WO2023004592A1

WO2023004592A1 - Method and apparatus for controlling power conversion circuit, storage medium, and program product

Info

Publication number: WO2023004592A1
Application number: PCT/CN2021/108727
Authority: WO
Inventors: 代胜勇; 杨滚; 秦亚霄
Original assignee: 华为数字能源技术有限公司
Priority date: 2021-07-27
Filing date: 2021-07-27
Publication date: 2023-02-02
Also published as: CN116368723A

Abstract

The present disclosure relates to a method and an apparatus for controlling a power conversion circuit, a storage medium, and a program product. The method for controlling a power conversion circuit comprises: receiving a detection signal, the detection signal representing a rate of change of a rectifier device voltage across a rectifier device with respect to time, and the rectifier device being connected to a secondary winding of a transformer in a power conversion circuit; determining, on the basis of the detection signal and a predetermined change rate range, a duration for which the rectifier device voltage is within the predetermined change rate range; and in response to the duration exceeding a time threshold, generating an enable signal for turning on the rectifier device. The solution of the present disclosure can effectively prevent erroneous turn-on of a synchronous rectifier device, thereby preventing damage to a power switch caused by erroneous turn-on in the power conversion circuit.

Description

Method and device for controlling power conversion circuit, storage medium and program product

technical field

The present disclosure mainly relates to the field of power electronics, and more specifically relates to methods and devices for controlling power conversion circuits, storage media, program products, corresponding power conversion circuits, and electronic equipment.

Background technique

Current power adapters widely use power conversion circuits such as flyback circuits to obtain power required by various electronic devices. In a power conversion circuit such as a flyback circuit, a rectifier diode is usually provided at the secondary winding of a transformer. When the power conversion circuit operates at low voltage and high current, the conduction voltage drop of the rectifier diode is high and the loss is large. This rectification loss sometimes even accounts for more than 60% of the total power loss. In order to reduce rectification loss, synchronous rectification technology can be used, that is, a power switch tube with extremely low on-state resistance (such as a metal oxide semiconductor field effect transistor) is used to replace the rectifier diode to complete the rectification operation.

When using the synchronous rectification technology, it is necessary to realize precise conduction of the synchronous rectification tube. However, under some conditions (such as current discontinuity), there may be oscillations in the voltage across the synchronous rectifiers. This oscillation will cause false conduction of the synchronous rectifier, thereby causing the power switching devices on the primary side and the secondary side of the transformer to conduct simultaneously, which will cause damage to the power switching device and affect the safety of the power adapter.

Contents of the invention

In order to solve the above problems, embodiments of the present disclosure provide a new solution for controlling a power conversion circuit.

In a first aspect of the present disclosure, there is provided a method for controlling a power conversion circuit, comprising: receiving a detection signal representing a rate of change of a rectification device voltage across a rectification device with respect to time, the rectification device being connected to a power converting a secondary winding of a transformer in the circuit; determining a duration for which the voltage of the rectifier device is within the predetermined range of rate of change based on the detection signal and the predetermined range of rate of change; and generating a signal for turning on the rectifier device in response to the duration exceeding a time threshold enable signal.

In the solution of the present disclosure, by detecting whether the rate of change of the voltage of the rectifier device is continuously stable within a certain range, it can be judged whether the voltage of the rectifier device oscillates, thereby effectively avoiding false conduction when the voltage of the rectifier device oscillates, and this This judgment will not be affected by other factors such as output voltage fluctuations.

In an implementation manner of the first aspect, receiving the detection signal includes: receiving the detection signal from a sensing device, the sensing device is connected in parallel with the rectification device and includes a resistive unit and a capacitive unit connected in series, and the detection signal includes a trans The signal of the voltage of the resistive cell. When the rectifying device voltage is applied across the capacitive unit, the current flowing through the capacitive unit corresponds to the rate of change of the rectifying device voltage with respect to time, therefore, by detecting the voltage of the resistive unit connected in series with the capacitive unit, one can The rate of change of the rectifier device voltage with respect to time is obtained directly in a simple manner.

