29 results about "Flyback converter" patented technology

A power converter includes a transformer, a main switch, an active clamp switch, and a primary side controller circuit. The primary side controller circuit is configured to indirectly measure a magnetizing current through the transformer during a first switching cycle of the power converter and estimate a zero-crossing point of the magnetizing current for a second switching cycle based on the indirect primary side measurement of the magnetizing current. Based on the estimated zero-crossing point, the primary side controller circuit generates an auto-tuned delay, for the second switching cycle, between disabling the main switch and enabling the active clamp switch before the zero-crossing of the magnetizing current occurs. The active clamp switch is enabled during the second switching cycle in accordance with the auto-tuned delay.

A circuit is disclosed. The circuit includes a transformer having a primary winding extending between a first terminal and a second terminal, and further including a secondary winding extending between a third terminal and a first output terminal; a first switch having a first gate terminal, a first source terminal and a first drain terminal, the first drain terminal coupled to the second terminal and the first source terminal coupled to a power source; a second switch having a second gate terminal, a second source terminal and a second drain terminal, the second source terminal coupled to the second terminal, and the second drain terminal coupled to the power source; and a third switch having a third gate terminal, a third source terminal and a third drain terminal, the third source terminal coupled to the third terminal and the third drain terminal coupled to a second output terminal.

This application provides a multi-output flyback converter and power supply system, relating to the field of power supply technology. The multi-output flyback converter includes a control module, a transformer, a primary-side switching module, and multiple synchronous rectifier modules. The primary-side switching module is connected to the primary winding of the transformer, and each synchronous rectifier module is connected to each secondary winding of the transformer. Each synchronous rectifier module includes two back-to-back connected switching transistors. The control module is connected to the control terminals of the primary-side switching module, the control terminals of the two switching transistors in each synchronous rectifier module, and the output terminal of each synchronous rectifier module. The control module is used to adjust the duty cycle of the primary-side switching module according to the actual output voltage of the actively regulated output path; and to adjust the duty cycle of the switching transistors in each non-actively regulated output path according to the actual output voltage of each non-actively regulated output path, thereby eliminating cross-regulation between the outputs.

The application relates to the technical field of power electronic converter control, and provides a three-port flyback DC-AC converter, characterized in that the three-port flyback DC-AC converter comprises a flyback circuit, a power frequency reverse bridge, an AC-DC converter and a CL filter which are sequentially connected in cascade; the AC-DC converter is an AC-DC three-winding flyback converter which can realize power factor correction function, and is realized through active device multiplexing and magnetic component multiplexing, and comprises a flyback transformer T 2, excitation inductance L f , output switch Q 3, Q 4; the modulation method is to calculate instantaneous output power P o , judge the operation mode of the system, and respectively perform active modulation, reactive modulation or mixed modulation, so that the power factor is adjusted through the modulation method.

This disclosure relates to a power supply circuit, a power adapter, and an electronic device. The power supply circuit includes at least two flyback converter units. On the voltage input side, the at least two flyback converter units are connected in series between two voltage input terminals. On the voltage output side, the at least two flyback converter units are connected in parallel between two voltage output terminals. The at least two flyback converter units are configured to receive control signals and, according to the control signals, control at least one of the at least two flyback converter units to release energy, while the other flyback converter units store energy. This effectively achieves wide-range voltage regulation and improves the overall efficiency of the power supply circuit.

This disclosure proposes a flyback converter, and a control circuit and a control method thereof. The control method comprises: working in a discontinuous conduction mode while the load state is light load; working in a boundary conduction mode while the load state is heavy load; working in a hybrid conduction mode while the load state is between light load and heavy load. A hybrid conduction mode cycle comprises N switching cycles, with the first N-1 switching cycles working in the boundary conduction mode while the Nth switching cycle working in the discontinuous conduction mode. Each switching cycle in the hybrid conduction mode cycle is controlled to work in the boundary conduction mode or the discontinuous conduction mode according to a set maximum value of the hybrid conduction mode cycle and a set first duty cycle. Each switching cycle in the hybrid conduction mode is adaptively control, thereby improving system efficiency.

