177 results about "Flyback converter" patented technology

Provided in the present application are a balanced charging method and apparatus for a battery pack, and a computer program product. Charging current control consists of two stages, i.e., a "pulse square-wave excitation" stage and a "multi-stage current-reduction charging" stage. During the pulse square-wave excitation stage, the parameter identification of an equivalent circuit model and the joint estimation of state variables are realized, thereby providing reliable battery parameters for a subsequent balancing process. During the multi-stage current-reduction charging stage, a flyback converter is used to control a balanced current of each battery cell, and the battery cells remain in a charging state throughout a balancing process, thereby effectively mitigating the impact of a hysteresis voltage.

The invention discloses a charging management circuit and a charger. The charging management circuit comprises a flyback converter, a first sampling feedback module, a second sampling feedback module and an optocoupler. The first sampling feedback module comprises a comparator, a first switch unit, a thermosensitive voltage dividing unit and a current sampling resistor. The duty ratio of a PWM chip is controlled through an optocoupler to achieve constant-current charging in the first charging stage. The resistance of the thermosensitive voltage dividing unit is increased when the temperature rises, the charging current is automatically reduced, and temperature self-adaptive protection is achieved. And when the charging current is reduced to a preset value, the second sampling feedback module takes over the control optocoupler to realize constant-voltage charging in a second charging stage. Constant-current and constant-voltage two-stage charging can be achieved, the function of automatically adjusting the charging current through the temperature is achieved, the charger is effectively prevented from being overheated in the high-temperature environment, and the safety of the charger and a battery is protected.

The invention discloses a flyback photovoltaic micro inverter grid-connected control method and system, and the method comprises the steps: sampling photovoltaic output voltage and current, power grid voltage and grid-connected current, and obtaining discrete sampling values; generating an input current reference value of the flyback converter, subtracting the input current reference value from an actual value, and outputting a grid-connected current amplitude through first PI regulation; a grid voltage sampling sequence obtains a phase through a phase-locked loop, and multiplies the phase with an amplitude and a phase sine absolute value to generate a grid-connected current reference value; the difference between the reference value and the grid-connected current is adjusted by a second PI to output a modulation wave, and the modulation wave is compared with a triangular carrier to generate an H-bridge switch tube PWM signal; mPPT control is executed through the flyback converter and a grid-connected current amplitude instruction is generated, and the H-bridge inverter performs current tracking inversion, so that a set of efficient and cooperative two-stage control strategy is formed, high-quality grid connection of photovoltaic energy is realized, and the problems of huge size, shortened service life and reduced reliability of the existing device are solved; and the overall performance and the long-term operation reliability of the photovoltaic micro inverter are obviously improved.

A control circuit and a control method for a flyback converter, and switching power supply are disclosed. The secondary side control circuit includes a volt-second acquisition unit and a volt-second determination unit. The volt-second acquisition unit calculates the volt-second product of the voltage across the secondary winding. The volt-second determination unit compares the volt-second product with a volt-second threshold to determine the communication status between the primary side control circuit and the secondary side control circuit. This detection process achieves a handshake between the primary and secondary sides and enables precise control of the primary side by the secondary side without the need for additional isolators, reducing circuit cost and loss.

A power supply system with power factor correction, includes: an AC rectifier, a power factor correction (PFC) conversion circuit, an asymmetric half-bridge (AHB) flyback converter and a communication protocol power delivery (PD) interface. When a power level of an adapter output power is lower than a power threshold, and a converted voltage of a converted power is higher than a first voltage threshold, the communication protocol PD interface generates a disable signal to disable a PFC conversion of the PFC conversion circuit, when the PFC conversion is disabled, the PFC conversion circuit operates a bypass coupling operation, as thus, the converted voltage is equal to a rectified voltage of a rectified power.

A battery pack charger having housing including a battery pack interface for removably receiving a battery pack and a power input. The battery pack charger including a hybrid flyback converter having a primary side including a DC-DC half-bridge and a secondary side including a synchronous rectifier. The hybrid flyback converter is electrically connected between the power input and the battery pack interface and is configured to provide charging power from the power input to the battery pack interface.

The application discloses a flyback converter and a starting control method thereof. The flyback converter comprises a transformer, a power switch tube, a rectifier tube, a primary side control circuit, and a secondary side control circuit. The primary side control circuit generates a first control signal to control the transmission of starting energy to a secondary side part of the flyback converter after the flyback converter is powered on. The secondary side control circuit transmits a stop signal and a second control signal to the primary side control circuit in sequence after starting. The application can prevent the primary side switch signal from suddenly changing during the starting process, realize the smooth transition of primary side and secondary side control, and realize the smooth starting of the output voltage. The application has good output characteristics, a simple control method, better compatibility, and lower cost.