In an implementation manner of the first aspect, receiving the detection signal includes: receiving a plurality of digital sampling voltages sequential in time from an analog-to-digital converter in the sensing device, the sensing device is connected in parallel with the rectifying device, and the analog-digital The converter is used to sequentially sample the voltage of the rectifying device multiple times in time to generate multiple digital sampling voltages, and the multiple digital sampling voltages represent the rate of change of the voltage of the rectifying device relative to time. In this implementation, the detection signal can also be a plurality of successive digital sampling voltages, which can also indicate the rate of change of the voltage of the rectifier device relative to time.

In an implementation manner of the first aspect, based on the detection signal and the predetermined rate of change range, determining the duration of the voltage of the rectifier device within the predetermined rate of change range includes: determining the plurality of digital sampling voltages relative to time based on the plurality of digital sampling voltages the rate of change; and determining the duration based on the determined rate of change and the predetermined range of rates of change. In this implementation, the rate of change of the rectifier device voltage with respect to time can be obtained entirely digitally and the desired duration can be determined.

In an implementation manner of the first aspect, generating the enabling signal for turning on the rectifying device in response to the duration exceeding the time threshold includes: starting timing by a timer in response to the voltage of the rectifying device falling within a predetermined rate-of-change range; and generating an enable signal in response to the time value of the timer exceeding the time threshold. By means of the timer, the determination of the duration of the voltage of the rectifier device falling within the range of the predetermined rate of change can be realized in a simple and reliable manner.

In an implementation manner of the first aspect, the method further includes: clearing the timer to zero in response to the voltage of the rectifying device being outside the predetermined rate-of-change range; or clearing the timer in response to generating the enable signal. Through this implementation method, false conduction during voltage oscillation can be effectively avoided, and preparations for the next conduction control can be made.

In a second aspect of the present disclosure, there is provided a control device for controlling a power conversion circuit, comprising: a processor; and a memory coupled to the processor, the memory having instructions stored therein, the instructions when executed by the processor A device is caused to perform the method according to the first aspect.

In a third aspect of the present disclosure, there is provided a computer-readable storage medium having stored thereon computer program code which, when executed, performs the method according to the first aspect.

In a third aspect of the present disclosure, there is provided a computer program product tangibly stored on a computer-readable medium and comprising computer-executable instructions which, when executed, cause a device to perform a device according to a first aspects of the method.

In a fourth aspect of the present disclosure, there is provided a power conversion circuit comprising: a transformer; a rectification device connected to a secondary winding of the transformer; and the control device according to the first aspect for controlling the rectification device.

In a fifth aspect of the present disclosure, there is provided an electronic device, including: a power supply device; and the power conversion circuit according to the fourth aspect, powered by the power supply device.

It should be understood that what is described in the Summary of the Invention is not intended to limit the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will be readily understood through the following description.

Description of drawings

The above and other features, advantages and aspects of the various embodiments of the present disclosure will become more apparent with reference to the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, identical or similar reference numerals denote identical or similar elements, wherein:

FIG. 1 shows a schematic block diagram of an electronic device in which some embodiments of the present disclosure can be implemented;

2 shows a schematic diagram of a power conversion circuit according to an embodiment of the present disclosure;

Fig. 3 shows a schematic diagram of an implementation of the circuit in the dotted box A of Fig. 1;

FIG. 4 shows a schematic diagram of another implementation of the circuit in the dotted box A of FIG. 1;

FIG. 5 shows a schematic diagram of waveforms of various signals and voltages in the power conversion circuit;

FIG. 6 shows a schematic flowchart of a method for controlling a power conversion circuit according to an embodiment of the present disclosure; and

Fig. 7 shows a schematic block diagram of an example device that may be used to implement embodiments of the present disclosure.

Detailed ways

Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the drawings, it should be understood that the disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein; A more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are for exemplary purposes only, and are not intended to limit the protection scope of the present disclosure.

In the description of the embodiments of the present disclosure, the term "comprising" and its similar expressions should be interpreted as an open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be read as "at least one embodiment". The terms "first", "second", etc. may refer to different or the same object. The term "and/or" means at least one of the two items associated with it. For example "A and/or B" means A, B, or A and B. Other definitions, both express and implied, may also be included below.

