47results about How to "Wide gain range" patented technology

A gain control amplification circuit of this invention has a gain control amplification section which has at least two stages and is arranged in the transmission circuit of a terminal equipment for communicating with a base station. The gain control amplification section includes gain control amplifiers of IF-GCA and RF-GCA arranged on the input side (former stage) and output side (latter stage) of an up converter in the transmission circuit. The gains of the gain control amplifiers are individually controlled by a control section.

A directional signal processing system for beamforming information signals. The system includes an oversampled filterbank, which has an analysis filterbank for transforming the information signals in time domain into channel signals in transform domain, a synthesis filterbank and a signal processor. The signal processor processes the outputs of the analysis filterbank for beamforming the information signals. The synthesis filterbank transforms the outputs of the signal processor to a single information signal in time domain.

An LNA circuit for providing a wide range of gain while maintaining the output headroom. In a radio frequency (RF) receiver, the signal received by the receiver may be extremely small. For a transmitter in a short distance, the received signal may be relatively strong. A low power amplifier usually is used to amplify the input signal. The LNA has to be designed to accommodate a wide range of gain. A convention LNA circuit supporting a wide range of gain often suffers from reduced output headroom due to increased current through the load resistor. The present invention discloses the use of current bleeding branch to allow a portion of current to flow through the current bleeding branch and consequently reduces the current that would have flown through the load resistor. Consequently, the voltage across the load resistor may be maintained low to allow adequate output headroom.

A method for dynamically controlling audio signal gain in a communication device starts with determining a level of an input audio signal. The level is then mapped against a table of predetermined corresponding gain targets to determine an appropriate gain target for that level. The gain targets are then applied to the audio signal, which is then output. The invention is particularly suited to speakerphone operation in a communication device, wherein the gain targets provide compression, expansion or limiting so that distant speakers can be heard clearly.

The invention relates to a bi-directional converter, and provides a novel DC converter circuit topology with relatively high conversion efficiency. Zero-voltage turn-on (ZVS) and zero current turn-off (ZCS) of switch tubes are achieved; the efficiency and the power density of the converter are improved; and the gain range is expanded. Therefore, a CLTC resonant soft switching bi-directional converter comprises three parts, namely a main transformer primary side full-bridge circuit, a CLTC resonant circuit, a main transformer secondary side full-bridge circuit; the three parts are sequentially connected with one another; the CLTC resonant circuit is provided with an auxiliary transformer Tr2; a primary side of the auxiliary transformer Tr2 is spliced to the primary side of the main transformer Tr1; a secondary side of the auxiliary transformer Tr2 is connected with the secondary side of the main transformer Tr1; and the positions of dotted terminals of the primary side and the secondary side of the auxiliary transformer Tr2 and the primary side and the secondary side of the main transformer Tr1 are in the same direction. The bi-directional converter is mainly applied to designing and manufacturing of the bi-directional DC converter.

The invention discloses an LLC resonant converter and a control method, and the LLC resonant converter is lower in design difficulty, and comprises an inverter circuit, an LLC resonant cavity, a transformer and a rectification network which are sequentially connected from the input to the output. The LLC resonant cavity comprises a resonant inductor Lr, an excitation inductor Lm and a resonant capacitor Cr, and is additionally provided with a two-way switch; the resonant inductor Lr and the resonant capacitor Cr are connected in series between the first output end of the inverter circuit and the first end of the primary side coil of the transformer. The second output end of the inverter circuit is connected with the second end of the primary side coil of the transformer, the excitation inductor Lm is connected with the primary side coil of the transformer in parallel, the first end of the two-way switch is connected with the first end of the primary side coil of the transformer by being connected between the resonance inductor Lr and the resonance capacitor Cr, and the second end of the two-way switch is connected with the second end of the primary side coil of the transformer; theresonant inductor Lr is connected between the first end of the two-way switch and the first end of the primary side coil of the transformer, and the resonant capacitor Cr is connected between the first end of the two-way switch and the first output end of the inverter circuit.

