68 results about "Pulse-frequency modulation" patented technology

The invention provides an infrared image sensor and a pixel-level reading circuit thereof, and relates to the field of infrared image sensors. The pixel-level reading circuit is integrated in a single pixel unit, and comprises a direct injection input-level circuit used for converting an infrared light-generated current generated by an infrared image sensor into an analog voltage signal; the pulse frequency modulation analog-to-digital converter is connected with the direct injection input stage circuit and is used for converting the analog voltage signal into a pulse signal; the SR latch is electrically connected with the pulse frequency modulation analog-to-digital converter and is used for carrying out accumulative counting on the pulse signals so as to form digital code words reflecting the infrared light intensity; and the digital logic control unit is electrically connected with the SR latch and is used for transmitting the digital code word to a reading bus of the infrared image sensor, so that the output of a digital signal is realized, and the reading rate of the image sensor is improved.

The invention discloses an air pressure sensor communication control method and system based on PFM pulse frequency modulation, in a multi-sensor networking scene, environmental parameters are converted into analog electric signals through signal conditioning and then mapped into a unique pulse change sequence, and coding optimization is carried out for the matching degree of the pulse sequence and the parameter variable quantity. High-fidelity and low-power-consumption data expression and transmission are realized; anti-interference filtering is implemented through a communication link in combination with a signal transmission protocol, and original parameter data is restored through inverse mapping after the integrity of a pulse sequence is ensured; then, the data of the multi-source sensor is integrated in the main control unit to form a networking parameter data set, abnormal deviation is judged through comparison logic, a control instruction is generated and fed back to a terminal to execute accurate adjustment, a complete link from sensing and optimized transmission to closed-loop regulation and control is formed, and finally high-reliability real-time monitoring and self-adaptive intelligent regulation and control of environmental parameters are achieved.

According to the light-load current limiting circuit of the switching circuit provided by the embodiment of the invention, the voltage and current conversion module generates the initial error current and the pulse frequency modulation current according to the fixed voltage when the clamping module locks the error voltage to the fixed voltage; the clamping module is used for locking the error voltage received by the voltage-current conversion module to a fixed voltage when the error current is smaller than the first reference current; the trigger signal generation module is used for generating a first trigger signal at a first preset moment and generating a second trigger signal at a second preset moment when the clamping module locks the error voltage received by the voltage and current conversion module to a pulse signal period corresponding to the fixed voltage; and the switch module is connected in a first mode when receiving the first trigger signal and determines a target voltage input to the pulse width modulation module, and the switch module is connected in a second mode when receiving the second trigger signal and the second resistor is connected to an output load of the switch circuit through the switch module.

The invention discloses a humanoid robot control method based on a neural circuit, and belongs to the technical field of robot control, and the method comprises the steps: S1, constructing a three-layer pulse neural control architecture comprising spinal cord reflex, brainstem balance and cortex decision, and carrying out the weight adaptive distribution and cooperative operation between layers through the dynamic adjustment of neurotransmitter concentration, organic cooperation of prediction and reflection is realized through a three-stage control system; the cerebellar prediction network executes attitude adjustment in advance through a delay compensation algorithm, and compared with pure feedback, the control energy consumption is reduced; the parallel reflex pathway of the spinal cord layer establishes a nerve bypass mechanism, and the emergency response is realized by bypassing high-level processing in an emergency; the multi-layer safety monitoring improves the triggering accuracy of a protection mechanism through error confidence evaluation and contact stability analysis; a weight transfer mechanism of pulse frequency modulation avoids sudden movement change during control mode switching; by means of the design, the stability retention rate of the robot walking on the inclined plane is remarkably improved compared with a traditional method.