It should be understood that for the technical solutions provided by the embodiments of the present application, in the introduction of the following specific embodiments, some repetitions may not be repeated, but it should be considered that these specific embodiments have been referred to each other and can be combined with each other.

In a power conversion circuit employing synchronous rectification technology, it is generally possible to determine when to turn on the synchronous rectification device by detecting the polarity and magnitude of the voltage across the synchronous rectification device. However, as mentioned earlier, in some cases, the voltage across the synchronous rectification device may oscillate after the synchronous rectification device is turned off. Therefore, when oscillation occurs, only judging the polarity and magnitude of the voltage across the synchronous rectification device to determine the turn-on timing may cause false conduction of the synchronous rectification device, which may damage the power switching device in the power conversion circuit.

In order to ensure that the synchronous rectification device can be turned on accurately, the present disclosure provides a new method for controlling the power conversion circuit. In the present disclosure, an additional turn-on condition is further set, so that the synchronous rectification device needs to satisfy the additional turn-on condition before turning on. Wherein, after the synchronous rectification device is turned off, by sensing the rate of change of the voltage across the synchronous rectification device with respect to time, and determining the duration of the rate of change within a predetermined range, it is possible to determine whether there is an undesired oscillation across the rectifier device Or other conditions that may cause false turn-on, so that the synchronous rectification device can only turn on when the turn-on condition is met.

FIG. 1 shows a schematic block diagram of an electronic device 1000 in which some embodiments of the present disclosure may be implemented. According to an embodiment of the present disclosure, the electronic device 100 includes a power conversion circuit 100 and a power supply device 200 . In addition, the electronic device 100 may also include a load 300 such as a smartphone or a notebook computer. It can be understood that although it is shown in the figure that the power conversion circuit 100 and the power supply device 200 are separate components independent of the load 300, they are not limited thereto, for example, at least one of the power conversion circuit 100 and the power supply device 200 can also be May be formed as part of load 300 such as a laptop computer. As an example, the power supply device 200 may convert AC power from an AC power source such as a utility grid into DC power and input it to the power conversion circuit 100 . Then, the power conversion circuit 100 can convert the received DC power into the DC power required for the load 300 to operate.

FIG. 2 shows a schematic diagram of a power conversion circuit 100 according to an embodiment of the present disclosure. In FIG. 2 , a power supply _Vin and a load _RL representing the power supply device 200 and the load 300 are also schematically shown. As an example, the power conversion circuit 100 is an asymmetrical half bridge flyback (AHBF). However, it can be understood that the power conversion circuit 100 can also be other types of power conversion circuits that can adopt synchronous rectification technology, such as active clamp flyback (active clamp flyback, ACF) circuit, active zero voltage switch (active zero voltage switch, AZVS) circuit, quasi-resonance flyback (quasi-resonance flyback, QF) circuit, etc.

According to some embodiments of the present disclosure, the power conversion circuit 100 may include a transformer 140 and a synchronous rectification device 110 connected to a secondary winding of the transformer 140 . As an example, the power conversion circuit 100 may also include a main power switch Q _main connected to the primary winding of the transformer 140 and an auxiliary power switch Q ₂ , wherein the main power switch Q _main is connected in series with the primary winding of the transformer 140 and the auxiliary power switch Q ₂ is connected in parallel with the primary winding of the transformer 140. In addition, the primary side of the transformer 140 may also include a bus capacitor C _B , a resonant capacitor C _r and a resonant inductor L _r , wherein the bus capacitor C _B is connected in parallel with the input power supply V _in , and the resonant capacitor C _r and the resonant inductor L _r are connected in series Between the drain of the auxiliary power switch Q ₂ and the primary winding of the transformer 140 . The secondary side of the transformer 140 may further include an output capacitor C ₀ , wherein the output capacitor C ₀ is connected in parallel with the load _RL . In FIG. 1 , the inductance L _m represents the excitation inductance of the transformer, and the resonant inductance L _r may be formed by the leakage inductance of the transformer, or may be formed by another inductance. It can be understood that, in different circuit topologies, the power conversion circuit 100 may omit some electrical components and power switches or add more electrical components and power switches as required.