The invention relates to a method for operating a flyback converter (2) having an active-clamp circuit (4), a main switching branch (3) being connected to a primary-side coil (51) of a transformer (5) in series between a first supply potential (VH) and a second supply potential (VL), the active-clamp circuit (4) being connected to a central node (M) between the main switching branch (3) and the primary-side coil (51) and one of the supply potentials (VH, VL), the active-clamp circuit (4) having an active-clamp switching branch (42) in series with an active-clamp capacitance (41), the main switching branch (3) and the active-clamp switching branch (42) each having two or more series-connected semiconductor switches (31, 32, 43, 44), one or more flying capacitances (7) each being connected to an intermediate node (ZH, ZAC) between the series-connected semiconductor switches (31, 32) of the main switching branch (3) and to an intermediate node between the series-connected semiconductor switches (43, 44) of the active-clamp switching branch (42), wherein the semiconductor switches (31, 32, 43, 44) of the main switching branch (3) and the active-clamp switching branch (42) are each switched to open and close in chronological succession, wherein, in order to open or close the main switching branch (3) and the active-clamp switching branch (42), that semiconductor switch (31, 32, 43, 44) of the main switching branch (3) or active-clamp switching branch (42) in question that leads to a current path through a freewheeling diode of at least one of the semiconductor switches (31, 32, 43, 44) of the other, main switching branch (3) or active-clamp switching branch (42) is opened or closed first so that a voltage (UC) across the flying capacitance is changed in the direction of a predefined setpoint voltage (Usoll).

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.

The invention relates to the technical field of circuit control, in particular to a circuit control module for adjusting circuit power through a light source. The system comprises a light source feedback unit, a control processing unit, a power output unit and a power supply unit for supplying power, wherein the light source feedback unit comprises a light sensor and a light intensity feedback assembly connected with the light sensor; the power output unit comprises a PWM control loop and a power adjusting circuit connected with the PWM control loop. A comparison circuit is used for processing, a light intensity signal is converted into a high / low-level comparison signal to be output to a single-chip microcomputer, and the single-chip microcomputer dynamically adjusts the output duty ratio of a PWM control loop; a PWM signal drives a power adjusting circuit with a flyback converter as a core, and the power transmitted to a load such as an LED light source is accurately adjusted by controlling the on and off of switch tubes Q1 and Q2, so that the ambient light intensity is stabilized near a target threshold value set by a slide rheostat VR1.

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 utility model discloses a flyback converter. The flyback converter comprises an input circuit, a primary side control and power conversion circuit and an output circuit, wherein the output circuit comprises an output winding; wherein the input circuit is used for converting alternating current voltage into direct current voltage; the primary side control and power conversion circuit is used for performing power conversion on the direct-current voltage; the output circuit is used for sensing to obtain the voltage after power conversion and outputting the voltage; wherein the primary side control and power conversion circuit comprises a first primary side main winding, a power switch and a second primary side main winding; when the power switch is closed, the first primary side main winding and the second primary side main winding are connected in series through the power switch; and the first primary side main winding, the second primary side main winding and the output winding form a transformer. By adopting the scheme, the electromagnetic interference of the flyback converter can be reduced.

A method (100) of operating a flyback converter (250) to charge a DC link capacitor (210), with the steps of: determining (120) a voltage (Ux), characterizing the voltage at the DC link capacitor (210), specifying (140) a target charging current level (I_L) for charging the DC link capacitor (210) and specifying a corresponding duty cycle (Tx) for actuating the first circuit breaker (252) for as long as the determined voltage (Ux) falls below a first voltage level value (U1), specifying (150) a target charging voltage level (U_L), for as long as the determined voltage (Ux) corresponds to the first voltage level (U1) or the determined voltage (Ux) exceeds the first voltage level (U1) and the determined voltage (Ux) falls below a second voltage level (U2).

The application provides a protection circuit, a method, a chip, a flyback converter and a switching power supply, and relates to the technical field of switching power supplies. The input end of an auxiliary winding voltage sampling module of the desaturation protection circuit is connected with an auxiliary winding of a flyback conversion circuit, the output end of the auxiliary winding voltage sampling module is connected with the first input end of a threshold detection module, the second input end of the threshold detection module inputs a preset threshold voltage; the control end of the threshold detection module is connected with the gate of a primary power switch tube to obtain a gate drive voltage signal, a sampling control signal is generated, the threshold detection module is used for comparing the auxiliary winding sampling voltage with the preset threshold voltage, a current saturation protection signal is generated according to the sampling control signal and the comparison result, and a logic drive module generates a drive control signal according to the current saturation protection signal, so that the primary power switch tube is controlled to desaturate. The application can realize current desaturation protection of the flyback converter.