The invention provides a driving system and method for a vehicle-mounted lamp and a vehicle, and relates to the technical field of vehicle lamps, and the driving system comprises a single-end primary inductance converter and a control module; the single-end primary inductance converter comprises a power supply module and a gallium nitride switch module, and the gallium nitride switch module is connected with the power supply module and the vehicle-mounted lamp; the control module is connected with the gallium nitride switch module and the vehicle-mounted lamp, the control module is used for detecting the load current of the vehicle-mounted lamp and switching the on-off state of the gallium nitride switch module and the working mode of the driving system based on the load current, and the working mode comprises a pulse width modulation mode, a pulse frequency modulation mode and a burst mode. The system is provided with the gallium nitride switch module, so that the synchronous rectification effect can be achieved, and the conduction loss and the switching loss are relatively low. And secondly, the system adopts a hybrid modulation strategy, so that the optimal working mode can be automatically switched in different load states, and the driving stability, reliability and efficiency of the system are improved.

The invention relates to a buck switched mode power supply. A buck-type switched mode power supply includes a switching unit formed of a first switch configured to be periodically set to an on state by a first control signal modulated by a pulse width or pulse frequency modulation type. The amplifier generates an error voltage representing a difference between a reference voltage and an output voltage of a power supply intended to be applied to an input of the amplifier. The delay circuit applies a delay to the first control signal to reduce a difference between the error voltage and the reference voltage. The delay modulation circuit modulates a value of the delay according to a difference between the error voltage and a reference voltage.

A power conversion circuit includes a transformer, a resonant capacitor, a resonant inductor, a high-side transistor, a low-side transistor, and a control circuit. The transformer includes a primary coil and a secondary coil. The primary coil, the resonant capacitor, and the resonant inductor are connected in series between a switch node and a ground. The high-side transistor provides an input voltage to a switch node based on the high-side driving signal. The low-side transistor couples the switch node to the ground based on the low-side transistor. The control circuit operates in a pulse frequency modulation mode to generate the high-side transistor and the low-side transistor with a switch frequency. When the switch frequency exceeds the first threshold, the control circuit switches from the pulse frequency modulation mode to the pulse width modulation mode.

The invention discloses a power conversion circuit and a control method thereof. The power conversion circuit comprises a transformer, a resonant capacitor, a resonant inductor, an upper bridge transistor, a lower bridge transistor and a control circuit. The transformer comprises a primary coil and a secondary coil. The primary coil, the resonant capacitor and the resonant inductor are connected in series between the switching node and the ground terminal. The upper bridge transistor supplies an input voltage to the switching node based on an upper bridge driving signal. The lower bridge transistor couples the switching node to a ground terminal based on a lower bridge driving signal. The control circuit is operated in a pulse frequency modulation mode to generate an upper bridge driving signal and a lower bridge driving signal at a switching frequency. When the switching frequency exceeds a first threshold value, the control circuit switches from the pulse frequency modulation mode to the pulse width modulation mode.

This invention discloses a method and system for resisting slice reconstruction interference based on alternating frequency modulation slope polarity and time-series agility. It mainly addresses the problems of high complexity, poor real-time performance, and high dependence on prior information and training data in existing technologies. The scheme is as follows: At the transmitting end, a joint agile transmission signal is established based on the number of sub-pulses, sub-pulse duration, sub-pulse interval, sub-pulse bandwidth, and sub-pulse frequency modulation slope; at the receiving end, the received signal is segmented according to the recorded sub-pulse timing to obtain each segment signal, and pulse compression and delay compensation for both matched and mismatched channels are performed simultaneously; dynamic weights are generated based on the energy of the two compensated channels; an anomaly suppression factor is constructed based on the energy of the matched channels of each segment, and the output of each segment's matched channels is weighted and accumulated using this factor and the dynamic weights to obtain a one-dimensional range profile result. This invention does not require a large amount of training data or estimation of interference parameters, has low computational complexity, can suppress false targets generated by slice reconstruction interference while maintaining the energy of the real target, and can be used for target detection.