The invention discloses an LLCT resonance type bidirectional direct-current converter. The topological structure of the converter comprises an inversion side full-bridge circuit, an LLCT resonance cavity and a rectification side full-bridge circuit which are connected in sequence. An auxiliary transformer T2 is introduced into the LLCT resonance cavity, the primary side of the T2 is connected in parallel between the point A and the point B in the resonant cavity inlet figure 2, the secondary side of the T2 is connected in series with the secondary side of the main transformer, and dotted terminals are in the same direction. Due to the introduction of the auxiliary transformer T2, the structure and the working frequency of the resonant cavity are changed. Compared with LLC, CLLC and other traditional resonant converters, the converter can realize high-gain buck-boost bidirectional work, has the soft switching characteristic of a switching tube, and ensures the high efficiency of the converter; high-voltage side parallel low-voltage side series connection of the auxiliary transformer is added, meanwhile, resonance inductance of a secondary side is removed, the gain range is widened,high-voltage side parallel low-voltage side series connection of the auxiliary transformer is added, resonance inductance of the secondary side is removed, and the gain range is widened.

The invention discloses a variable structure combined LLC resonant converter. The converter comprises a direct current source, a square wave generator, a combined resonance circuit, a combined transformer, a combined rectification filter circuit and a load, wherein the combined resonance circuit includes a first LLC resonance circuit and a second LLC resonance circuit; the combined transformer includes a first transformer and a second transformer; the direct-current source is connected with the square-wave generator; the square-wave generator is connected with the combined resonance circuit, the combined resonance circuit is connected with a primary side of the combined transformer, and a secondary side of the combined transformer is connected with the combined rectification filter circuit; and the combined rectification filter circuit is connected with the load. According to the variable structure combined LLC resonant converter, four working modes can be combined and converted, a gain range of the converter can be widened, stable output can be guaranteed through mode transition, conduction losses are not increased due to the added rectifying device, and the advantages of the LLCresonant converter are reserved.

The invention discloses a control method of a bidirectional LLC circuit of a power converter. The bidirectional LLC circuit comprises a first H-bridge circuit, a second H-bridge circuit and a transformer, and the first H-bridge circuit and the second H-bridge circuit are respectively connected to windings at two sides of the transformer; when the bidirectional LLC circuit works in a forward direction, the first H-bridge circuit is the input side, and the second H-bridge circuit is the rectification side. When the bidirectional LLC circuit works in a reverse direction, the second H-bridge circuit is the input side, and the first H-bridge circuit is the rectification side. The control method comprises adjustment in a transmission gain range of greater than 1, a switching tube on the input side works in a mode of fixed switching frequency and a fixed switching duty ratio of 50%, switching tubes of two half-bridges on the rectification side work in a phase shift control mode, alternate Boost voltage increase is realized, and the Boost voltage increase ratio is adjusted by adjusting a phase shift value, so that the gain of the bidirectional LLC circuit is greater than 1. According to the invention, the bidirectional converter can work in a relatively wide gain range in a bidirectional manner through a software modulation method without independently adding devices.

The invention discloses a PO mode enhanced CLLC resonant bidirectional DC/DC converter topology, which is characterized in that an auxiliary switching tube is additionally added between an input bridge arm and an output bridge arm on the basis of a CLLC resonant bidirectional DC/DC converter, and the PO mode operation range of the CLLC resonant bidirectional DC/DC converter can be widened by controlling the auxiliary switching tube. Therefore, the converter topology can maintain PO mode operation at a lower frequency and a higher power without falling into a PON mode, so that the converter topology has stronger load capacity and a wider voltage gain range. When the inverter works below the resonance point frequency, the inverter side switch tube is switched on at zero voltage, and the rectifier side switch tube is switched on at zero current and switched off at zero current, so that the inverter has very high efficiency.

The embodiment of the invention provides a gain frequency modulation method applied to a flying capacitor type half-bridge three-level LLC resonant converter and a related device, and the method comprises the steps: controlling the flying capacitor type half-bridge three-level LLC resonant converter to be switched between a high gain frequency modulation mode and a low gain frequency modulation mode according to different input and output voltages; when the input voltage is high and the output voltage is low, enabling the resonant converter to work in a low-gain frequency modulation mode. Forthe same input voltage, the peak-to-peak value of the LLC resonant cavity input voltage of the flying capacitor type half-bridge three-level LLC resonant converter in the low-gain frequency modulationmode is less than the peak-to-peak value of the LLC resonant cavity input voltage in the high-gain frequency modulation mode, so that the gain of the circuit is reduced. By changing the frequency modulation mode, the gain range of the flying capacitor type half-bridge three-level LLC resonant converter is expanded.