The basic working process of the power conversion circuit 100 will be briefly described below. When the main power switch Q _main is turned on, the input power of the power conversion circuit 100 is applied to the primary winding of the transformer, the current of the primary winding rises, the magnetic flux increases and the energy storage inductance increases. The induced potential V _BF at both ends of the secondary winding of the transformer (that is, the voltage between the upper terminal B and the lower terminal F of the secondary winding in the figure) is negative, the synchronous rectification device is in the off state, and the current of the load _RL is controlled by the capacitor C ₀ provided. When the main power switch Q _main is turned off, the input power of the power conversion circuit 100 stops supplying power to the transformer 140, the magnetic flux of the secondary winding decreases from the maximum value, and the induced potential V _BF at both ends of the secondary winding is positive (reversed) . The synchronous rectification device 110 is turned on to turn on the synchronous rectification device 110 . Thus, through the current flowing through the synchronous rectification device 110, the magnetic energy of the transformer inductance becomes electric energy, so as to supply power to the load _RL and charge the capacitor _C0 .

It can be seen that during the energy storage stage of the transformer inductance, the synchronous rectification device 110 will bear the negative voltage, and the synchronous rectification device 110 remains in the off state. During the discharge phase of the transformer inductor, the synchronous rectification device 110 bears the forward voltage, and the synchronous rectification device 110 is turned on. Therefore, by detecting the polarity of the voltage across the synchronous rectification device 110 and determining whether the magnitude of the voltage exceeds a certain threshold, it can be determined when to turn on the synchronous rectification device 110 . However, as mentioned above, after the synchronous rectification device is turned off, there may be oscillations in the voltage across the synchronous rectification device. Therefore, if only the polarity and magnitude of the voltage across the synchronous rectification device 110 are used as the conduction condition, it may cause false conduction of the synchronous rectification device 110 .

According to some embodiments of the present disclosure, the power conversion circuit 100 further includes a sensing device 120 and a control device 130 . The control device 130 may provide an additional conduction condition for the synchronous rectification device 110 based on the detection signal, so as to avoid false conduction of the synchronous rectification device 110 . As an example, the sensing device 120 is connected to the synchronous rectification device 110 to sense the electrical quantity of the synchronous rectification device 110 , and the sensing device 120 is also coupled to the control device 130 to provide the detection signal to the control device 130 for processing. The working process of the control power conversion circuit 100 according to the embodiment of the present disclosure will be described in detail below with reference to FIG. 2 .

The control means 130 may receive a detection signal from the sensing means 120, the detection signal being representative of the rate of change of the rectification device voltage across the rectification device 110 connected to the secondary winding of the transformer 140 in the power conversion circuit 100 with respect to time . As an example, the sensing device 120 may sense a voltage across the rectifying device 110 and obtain a rate of change of the rectifying device voltage with respect to time based on the voltage. It will be appreciated that sensing device 120 may comprise any suitable device capable of sensing the rate of change of voltage. FIG. 5 shows schematic waveforms of various signals and voltages in the power conversion circuit 100 , where V _SR represents the voltage across the rectifying device 110 , and V _dec represents the rate of change of the voltage across the rectifying device 110 with respect to time. It can be seen that V _dec essentially corresponds to the slope of the V _SR curve.