The present disclosure relates to multiphase switching voltage regulators and controllers. A controller for a multiphase switching voltage regulator includes a first control loop and a second control loop. The first control loop has a first set of coefficients for implementing pulse width modulation (PWM) and a second set of coefficients for implementing pulse frequency modulation (PFM). The second control loop is configured to implement phase current balancing for the multiphase switching voltage regulator. In a first configuration, the first control loop is configured to implement PWM-based control of the multiphase switching voltage regulator using the first set of coefficients. In a second configuration, the first control loop is configured to implement PFM-based control of the multiphase switching voltage regulator using the second set of coefficients.

The invention provides a soft switching implementation and synchronous hybrid control method for a bidirectional symmetric CLLLC resonant converter, which relates to the technical field of converter control and comprises three steps of constructing a bidirectional symmetric network and setting soft switching conditions, executing synchronous hybrid control and monitoring the state of the soft switching. According to the invention, the CLLLC resonant network is constructed by adopting the design that the parameters of the primary side and the secondary side are symmetrical, the symmetrical soft switching control can be realized when the converter is in the forward and reverse working modes, the stability and the symmetry of the system are improved, and the stability and the symmetry of the system are improved by optimizing the soft switching condition and combining the two control modes of pulse frequency modulation and pulse width modulation. The working state of the system can be automatically adjusted within the wide input / output voltage and load change range, soft switching is kept all the time, and therefore the problems that in a traditional method, due to input voltage fluctuation and load change, system efficiency is reduced, and stability is poor are solved.

A system may include a power converter comprising a power inductor and a plurality of switches and a controller configured to control the power converter, including controlling the power converter in discontinuous conduction mode to magnetize and demagnetize the power inductor, wherein the controller is further configured to, in each switching cycle of the power converter, terminate a magnetization period of the power inductor based on a function dependent upon an output voltage of the power converter and a power inductor current flowing through the power inductor.

The application provides an adaptive optimization charging method for a LCC resonant converter with a capacitive load based on an improved fundamental equivalent model, to solve the long charging time, large frequency variation range, narrow ZVS range and other defects of a traditional CC charging method. The charging method comprises the following steps: establishing an enhanced fundamental approximation (E-FHA) model; obtaining an analytical expression of a voltage gain M, a resonant current effective value I rms , an average output current I o and a switching frequency f s ; determining the relationship between the maximum average output current and the switching frequency during charging directly through the analytical expression and an AOC method, and realizing a pulse frequency modulation (PFM) frequency control curve. The method provided by the application fully utilizes the working current limit of the switch and the switching frequency limit to obtain a higher average output current, thereby improving the charging speed and reducing the switching frequency range and temperature rise.

The invention provides a soft switching three-level boost converter topological structure and a working method thereof. The topological structure comprises a direct-current power supply, a resonant structure and an output circuit structure which are connected in sequence, the resonant structure comprises a switching tube S1, a switching tube S2, a diode D1, a diode D2, a diode D3, a diode D4, a resonant inductor Lr and a resonant capacitor Cr, and zero-current switching-on of the power switching device is realized through combination of the resonant inductor Lr, the resonant capacitor Cr and other elements. And the switching loss is effectively reduced. High-frequency loss is avoided by combining pulse frequency modulation of the CRM mode and the DCM mode. According to the topology, zero-current switching-on of the switching tubes, reduction of the inductor size and improvement of the overall efficiency are achieved, and the topology is suitable for various working conditions such as high gain and low gain.

This invention discloses an LLC resonant converter with a wide output voltage range based on a voltage doubler rectifier, applicable to DC fast charging of new energy vehicles. The converter achieves primary-side inversion and secondary-side rectification topology reconfiguration through switch drive signals, enabling wide-range voltage output in four operating modes. The primary side can switch between half-bridge and full-bridge inversion modes, while the secondary side can switch between full-bridge, voltage doubler, and voltage quadruple rectifier modes. This invention reduces diode voltage stress, possesses self-balancing capability of the voltage doubler capacitor, and achieves soft switching across the entire voltage range. Ultra-wide voltage gain is achieved within a narrow frequency adjustment range across the entire voltage range through simple pulse frequency modulation (PFM), allowing the converter to adapt to the charging needs of new energy vehicles with different voltage platforms.

