256 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.

A driver circuit for controlling a high-power switch. The driver circuit comprises a flyback converter having a positive output rail and a negative output. The driver circuit also comprises: a driving stage that is connected between the positive output rail and the negative output rail; a shunt regulator configured to regulate the negative output voltage on the negative output rail based on a difference between the negative output voltage and a target negative voltage value, wherein the shunt regulator is powered by the positive output voltage on the positive output rail; a short-circuit transistor having a conduction channel that is connected between the negative output rail and a ground terminal; and a regulation control circuit configured to: provide a short-circuit control signal to a control terminal of the short-circuit transistor in order to short the negative output rail to the ground terminal until the positive output voltage reaches a positive threshold.

An active clamp flyback converter with safe operation is discussed. The active clamp flyback converter has a main power switch and an auxiliary switch integrated at a same IC chip. The active clamp flyback converter enables a first charge path from the power supply voltage to a floating capacitor when the main power switch is turned on. The first charge path is disabled and a second charge path from a second pin of the IC chip to the floating capacitor is enabled when a voltage at the second pin is higher than a reference voltage.

A flyback converter to receive an input voltage and provide an output voltage is provided, and may include a transformer having a primary winding and secondary winding, a primary switch coupled to the primary winding, a synchronous rectifier device coupled to the secondary winding, and a secondary side control circuit to turn on the synchronous rectifier device by outputting a control signal at a first amplitude, subsequently modify the control signal to maintain a voltage across the synchronous rectifier device substantially constant until a predicted time that precedes a current in the synchronous rectifier device reaching substantially zero, subsequently turn off the synchronous rectifier device based on the voltage across the synchronous rectifier device reaching substantially zero, and subsequently turn on the synchronous rectifier device by outputting the control signal at a second amplitude, before the primary switch is turned on. The second amplitude is less than the first amplitude.

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 belongs to the technical field of switching power supplies, and provides a multi-output flyback converter with a low cross regulation rate, which comprises a primary side loop comprising a switching tube and a primary side winding of a transformer, and the switching tube is used for controlling the energy transfer of the transformer; the secondary loop comprises a main output loop, a first secondary output loop and a second secondary output loop, the main output loop comprises a secondary winding of the transformer, and the secondary winding of the first secondary output loop is led out from the secondary winding of the main output loop through a tap; a secondary winding of the second secondary output loop is connected with an inductor; two ends of the inductor are connected with an energy absorption loop in parallel; and the feedback control loop is used for acquiring the sampling voltage of the main output loop, comparing the sampling voltage with the reference voltage, and controlling the output voltage of multi-path output by controlling the duty ratio of a switching tube. According to the flyback converter, the low cross adjustment rate of multi-path output of the flyback converter is realized, and mutual interference among the multi-path output is avoided.

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.

The control circuit and conversion circuit of the forced resonance soft-switching flyback power converter of the present invention. The input ends of the Schmidt inverter U2 in the control circuit are all connected to the anode of the diode D2, one end of the resistor R2, and one end of the resonance capacitor C2. The output end of the Schmidt inverter U2 is connected to the input end of the Schmidt inverter U3. The input ends of the Schmidt inverter U1 are all connected to the anode of the diode D1, one end of the resistor R1, and one end of the resonance capacitor C1. The output end of the Schmidt inverter U1 is connected to the input end of the high-speed AND gate U4. It is not restricted by the bus voltage and switching frequency, has a fast signal conversion speed, good waveform quality, simple application circuit, and low cost, and can meet the drive control application of the forced resonance soft-switching flyback power converter. The conversion circuit includes the control circuit of the forced resonance soft-switching flyback power converter and a single-ended flyback converter described above.

A driver circuit for controlling a high-power switch. The driver circuit comprises a flyback converter and a driving stage. The flyback converter includes a controller that configured to: receive a PWM control signal, which is for controlling the high-power switch; receive a feedback voltage signal, representative of a measured voltage of a positive output rail or the negative output rail of the flyback converter; and provide a primary-side switch control signal that comprises a bursts of pulses for operating the primary switch, wherein the controller is configured to start a burst of pulses in response to an edge of the PWM control signal, and stop the burst of pulses in response to the feedback voltage crossing a threshold. The driving stage is connected between the positive output rail and the negative output rail. The driving circuit is configured to provide a high-power switch control signal for controlling the state of the high-power switch based on the PWM control signal.