FIG. 3 shows a schematic diagram of an implementation of the circuit in the dotted box A of FIG. 2 . In the implementation manner shown in FIG. 3 , the circuit within the dotted box A includes a rectifying device 110 and a sensing device 120 - 1 . As an example, the rectifier device 110 may include a power switch tube, a freewheeling diode, and a parallel capacitor. In some embodiments, the freewheeling diode and the parallel capacitor can be the body diode and parasitic capacitor of the power switch. In some other embodiments, the freewheeling diode and the parallel capacitor may be diodes and capacitors added separately. Alternatively, the freewheeling diode and the shunt capacitor can also be removed in some cases. In some embodiments of the present disclosure, the control device 130 receives a detection signal from the sensing device 120 - 1 connected in parallel with the rectifying device 110 . In one embodiment, the sensing device 120 - 1 includes a resistive unit 121 and a capacitive unit 122 connected in series, and the detection signal includes a voltage signal across the resistive unit 121 . As an example, the resistive unit 121 and the capacitive unit 122 connected in series are connected across the rectifying device 110, and thus the rate of change of the rectifying device voltage with respect to time can be directly sensed. Specifically, when the rectifying device voltage is applied to the capacitive unit 122 , as the capacitive unit 122 is charged and discharged, the current passing through the capacitive unit 122 substantially corresponds to the rate of change of the rectifying device voltage with respect to time. Therefore, by detecting the voltage of the resistive unit 121 connected in series with the capacitor device 122 by the detection circuit or detector 123, the rate of change of the voltage of the rectification device with respect to time can be obtained. In one embodiment, the resistive unit 121 and the capacitive unit 122 may be a resistor and a capacitor, respectively. However, the resistive unit and the capacitive unit are not limited to resistors and capacitors, but may be any elements having resistive and capacitive characteristics. For example, the resistive unit may be a MOSFET or a diode, and the capacitive unit may be a suitable component exhibiting a capacitance. Alternatively, a resistive unit may be formed by combining a plurality of elements with resistive properties in series and/or in parallel, and a capacitive unit may be formed by combining a plurality of elements with capacitive properties in series and/or in parallel . Alternatively, the resistive unit may also be a resistive network composed of a plurality of electrical elements and exhibit resistivity as a whole, and the capacitive unit may be a capacitive network composed of a plurality of electrical elements and exhibit capacitive properties as a whole.

Based on the detection signal and the predetermined rate-of-change range, the control device 130 can determine the duration for which the voltage of the rectifier device is within the predetermined rate-of-change range. As an example, the predetermined change rate range may include a predefined upper threshold Th1 and a lower threshold Th2. The upper threshold Th1 and the lower threshold Th2 can be defined as a pair of positive and negative values whose absolute value is slightly greater than zero. Therefore, the fact that the slope of the voltage of the rectifying device is continuously within the predetermined range means that the rate of change of the voltage with respect to time is continuously close to zero. That is, the voltage of the rectifying device 110 tends to be stable instead of being in an oscillating state. Referring to FIG. 5 , in the waveform diagram associated with V _dec , upper and lower thresholds Th1 and Th2 indicated by dashed lines above and below the horizontal axis (corresponding to zero) indicate exemplary predetermined rate-of-change ranges. It can be understood that the upper threshold and the lower threshold or the specific size of the predetermined change rate range can be determined according to specific working conditions and actual needs. The control device 130 can compare the voltage change rate corresponding to the detection signal with the predefined upper threshold and lower threshold, so as to continuously judge whether the change rate of the voltage of the rectifier device is within the predetermined range of change rate, so as to determine whether the voltage of the rectifier device is larger or not. oscillation. For example, in the case of obtaining the detection signal from the resistive unit of the sensing device 120-1 shown in FIG. Compare and judge whether the rate of change continues to fall within the predetermined range according to the comparison results.

FIG. 4 shows a schematic diagram of another implementation of the circuit in the dotted box A of FIG. 2 . In the implementation shown in FIG. 4 , the circuit within the dotted box A includes a rectifying device 110 and a sensing device 120 - 2 , and the sensing device 120 - 2 includes a detection circuit or detector 124 and an analog-to-digital converter 125 . In some embodiments of the present disclosure, the control device 130 receives a plurality of digital sampling voltages sequentially in time from the analog-to-digital converter 125 in the sensing device 120-2, and the sensing device 120-2 is connected in parallel with the rectifying device 110 connected, and the analog-to-digital converter 125 is used to sequentially sample the voltage across the rectifying device 110 multiple times in time to generate a plurality of digital sampling voltages, and the plurality of digital sampling voltages represent the rectifying device voltage across the rectifying device 110 with respect to time rate of change. As an example, in the sensing device 120-2, a detection circuit or detector 124 may detect the voltage across the rectifying device 110 and provide to an analog-to-digital converter 125 to convert the voltage-related analog signal into a digital signal, thereby obtaining A plurality of digital sampling voltages successive in time, these successive digital sampling voltages can represent the rate of change of the voltage of the rectifier device relative to time.

