761 results about "DC bias" patented technology

The invention discloses a broadband high-efficiency 1bit circularly polarized reconfigurable transmission unit and an array antenna. The reconfigurable transmission unit comprises a circularly polarized wave receiving patch, an upper-layer dielectric substrate, an upper-layer metal ground plane, a middle dielectric substrate, a DC bias line, a lower-layer metal ground plane, a lower-layer dielectric substrate and a radiation patch which are sequentially arranged from top to bottom, and can directly realize two unit phases of 0 degree and 180 degrees of circularly polarized transmission waves; the equivalent rotation phase is free of dispersion; the state of each unit in the transmission array is controlled through the FPGA, + / -60-degree large-angle scanning of circular polarization transmission beams can be achieved, the beam performance is good, and high circular polarization purity is achieved. The array antenna provided by the invention has the advantages of wide axial ratio bandwidth and high aperture efficiency, and has relatively high application potential and value in scenes requiring real-time electric control circular polarization beam scanning antennas, such as application of long-distance radar detection, communication systems and the like.

The invention relates to the technical field of magnetic bias monitoring, in particular to a real-time monitoring method and system for direct-current magnetic bias of a transformer. The method comprises the following steps: acquiring a primary side current signal and an iron core vibration signal of the transformer; analyzing the zero-flux closed-loop characteristic of the primary side current signal of the transformer and performing temperature drift elimination on the primary side current signal of the transformer to generate a primary side optimization signal of the transformer; performing magnetostrictive vibration noise separation on the iron core vibration signal to generate an iron core vibration separation signal; dynamically filtering a power frequency fundamental wave of the primary side optimization signal of the transformer to extract a pure direct current component; and performing wavelet packet decomposition on the iron core vibration separation signal, and performing magnetostriction characteristic spectrum extraction on the decomposed iron core vibration separation signal to obtain an iron core magnetostriction characteristic spectrum. According to the invention, through multi-source signal fusion and material characteristic modeling, the accuracy, real-time performance and graded protection response capability of transformer DC magnetic bias monitoring are improved.

A RF generator includes a RF power source. The RF power source outputs a time-varying signal to a load. At least one controller is coupled to the RF power source. The at least one controller is configured to generate an impedance control signal to control an impedance between the RF power source and the load. The at least one controller is further configured to generate the impedance control signal in response to a pulsed DC output signal from a second power source.

The invention discloses a linear polarization in-band scattering reconfigurable radiation time-sharing regulation array antenna, which belongs to the technical field of antenna engineering, and comprises an antenna unit and a one-to-sixteen power divider, the antenna unit is connected with the one-to-sixteen power divider, and the antenna unit is connected with the one-to-sixteen power divider. The antenna unit comprises a first radiation patch, a first dielectric substrate, a second radiation patch, a second dielectric substrate, a feed coupling branch knot, a feed metal column, a third dielectric substrate, a perforated metal floor and a fourth dielectric substrate, and a first PIN tube, a second PIN tube, a feed transmission line, a direct current bias device, a reflective phase shifter and a low-pass filter are arranged at the bottom of the fourth dielectric substrate; the direct-current bias device is connected with the reflection type phase shifter and the feed transmission line through the low-pass filter, and the feed metal column sequentially penetrates through the third dielectric substrate, the perforated metal floor and the fourth dielectric substrate and is connected with the feed transmission line. According to the invention, the normal radiation efficiency of the antenna can be ensured, and the reconfigurability of antenna scattering can be effectively improved.

The invention discloses a DC bias suppression method and system and a storage medium, and relates to the technical field of DC power transmission, and the method comprises the steps: building a switching function model according to the voltage of each phase of bridge arm of a three-phase bridge arm in a flexible DC converter valve; according to the switching function model, representing a bridge arm current as a direct current component and an alternating current fundamental frequency component of the bridge arm to obtain a bridge arm current component expression; according to the bridge arm current component expression, obtaining a voltage input quantity and a current input quantity of the converter valve transformer side in a steady state; and generating a DC bias suppression strategy of the flexible DC system according to the voltage input quantity and the current input quantity. By adopting the embodiment of the invention, the three-phase generation mechanism of the direct current bias can be analyzed from the current and voltage conditions of the three-phase bridge arm in the flexible direct current converter valve, the direct current component in the asymmetric scene can be identified in time, and the control of the flexible direct current system can be effectively inhibited and optimized from the transformer valve side.