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.

A controller for an asymmetric half bridge flyback converter as discussed herein. The control may include control logic configured to control one of a high-side switch and low-side switch of a half bridge of the asymmetric half bridge flyback converter based on a peak current control. For example, the control logic can be configured to limit an on-time of the one of the high-side switch and the low-side switch based on a threshold value.

A power detector is disclosed. The power detector includes a primary-side sense circuit configured to generate a sense signal representative of an output voltage of a flyback converter. The power detector also includes a primary-side reference generator configured to generate a reference signal representative of an average output current of the flyback converter. The power detector further includes a primary-side power calculation circuit configured to generate an output-power signal in response to the sense signal and the reference signal.

This application provides an output control circuit, a flyback converter, a chip, and an electronic device. The output control circuit can obtain a first output voltage from a first output circuit and a second output voltage from a second output circuit, and control the first and second output circuits to conduct sequentially based on the first and second output voltages in each switching cycle. Therefore, the output control circuit can determine a first freewheeling circuit and a second freewheeling circuit in the first and second output circuits, so that the magnetizing inductance of the transformer in the flyback converter transfers energy to the first and second freewheeling circuits respectively during the secondary freewheeling phase. That is, the magnetizing inductance transfers energy using high-frequency chopping in each switching cycle, making the high-frequency chopping frequency of the first and second output circuits equal to the switching frequency. Since the switching frequency is usually higher than the range of human hearing, the problem of audio noise can be solved, and the performance of the flyback converter can be improved.

The utility model discloses a direct-current high-voltage power supply module and high-voltage operation equipment. The direct-current high-voltage power supply module is formed by sequentially connecting an input filter circuit, an input protection circuit, a flyback converter circuit and an output rectification filter circuit, the input end of the input filter circuit is connected with an external direct-current low-voltage power supply; the output end of the output rectifier filter circuit outputs direct-current high voltage; the input end of the voltage feedback circuit is connected with the second feedback signal end of the output rectification filter circuit, and the output end of the voltage feedback circuit is connected with the voltage feedback signal end of the PWM control circuit; the input end of the PWM control circuit is connected with the output end of the input protection circuit, and the output end of the PWM control circuit is connected with the duty ratio adjusting signal end of the flyback converter circuit. According to the utility model, the stability of output voltage can be ensured, the conversion efficiency is higher, the size is smaller, and the heat dissipation performance is better.

A bidirectional flyback converter using a full bridge circuit is disclosed. The flyback converter includes: a transformer; a primary-side circuit located on a primary side of the transformer and having a first switching unit; and a secondary-side circuit located on a secondary side of the transformer and having a second switching unit. Here, each of the first switching unit and the second switching unit is implemented with two bridge circuits and a capacitor between the bridge circuits.

Embodiments of the present application provide a secondary side controller, a control method and a control system of a flyback converter. The secondary side controller comprises a sampling circuit, a processing circuit and a control circuit; two input ends of the sampling circuit are electrically connected to a drain end of a secondary side power tube and an output end of the flyback converter respectively, and an output end of the sampling circuit is electrically connected to a control end of the secondary side power tube through the processing circuit and the control circuit in sequence; the sampling circuit is configured to determine an output sampling voltage and an input sampling voltage based on a drain end voltage and an output voltage; the processing circuit is configured to determine a conduction duration based on the output sampling voltage, the input sampling voltage and a preset value; and the control circuit is configured to control on-off of the secondary side power tube based on the conduction duration, so that a valley value of a drain end voltage of a primary side power tube is zero. The secondary side controller can realize zero voltage conduction of the primary side power tube by controlling the secondary side power tube, thereby reducing loss of the converter; in addition, the conduction duration can be adaptively adjusted, thereby improving applicability.

The invention discloses a synchronous rectification driving circuit and a flyback converter, and realizes synchronous rectification control with efficient conversion and current backflow prevention. The circuit comprises a primary driving circuit, an isolating circuit, a secondary driving circuit and a duty ratio limiting circuit, the primary driving circuit is connected with the output end of the PWM controller and the control end of the primary switching tube; the isolating circuit is connected with the output end of the PWM controller, the first input end of the duty ratio limiting circuit and the first input end of the secondary driving circuit; the output end of the secondary driving circuit is connected with the second input end of the duty ratio limiting circuit and the control end of the secondary synchronous rectification switch tube, and the output end of the duty ratio limiting circuit is connected with the second input end of the secondary driving circuit; the duty ratio limiting circuit samples the secondary driving signal through an internal voltage sampling circuit, resets the voltage sampling circuit cycle by cycle according to a first input end signal of the duty ratio limiting circuit, and turns off the secondary driving circuit when the duty ratio of the secondary driving signal exceeds a preset threshold value.