The application discloses a working mode detection method and circuit of an active clamp flyback converter, a main control chip, samples a drain end voltage VDS of a main power tube QL in a current period, detects a first voltage drop time of the main power tube QL after the main power tube QL is turned off, and determines the working mode of the current period of the active clamp flyback converter by judging the sequence of the first voltage drop time and a clamp tube driving time. Furthermore, based on the working mode determination result, the dead time of the active clamp flyback converter is accurately adjusted to be suitable for the detected working mode, the problem of mismatching between the dead time and the working mode is avoided, the main power tube QL of the active clamp flyback converter can keep realizing soft switching in a full load range, the switching loss of the active clamp flyback converter is greatly reduced, and the efficiency of the converter is improved.

The present application relates to the field of switching power supply control, and particularly relates to a flyback converter synchronous rectification control method, a flyback converter circuit and a chip. The control method comprises obtaining a first drain-source voltage signal of a secondary side synchronous rectification tube, a voltage holding time threshold value; when the first drain-source voltage signal is a high level and the holding time is greater than the voltage holding time threshold value, obtaining a rectification tube enable signal allowing the rectification tube to conduct, and when the rectification tube conduction signal is obtained, the secondary side synchronous rectification tube conducts; when the holding time of the high level of the first drain-source voltage signal is not greater than the voltage holding time threshold value, the secondary side synchronous rectification tube does not conduct. Based on the first drain-source voltage signal of the secondary side synchronous rectification tube and the voltage holding time threshold value, the rectification tube enable signal and the rectification tube conduction signal allowing the rectification tube to conduct are obtained, the true rectification demand of the secondary side synchronous rectification tube is judged, and the conduction or non-conduction of the secondary side synchronous rectification tube is regulated.

The application provides a flyback converter and a control method thereof. The flyback converter is provided with a first sampling unit and a second sampling unit to sample inductance current and resonance current of the flyback converter during the turn-on of a first switch tube and a second switch tube respectively, and a control circuit is arranged to receive sampling signals output by the first sampling unit and the second sampling unit through the same sampling pin, and then realize corresponding current control functions according to the received sampling signals. The different types of current sampling operations are performed by using the same pin time multiplexing mode, which ensures the diversity of the functions of the flyback converter, reduces the required pin number, is beneficial to simplifying the system structure and reducing the system cost.

The application provides a flyback converter and a control circuit and a control method thereof. In a DCM mode, by adjusting the driving signals of the first switch tube and the second switch tube in the flyback converter, the driving signals of the first switch tube and the second switch tube each include at least two pulses in each switching cycle, so that the first switch tube and the second switch tube are turned on at least once additionally in each switching cycle. The application can ensure that the system can realize zero-voltage turn-on of the main switch tube under light load, reduce turn-on loss, and is also conducive to reducing the rectification stress of the secondary side.

The disclosure provides a multi-port charger, a flyback converter and a secondary side control circuit and a control method thereof. The flyback converter comprises an input voltage circuit, a transformer, a main power tube, a synchronous rectification tube, n output circuits and a control circuit. The n output circuits are connected in parallel to one end of a secondary winding of the transformer and output corresponding output voltages in time. n is an integer and n>1. The secondary side control method comprises: setting a false turn-off protection phase at the start time of secondary side current continuation; controlling the synchronous rectification tube to turn off according to a first reference voltage in the false turn-off protection phase and controlling the synchronous rectification tube to turn off according to a second reference voltage outside the false turn-off protection phase, wherein the first reference voltage is greater than the second reference voltage. The disclosure increases the turn-off reference of the synchronous rectification tube in the false turn-off protection phase to avoid the false turn-off of the synchronous rectification tube when multiple output branches are switched on, thereby improving the reliability of the flyback converter and the multi-port charger.

Embodiments of the present disclosure relate to methods of operating an active-clamp flyback converter and corresponding apparatuses. The active flyback converter transitions between a plurality of operating states based on a comparison of a control voltage signal to a voltage threshold and a count of consecutive switching periods during which a clamp switch remains off. The plurality of operating states includes a run state, an idle state, a first burst state, and a second burst state. Each group of consecutive switching periods of the first burst state includes a determined number of switching periods during which signals are generated to turn on and off a power switch and maintain an off state of a clamp switch, and a switching period in a determined position in a group of switching periods in which signals are generated in sequence to turn on the power switch, turn off the power switch, turn on the clamp switch, and turn off the clamp switch.

