies working electric energy for the electronic switch and also eliminates the sparkling phenomenon of a load lamp; the switch executive circuit is used for executing the starting or the closing of the loads, not only has low power consumption, but also provides the switch state indication; and when the loads are started, the on-state electrification circuit provides a heavy current path for the loads and also supplies the working electric energy for the electronic switch. The invention not only solves the problem on the working power supply of the two-wire-system electronic switch, but also enhances the loading capacity of the two-wire-system electronic switch.

A method and apparatus is described for interacting with electronic devices via motional commands. The method uses perturbations of the background quasistatic electric fields. The apparatus measures perturbations in electric potential relative to the background. Body movement is recognized by comparing changes in signals in time with signals collected from training sets for specified motional commands or gestures. Upon recognizing the commands, the apparatus issues the predetermined response to the motion.

To provide a measurement device which allows long-term accurate measurement of voltage without adversely affecting a device under test, by ensuring a predetermined level of resistance to ESD and reducing leakage current. A measurement device includes a probe needle for contacting a device under test, a first FET for detecting voltage of the device under test, and a protection circuit for protecting the first FET from static electricity. The protection circuit includes a second FET having an oxide semiconductor film as a channel formation region.

The invention discloses a circuit and a method for weak current detection and belongs to the current detection field. Geminate field effect transistors are employed by an input end to form a difference amplifier, and I-V conversion of a weak current is carried out; a voltage signal after conversion is sent to two sets of proportion operation circuits having symmetric in-phase input modes for proportion operation amplification; difference operation amplification of the voltage signal after proportion operation amplification is carried out, and a difference operation amplification voltage magnitude is measured. According to the method and the device, the junction type geminate field effect transistors are employed to form the difference amplifier as an input level, so input impedance is improved, and the relatively high common-mode inhibition ratio is acquired; the precise proportion operation circuit structures in the symmetric in-phase input modes are employed as the middle level, input impedance is further improved, and measurement precision is improved; the multiple operation amplifier difference amplification detection technology is employed, conflicts of useful-signal weakness and relatively high common-mode interference can be effectively solved, and high gain, high input resistance and the high common-mode inhibition ratio of the detection circuit are realized.

A differential input comparator circuit comprises an input stage comprising dual polarity input voltages and an output stage adapted to output a differential voltage based on the input voltages, wherein the differential voltage is adapted to be transmitted to a comparator and wherein the circuit has high input impedance and works with high input voltage swings.

According to one example embodiment, a bridgeless boost power factor correction (PFC) system includes a first input for connection to a first line of an alternating current (AC) source and a second input for connection to a second line of the AC source. The PFC system includes an output for delivering an output of the bridgeless boost PFC system, a first boost choke coupled to the first input and a second boost choke coupled to the second input. A common mode choke is coupled between the first and second input and the first and second boost choke. A first X capacitor is coupled between the first input and the output and a second X capacitor coupled between the second input and the output.

A power generating device is specified, which comprises a generator (1) , which is coupled to a drive unit, in particular to a turbine, and is connected via a rectifier (2) to a DC voltage intermediate circuit (3), an inverter (4), which is connected to the DC voltage intermediate circuit (3) and, on the AC voltage output side, has n phases with n AC voltage connections (5), and a filter arrangement (6), which is connected to the AC voltage connections (5). Furthermore, the filter arrangement (6) has a first filter inductance (7) and a second filter inductance (8), which is connected in series with the first, for each AC voltage connection (5), with a filter capacitor (9) being connected to the junction point of the first filter inductance (7) and the second filter inductance (8), and the filter capacitors (9) being connected to one another in a star circuit at a star point (10).

System and method for providing isolated power to a component that is also subject a set of RF signals that includes at least a first RF signal having a first RF frequency is provided. There is included providing a DC voltage signal and modulating the DC voltage signal into an isolated power signal using an isolation transformer. The isolated power signal has an intermediate frequency that is higher than 60 Hz and lower than the first RF frequency. There is included supplying the DC voltage signal to the primary winding and obtaining the isolated power signal from the secondary winding; and delivering the isolated power to the component using the isolated power signal.