The invention relates to a direct current bias suppression device and method for a dual-active bridge and a dual-active bridge system, and the device comprises a high-frequency signal detection module which receives the primary side current and the secondary side current of a high-frequency transformer in the dual-active bridge, converts the primary side current and the secondary side current into voltage signals, and outputs the voltage signals to a control module; obtaining a primary side current detection signal and a secondary side current detection signal; the peak value detection module is used for detecting the maximum value and the minimum value of the primary side current in the primary side current detection signal and the maximum value and the minimum value of the secondary side current in the secondary side current detection signal; the sampling module is used for sampling the maximum value and the minimum value of the primary side current and the maximum value and the minimum value of the secondary side current; the control module is used for calculating the difference value between the sum value of the maximum value and the minimum value of the primary side current and zero and the difference value between the sum value of the maximum value and the minimum value of the secondary side current and zero, and obtaining the duty ratio adjustment amount of the primary side and the duty ratio adjustment amount of the secondary side by using the PI controller; and the direct-current bias current on the two sides of the dual-active bridge is suppressed according to the duty ratio adjustment amount.

The invention discloses a general transient DC bias suppression method for a dual-active-bridge converter under bidirectional power flow. The method comprises the following steps: when the dual-active-bridge DC converter operates stably, asynchronous carriers are generated; a certain modulation and control strategy is adopted, closed-loop operation is carried out in each switching period, and a primary side inner shift phase ratio D1, a secondary side inner shift phase ratio D2 and an outer shift phase ratio Df are generated; different working modes are selected according to the positive and negative relation of the external shift comparison between the current switching period and the previous switching period, and an asynchronously updated modulation wave is generated; and according to the selected working mode, determining a lead and lag relationship of the modulation wave, comparing the modulation wave with the carrier wave, and generating a driving signal of a power switch of the dual-active bridge converter. According to the method, the problem that an existing transient direct current bias suppression method is only suitable for a specific power flow direction or a specific modulation strategy can be solved, transient direct current bias suppression under power bidirectional flow is achieved, and safe operation of the dual active bridge converter is guaranteed.

The embodiment of the invention provides a permanent magnet synchronous motor electrical eddy current sensor angle error compensation method, and belongs to the technical field of motor driving. The compensation method comprises the following steps: acquiring differential sine and cosine signals output by the eddy current sensor; calculating a direct-current bias error according to the differential sine and cosine signals so as to obtain differential sine and cosine signals after direct-current bias error compensation; calculating an amplitude asymmetric error compensation coefficient according to the extreme values of the differential sine and cosine signals after the DC bias error compensation so as to obtain the differential sine and cosine signals after the amplitude asymmetric error compensation; and calculating the position angle of the motor rotor according to the difference sine and cosine signals after the amplitude asymmetric error compensation, and compensating the position angle by using the second harmonic cosine wave component of the position angle to obtain the real position angle of the motor rotor after compensation. According to the method, only algebraic addition and subtraction and multiplication are used, the execution time of the system is saved, the operation efficiency is improved, and the requirement for obtaining the position angle in real time is met.