This application provides a flyback converter control system, relating to the field of power converter technology. The control system includes: a primary-side circuit, a primary-side control module, a transformer, a secondary-side circuit, and a secondary-side control module. During the switching process from no-load or very light-load conditions to full-load conditions, the secondary-side control module detects the output voltage. If the output voltage is less than a first preset threshold, the secondary-side control module sends an activation signal to the primary-side control module through the transformer. The primary-side control module generates a corresponding frequency and a corresponding conduction time based on the activation signal to control the primary-side switching transistor in the primary-side circuit, making the output voltage match the rated output voltage corresponding to the full-load condition. This application provides a technical solution to address the technical problems of lag in the converter's response to load changes and low overall power conversion efficiency of the system.

This application provides a secondary-side current calculation circuit, calculation method, and flyback converter. A secondary-side current calculation circuit is provided on the secondary side of the flyback converter. The output current can be calculated using information such as output voltage, secondary-side freewheeling time, freewheeling duty cycle, transformer turns ratio, and transformer magnetizing inductance. Therefore, the output current information of the secondary side can be obtained without setting a current sampling resistor on the secondary side of the flyback converter. This enables the flyback converter to achieve constant current control function with lower loss and cost in SSR (Secondary Side Regulator) applications.

The application discloses a starting control method and device of a flyback converter. The method comprises the following steps: in a first working mode, a first control signal controls a primary side switch unit to be off, and a second control signal controls an auxiliary switch unit to be off; in a second working mode, the first control signal controls the primary side switch unit to be soft-started, and the second control signal controls the auxiliary switch unit to be off; and in a third working mode, the first control signal controls the primary side switch unit to work, the second control signal controls the auxiliary switch unit to be soft-started, and the turn-on time of the auxiliary switch unit is increased from a first turn-on time to a second turn-on time according to the second control signal. The application controls the turn-on time sequence and the turn-on time of the primary side switch unit and the auxiliary switch unit, thereby effectively solving the problem of excessive stress of the auxiliary switch unit in the starting process, and further improving the working reliability of the flyback converter.

The present application relates to the field of distributed photovoltaic power generation, and aims to provide a flyback micro-inverter critical discontinuous mode simulation control method. The inverter comprises a flyback converter, a power frequency inverter filter circuit and an inverter control circuit; wherein the inverter control circuit comprises an MPPT control circuit and a PWM wave generation circuit; the former comprises a reference voltage V ref generation circuit, a PI regulation circuit and a peak current reference value i ref generation circuit, a peak current reference value i ref generation circuit contains two multipliers and a divider circuit, by collecting the output voltage V pv of the photovoltaic module and the output current I pv , the peak current reference value i ref is obtained; the latter outputs the WM signal as the input of the MOS tube Q s , which is used for realizing the control of the flyback converter. The present application realizes the simulation control of the critical discontinuous mode flyback micro-inverter, can save the digital chip commonly used in the existing control mode, and reduces the complexity and control cost of the system.

This disclosure provides a multi-port charger, a flyback converter, and its secondary-side control circuit and control method. The secondary-side control method includes: determining the load state of the flyback converter; under light load conditions, starting a timer when the secondary-side freewheeling ends, and after a certain time, distinguishing between the free oscillation stage and the primary-side conduction stage based on a first volt-second product; and enabling switching to different output voltages after the primary-side conduction stage. The first volt-second product represents the product of the voltage difference when the synchronous rectifier is turned off and the time, where the voltage difference is the difference between the drain-source voltage of the synchronous rectifier and the output voltage. This disclosure, under light load conditions, filters out the large first volt-second product at the beginning of the free oscillation stage by setting a timer, thereby accurately distinguishing between the free oscillation stage and the primary-side conduction stage after the timer expires, and thus providing an effective output switching enable signal to enable switching to different output voltages after the primary-side conduction stage.

This disclosure provides a multi-port charger, a flyback converter, and their control circuit and control method. The control circuit includes: a primary-side control circuit for generating a primary-side control signal to control the main power transistor to turn on or off; and a secondary-side control circuit for generating a synchronous rectification control signal to control the synchronous rectifier transistor to turn on or off, and generating an output switching enable signal to control the n-channel output circuit to switch and output different output voltages during the secondary-side freewheeling phase. This disclosure avoids the technical problem of overvoltage stress caused by the output switching enable being later than the freewheeling turn-on or earlier than the freewheeling turn-off, and achieves a low-cost, simple, and reliable multi-port charger and flyback converter.

