226 results about "Synchronous rectifier" patented technology

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 present invention provides a control circuit of an isolated power supply and an isolated power supply. A secondary side controller in the control circuit can turn on and off a synchronous rectifier based on a voltage from a secondary side winding, enabling adaptive turn-on and turn-off control of the synchronous rectifier. Specifically, when the voltage from the secondary side winding reaches a second predetermined voltage, an instruction for turning off the synchronous rectifier is provided. The second predetermined voltage is adjusted based on a comparison between a time interval for the previous switching period and a predetermined reference interval. In this way, a delay from a turn-off time of the synchronous rectifier to a turn-on time of a primary transistor switch is substantially maintained at the predetermined reference interval. This prevents cross-conduction of the primary and secondary side circuits, ensuring safe operation of the isolated power supply.

The embodiments of the present disclosure provide a synchronous rectifier module, comprising: a transformer provided with a plurality of secondary windings, a first circuit board and a second circuit board disposed on opposite sides of the transformer, and a first connecting piece electrically connected to the first circuit board and a second connecting piece electrically connected to the second circuit board; the first connecting piece and the second connecting piece comprise current sharing portions connected to the first circuit board and the second circuit board respectively, and inductor portions which penetrate an inductance core side by side to form an output inductor, resistance values of the current sharing portions of the first connecting piece and the second connecting piece being equal or a resistance difference value therebetween being within a preset range. The present disclosure can quickly, accurately and conveniently improve the efficiency and the heat dissipation of the synchronous rectifier module, and achieve a better current sharing effect of the connecting pieces by adjusting the resistance value numerical range of the two connecting pieces.

A magnetic inductive resonance charging circuit includes a resonant network having an inductive secondary coil that converts a magnetic field received from an inductive primary coil into an alternating current (AC) signal and a synchronous rectifier that rectifies the AC signal to generate a direct current (DC) signal for application to a load. The synchronous rectifier includes a variety of configurations for shunting the AC waveform of an AC current source in the event of a fault. For example, a rectifier controller may hold a pair of normally open switches of the rectifier off and a pair of normally closed switches of the rectifier on to shunt the AC current source when an over-voltage, over-current fault condition or an over-temperature fault condition is detected. Configurations are provided for grounding the capacitive electromagnetic interference produced in the chassis of an electric vehicle when the resonant network is unbalanced.

A control circuit and method for an isolated switching-mode converter are disclosed. In the control circuit, in preparation for turning on a primary transistor switch in a primary-side circuit, preferably, a secondary-side controller transmits an inquiry signal to a primary-side controller, and the primary-side controller transmits, after confirming that it has been prepared, a feedback signal to the secondary-side controller to allow the secondary-side controller to confirm that the primary transistor switch has been turned off. After that, the primary-side controller turns on the primary transistor. In other words, in the control circuit and method of the present invention, in preparation for turning on the primary transistor switch, information exchange is conducted between the primary and secondary sides to make sure that the primary transistor switch is turned on after the synchronous rectifier transistor is turned off.

The invention relates to an LLC resonant soft switching converter based on self-detection synchronous rectification and a control method thereof. The converter comprises an LLC resonance circuit, a secondary transformer with a center tap, a self-detection synchronous rectification circuit, an input filter circuit, an output filter circuit, an LLC resonance control circuit, a primary PFM drive circuit, an optocoupler isolation circuit, an output voltage sampling circuit and an operational amplifier compensation circuit. Switching tubes S1 and S2 in the primary PFM drive circuit adopt high-voltage MOS tubes, secondary synchronous rectifier tubes S3 and S4 adopt low-voltage MOS tubes, output voltage feedback control and secondary synchronous rectifier tube self-detection drive control are adopted, and the resonant soft switching converter with the 240V-300V input voltage range, the constant output of 28V / 300W and the full-load efficiency of 92% is realized. According to the invention, zero-voltage switching-on of the primary switch tube, zero-current switching-off of the secondary synchronous rectifier tube and accurate synchronous rectification control are realized, the loss of the rectifier circuit is reduced, the efficiency of the converter is improved, and the electromagnetic compatibility characteristic of the converter is optimized.