The invention discloses a dual active bridge converter and a DC bias suppression method thereof, and belongs to the technical field of power electronic converters, and the method comprises the steps: carrying out the bilateral single-phase shift modulation according to a distribution coefficient p when the dual active bridge converter operates in a steady state; establishing an inductive current function model of the dual-active bridge converter considering the high-frequency link resistance; when a phase shift angle between the primary side and the secondary side of the dual-active bridge converter changes, according to circuit parameters of the dual-active bridge converter, an inductive current function model and a phase shift ratio before and after the change, a transient phase shift ratio is calculated and allocated to the primary side and the secondary side for bilateral single phase shift modulation. By introducing the transient phase shift ratio and the distribution coefficient and combining a bilateral phase shift control mode, transient direct current bias generated by transient inductive current and converter magnetic flux can be eliminated, excessive design of a magnetic element is avoided, and the ratio of any high-frequency link resistance value to a shift term can reach a stable state within a switching period.

The invention discloses a sensor array acquisition system for detecting gas, and relates to the field of gas sensors. The sensor array acquisition system for detecting gas comprises a gas sensor array, a signal conditioning circuit, an analog-to-digital conversion module, a control module and a power supply module. According to the sensor array acquisition system for detecting the gas, the voltage follower circuit with high input impedance is adopted, so that the problem of attenuation during signal acquisition of a high-impedance sensor is effectively solved, and the signal acquisition precision is improved. Through the adjustable direct-current bias circuit and the differential amplification circuit, the dynamic adjustment of the measurement range is realized, the gas detection requirements of different concentration ranges can be met, and hardware does not need to be replaced. A constant-current driving chip is adopted to control a sensor heating circuit, heating current can be accurately set by adjusting external resistance, it is ensured that the sensor works at the optimal temperature, and the stability and response speed of the sensor are improved.

The invention is suitable for the technical field of resonant converters, and provides a starting control circuit and a resonant converter. The starting control circuit comprises a feedback module, a comparison selection module and a logical operation module, the comparison selection module is electrically connected with the feedback module and the logical operation module, the feedback module is used for being electrically connected with the output end of a resonant conversion circuit in the resonant converter, and the logical operation module is used for being electrically connected with a driving circuit in the resonant converter. According to the starting control circuit provided by the embodiment of the invention, the resonant capacitor voltage constraint threshold value which is gradually enlarged along with the starting process can be constructed, smooth establishment of resonant capacitor direct current bias is realized, the fluctuation amplitude of the resonant capacitor voltage is limited, the problem that the total bus voltage is applied to the resonant inductor in a traditional scheme is avoided, and the starting control circuit is suitable for a high-voltage power supply. Finally, the resonance current peak value in the starting stage is effectively suppressed, and the impact of current stress on core devices such as a switching tube and a resonance inductor is reduced.

The invention discloses a transmission type one-bit phase metasurface unit for 5G millimeter waves, and belongs to the field of reconfigurable metasurfaces. The two sides of the receiving patch of the unit are respectively bridged with two PIN diodes which are arranged in the same direction; the radiation patch is respectively connected with the receiving patch and the metal ground through the metal through hole and the metal blind hole; a direct-current bias microstrip circuit and a metal ground which are separated by a semi-solidified substrate are arranged between the two dielectric plates, and the direct-current bias microstrip circuit is connected with the two rectangular patches through metal blind holes. Therefore, the center of the receiving patch is equipotential with the metal ground, and the two sides of the receiving patch are equipotential with the direct-current microstrip circuit, so that the two PIN tubes are always in opposite conduction conditions when the voltage is changed. When the state changes, the induction current directions of electromagnetic waves on the upper surface receiving patch are opposite, and transmission electromagnetic waves excited on the lower surface radiation patch through the metalized through holes generate a phase difference approximate to 180 degrees. The one-bit transmission phase regulation of 5G millimeter waves is realized, and the method has important application prospects in the fields of wireless communication, beam forming and the like.