A broadband RF signal amplifier includes a plurality of transistors attached to a surface of a pedestal, each transistor having an input and an output. An RF input path electrically connected to the transistor inputs includes a passive splitter implemented in a multi-layer printed circuit board and configured to split a RF input signal into a plurality of component input signals. A plurality of corresponding input matching networks including one-quarter wavelength transmission lines implemented in the printed circuit board couple respective component input signals to the transistor inputs at an input impedance, the input matching networks further comprising respective input matching capacitors attached to the pedestal. An RF output path electrically connected to the transistor outputs includes a passive combiner implemented in the printed circuit board and configured to combine component output signals received at the transistor outputs into a RF output signal. A plurality of corresponding output matching networks including one-quarter wavelength transmission lines implemented in the printed circuit board couple the respective component output signals at the transistor outputs to an output impedance.

The invention relates to animal muscle diagnosis and human body bioelectricity acquisition and recognition. The invention relates to electrode conductors for collecting surface electromyography signals, a functional buffer stage circuit, a preposing differential amplifying circuit, a filter circuit, a double T trap circuit and a back-stage amplifying circuit; the preposing differential amplifying circuit comprises a preceding stage differential amplifying circuit and a secondary differential amplifying circuit; the output end of the preceding stage differential amplifying circuit is also connected with a voltage follower circuit and an inverse amplifying feedback circuit which is communicated with the voltage follower circuit; the output of the inverse amplifying feedback circuit is communicated with the root of the electrode conductor; the filter circuit is the fifth-order Butterworth filter circuit; the electrode conductors are two silver electrodes which are pasted on the surface of skin; and the distance between the two silver electrodes is 8-12mm. The active double electrode surface electromyography sensor has good fixed mode, stable collected signals and strong signal filtering function, causes the capability of the circuit resisting the interfering of the power frequency to be increased and overcomes the defects of the high noise brought about by the electrode wiring, larger whole volume of the sensor and the like.

A front end circuit for coupling an antenna to a radio frequency (RF) transceiver is disclosed. An antenna port connectible to the antenna is provided, as well as a power amplifier coupled to a signal output of the RF transceiver and a low noise amplifier coupled to the signal input of the RF transceiver. The front end circuit includes a switching network that is connected to the antenna port, the power amplifier, and the low noise amplifier. Additionally, there is at least one resonant circuit and a control circuit coupled to a receive enable line of the transceiver. This resonant circuit defines a parallel resonance with a first resonant resistance in the operating frequency band upon activation in the receive mode. The resonant circuit also defines a substantially high transistor impedance upon deactivation in the transmit mode.

System and method for providing isolated power to a component that is also subject a set of RF signals that includes at least a first RF signal having a first RF frequency is provided. There is included providing a DC voltage signal and modulating the DC voltage signal into an isolated power signal using an isolation transformer. The isolated power signal has an intermediate frequency that is higher than 60 Hz and lower than the first RF frequency. There is included supplying the DC voltage signal to the primary winding and obtaining the isolated power signal from the secondary winding; and delivering the isolated power to the component using the isolated power signal.

The invention discloses a chopping amplifying circuit. A differential signal is connected to a circuit from a differential input end, and the differential input end is connected with an input end of a first-grade chopping switch; an output signal of the first-grade chopping switch is connected to the same-phase input ends of two differential operation amplifiers of a first-grade amplification circuit, and output ends of two differential operation amplifiers in the first-grade amplification circuit are connected to an input end of a second-grade chopping switch; an output signal of the second-grade chopping switch is connected to the same-phase and reverse-phase input ends of a second-grade amplification circuit; an output end of the second-grade amplification circuit is connected with input ends of a low pass filtering circuit and a negative feedback loop chopping switch, the other input end of the negative feedback loop chopping switch is connected with a common mode voltage; an output signal of the negative feedback loop chopping switch is connected to reverse-phase input ends of the two differential operation amplifiers in the first-grade amplification circuit after passing through pressure differential of a feedback network, and the low-pass filter wave circuit outputs a final amplifying signal of the chopping amplifying circuit.