A power converter incorporating a synchronous rectifier implements adaptive turn-off voltage control for fast turn-off of the synchronous rectifier in the continuous conduction mode. In some embodiments, the synchronous rectifier turn off detection threshold is adaptively changed as a function of the detected operation mode of the power converter. In response to detecting the power converter being operated in the continuous conduction mode, the synchronous rectifier turn off detection threshold is set to a voltage value farther away from zero volt as compared to the nominal turn off detection threshold. In this manner, the synchronous rectifier can be turned off earlier while in the continuous conduction mode. When the synchronous rectifier can be turned off quickly, large reverse current or negative current as well as large drain voltage spike at the synchronous rectifier can be avoided. The reliability of the synchronous rectifier and the power converter is improved.

The invention belongs to the technical field of planar transformers, and relates to a fractional-turn planar transformer of a matrix type integrated structure and a converter. Comprising M magnetic cores and a PCB (printed circuit board), and each magnetic core is provided with a plurality of layers of primary windings and N sections of secondary windings; a circuit structure is arranged between the secondary winding on the first surface and the secondary winding on the second surface, and a source electrode of a synchronous rectifier tube in the circuit structure is connected with a grounding end of an output capacitor; positive potential ends, back to two output capacitors in the circuit structure, on the first surface and the second surface are connected; according to the planar transformer, the advantages of the fractional turn scheme and the matrix scheme of the existing planar transformer are combined, the defects of the fractional turn scheme and the matrix scheme are suppressed, and the requirements of the market for the high-transformation-ratio transformer on the higher server power supply bus voltage are met.

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.

This disclosure presents an embodiment of a power supply device for a submarine data center. One specific embodiment of the power supply device includes a pre-stage voltage regulator / conversion component, a post-stage DC-DC converter component, and a combined protection circuit. The pre-stage voltage regulator / conversion component includes several parallel single-group voltage regulator branches, each branch connected in series with a varistor and a color-coded resistor. A thin-film capacitor is connected in parallel to the output terminal of the pre-stage voltage regulator / conversion component. The post-stage DC-DC converter component, electrically connected to the pre-stage voltage regulator / conversion component, includes at least two sets of full-bridge DC synchronous rectifier circuits. The combined protection circuit includes a pre-stage combined protection circuit, a post-stage active voltage clamping circuit connected in parallel to the output side of the post-stage DC-DC converter component, and a rectifier diode bridge connected between the constant current input port and the pre-stage voltage regulator / conversion component. The pre-stage combined protection circuit is connected in series to the input side of the rectifier diode bridge. By connecting multiple voltage regulator branches in parallel and combining them with the combined protection circuit, ripple is reduced. This embodiment can improve the power supply stability of the power supply device.

A power converter can include: M transformer units, each including primary and secondary windings; M bridge arms, each being is coupled between two input terminals of the power converter to receive a DC input voltage, and each bridge arm comprises a high-side switch, a low-side switch, and a synchronous rectifier coupled in series; where a first terminal of each of the primary windings is coupled to a common node between the high-side switch and the low-side switch in one of the M bridge arms, and a second terminal of each primary winding is coupled together; and where one terminal of each of the secondary windings is coupled to a common node between the low-side switch and the synchronous rectifier in one of the M bridge arms, and the other terminal of each of the secondary windings is coupled to a first output terminal of the power converter.

A secondary side controller for an AC-DC converter, the secondary side controller having a single synchronous rectifier sense (SR_SNS) terminal coupled to a synchronous rectifier (SR) of the AC-DC converter, and a voltage divider circuit coupled to the single SR_SNS terminal, the voltage divider circuit configured to provide a signal to a sense circuit. The voltage divider includes an active diode, an internal resistive element, and a switch, wherein the active diode is configured to control the switch to enable or disable the internal resistive element based on a comparison of a voltage at the single SR_SNS terminal to a reference voltage.

The application relates to a critical conduction mode control method of a totem-pole PFC converter, which utilizes energy equivalence to determine the resonance process of inductor current at switching commutation, carries out totem-pole Boost inductor current value estimation, and on this basis, utilizes a current zero-crossing point prediction algorithm to calculate the turn-on and turn-off time to generate corresponding active tube-synchronous rectifier tube commutation dead time T d,f , synchronous rectification conduction time T SR , rectifier tube-active tube commutation dead time T d,r ; the PWM drive signals of high-speed switching tubes Q1 and Q2 are generated by T on , T d,f , T SR , T d,r ; the power frequency drive signals of low-speed switching tubes Q3 and Q4 are generated by comparing the input alternating voltage v ac with a hysteresis comparison loop and 0. The method can effectively get rid of the dependence on a current zero-crossing detection circuit and a current sensor, reduces the cost and improves the system stability.