The utility model discloses a detection circuit based on power system transistor driving, which comprises a signal input circuit and a direct current bias circuit, the signal input circuit and the direct current bias circuit are both electrically connected with a differential reduction circuit, the differential reduction circuit is electrically connected with an isolation operational amplifier module, and the isolation operational amplifier module is electrically connected with a differential proportion circuit. The differential proportion circuit is electrically connected with the comparator; the differential proportion circuit and the comparator are electrically connected with an MCU. The direct current bias circuit, the differential reduction circuit, the isolation operational amplifier module, the differential proportion circuit and the MCU are all electrically connected with the DCDC isolation system. The sampling isolation voltage operational amplifier ensures that the system is safe and reliable; single power supply sampling is adopted, the cost is reduced, expansion is facilitated, and the detection cost can be greatly reduced when a system needs to detect driving circuits of multiple transistors at the same time; reference voltage is added to the in-phase end through operational amplifier following, and noise interference is reduced.

The present invention discloses a broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonant structure, which includes a reconfigurable circularly polarized reflection functional layer, a circularly polarized horn antenna, and an acrylic bracket. The reconfigurable circularly polarized reflection functional layer is composed of M×N circularly polarized reflectarray antenna elements with the same structure, which are periodically arranged at an interval of 0.4125λ0. The circularly polarized reflectarray antenna element consists of a radiation layer and a DC bias layer. The radiation layer includes a circuit pattern designed based on a multi-resonant structure, PIN diodes, a radiation dielectric layer, and a reflection bottom plate. The DC bias structure includes a DC bias dielectric layer and a DC bias circuit. By controlling the on-off states of four PIN diodes, 1-bit regulation of the unit reflection phase can be achieved. By adjusting the states of each circularly polarized reflectarray antenna element, a beam scanning function of ±60° can be realized, and it can be applied in wireless communication and satellite communication systems.

The invention discloses a wavelength demodulation system for wavelength division multiplexing based on a microring resonator, comprising a microring resonator chip, a modulation signal generating circuit, a photoelectric signal conversion circuit and a frequency mixing filter circuit; the modulation signal generating circuit generates a sinusoidal oscillation modulation signal with a DC bias, and transmits it to the microring resonator chip and the frequency mixing filter circuit; the microring resonator chip converts input optical signals of different wavelengths into optical signals related to the wavelength, and transmits them to the photoelectric signal conversion circuit; the photoelectric signal conversion circuit converts the optical signal output by the microring resonator chip into an electrical signal, and transmits it to the frequency mixing filter circuit after amplification, and the frequency mixing filter circuit realizes the mixing and filtering of the sinusoidal oscillation modulation signal transmitted by the modulation signal generating circuit and the converted electrical signal, and outputs the demodulated voltage signal. The demodulation system disclosed by the invention can demodulate the sensor reflection signal based on a wide-spectrum light source, has low cost and small size, and can realize large-scale multiplexing.

The invention discloses a terahertz wave band composite beam RF MEMS switch with low driving voltage, and belongs to the field of radio frequency front-end devices. The device is composed of a direct current port metal block, a direct current bias line, a microstrip line matching structure, a composite beam MEMS switch, a composite beam middle conduction structure, a metal electrode of a composite beam, a silicon nitride insulating layer, a quartz glass substrate, a coplanar waveguide metal ground and a metal ground. The composite beam MEMS switch is formed by combining a silicon dioxide material clamped beam and a metal beam adsorbed below the silicon dioxide material clamped beam, a direct current port is connected to the anchor point position of the metal beam and a metal electrode through a direct current bias line, and different direct current voltages can be input through the direct current port to control the lifting state of the composite beam and the pull-down state of the composite beam adsorbed to the electrode. The two switches respectively correspond to an off state and an on state of the switch. The composite beam MEMS switch works below 140GHz, so that low driving voltage, low insertion loss and high isolation are realized. The reaction time of microsecond magnitude is achieved, destructive deformation is not prone to occurring, the structure is simple, and manufacturing is easy.