The application discloses a control circuit, a control method and a resonant converter compatible with LLC and DCX, the control circuit comprises: a reference voltage generation circuit, which is used for generating a corresponding pulse width modulation reference voltage according to a selected control mode; a modulation signal generation circuit, which is used for comparing a slope voltage with the pulse width modulation reference voltage to output a pulse width modulation signal, and comparing the slope voltage with a correlation voltage of the pulse width modulation reference voltage to output a pulse frequency modulation signal; the correlation voltage comprises at least one voltage used for generating the pulse width modulation reference voltage; and a logic control circuit, which is used for generating an upper tube driving signal and a lower tube driving signal according to the pulse width modulation signal and the pulse frequency modulation signal. The application can configure the resonant converter to work in the DCX mode or the LLC mode according to different scenes, and reduces the design complexity and cost of the resonant converter system.

The utility model discloses a load detection circuit which is used for detecting the connection state of a load in a charging and discharging circuit. The load detection circuit includes a switching element, a first resistor, and a controller. The input end of the switch element is connected with the power supply, and the output end is connected with the controller. The input end of the first resistor is connected with the first output end of the switch element, and the output end of the first resistor is connected with the common end of the DC-DC converter switch pin and the energy storage element in the charging and discharging circuit. The direct current-direct current converter comprises a pulse frequency modulation working mode, in the pulse frequency modulation working mode, the common end transmits a low level signal to the first output end of the switch element through the first resistor, so that the switch element is in a conducting state, and the second output end of the switch element transmits a first electric signal output by the power supply end to the controller; when the first electric signal is smaller than a preset value, the controller sends a load disconnection instruction to the charging and discharging circuit or a load in the charging and discharging circuit is in a disconnection state.

The invention discloses a five-switch multi-mode wide-voltage-range LLC resonant converter. The five-switch multi-mode wide-voltage-range LLC resonant converter is mainly composed of a five-switch inverter stage, a resonant cavity, a high-frequency transformer and a full-wave rectifier stage. A hybrid modulation mode is adopted in a control strategy, the duty ratio is adjusted through fixed-frequency pulse width modulation (PWM) so as to increase the voltage of a direct-current bus, and the voltage gain range of more than three times is achieved in cooperation with fixed-duty-ratio pulse frequency modulation (PFM). In addition, the topology can maintain excellent soft switching characteristics in a full working range, and high-efficiency operation under wide voltage output is ensured. Compared with a traditional wide-range resonant converter, only five weighted switch tubes, one transformer and two diodes are needed, the hardware cost is remarkably reduced, the power density is improved, and the wide-range resonant converter has remarkable engineering application value.

The invention discloses a control method of a synchronous rectification device, and the control method comprises the following steps: 1, obtaining the current working state of the synchronous rectification device in real time, and carrying out the driving control of each switching tube of a primary side through employing a pulse frequency modulation (PFM) mode, so as to adjust the working frequency of the synchronous rectification device, the gain requirement required by the synchronous rectification device is met; step 2, acquiring an input voltage Vin, a current switching frequency and a load output current of the synchronous rectification device in real time, and modulating a synchronous rectification driving signal of each rectification switching tube in the rectification network according to the acquired input voltage Vin, the current switching frequency and the load output current, controllable rectification control is carried out on each rectification switch tube through a synchronous rectification driving signal, and conversion from alternating current to direct current is realized. Cooperative control of adjusting the primary side frequency to the secondary side rectification adaptation can be realized, the stability of conversion from alternating current to direct current is ensured, the output voltage fluctuation is reduced, and the rectification precision and efficiency are improved.