The application belongs to the technical field of digital signal processing, and particularly discloses a digital signal generation and processing method and system for synchronous rectification, wherein the method comprises the following steps: obtaining the staggered sampling code stream of a synchronous rectification device, and outputting time-aligned voltage and current characteristic values after group delay hard compensation; performing polynomial thermodynamic school correction in combination with discrete shell temperature sampling values; performing physical safety working area boundary checking on the corrected characteristic values, addressing and interpolating output of the target optimal conduction timing value in the irregular lattice space; extracting a feature vector to perform recursive least square prediction, and outputting an overshoot prediction extreme value; performing discrete charge integration in combination with a nonlinear capacitance function, and iteratively outputting a target dead time value based on the charge conservation criterion; and the application has the advantages of accurate control timing, physical boundary safety and dead time self-adaptation.

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.

Systems for power conversion, and controllers and methods for operating a power converter. The method includes receiving high-side and low-side primary signals that drive primary transistors of a power converter. The method also includes receiving a combined drain voltage signal for high-side and low-side synchronous rectifier (SR) transistors of the power converter. The method further includes generating a high-side SR signal based on the low-side primary signal and generating a low-side SR signal based on the high-side primary signal. The method also includes determining high-side and low-side body diode conduction times based on the combined drain voltage signal. The method further includes adjusting the high-side SR signal based on the high-side body diode conduction time and adjusting the low-side SR signal based on the low-side body diode conduction time.

The present invention relates to the field of power electronic converter control, aiming to provide a converter and its control method for achieving the optimal efficiency of a hydrogen production system. The converter is connected to a three-phase AC power supply and an electrolytic cell, and is an isolated AC / DC converter composed of two-stage converters, including a three-phase power correction rectifier module and a phase-shifted full-bridge module that are electrically connected in sequence, and an electrolytic capacitor is provided between the two modules; wherein, the three-phase power correction rectifier module is composed of six switching tubes, and the switching tubes are interconnected to form three H-bridge structures; the phase-shifted full-bridge module includes a DC / AC sub-module and an AC / DC sub-module; wherein, the DC / AC sub-module includes a primary H-bridge composed of four switching tubes; the AC / DC sub-module is located on the secondary side of the transformer and includes a synchronous rectifier switching tube and an inductor-capacitor filter circuit, and its output terminal is connected to the electrolytic cell. The present invention has the advantages of low switching loss and wide load voltage regulation range, and can meet the requirements of the hydrogen production system.

The present invention discloses a two-output charging circuit and a method for controlling its auxiliary circuit switch. The two-output charging circuit includes two first-stage switch transistors in the half-bridge inverter circuit generating dead time at changing-over and turn-on, and the second-stage switch transistor being turned off within the dead time. In the present invention, making use of a magnetic core to return from the reverse in its bidirectional magnetization process generates dead time, and controlling the time sequence of the switch device of the post-circuit in the dead time abates the voltage stress of the synchronous rectifier diode and reduces the loss of the absorption circuit of the synchronous rectifier circuit.

The present invention discloses a synchronous rectification method and device, including: Step S1, obtaining the resonant current in the charge control circuit of an LLC resonant converter; Step S2, obtaining the magnetizing current in the charge control circuit of the LLC resonant converter; Step S3, obtaining a drive signal applied to a synchronous rectifier tube according to the resonant current and the magnetizing current. By adopting the technical solution of the present invention, the problem that it is difficult to determine the drive signal of the synchronous rectifier tube in a charge control type resonant converter is solved, and at the same time, the problems that the cost of using a synchronous rectification chip is high and it is difficult to achieve multi-degree-of-freedom phase-shift control are solved.

A power converter includes a controller for controlling a synchronous rectifier (SR) switch. The controller includes a request control circuit and a discharge prevention circuit. The request control circuit is configured to generate a request signal in response to the output of the power converter. The request control circuit generates a secondary control signal to control the SR switch. The discharge prevention circuit is configured to prevent the discharge of parasitic capacitance of the power switch caused by the activating of the SR switch. The discharge prevention circuit further generates a prevention signal to: disable the control of the synchronous rectifier switch by the secondary control signal when the period of the request signal is greater than a first time threshold; and enable the control of the synchronous rectifier switch by the secondary control signal when the period of the request signal is less than a second time threshold.

