332 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 control circuit for an asymmetrical half-bridge flyback converter with a first switch, a second switch, a transformer and a resonant capacitor is provided. The control circuit includes an input terminal and an output terminal. The input terminal receives resonant current information. The resonant current information is associated with a resonant current flowing through a resonant tank formed by a primary winding of the transformer and a resonant capacitor. The output terminal provides a first control signal to turn off the first switch of the asymmetrical half-bridge flyback converter based on the resonant current information.

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.

The invention discloses a direct-current transformer power self-balancing control system, which belongs to the technical field of direct-current self-energy taking under a direct-current power distribution network, and comprises a plurality of flyback converters, and a master-slave control framework is formed by taking the actually grounded flyback converter as a master module and taking other flyback converters as slave modules; the main module controls an MOS tube in the main module to be switched on or switched off according to the reference duty ratio; and the slave module controls on or off of an MOS tube in the slave module according to the reference duty ratio and the duty ratio correction. The master module adopts a system output voltage loop to maintain the stability of the system output voltage, the slave module input stage adopts an input grading ring to realize the sharing of the input voltage between flyback modules, and the slave module output stage adopts an output current sharing ring to improve the dynamic response effect of the system. The system can solve the problem of power distribution imbalance caused by inconsistent parameters between flyback modules.

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.

A flyback converter comprising: a transformer having a primary side winding and a secondary side winding; a primary side switch located at the primary side of the transformer; two secondary side switches located at the secondary side of the transformer; in which the two secondary side switches are connected in parallel and have different characteristics; and a control unit configured to generate a rectification signal and a Zero Voltage Switching (ZVS) pulse and to drive the two secondary side switches; in which a secondary side switch is driven by the rectification signal and the other secondary side switch is driven by the ZVS pulse. At the end of a switching cycle, before turning on the primary side switch: the control unit is configured to generate the ZVS pulse in the secondary side winding such that the parasitic capacitor of the primary side switch is discharged, and to consequently turn on the primary side switch in ZVS conditions or near ZVS conditions.

The embodiment of the invention provides a control method and control circuit of a half-bridge flyback converter, a chip and power supply equipment. The control method comprises the steps that when the half-bridge flyback converter works in a free resonance state, in a first switching period, the second primary switching tube is controlled to be switched on so that the half-bridge flyback converter can exit from the free resonance state, after a preset switching-on duration, the second primary switching tube is controlled to be switched off so that excitation current can be negative current, and the half-bridge flyback converter can be switched off. And the half-bridge flyback converter enters the free resonance state again, and the first primary switch tube is controlled to be switched on at the moment which is separated from the switching-off moment of the second primary switch tube by odd number times of the free resonance half cycle, so that the valley bottom of the first primary switch tube is switched on, the efficiency of the half-bridge flyback converter can be improved, and the service life of the half-bridge flyback converter is prolonged. And the peak stress when the secondary switch tube is turned off can be reduced, so that the EMI of the half-bridge flyback converter is improved.

Disclosed is a flyback converter and a control method thereof. The flyback converter includes a first switching transistor, a second switching transistor, a transformer, a first capacitor, a power supply device. A resonant loop circuit is formed by connecting the first capacitor to a primary side winding of the transformer and the second switching transistor. In a first operating mode, a controllable switching transistor of the power supply device is turned on before the second switching transistor is turned off, and after the second switching transistor is turned off, the charging capacitor is charged and stores energy. In a second operating mode, before the first switching is turned on, the controllable switching transistor is turned on, and the charging capacitor is charged and stores energy. The conversion efficiency of the power supply is enhanced while enabling the first switching transistor to operate under zero voltage switching, thereby reducing switching losses.

According to an embodiment, a converter includes a bootstrap capacitor, a high-side switch, a low-side switch, an auxiliary switch, and a controller. The bootstrap capacitor has a first terminal coupled to a floating ground node. The high-side switch has a source terminal coupled to the bootstrap capacitor through the floating ground node. The auxiliary switch has a drain terminal coupled to the bootstrap capacitor through the floating ground node. The controller provides a first control signal to a control terminal of the high-side switch, provides a second control signal to a control terminal of the low-side switch, and provides a third control signal to a control terminal of the auxiliary switch. The third control signal is based on a condition associated with the converter after the first control signal and the second control signal deactivate the high-side switch and the low-side switch respectively.