The invention discloses a monopole directional diagram reconfigurable antenna based on RF MEMS switch control, and belongs to the field of radio frequency front-end devices. The antenna is composed of a monopole radiation unit, parasitic units located on the left side and the right side of the monopole radiation unit, a composite beam ohmic contact type MEMS switch, a direct current bias line, a test patch bonding pad, a coplanar waveguide, a gradient microstrip line, a dielectric substrate and a metal ground backboard. When the MEMS switch on the parasitic unit is switched on, the length of the parasitic unit is slightly smaller than that of the monopole radiation unit, and the parasitic unit plays a role of a director. When the MEMS switch is turned off, the first-stage leading unit is divided into two parts from the fracture, the length of the first-stage leading unit is far smaller than that of the monopole radiation unit, and backflow is generated by the open circuit of the terminal, so that the effect of reducing and offsetting the second-stage leading unit is achieved. When the switch on one side is pulled down, a directional diagram generates beam deflection towards the side where the switch is closed, the adjustable deflection angle can reach 41 degrees, the gain can reach 6.14 dB, the beam width is about 90 degrees, when the switches on the two sides are both switched off, the beam deflection is 0 degree, the directional diagram points to the positive Z axis, and the gain is 5.15 dB.

The invention provides an excitation amplitude automatic closed-loop control system and method for a DLCP test. The system comprises a multi-frequency alternating current excitation and direct current bias voltage applying module which is used for automatically applying alternating current excitation signals and direct current bias voltage signals according to a preset excitation amplitude sequence under a plurality of test frequencies; the PID closed-loop control module is used for performing closed-loop correction on the applied voltage according to the response of the test port of the tested semiconductor device, so that the condition of the applied voltage at the test port meets a preset requirement; the capacitance measurement module is used for acquiring an equivalent capacitance response signal of the tested semiconductor device; the capacitance test data caching module is used for performing associated marking and classified caching on the capacitance test data according to the test frequency, the excitation level and the bias voltage set point; and the main control module is used for coordinating automatic test processes under the conditions of a plurality of test frequencies and different excitation amplitudes and outputting corresponding capacitance test data so as to improve the consistency, stability and automation degree of the DLCP test.

An electronic device may include wireless circuitry with a mixer. The mixer may include a transconductor with first and second input transistors, a switching quad with first and second pairs of mixer transistors, and a transformer coupled between the transconductor and the switching quad. The transformer may have a primary winding and a secondary winding. The transformer may have a conductive path that couples a center tap contact of the primary winding to a center tap contact of the secondary winding. The conductive path may configure the transformer to share a DC bias current between the transconductor and the switching quad. This may eliminate the need to bias the transconductor and the switching quad using different power supply voltages, thereby minimizing power consumption without sacrificing performance.

The invention discloses a voltage transformer direct current bias test device for photovoltaic power generation and a control method thereof in the field of electrical measurement. The device and the control method thereof comprise a first voltage regulator, an alternating current booster, a direct current voltage source and a voltage divider for monitoring. The components form a direct current bias voltage source which is connected with a primary coil of a voltage transformer for photovoltaic power generation in parallel and applies direct current bias power frequency test voltage, a second alternating current voltage source is connected with a standard voltage transformer in parallel and applies processing frequency alternating current test voltage, and a voltage divider for monitoring monitors voltage output by the direct current bias voltage source. Secondary coil output voltages of a tested mutual inductor and a standard mutual inductor, a voltage of a primary current flowing through a sampling resistor and an output voltage of a voltage divider are measured and input to a voltage transformer direct current bias performance measurement unit; and obtaining an error of the tested voltage transformer for photovoltaic power generation under a direct current bias condition, a primary current waveform, and a power frequency alternating current component and a direct current bias component of output voltage of a direct current bias voltage source.

The invention relates to the field of quantum sensing and quantum precision measurement, and particularly provides a frequency stabilization device and method for a Rydberg atom receiver, a sensing device and a receiver. Wherein the frequency stabilization device comprises a narrow linewidth semiconductor laser 1, a narrow linewidth semiconductor laser controller 2, a single-frequency fiber laser 16, a single-frequency fiber laser controller 15, a photoelectric detector 12, a frequency stabilization integrated circuit 13, a direct current bias device 14, a frequency stabilization integrated circuit 22, an alkali metal atom gas chamber 8, a photoelectric detector 21 and a light path assembly. The frequency stabilization device is simple in structure, does not need a complex optical path system and a circuit system, can realize simultaneous locking of frequencies of two Rydberg lasers by using a single bubble and sensing detection of a microwave field by using a parallel plate waveguide optical fiber integrated probe, and is small in receiver size and high in portability.