To provide a method for using a secondary switch for enabling zero-voltage switching of the secondary switch in a flyback converter.SOLUTION: A method relates to zero-voltage switching (ZVS) of a secondary switch (e.g., a synchronous rectifier) in a flyback converter. The method causes a secondary control device to enable dynamic calculation of a secondary switch hold time required to achieve the ZVS of a primary switch during a switching cycle and thereby to determine the required secondary switch hold time without requiring communication from a primary side to a secondary side by measuring the charge time and discharge time during the switching cycle.SELECTED DRAWING: Figure 3A

The utility model discloses a single live wire electricity taking circuit and an intelligent switch, the single live wire electricity taking circuit comprises an isolation voltage transformation module, the isolation voltage transformation module comprises a high-frequency transformer and a switch control unit, and the switch control unit is connected with a main winding and an auxiliary winding of the high-frequency transformer; the isolation transformation module is used for receiving alternating current of a live wire, the switch control unit controls the high-frequency transformer to convert the alternating current into target alternating current voltage and output the target alternating current voltage in an isolated mode, and the auxiliary winding of the high-frequency transformer is further used for outputting power supply voltage to a load connected with the auxiliary winding. The switch control unit receives the power supply voltage to work; and the synchronous rectification module is connected with the isolation transformation module and is used for converting the target AC voltage into a first power supply voltage and outputting the first power supply voltage. According to the invention, the complexity of a circuit for simultaneously performing isolated and non-isolated power taking from the live wire can be reduced, and the layout difficulty of a single-live-wire power taking circuit is further reduced.

The invention discloses a multi-output switching power supply and a control method thereof. A first output loop in the multi-output switching power supply comprises a first synchronous rectifier tube and a first output switching tube; a first feedback signal is obtained according to the output feedback signal of the first output loop, and a second feedback signal is obtained according to the output feedback signal of at least one of the other output loops; a zero-voltage conduction pulse signal is generated according to the second feedback signal to conduct a first synchronous rectifier tube, so that a negative current is generated on a main power tube in the input loop; a first output control signal synchronous with a zero voltage conduction pulse signal is generated according to the first feedback signal and the zero voltage conduction pulse signal so as to control the on-off state of the first output switch tube; according to the invention, the synchronization between the first output switch tube and the main power tube can be realized without adopting a complex synchronization signal generation circuit, the control is simple, and the cost is low.

To provide safety circuits that decrease the likelihood of an electric shock caused by a high current source and a high voltage source.SOLUTION: A magnetic inductive resonance charging circuit includes: a resonant network 101 having an inductive secondary coil 104 that converts a magnetic field received from an inductive primary coil into an alternating current (AC) signal; and a synchronous rectifier that rectifies the AC signal to generate a direct current (DC) signal for application to a load. The synchronous rectifier includes a variety of configurations for shunting the AC waveform of an AC current source in the event of a fault. For example, a rectifier controller 115 may hold a pair of normally open switches 107, 108 of the synchronous rectifier off and a pair of normally closed switches 109, 110 of the synchronous rectifier on to shunt the AC current source when an over-voltage, over-current fault condition in a current and voltage sensor 113 or an over-temperature fault condition in a temperature sensor 117 is detected. The capacitive electromagnetic interference produced in the chassis of an electric vehicle is grounded when the resonant network is unbalanced.SELECTED DRAWING: Figure 1

The present invention relates to an active buffer absorption circuit for a synchronous rectifier, which includes a driving unit and an active buffer absorption unit; the driving unit is used to control the operation of the active buffer absorption unit, and the active buffer absorption unit is used to absorb the voltage spike caused when the synchronous rectifier is turned off; the active buffer absorption unit includes an active absorption tube and an active absorption capacitor. During the period when the synchronous rectifier is turned off, the active absorption tube conducts for a period of time, so that the active absorption capacitor absorbs the spike voltage generated when the synchronous rectifier is turned off during this period. The active buffer absorption circuit of the present invention uses the driving unit to drive the active absorption capacitor in the active buffer absorption unit to absorb the spike voltage of the synchronous rectifier during the turn-off period of the synchronous rectifier, reduces additional losses, and improves the performance of the switching device.