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.

The invention discloses a flyback conversion circuit, which comprises N flyback conversion sub-circuits and an input power supply circuit, and is characterized in that the input end of each flyback conversion sub-circuit is connected with the output end of the input power supply circuit; the flyback conversion sub-circuit comprises an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit and M power conversion circuits; the first input end of the active absorption circuit is connected with the first end of the clamping capacitor, the second input end of the active absorption circuit is connected with the first end of the input filter capacitor or the second end of the input filter capacitor, and the first output end of the active absorption circuit is connected with the first input end of the output filter circuit. The second output end of the active absorption circuit is connected with the second input end of the output filter circuit. By adopting the design of multi-path staggered conduction control and unified energy absorption, the power conversion efficiency and power density of the circuit can be effectively improved, the voltage stress of the device is reduced, and the electromagnetic compatibility is improved.

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).

The invention discloses a light load efficiency optimization method for an asymmetric half-bridge flyback converter in the technical field of asymmetric half-bridge flyback converters, which comprises the following steps of: starting a first switching period, and starting a second switching period when the first switching period is finished, and switching on the input voltage of a first switching tube in the asymmetric half-bridge flyback converter at the beginning of a second switching period, increasing the excitation current to an excitation current peak value based on the input voltage, and switching off the first switching tube. The asymmetric half-bridge converter is controlled by using the N first switching periods and the first interval time to form the second switching period, and the output voltage is stabilized by cooperatively adjusting the length of the second switching period, so that the switching frequency of the first switching period can be prevented from being too high under the condition of realizing soft switching of the converter; therefore, driving loss and switching loss are reduced, and the light-load efficiency of the converter is improved.

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.

The present invention relates to the technical field of photovoltaic power generation. Disclosed are a bidirectional flyback converter-based grid-forming microinverter and a method therefor. The method comprises: by means of an output voltage and an output current of the grid-forming microinverter, calculating an active power and a reactive power; on the basis of a power loop control principle, generating a reference signal of a voltage loop by means of using a preset power reference value; generating a reference signal of a peak current control loop according to an actual output voltage; and, according to primary side current signals of a first bidirectional flyback converter and a second bidirectional flyback converter, generating a drive signal for each switch transistor under the regulation of the peak current control loop. The present invention generates power grid voltage phases directly by means of the power loop without requiring a phase-locked loop stage, thus ensuring stable operation even in weak power grid environments; in addition, the present invention uses a bidirectional structure topology, involves a simple topological structure, low cost, high efficiency and low control complexity, and achieves bidirectional power flow, and furthermore, the present invention adjusts an output power factor, thus providing reactive power support for power grids.

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.

The invention relates to an auxiliary unit (6) for a motor vehicle (2), in particular to an electromotive refrigerant compressor, which auxiliary unit has a first connection (12) for a low-voltage on-board electrical system (8). A supply input (36) of a control unit (24) is connected to the first connection (12) by means of a flyback converter (34) which has a primary coil (40) which is in electrical contact with the first connection (12), and a secondary coil (46) which is in electrical contact with the supply input (36). A voltage tester (54) is connected in parallel with the secondary coil (46) and is in contact with a monitoring input (38) of the control unit (24). The invention also relates to a motor vehicle (2).

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.

The present invention relates to a burst power control method and circuit for a clamped asymmetric half-bridge flyback converter. The method comprises: real-time detection of a load value of the clamped asymmetric half-bridge flyback converter; determining whether the load value meets a condition for entering a burst power mode; if so, entering burst power mode, increasing the converter's switching frequency and peak current limit maximum value based on the load value; determining whether the current load value and the burst power mode operating time meet a condition for terminating the burst power mode; if so, terminating the burst power mode and entering a cooling mode; comparing the load value with a preset maximum output load value in real time; and if the load value is greater than the preset maximum output load value, reducing the transformer's output voltage based on the load value and the maximum output load value to limit the converter's maximum output power. This method accurately limits the maximum burst power without detecting the secondary current, thereby improving prototype reliability.