The invention relates to a system and method for controlling a switching converter operating at pulse frequency modulation. A control unit for controlling a converter having a PFM regulated switching operation is configured to generate a square wave control signal to control switching of at least one switching element of the converter, the square wave control signal having a switching period defining a first time interval and a second time interval, the first and second time intervals are associated with respective values of the control signal, where the control unit determines a constant duration of the first time interval and a minimum duration of the second time interval in order to determine a maximum operating frequency of the converter. The control unit implements a detection stage for detecting an abnormal current event as a function of a count of a predetermined number of temporally consecutive cycles of the control signal, during which the converter operates at a minimum duration of a second time interval, and thus at a maximum operating frequency.

A switching regulator is arranged to receive an input voltage to generate an output voltage, and includes an inductor, a mode selection circuit, a multiplexer, and a driving circuit. The mode selection circuit is arranged to generate a selection signal, wherein the selection signal indicates whether the switching regulator operates in a PWM mode or a PFM mode. The multiplexer is arranged to output a PWM signal or a PFM signal according to the selection signal. The driving circuit is arranged to generate a driving signal according to the PWM / PFM signal to control switches in the switching regulator. In response to the switching regulator operating in the PFM mode, an energy storage time of the inductor in one cycle of the PFM signal is generated according to a period length of the PWM signal.

A feedback control circuit of a pulse-frequency modulation (PFM) converter includes an on-time timer circuit and a detection circuit. The on-time timer circuit generates an on-time control signal for controlling an on-time duration of a switch circuit included in a power stage circuit of the PFM converter. The detection circuit controls the on-time timer circuit to adaptively adjust the on-time control signal according to a pulse interval between two successive inductor current pulses of the PFM converter.

A load control device for controlling the intensity of a lighting load, such as a light-emitting diode (LED) light source, may include a power converter circuit operable to receive a rectified AC voltage and to generate a DC bus voltage, a load regulation circuit operable to receive the bus voltage and to control the magnitude of a load current conducted through the lighting load, and a control circuit operatively coupled to the load regulation circuit for pulse width modulating or pulse frequency modulating the load current to control the intensity of the lighting load to a target intensity. The control circuit may control the intensity of the lighting load by pulse width modulating the load current when the target intensity is above a predetermined threshold and control the intensity of the lighting load by pulse frequency modulating the load current when the target intensity is below the predetermined threshold.

The invention relates to a pulse frequency modulation type digital pixel circuit with fixed charge extraction capability and a working method, and belongs to the technical field of infrared focal planes. Comprising a photocurrent injection tube M4, a reset switch tube M5, an auxiliary capacitor C1, a fixed charge packet storage capacitor C2, a charge reset switch, a charge distribution self-starting switch, a feedback loop switch, an inverter, a current source and a counter. According to the invention, a brand new voltage feedback loop is designed, and the self-adaptive current-pulse generation circuit with zero charge leakage, low power consumption and high speed is realized by using a very simple circuit structure, so that the core problems of high power consumption, high circuit complexity and low speed of a traditional digital pixel structure are solved. Meanwhile, the novel circuit structure still has the key function of fixed charge extraction of the IADC, and has better linearity compared with a traditional pulse frequency modulation (PFM) structure.

The invention discloses a single-stage isolated AC-DC converter with a wide gain range and a modulation method thereof.The converter comprises a power frequency full-bridge circuit module, an FSBB converter module and an LLC resonant converter module which are connected in sequence, and each of the FSBB converter module and the LLC resonant converter module comprises two bridge arms which are connected in parallel; each bridge arm comprises two branches which are connected in parallel and formed by connecting two switching tubes in series, and the inductor is connected to a common node between the two bridge arms of the FSBB converter module in series; in the LLC resonant converter module, a primary winding of a transformer is connected in parallel with an excitation inductor and then connected in series with a common node between two bridge arms, and a resonant inductor is connected in series with a resonant capacitor and then connected in parallel with the excitation inductor to form a resonant cavity; the modulation method comprises the following steps: implementing a simplified frequency conversion control strategy on the FSBB converter module, performing fixed-frequency control in an intermittent conduction mode during light load, and performing frequency conversion control in a continuous conduction mode during heavy load; pulse frequency modulation control is carried out on the LLC resonant converter module; according to the invention, high-efficiency energy conversion in a wide input and output range is realized.