In some embodiments of the present disclosure, the control device 130 may determine the rate of change of the multiple digital sampled voltages relative to time based on the multiple digital sampled voltages, and the control device 130 may determine the rate of change based on the determined rate of change and the predetermined rate of change range, A duration of time that the voltage of the rectifier device is within a predetermined rate of change is determined. For example, when the detection signal is obtained from the digital-to-analog converter 125 in the sensing device 120-2 shown in FIG. The rate of change of these sampled voltages over time is obtained. Thus, the rate of change of the voltage of the rectifying device relative to time can be determined, and the duration can be further determined based on a predetermined range of rate of change.

The control means 130 may determine whether the duration determined above exceeds a time threshold. As an example, the time threshold can be properly set according to actual needs.

In response to the determined duration exceeding the time threshold, the control device 130 may generate an enable signal for turning on the rectifying device 110 . As an example, the determined duration exceeding the time threshold means that the rectification device voltage remains stable for a long enough time without oscillation, so the control device 130 may generate an enable signal for turning on the rectification device 110 . The enabling signal can make the rectifying device 110 in a state capable of triggering conduction. The enabling signal together with the driving signal for triggering the rectification device 110 will trigger the conduction of the rectification device 110 . The drive signal for triggering the conduction of the rectifier device can also be generated, for example, by the control device 130 , or by another separate control device. For example, the control device 130 or another separate control device judges that the transformer secondary winding of the power conversion circuit 100 has entered the discharge phase according to the received detection signal, for example, according to the polarity and magnitude of the voltage across the rectification device 110 and The rectifier device 110 needs to be turned on. Therefore, the control device 130 or another separate controller can send out the driving signal to finally trigger the rectifying device 110 to conduct.

In some embodiments of the present disclosure, the control device 130 may include a timer, and in response to the voltage of the rectifying device falling within the range of the predetermined rate of change, the timer may start timing. Thus, the time value of the timer may indicate the duration for which the voltage of the rectifying device falls within the predetermined rate-of-change range. The time value of the timer exceeding the time threshold means that the duration for which the voltage of the rectifying device falls within the predetermined rate-of-change range exceeds the time threshold. Therefore, in response to the time value of the timer exceeding the time threshold, the control device 130 may generate an enable signal for turning on the rectifying device 110 .

According to an embodiment of the present disclosure, the process of controlling the power conversion circuit 100 may further include: the control device 130 clearing the timer to zero in response to the rectification device voltage being outside the predetermined rate of change range; or the control device 130 in response to generating the enable signal, 130 clear the timer. As an example, the timer may be cleared once the rectifier device voltage leaves or is not within a predetermined rate-of-change range. Therefore, if the voltage of the rectifier device oscillates, the rate of change of the voltage of the rectifier device will repeatedly enter and leave the range of the predetermined rate of change within a short period of time, so the timer will be cleared to zero and the time threshold cannot be reached, thereby avoiding the rectification device voltage. False turn-on occurs during oscillation. In addition, once the control device 130 generates the enable signal, the timer can be cleared to be ready for the next conduction control of the rectifier device.

Various signals and outputs of the power conversion circuit 100 in the process of controlling the power conversion circuit 100 according to an embodiment of the present disclosure are described below with reference to FIG. 5 . In FIG. 5 , the waveform diagram associated with Qmain gate represents the gate signal waveform of the main power switch Q _main of the power conversion circuit 100, and the waveform diagram associated with Q2gate represents the gate signal waveform of the main power switch Q _main of the power conversion circuit 100. Pole signal waveform, the waveform diagram associated with V _dssw represents the potential waveform of V _dssw of the power conversion circuit 100, the waveform diagram associated with V _SR represents the waveform of the voltage V _SR across the rectifier device 110 of the power conversion circuit 100, and the waveform associated with V The waveform diagram associated with _dec represents the waveform of the rate of change of the voltage V _SR with respect to time.