The invention belongs to the technical field of converters, and relates to a transformer magnetic core for a flyback converter and a frameless transformer, and the transformer magnetic core comprises a T-shaped magnetic core and a U-shaped magnetic core which are buckled with each other; the T-shaped magnetic core comprises a first magnet yoke and a magnetic core middle column arranged in the center of the upper end face. The U-shaped magnetic core comprises a second magnet yoke, and a first magnetic core side column and a second magnetic core side column which are arranged on two opposite sides of the upper end surface; during buckling, the magnetic core middle column is inserted into a cavity between the first magnetic core side column and the second magnetic core side column, a second air gap is reserved between the end face of the magnetic core middle column and the surface of the second magnet yoke, and first air gaps are reserved between the end face of the first magnetic core side column and the surface of the first magnet yoke and between the end face of the second magnetic core side column and the surface of the first magnet yoke respectively. The flyback converter has the advantages of high magnetic core efficiency, uniform magnetic flux distribution, good temperature rise performance and the like, a transformer framework is omitted to increase the power density, and the requirements of high efficiency, high power density, temperature rise optimization and the like of the flyback converter are met.

This invention discloses a constant current control method for a primary-side feedback flyback converter, relating to the field of isolated converter technology. The method includes: when the primary-side feedback flyback converter operates in continuous current mode, determining the transformer demagnetization duration, cycle duration, and primary winding current valley value for the nth switching control cycle; obtaining the switching turn-off duration for the (n+1)th switching control cycle based on the transformer demagnetization duration, cycle duration, primary winding current valley value, a set reference primary current peak value, and the desired target current value; controlling the switching turn-on duration for the (n+1)th switching control cycle based on the reference primary current peak value, and controlling the switching turn-off duration for the (n+1)th switching control cycle to be the calculated turn-off duration. This method avoids low-frequency current ripple by eliminating the need for PID modulation calculations and can eliminate subharmonic oscillations at low input voltages.

A resonant hybrid flyback converter (100) with overcurrent detection and / or protection for LED lighting means (34) is provided. Said resonant hybrid flyback converter (100) comprises a half-bridge (10), and a flyback resonant tank (20) comprising a transformer with a primary side (61) and a secondary side (62). In this context, the half-bridge (10) is configured to supply said primary side (61). In addition to this, the resonant hybrid flyback converter (100) comprises a control unit (70) controlling the operation of switches (11, 12) of the half-bridge (10) and being supplied with a feedback signal (sensing) from a sensing circuit (Rshunt) configured to sense a primary-side current in the flyback resonant tank (20).

This document describes techniques for avoiding spurious negative sensing (NSN) detection in flyback AC-DC converters. In an exemplary embodiment, the secondary-side controller of the AC-DC converter includes a frequency detector, a negative sensing detector, and a control logic unit. The frequency detector is configured to determine the frequency of an input signal from the drain node of a synchronous rectifier (SR) circuit on the secondary side of the AC-DC converter. The negative sensing detector is configured to determine a negative voltage of the input signal. The control logic unit is configured to: enable the negative sensing detector when the frequency of the input signal rises above a frequency threshold; and turn on the SR circuit to transfer power to the secondary side of the AC-DC converter when the negative voltage of the input signal falls below a voltage threshold.

A control system (100-Fig.1) controls a vehicle charging system 200 that comprises an on-board charger (OBC 220) that is: electrically connectable to an electric vehicle supply equipment (EVSE 230); and configured to charge one or more electrical components of the vehicle in dependence on an initiation of a charging process operable on receipt of a low-voltage (LV) power supply. The control system comprises one or more processors (120-Fig.1) collectively configured to: receive a battery condition signal (160-Fig.1) indicative of a condition (e.g., state-of-charge (SOC), power output) of a LV battery 240; determine, in dependence on the battery condition signal, that the condition of the LV battery is less than a threshold condition; and, in dependence on the determination, output a control signal to control an auxiliary system 222 (e.g. AC-DC flyback converter) of the OBC to source the LV power supply from the EVSE to initiate the charging process. The threshold condition may comprise: a threshold SOC corresponding to a SOC required to initiate the charging process; and / or a threshold power output corresponding to a power output of the LV battery required to initiate the charging process.

A system is provided that includes a diode bridge for rectifying an AC input voltage. A main switching power converter converts a rectified input voltage of the diode bridge to an output voltage. The flyback converter is coupled to the pre-bridge node or the post-bridge node to receive an input voltage that is converted to a supply voltage for the controller integrated circuit. The controller integrated circuit regulates both the output voltage and the supply voltage.