This utility model discloses a 4G intelligent connected charging control electric vehicle charger. Its internal circuitry includes a mains power input and rectification / filtering circuit, a flyback converter and transformer circuit, a secondary rectifier circuit, a battery detection and reverse connection protection circuit, a flyback IC control circuit, a dual-channel temperature detection circuit, an intelligent MCU circuit, a one-line communication protocol circuit, a 5V linear regulator circuit, a main control MCU circuit, a 4G communication module circuit, and a 3.3V linear regulator circuit. This 4G intelligent connected charging control electric vehicle charger provides dual communication functions: wireless 4G network communication and wired communication. It also features overvoltage protection, overcurrent protection, short-circuit protection, overtemperature protection, and intelligent charging capabilities. Furthermore, it allows for remote control of the charger, making it more convenient and safer to use, better meeting people's needs.

This application provides a flyback converter and its sampling fault protection circuit and method. The flyback converter incorporates a fault detection and protection strategy for insufficient sampling time. This includes using a time window signal generation circuit to generate a time window signal with a second duration after a predetermined blanking time has elapsed for a first duration. A sampling fault judgment circuit determines a sampling error when both the time window signal and a zero-voltage detection signal are simultaneously valid (i.e., a valid zero-voltage detection signal is detected within the validity period of the time window signal). This generates a sampling fault protection signal to trigger sampling fault protection action on the flyback converter, effectively preventing abnormal output voltage drift, reducing the risk of system damage, and enhancing system robustness.

This invention discloses a flyback converter modulation chip and device. The chip uses a state detection module to acquire the output voltage fed back from the auxiliary winding on the primary side of the flyback converter and detects the current operating state of the flyback converter based on the output voltage. When the operating state is constant voltage, the mode selection module outputs a pulse width modulation (PWM) signal to the drive module, causing the drive module to adjust the flyback converter's operating mode to PWM. When the operating state is constant current, the mode selection module outputs a pulse frequency modulation (PWM) signal to the drive module, causing the drive module to adjust the flyback converter's operating mode to PWM. This invention, by adjusting the flyback converter to PWM mode in constant voltage mode and PWM mode in constant current mode, avoids a single operating mode and effectively improves the operating efficiency of the flyback converter.

A battery SOC active balancing circuit contains an n-winding output flyback converter, n-1 cross-over capacitors, and n lithium ion batteries, wherein: the n-winding output flyback converter comprises a power switch S1, an excitation inductor L m , a transformer T, a first output diode D1, an output capacitor C1, a second output diode D2, an output capacitor C2, …, an n-th output diode D n , and an output capacitor C n . The n-1 cross-over capacitors are: cross-over capacitors C p1 , C p2 , …, and C p(n‑1) ; and the batteries are B1, B2, …, and B n . Compared with the conventional multi-winding transformer balancing structure, the battery SOC active balancing circuit only uses one switch to realize the balancing of the battery pack, thereby reducing the control difficulty and cost of the circuit.

The embodiment of the present application provides a control device of a flyback switching power supply and related method and charger, the control device comprises: a PWM logic module, and a valley bottom detection module, a valley bottom quantity judgment module and a peak current control module connected with the PWM logic module; the valley bottom detection module detects valley bottoms in a working process of a flyback converter; the valley bottom quantity judgment module judges the valley bottom quantity when a main power switch tube is turned on through a feedback voltage; the peak current control module obtains a peak current signal when the main power switch tube is turned off according to the feedback voltage, specifically: the peak current control module reduces the peak current signal by an offset amount when the valley bottom quantity decreases, or increases the peak current signal by an offset amount when the valley bottom quantity increases, so that transmission power between adjacent valley bottoms of the flyback converter is overlapped, and the PWM logic module generates a PWM pulse for driving the main power switch tube. The embodiment of the present application can realize a valley bottom locking function of the flyback converter.