A complementary metal oxide semiconductor (CMOS) variable gain amplifier has a wider decibel-linear gain variation characteristic with respect to a control voltage when a signal is amplified. The variable gain amplifier includes: a bias input circuit for supplying a current corresponding to a bias voltage; an operation region combination and feedback circuit connected to the bias input circuit and combining at least two amplifiers by feedback in response to a control voltage, each amplifier having a decibel-linear characteristic in saturation and triode regions of a complementary metal oxide semiconductor (CMOS); and a bias output circuit connected to the bias input circuit, and outputting bias current controlled by the operation region combination and feedback circuit.

The invention relates to the technical field of power electronic converters and electric energy conversion, particularly to a cubic buck converter. On the basis of intrinsic characteristics of an inductor-capacitor-diode network, three power inductors store energy at the same time and two intermediate energy storage capacitors release energy externally when a power switch tube is turned on; and when the power switch tube is turned off, the three power inductors release the stored energy to two intermediate energy storage capacitors and a load. Therefore, the high buck of the output voltage isrealized by using one power switch tube and thus the value of the output voltage is D3 times that of the input voltage, wherein the D expresses a duty ratio of the power switch tube when the converterworks.

The invention relates to the technical field of power electronic converters and electric energy conversion, in particular to a novel wide-gain secondary buck converter which comprises a power switch tube, three power inductors, two middle energy storage capacitors, an output capacitor and seven diodes. Intrinsic characteristics of an inductor-diode network and an inductor-diode network are utilized. When the power switch tube is turned on, the three power inductors are connected in series and store energy, the two middle energy storage capacitors are connected in parallel and release energy tothe outside at the same time, and when the power switch tube is turned off, the three power inductors independently release energy to the two middle energy storage capacitors and a load, and voltagegain expansion of the buck converter is achieved. The invention has the advantages that the gain of the buck converter can be changed within the range of 0.003-0.669, that is to say, the minimum output voltage can reach 0.003 time of the input voltage, and the gain range of a traditional buck converter is greatly expanded; an extra power switch tube is not needed, the structure is simple, and control is convenient.

The invention discloses a power supply circuit for applying LLC to a restaurant service robot, and a control method. According to the invention, a LLC topological power supply circuit is designed fordifferent working occasions such as standby, welcoming, dish taking, moving, carrying and the like of a service robot in a restaurant, a full-bridge double-resonant-cavity LLC topological structure isadopted, efficient conversion of electric energy in a full-power range is achieved through various switch combinations of N-channel field-effect tubes, and according to different working conditions of the service robot in the restaurant, four working modes including a standby mode, a light load mode, a medium load mode and a heavy load mode are set and correspond to different circuit structures and control methods respectively, so that under the condition that LLC narrow-frequency range work is met, high efficiency of the robot servo power supply in the full-power range is achieved, large loss and large heat productivity of a long-time work system are avoided, the service life of the power supply can be prolonged, interference of the servo power supply to other auxiliary power supplies isreduced, the system reliability is enhanced, and energy consumption is reduced.

The invention discloses a topological structure of an isolated boost bidirectional DC-DC converter. The circuit comprises a pre-stage Boost circuit, an integrated transformer and a post-stage H-bridgecircuit, wherein the pre-stage Boost circuit comprises a first two-phase interleaved Boost converter, a second two-phase interleaved Boost converter and a third two-phase interleaved Boost converter;the integrated transformer is of a coupling inductance structure and comprises a Boost inductance part and an ideal transformer structure, the first two-phase interleaved Boost converter is connectedwith the Boost inductance part of the integrated transformer in series, and the ideal transformer structure of the integrated transformer is connected with the post-stage H-bridge circuit in series.The topological structure is few in selected devices, simple in circuit and high in integration level, the problem that input current is discontinuous can be well solved, input current ripples and output voltage ripples are greatly restrained, and the topological structure can be applied to a lithium battery application scene with higher requirements for the current ripples.