The application discloses a kind of three-port converter energy balance control method based on power distribution of pulse frequency sudden drop, in the case where load frequency suddenly drops, the power distribution mode of AC / DC converter is switched, and the fastest change rate that AC / DC converter can provide is controlled to control input source power linearly decreases and linearly increases, after a short adjustment time, energy storage capacitor charging and discharging can be balanced, then the system enters new steady state.Compared with load frequency sudden increase, when three-phase alternating current source input power is too small, pulse load frequency sudden drop is limited by the power distribution mode of AC / DC converter, and it can make pulse load voltage fluctuate, so that the dynamic recovery time of decoupling capacitor voltage is too long, and the original power distribution mode cannot meet the demand of pulse load, so the power distribution mode of AC / DC converter needs to be switched.The problem that the dynamic performance of existing pulse power compensation control method is not optimal after load pulse frequency suddenly drops is solved.

A system may include a power converter comprising a power inductor and a plurality of switches and a controller configured to control the power converter, including controlling the power converter in discontinuous conduction mode to magnetize and demagnetize the power inductor, wherein the controller is further configured to, in each switching cycle of the power converter, terminate a magnetization period of the power inductor based on a function dependent upon an output voltage of the power converter and a power inductor current flowing through the power inductor.

The application discloses a single-photon laser ranging method based on laser pulse frequency modulation deblurring, and belongs to the field of laser ranging. In the ranging process, two different pulse frequency references are set to correspond to two encoding code elements, n-bit random codes are generated according to n times non-blurring distance expansion requirements, and the n-bit random codes are ensured to have no shift symmetry, then a laser source repeatedly emits corresponding pulse signals according to a sequence represented by the random codes, then a sequence of echo signals is received, a single-photon cumulative histogram is obtained, and a cross-correlation operation is performed on the single-photon cumulative histogram and the pulse sequence represented by the known random codes to obtain an operation result, one having the maximum amplitude in the operation result is determined, and a histogram time position corresponding to the operation result is calculated, that is, a ranging result without blurring can be calculated. The application can overcome the distance blurring problem of pulse radar ranging, and the time sliding sequence matching method proposed in the cross-correlation operation has the characteristics of high efficiency and flexibility, and effectively reduces the time complexity of the cross-correlation operation.

A controller circuit for generating a pulse width modulation (PWM) signal for activating a switching device of a switching power supply (SMPS) includes gap detection circuitry, pulse frequency modulation (PFM) circuitry, PWM circuitry, and logic circuitry. The gap detection circuitry is configured to generate a shift signal based on an indication of a voltage difference between a reference voltage and a feedback voltage corresponding to a voltage output by the SMPS. The PFM circuitry is configured to generate a hold signal indicative of a target PFM frequency of the PWM signal. The PWM circuitry is configured to shift a base current based on the shift signal to generate a shifted base current, and generate a peak signal indicative of a target PWM on-time of the PWM signal based on the shifted base current.

The invention discloses a control method of an ISOP type seabed direct-current converter system based on LLC. The control method comprises the steps that the total input voltage of the system and the input and output voltage of each converter are acquired; equally dividing the total input voltage to each converter to obtain an equally divided voltage of each converter; comparing the input voltage of each converter with the average voltage, and performing PI control to obtain first data of each converter; comparing the output voltage of each converter with a preset reference value to obtain a deviation value of each converter; inputting the deviation value into an output voltage loop PI controller of phase shift control and frequency conversion control, and superposing the output of the controller with the first data to respectively obtain second data and third data; carrying out hysteresis control on the input voltage of each converter to obtain fourth data of each converter; and when the fourth data is smaller than the preset switching voltage, controlling the converter according to the third data in combination with pulse frequency modulation, otherwise, adjusting a carrier phase-shift angle according to the second data to control the converter.