The application discloses a soft switching control circuit and a control method of a flyback converter. The soft switching control circuit of the flyback converter comprises a negative excitation module connected with a winding of a transformer, the negative excitation module forms a current loop with the winding when turned on, a negative excitation current is generated on the transformer, and the junction capacitance charge of a first switch tube is released after the negative excitation module is turned off; and a switch control module connected with the first switch tube, a second switch tube and the negative excitation module, outputs a switch control signal to control the turn-on and turn-off of the first switch tube and the second switch tube, and outputs a negative excitation signal to control the turn-on or turn-off of the negative excitation module. The scheme of the application can generate a negative excitation current in the transformer when the first switch tube and the second switch tube of the flyback converter are both in the turn-off state, release the junction capacitance charge of the first switch tube, make the source-drain voltage drop to zero, realize the soft switching control of the first switch tube, reduce the switching loss and improve the transmission efficiency.

A series battery pack active balancing circuit, comprising n-way output double-tube flyback converter, n-1 cross-over capacitor, n lithium ion battery; n-way output double-tube flyback converter comprises: a power switch S1, power switch S2, excitation inductance L m , n-way output transformer T, clamping diode D 1p , clamping diode D 2p ; first output diode D1, second output diode D2,..., n-way output diode D n ; first output capacitor C 1, second output capacitor C 2,..., n-way output capacitor C n Compared with the traditional multi-winding transformer balancing structure, the present application realizes the automatic voltage balancing between battery units through the cross-over capacitor, without the need for complex sampling and control algorithm, and avoids the end voltage imbalance problem caused by the cross regulation ratio of the transformer in the multi-winding output, effectively reduces the voltage deviation, and improves the battery balancing accuracy.

Disclosed is a resonant hybrid flyback converter (1) for a light source (4). The converter (1) comprises a transformer (101, 102), comprising a primary-side inductance (101, L p ) and a secondary-side inductance (102, Ls); a high-side switch (104) and a low-side switch (105), connected in series between an input electric potential and a primary-side ground electric potential of the converter (1); a resonant tank circuit (101, 101", 106), connected in series between a common electric potential of the switches (104, 105) and the primary-side ground electric potential, wherein the resonant tank circuit (101, 101", 106) comprises the primary-side inductance (101, L p ). The converter (1) further comprises a current sensing circuit, configured to sense a positive peak current (301, I magpos ) through the primary-side inductance (101, L p ); a voltage sensing circuit (103, 107-110), configured to sense a voltage (302, V Lmsec ; 302', V Lmpri ) across an inductance (101, 102) of the transformer (101, 102); and a control circuit, configured to estimate a current (303, I LEDest ) through the light source (4) in accordance with the positive peak current (301, I magpos ) through the primary-side inductance (101, L p ) and the voltage (302, V Lmsec ; 302', V Lmpri ) across the inductance (101, 102) of the transformer (101, 102); and regulate the current (305, I LED ) through the light source (4) in accordance with a setpoint value (304, I LEDref ) and the estimated current (303, I LEDest ) through the light source (4). This avoids a sensing of the current (305, I LED ) through the light source (4) and an associated signal transfer across a SELV barrier of the converter (1).

This application discloses a method, device, and medium for suppressing electromagnetic interference (EMI) at the source end of an inverter. The method includes: constructing a three-phase inverter topology with each phase arm consisting of N series-connected insulated-gate bipolar transistors (IGBTs), and connecting an RCD buffer circuit in parallel to each IGBT; generating a main pulse width modulation (PWM) signal through sinusoidal pulse width modulation; delaying the PWM signal using a shift register chain composed of cascaded D flip-flops in the CPLD control module to generate N gate drive signals with sequentially increasing preset delays; sequentially driving the IGBTs on the same bridge arm to turn on and off using the N drive signals, shaping the output voltage pulse edges into a stepped waveform with N voltage steps to periodically suppress high-frequency EMI; and feeding energy back to the DC bus through a flyback converter recovery buffer circuit. This invention has a simple structure and low cost, reducing total switching losses while suppressing source-end EMI.

An active clamp flyback converter with accurate sense of an output voltage is discussed. The active clamp flyback converter adopts a feedback voltage generator which generates a feedback voltage in response to an input voltage, a voltage at a switch node, an auxiliary control signal, and a current signal indicative of a current flowing through a primary winding.