The lower part of the horizontal axis of time in FIG. 5 exemplarily shows six moments from t1 to t6 . At t1, the rectifying device 110 is turned off, the voltage V _SR across the rectifying device 110 is negative and its absolute value increases rapidly; at t2, the voltage V _SR across the rectifying device 110 tends to be stable, and the voltage V _SR is relatively time-dependent The rate of change V _dec enters the predetermined rate of change range; at t3, the duration of the rate of change V _dec entering the predetermined rate of change range exceeds the time threshold t _hold , which indicates that the voltage V _SR is in a steady state, so the control device 130 generates a valid enable signal , that is, the SR flag signal changes from low to high; during the period from t4 to t5, the voltage V _SR across the rectifier device 110 oscillates, and the duration of the rate of change V _dec in the predetermined range of rate of change never exceeds the time threshold t _hold , so SR The flag signal is always low; at t5, the voltage V _SR across the rectifier device 110 becomes a stable voltage, and the rate of change V _dec enters a predetermined rate of change range; at t6, the duration of the rate of change V _dec into the predetermined rate of change range exceeds time The threshold t _hold means that the voltage V _SR stops oscillating and enters a stable state, so the control device 130 generates an effective enable signal, that is, the SR flag signal changes from low to high.

It can be seen that, the solutions of the embodiments of the present disclosure can avoid outputting a valid enable signal when the voltage V _SR oscillates, thereby prohibiting the rectifier device 110 from being turned on. This solution simply and effectively avoids the false conduction of the synchronous rectification device, and will not be affected by other factors such as output voltage fluctuations.

The control device 130 in the power conversion circuit 100 can be realized in various ways. In some embodiments of the present disclosure, the control device 130 may be, for example, a control device including a processing unit. Alternatively, the control device 130 may be any other device with calculation and control functions, for example, the control device 130 may be implemented in the form of an analog circuit or a digital circuit.

FIG. 6 shows a schematic flowchart of a method 600 for controlling a power conversion circuit according to an embodiment of the present disclosure. The method 600 can be implemented in the power conversion circuit 100 and executed by the control device 130 . Accordingly, various aspects described above with respect to FIGS. 1-5 may apply to method 600 .

At block 601 , a detection signal is received representing a rate of change of a rectifying device voltage with respect to time across a rectifying device 110 connected to a secondary winding of a transformer 140 in a power conversion circuit 100 .

At block 602, based on the detection signal and the predetermined rate-of-change range, a duration for which the voltage of the rectifying device is within the predetermined rate-of-change range is determined.

At block 603, it is determined whether the duration exceeds a time threshold.

At block 604 , an enable signal for turning on the rectifying device 110 is generated in response to the duration exceeding the time threshold.

FIG. 7 shows a schematic block diagram of an example device 700 that may be used to implement embodiments of the present disclosure. The device 700 can be used to implement the control device 130 in FIG. 2 . As shown in FIG. 7, the device 700 includes a computing unit 701 that can be loaded into RAM and/or Computer program instructions in ROM 702 to perform various appropriate actions and processes. In the RAM and/or ROM 702, various programs and data necessary for the operation of the device 700 may also be stored. The computing unit 701 and the RAM and/or ROM 702 are connected to each other via a bus 703. An input/output (I/O) interface 704 is also connected to the bus 703 .

Multiple components in the device 700 are connected to the I/O interface 704, including: an input unit 705, such as a keyboard, a mouse, etc.; an output unit 706, such as various types of displays, speakers, etc.; a storage unit 707, such as a magnetic disk, an optical disk, etc. ; and a communication unit 708, such as a network card, a modem, a wireless communication transceiver, and the like. The communication unit 708 allows the device 700 to exchange information/data with other devices over a computer network such as the Internet and/or various telecommunication networks.