The invention relates to a pre-amplifier and a signal acquisition device. The pre-amplifier is used for amplifying acquired weak signals and comprises an amplifying module and a common-mode feedback module. The amplifying module comprises an input circuit and a fully-differential output circuit. The output end of the input circuit is connected with the input end of the fully-differential output circuit. The fully-differential output circuit is provided with two differential mode output ends. The amplifying module is used for amplifying an input signal and acquiring an output signal. The common-mode feedback module comprises a common-mode feedback circuit and a common-mode feedback circuit of a source electrode degradation structure. The common-mode feedback module is connected with the amplifying module and used for suppressing common-mode gains of the output signal. The pre-amplifier and the signal acquisition device can reduce the size of a chip and reduce influences of capacitance matching on the common-mode rejection ratio.

The invention provides bidirectional thyristor trigger circuit and method. The circuit comprises a full-wave rectifier unit, a direct-current voltage-stabilized power unit, a zero-crossing synch pulse generation unit, an input signal photoelectric isolation unit, a phase shift trigger unit, and a bidirectional thyristor master circuit unit. According to the method, phase shifting is achieved by directly counting of input phase shift control frequency signals with a counter, and phase can be shifted by changing the input phase shift control frequency signals; the phase shift control signals input to the counter are subjected to photoelectric isolation and Schmitt rectification. The circuit is low in cost, small in size, stable and reliable in operation, and applicable as alternating-current voltage regulating switches in automatic control systems.

The invention discloses a device and a method for underground long-distance transmission of Manchester code (Man code), and belongs to the technical field of communication and the technical field of oil exploration. The device for the underground long-distance transmission of the Man code comprises a Man code sending unit and a Man code receiving unit. The Man code sending unit comprises a Man code encoding module, a bipolar pulse generating module and a push-pull driver module. The Man code receiving unit comprises an inductance-capacitance (LC) parallel resonant module, a unipolar pulse generating module, a Man code decoding module and a communication module. The Man code sending unit is used to compile data into a unipolar pulse and then generate a bipolar pulse, and the improved push-pull driver module is used to drive the bipolar pulse to be sent to a cable transmission unit. Appropriate inductance is selected in the Man code receiving unit and connected in parallel between a signal line of the receiving end of the cable transmission unit and a ground wire, LC parallel resonance is generated on the highest frequency component of Man code pulses, then the Man code unipolar pulse is generated, and the Man code unipolar pulse is decoded and transmitted to a host computer. The device and the method for the underground long-distance transmission of the Man code are suitable for an underground high temperature severe environment, the severe attenuation distortion drifting problem of single-ended signals in long-distance transmission can be resolved, and the unipolar pulse can be decoded correctly.

A microwave amplifier device with a bypass segment, the device operating either in active mode or in bypass mode. The bypass segment (2) comprises at least one section (13) of coupled transmission lines (14,15) whereby the isolation is increased. The amplifier unit (1) includes two LNAs arranged in parallel in a balanced configuration, and the bypass segment (2) has a relatively high input impedance in active mode, whereby a balanced operation of the amplifier unit is maintained. Consequently, a low noise factor is obtained, as well as reduced input and output reflections.

A Sallen-Key filter requires an operational amplifier with a large input impedance and a small output impedance to meet the external filter characteristics. The operational amplifier requires an internal feedback path for stability that limits performance. This invention eliminates the need for internal feedback and increases the gain of a source follower which has characteristics matching the operational amplifier in the Sallen-Key filter. The source follower provides 6 dB of AC voltage gain and is substituted for the operational amplifier in the Sallen-Key filter. The Sallen-Key filter requires a differential configuration to generate all the required signals with their compliments and uses these signals in a feed forward path. Furthermore, since the source follower uses only two n-channel stacked devices, the headroom voltage is maximized to several hundred millivolts for a 1.2V voltage supply in a 40 nm CMOS technology. Thus, the required 880 MHz bandwidth of the Sallen-Key filter can be easily met using the innovative source follower.