The invention belongs to the technical field of communication, and particularly relates to a 3-bit phase reconfigurable metasurface. The metasurface comprises a two-dimensional array formed by metasurface units and a direct-current bias network formed by bias lines of the metasurface units. Each unit is composed of three metal layers and two dielectric layers, the top layer is used for receiving and radiating electromagnetic waves, the middle layer serves as a ground layer, and the bottom layer serves as a phase shifter to achieve a 3-bit reconfigurable function. The phase shifter is divided into three parts which respectively realize 45-degree, 90-degree and 180-degree phase shifting functions, and eight phase states are realized through combined work of the three parts; the three parts are respectively controlled by a direct-current bias line, the direct-current bias lines of the units form a bias network, and independent regulation and control of the units are realized by loading direct-current control voltage from an external field FPGA (field programmable gate array) for the phase shifter. By changing the phase array coding of the metasurface, the functions of invisible cloak and RCS reduction can be realized. The metasurface has the characteristics of high precision, low loss and multiple functions.

The invention discloses a constant voltage ring and constant current ring automatic switching circuit and a linear power supply, and belongs to the technical field of electrical variable adjustment. Wherein the constant voltage ring comprises a differential sampling link, a direct current bias link and an integration link; the constant current loop comprises a proportional element and an integral element. A differential sampling circuit is arranged in the constant-voltage ring to sample the output voltage of the power supply, the differential sampling circuit is matched with a direct-current bias link to provide superposed voltage for an integration link in the constant-voltage ring, the superposed voltage is compared with set voltage, the switching-in time of the constant-voltage ring is determined, and therefore the constant-current ring can be switched to the constant-voltage ring in advance, and the switching-in time of the constant-voltage ring is determined. And the problem of overshoot of the output voltage of the power supply is prevented. According to the linear power supply, in the process of switching from the constant current stage to the constant voltage stage, the output voltage can be smoothly transited to the target voltage, the condition of step-shaped rising cannot occur, and the switching process is natural and rapid.

An electronic assembly heterogeneously integrates radio-frequency (RF) transistor chiplets into a host wafer, and the chiplets have interconnections to host wafer circuits. The assembly has at least one RF transistor chiplet having a chiplet circuit including a high-electron-mobility transistor (HEMT) or a heterojunction bipolar transistor (HBT). The host wafer has at least one host wafer circuit for the purpose of producing bias conditions that optimize performance of the HEMT or HBT. The host wafer circuit includes first circuitry to provide a DC bias of the HEMT or HBT; or second circuitry configured to sense radio-frequency operating conditions of the HEMT or HBT. The electrical interconnects are between the chiplet and the wafer, and electrically connect the host wafer circuit to the chiplet circuit.

An optical modulators is disclosed. The optical modulator includes a substrate, an optical waveguide formed on the substrate, a signal electrode formed on the optical waveguide via a first buffer layer and applying a modulation signal to the optical waveguide, and a bias electrode formed on the optical waveguide via a second buffer layer and applying a DC bias to the optical waveguide, the first buffer layer and the second buffer layer are formed in such a way that either one of the first buffer layer and the second buffer layer covers an end surface of the other one of the first buffer layer and the second buffer layer at a boundary part of the first buffer layer and the second buffer layer. Accordingly, an optical modulator with high reliability can be provided.

Laser control circuitry is described. In one example, a laser controller integrated circuit (IC) includes first and second input ports, a sideband direct digital synthesizer (DDS) coupled to the first input port and configured to produce a modulation signal and a reference signal based on an input signal received via the first input port, the modulation signal and the reference signal having a same frequency. The laser controller IC further includes a Pound-Drever-Hall frequency-locking control loop coupled to the second input port and to the sideband DDS, and configured to produce a corrected DC bias current signal based on the reference signal and a measurement signal received via the second input port, and a thermal management circuit configured to produce at least one thermal control signal.