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 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 utility model provides a magnetic element and a topological structure used for an interleaving flyback converter, and relates to the technical field of power electronics, and the magnetic element comprises a magnetic core structure and a coil structure. The magnetic core structure comprises an upper magnetic core base, a lower magnetic core base, N magnetic core middle columns and at least one side column, wherein the upper magnetic core base and the lower magnetic core base are oppositely arranged, the N magnetic core middle columns and the at least one side column are arranged between the upper magnetic core base and the lower magnetic core base, and N is a natural number larger than 1. The coil structure comprises N coils wound on the magnetic core middle columns respectively, the winding directions of the coils on the adjacent magnetic core middle columns are opposite, and an air gap is formed in at least one of the three positions including the position between the upper bottom face of each magnetic core middle column and the upper magnetic core base, the position between the lower bottom face of each magnetic core middle column and the lower magnetic core base and the side face of each magnetic core middle column. According to the magnetic element, the magnetic core columns are integrated on the same magnetic core base, and the winding directions of the coils of the adjacent magnetic core middle columns are opposite, so that the purposes of reducing the weight of the magnetic core and reducing the loss of the magnetic core can be achieved.

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 present disclosure provides an active clamp flyback converter and a control method, and relates to the technical field of converter. The control method includes: in response to that an input voltage of the active clamp flyback converter is less than a preset voltage threshold, or the input voltage of the active clamp flyback converter is less than a product of an output voltage of the active clamp flyback converter and a turns ratio of the transformer, in a same switching cycle, controlling the clamp switch to turn on when the transformer is in a demagnetization stage; and controlling the clamp switch to turn off when a resonant current of the clamp capacitor and a leakage inductance of the transformer reaches a preset current threshold.

The invention relates to automatic reverse current regulation in an active clamped flyback converter. According to one embodiment, a method is presented that includes sensing a reverse current through a main switch of an active clamped flyback (ACF) converter. The ACF converter includes a flyback transformer and an auxiliary switch. The method further includes determining whether a sensed voltage corresponding to the reverse current exceeds a threshold; reducing a duration of the reverse current by an incremental time interval, the duration of the reverse current including a first incremental time interval, the duration of the reverse current corresponding to a duration in which the auxiliary switch is activated; increasing the duration by a second incremental time interval greater than the first incremental time interval, the increasing in response to the reverse current not exceeding the threshold; and activating the auxiliary switch for the duration to achieve zero voltage switching (ZVS).

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.

According to an embodiment, a converter is provided. The converter includes a bootstrap capacitor having a first terminal coupled to a floating ground node; a high-side switch, a source terminal of the high-side switch coupled to the bootstrap capacitor through the floating ground node; a low-side switch; and a controller. The controller is configured to provide a first control signal to a control terminal of the high-side switch, and a second control signal to a control terminal of the low-side switch, wherein a transitioning of the second control signal to turn OFF the low-side switch is delayed after a duration from a transitioning of the first control signal to turn OFF the high-side switch, wherein the delay is automatically adjusted by detecting a condition associated with the converter, wherein the delay begins in response to a voltage at the floating ground node being less than zero.

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 invention provides a multi-path flyback converter and a three-phase power converter. The multi-path flyback converter comprises a primary side feedback module, a plurality of transformers and a plurality of driving power supply modules, the plurality of transformers are arranged in a split manner; the transformers and the driving power supply modules are arranged in a one-to-one correspondence manner; the driving power supply module is connected with a secondary winding of the corresponding transformer; the primary side feedback module comprises a feedback winding and a feedback control circuit, the feedback winding is arranged on the primary side of any transformer, the input end of the feedback control circuit is connected with the feedback winding, the output end of the feedback control circuit is connected with the primary side windings of the transformers, and the output end of the feedback control circuit is connected with the primary side windings of the transformers. The feedback control circuit adjusts the input of the primary windings of the plurality of transformers based on the feedback output signal of the feedback winding. According to the configuration, the PCB wiring of the high-voltage area can be simplified, the PCB wiring difficulty is effectively reduced, noise and interference are reduced, and the cost is effectively reduced.

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 flyback converter with electromagnetic interference suppression function includes an input end, an output end, a rectifying element, and a transformer. The output end includes a first output terminal and a second output terminal. The transformer includes a primary winding, a first secondary winding, and a second secondary winding. The primary winding is connected to the input end. The upper terminal of the first secondary winding is connected to the first output terminal, and the lower terminal of the first secondary winding is connected to the first end of the rectifying element. The upper terminal of the second secondary winding is connected to the second end of the rectifying element, and the lower terminal of the second secondary winding is connected to the second output terminal.

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.