This invention proposes a synchronous rectification controller suitable for power conversion circuits. The synchronous rectification controller includes a first terminal, a second terminal, and a switch detection unit. The first terminal is coupled to the primary side of the power conversion circuit. The second terminal is coupled to the secondary side of the power conversion circuit. The switch detection unit, coupled to the first terminal, detects the switching of the primary side of the power conversion circuit. When the switch detection unit detects a trigger signal, it drives the second terminal to send a synchronization signal, thereby controlling the secondary side of the power conversion circuit.

The invention relates to a control method and device of a synchronous rectifier, a medium, a processor and a switching power supply, and the control method comprises the steps: a first obtaining step: obtaining a first voltage signal representing the drain-source voltage of the synchronous rectifier; a second obtaining step: obtaining duration time representing that the first voltage signal is smaller than or equal to a first voltage threshold value; an execution step: giving the initial control mode of the synchronous rectifier as a second control mode, and switching the control mode of the synchronous rectifier between the first control mode and the second control mode according to a preset condition; wherein the first control mode is that the synchronous rectifier is switched on only when the duration time is longer than or equal to first time, the second control mode is that the synchronous rectifier is switched on only when the duration time is longer than or equal to second time, and the second time is longer than the first time. The control method is simple, and the anti-interference capability of the synchronous rectifier and the efficiency of the switching power supply can be improved.

The invention discloses a flyback converter, a control method thereof and a switching power supply. The flyback converter comprises a primary main switching tube, a transformer, a secondary synchronous rectifier tube, a primary control module and a secondary control module, the primary control module is used for selecting a working mode of a current switching period according to a feedback signal generated by a system output voltage signal, and controlling on and off of the primary main switching tube in the current switching period according to the working mode; and the secondary control module is used for controlling the on and off of the secondary synchronous rectifier tube in the secondary demagnetization and resonance process after the primary inductance excitation of the transformer is finished, so as to reduce the rectification loss. By means of the scheme, the situation that the starting moment of the synchronous rectifier tube is not matched with the starting valley bottom position of the primary main switch tube in the resonance process can be avoided to a great extent, and energy waste is reduced.

The present invention relates to a closed-loop adaptive zero-crossing detection circuit suitable for a BOOST-type switching power supply. The circuit comprises a state detector, a state encoder, an up-down counter, a digital-to-analog converter, and a comparator connected in sequence. The state encoder comprises a delay circuit, a first trigger and a second trigger connected to the delay circuit, and a first AND gate, a second AND gate, and a third AND gate connected to the first trigger, wherein the first AND gate, the second AND gate, and the third AND gate are all connected to the second trigger. The present invention uses a closed-loop adaptive zero-crossing detection circuit to detect the inductor current in the switching power supply, samples the current of a synchronous rectifier, and utilizes the state detector, the state encoder, the up-down counter, and the digital-to-analog converter to dynamically adjust the reference voltage of the comparator, adaptively and accurately detecting the inductor zero-crossing signal, reducing the impact of delay or circuit imbalance on zero-crossing detection, thereby reducing the power consumption of the switching power supply and increasing system efficiency.

This invention provides a flyback power supply, a synchronous rectification control circuit, and a method, comprising: a turn-on control module for generating a turn-on control signal for the synchronous rectifier; a turn-off control module for generating a turn-off control signal for the synchronous rectifier when the drain-source voltage of the synchronous rectifier rises to a turn-off threshold, and simultaneously adjusting the turn-off threshold based on the peak value of the drain-source voltage of the synchronous rectifier; and a drive signal generation module for generating a drive signal for the synchronous rectifier based on the turn-on control signal and the turn-off control signal; wherein the turn-off threshold is a negative value. This invention automatically adjusts the turn-off threshold according to the drain-source voltage of the synchronous rectifier, solving the voltage stress problem caused by common operation in continuous mode, enabling the system to operate safely and efficiently in continuous mode; simultaneously, it achieves maximum conduction time in discontinuous mode, resulting in high system efficiency; furthermore, this invention reduces the comparator delay requirement and eliminates the need for specific processing of the primary-side control drive, making it simple and easy to implement.