The computing unit 701 may be various general-purpose and/or special-purpose processing components having processing and computing capabilities. Some examples of computing units 701 include, but are not limited to, central processing units (CPUs), graphics processing units (GPUs), various dedicated artificial intelligence (AI) computing chips, various computing units that run machine learning model algorithms, digital signal processing processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 701 executes various methods and processes described above, such as the method 600 . For example, in some embodiments, method 600 may be implemented as a computer software program tangibly embodied on a machine-readable medium, such as storage unit 707 . In some embodiments, part or all of the computer program may be loaded and/or installed onto device 700 via RAM and/or ROM and/or communication unit 708 . When a computer program is loaded into RAM and/or ROM and executed by computing unit 701, one or more steps of method 600 described above may be performed. Alternatively, in other embodiments, the computing unit 701 may be configured to execute the method 600 in any other suitable manner (for example, by means of firmware).

Program codes for implementing the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a special purpose computer, or other programmable data processing devices, so that the program codes, when executed by the processor or controller, make the functions/functions specified in the flow diagrams and/or block diagrams Action is implemented. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media would include one or more wire-based electrical connections, portable computer discs, hard drives, random access memory (RAM), read only memory (ROM), erasable programmable read only memory (EPROM or flash memory), optical fiber, compact disk read only memory (CD-ROM), optical storage, magnetic storage, or any suitable combination of the foregoing.

In addition, while operations are depicted in a particular order, this should be understood to require that such operations be performed in the particular order shown, or in sequential order, or that all illustrated operations should be performed to achieve desirable results. Under certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while the above discussion contains several specific implementation details, these should not be construed as limitations on the scope of the disclosure. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination.

Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are merely example forms of implementing the claims.

Claims

A method for controlling a power conversion circuit comprising:

receiving a detection signal indicative of a rate of change with respect to time of a rectification device voltage across a rectification device connected to a secondary winding of a transformer in the power conversion circuit;

determining a duration for which the voltage of the rectifying device is within the predetermined rate-of-change range based on the detection signal and the predetermined rate-of-change range; and

An enable signal for turning on the rectifying device is generated in response to the duration exceeding a time threshold.
The method of claim 1, wherein receiving the detection signal comprises:

The detection signal is received from a sensing device connected in parallel with the rectifying device and comprising a resistive unit and a capacitive unit connected in series, and the detection signal comprises a voltage across the resistive unit Signal.
The method of claim 1, wherein receiving the detection signal comprises:

A plurality of digitally sampled voltages successive in time are received from an analog-to-digital converter in a sensing device connected in parallel with the rectifying device, and the analog-to-digital converter is used to convert the rectifying device voltage at A plurality of samplings are sequentially performed in time to generate the plurality of digital sampling voltages, and the plurality of digital sampling voltages represent the rate of change of the voltage of the rectifying device relative to time.
The method according to claim 3, wherein based on the detection signal and the predetermined range of rate of change, determining the duration of the voltage of the rectifying device within the range of the predetermined rate of change comprises:

determining a rate of change of the plurality of digital sampled voltages with respect to time based on the plurality of digital sampled voltages; and

The duration is determined based on the determined rate of change and the predetermined rate of change range.
The method according to any one of claims 1-4, wherein generating an enable signal for turning on the rectifying device in response to the duration exceeding a time threshold comprises:

starting a timer in response to the rectifying device voltage falling within the predetermined rate-of-change range; and

The enable signal is generated in response to a time value of the timer exceeding the time threshold.
The method according to claim 5, further comprising:

clearing the timer in response to the rectifier device voltage being outside of the predetermined rate-of-change range; or

In response to generating the enable signal, the timer is cleared.
A control device for controlling a power conversion circuit, comprising:

processor; and

A memory coupled to the processor, the memory having instructions stored therein which when executed by the processor cause the apparatus to perform the method of any one of claims 1-6.
A computer readable storage medium having stored thereon computer program code which, when executed, performs the method of any one of claims 1 to 6.
A computer program product tangibly stored on a computer-readable medium and comprising computer-executable instructions which, when executed, cause a device to perform the method described in the item.
A power conversion circuit comprising:

transformer;

a rectifying device connected to the secondary winding of the transformer; and

The control device according to claim 7, for controlling the rectifying device.
An electronic device comprising:

power supply unit; and

The power conversion circuit according to claim 10, powered by the power supply device.