451 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 relates to a quick battery active equalization method based on a flyback converter, and belongs to the technical field of lithium battery equalization. According to the method, a bidirectional flyback converter is adopted as an energy transfer circuit, and a finite-state machine algorithm FSM and an external auxiliary power supply are introduced, so that the following functions are realized: when the battery with the highest electric quantity reaches a set value, the flyback converter is utilized to transfer energy to the battery with the low electric quantity, the charging speed is accelerated, and the charging time of the whole battery pack is shortened. By limiting the charging and discharging times of the high-energy battery, the aging speed is effectively slowed down, and the service life of the battery is prolonged. The optimal energy transfer algorithm judges the optimal energy transfer direction, efficient utilization of energy is ensured, and energy loss is reduced. The method is suitable for series battery packs, can be widely applied to the fields of electric vehicles, energy storage systems and the like, and effectively improves the performance and service life of the battery packs.

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 utility model discloses an AC-DC conversion circuit and a charging device, the AC-DC conversion circuit comprises a power factor correction circuit, a DC / DC conversion circuit and an auxiliary power supply circuit, the auxiliary power supply circuit comprises an auxiliary source power supply circuit, a flyback converter, a controllable switch and a control module, and the auxiliary source power supply circuit is connected in parallel between the positive output end and the negative output end of the power factor correction circuit; the flyback converter is connected in parallel with the auxiliary source power supply circuit, and the primary side midpoint is connected with the midpoint of the auxiliary source power supply circuit; one end of the controllable switch is connected with the midpoint of the output bus of the power factor correction circuit, and the other end is connected with the midpoint of the auxiliary source power supply circuit; the input end of the control module is connected with the output end of the DC / DC conversion circuit, the output end of the control module is connected with the control end of the controllable switch, and the control module is used for controlling the controllable switch to be switched off under the condition that the electrical parameters meet preset conditions. Therefore, when the charging module is in light load, voltage regulation is performed on the power factor correction circuit bus, and when the charging module is in heavy load, failure of the auxiliary source is avoided.

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.

A flyback-converter with synchronous-rectifier (SR) sense architecture is provided. A secondary side controller includes a SR-sense pin coupled through an external resistor to a drain of an SR on the secondary-side, a negative-sensing-detector, a peak-detector, a zero-crossing-detector, all coupled to the pin, and a resistor network (Rn) coupled between the pin and ground. The Rn includes a first resistor (R1) to couple the pin and to ground through a first switch (S1) during negative-sensing to divide a voltage (VSR_drain) coupled to the pin, and a second, higher resistance resistor (R2) to couple the pin to ground through a second switch (S2) during peak-detection to divide VSR_draincoupled to the pin. S1 and S2 are controlled by register-transfer-level circuit in the SSC. A line-feed-forward (LFF) circuit is coupled to the pin through an active diode to receive an undivided VSR_drain and mirrors diode current to control the converter in LFF mode.

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.

The embodiment of the invention provides a half-bridge flyback converter, a control method thereof, a control circuit and a chip. The control method comprises the steps that when the half-bridge flyback converter works in a free resonance state, in a first switching period, a second primary switching tube is controlled to be conducted for a first time length, and according to sampling voltage information of a secondary power loop, after it is detected that the second primary switching tube is conducted, a secondary switching tube is controlled to be conducted for a second time length, the half-bridge flyback converter can perform reverse excitation so as to generate negative excitation current, the zero voltage at the two ends of the first primary switch tube is reduced to zero, and when the first primary switch tube is controlled to be switched on, zero-voltage switching-on of the first primary switch tube can be realized. According to the method, the noise of the half-bridge flyback converter can be reduced, and zero-voltage switching-on of the first primary switching tube can be realized under the DCM of the wide-range output voltage of the half-bridge flyback converter, so that the efficiency of the half-bridge flyback converter under the DCM is improved.

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.

According to the frequency jittering method and circuit and the quasi-resonant flyback converter applying the same, when the quasi-resonant flyback converter works in an intermittent conduction mode, frequency jittering is carried out in the following mode that in an Mth switching period group, after the system working frequency reaches a frequency limiting line, a main switching tube is controlled to be conducted at the valley bottom after an ith zero-crossing signal is detected; in the Nth switching period group, when the working frequency of the system reaches a frequency limiting line, the main switching tube is controlled to be switched on at the valley bottom after the jth zero-crossing signal is detected; wherein M and N are two adjacent switching period groups; i is not equal to j. Through the above arrangement, when the quasi-resonant flyback converter is in an intermittent conduction mode, the two adjacent switching period groups control the conduction of the main switching tube at two different valley bottoms, the frequency spectrum of EMI can be effectively dispersed, the function of optimizing EMI is realized, and compared with a mode of jittering peak current or jittering working frequency in the prior art, the frequency spectrum of the quasi-resonant flyback converter is greatly improved. And a better EMI optimization effect is achieved.

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.

The utility model provides a flyback converter and a primary state detection circuit thereof, in a detection interval, when a drain terminal voltage of a synchronous rectifier is greater than an output voltage, integration is carried out from zero based on a difference value between the drain terminal voltage and the output voltage to obtain a first volt-second integral; the volt-second integral judgment module compares the first volt-second integral with a preset integral threshold value and outputs a first judgment signal; the pulse signal generation module generates a first short pulse signal and a second short pulse signal at the starting moment and the ending moment of a detection interval respectively; the pulse counting module counts pulses based on the first judgment signal, the first short pulse signal and the second short pulse signal and outputs a first count value; the synchronous rectifier driving control module judges that the flyback converter primary stage is in a fault state based on the first count value; and when the flyback converter is in the primary fault state, stopping driving the synchronous rectifier. By means of the arrangement, when the primary stage breaks down, the common phenomenon of the primary stage and the secondary stage can be avoided.

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.

An active flyback converter according to one or more embodiments may include a transformer, a first series circuit including the primary winding and a main switch connected in series at both terminals of the DC power supply, a second series circuit including a switch and a capacitor connected in series at both terminals of the primary winding, a controller that turns on and off the main switch and the switch, a rectifier smoothing circuit, and an output voltage detector that detects the output voltage of the rectifier smoothing circuit. In one or more embodiments, the controller may control a first off period from a first drive signal is turned off to a second drive signal is turns on, and a second off period from the second drive signal is turned off to a third drive signal is turned on.

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.