The invention discloses a simulation analysis method and system for transformer vibration noise under direct current magnetic bias, and the method comprises the steps: building a transformer geometric model, and carrying out the mesh generation of the transformer geometric model; external excitation of the transformer is set in the field-circuit coupling model of the transformer under the direct-current magnetic bias condition, and magnetic density distribution of the transformer under different magnetic bias currents is obtained through simulation; in the transformer electromagnetic structure coupling model, calculating to obtain vibration acceleration of the transformer under different bias currents; the vibration acceleration of the transformer serves as excitation, and sound pressure levels around the transformer under different bias currents are calculated; and analyzing the influence rule of different bias currents on the vibration noise of the transformer through the characteristic quantity of the frequency spectrum signal. According to the invention, the vibration noise characteristics of the transformer under different magnetic bias currents can be accurately simulated, and technical support is provided for judging whether the transformer has a direct current magnetic bias phenomenon or not. The method can improve the evaluation efficiency and simulation accuracy, and improve the noise pollution and overall performance of the transformer.

To provide a layered ceramic electronic component that maintains high dielectric constant and has good DC bias characteristics.SOLUTION: The layered ceramic electronic component includes an element assembly formed by alternately stacking internal electrode layers and dielectric layers. The proportion of cubic crystal structures in the particles forming the dielectric layer sandwiched between the internal electrode layers is 25 mass% or more and 75 mass% or less. The average particle size of the particles forming the dielectric layer sandwiched between the internal electrode layers is 30 nm or more and 70 nm or less.SELECTED DRAWING: Figure 4

The invention relates to the technical field of radio frequency integrated circuits, and discloses a low-noise voltage-controlled oscillator circuit which comprises a source electrode following low-noise bias circuit with digital calibration, a source electrode following low-noise bias circuit with digital calibration, a source electrode following low-noise bias circuit with digital calibration and a source electrode following low-noise bias circuit with digital calibration, the cross-coupled amplifier array is composed of a plurality of units, and the source electrode of the cross-coupled amplifier array suppresses low-frequency noise through a resistance-capacitance feedback network and receives a digital amplitude calibration signal so as to dynamically adjust the number of working units and stabilize the output amplitude; the amplitude self-calibration loop consists of digital logic and a peak detector; the switched capacitor unit array is provided with stable direct-current bias; and a wide linear variable capacitor array driven by the stepped bias voltage. Through deep fusion of digital and analog technologies, the phase noise is remarkably reduced, the linear tuning range is widened, the amplitude stability is ensured, the power consumption is reduced, and the method is particularly suitable for a high-performance radio frequency communication chip of the Internet of Things.

The invention provides an open-circuit fault positioning and detecting system and an open-circuit fault positioning and detecting method based on a dual active bridge resonant converter (DBSRC). The open-circuit fault positioning and detecting system and the open-circuit fault positioning and detecting method based on the dual active bridge resonant converter (DBSRC). Aiming at DBSRC single-tube and multi-tube open-circuit faults, by analyzing characteristic quantities such as resonant capacitor voltage direct-current bias, bridge arm midpoint voltage mean deviation and resonant current direct-current bias and combining a threshold value correction strategy, rapid fault detection and accurate positioning are achieved. According to the method, a plurality of characteristic quantity joint criteria are introduced, the problem of positioning fuzziness caused by the fact that a traditional method depends on a single characteristic quantity is solved, and the reliability and the response speed of fault detection are remarkably improved by means of collaborative optimization of a hardware sensor and a software algorithm. The method does not need a complex control algorithm, has the advantages of being easy to implement, low in cost, high in compatibility and the like, and is suitable for the fields of direct-current microgrids, energy storage systems, power electronic transformers and the like.