Control Modules and Adapters

Abstract

A control module and an adapter are provided. The control module is configured to determine the input current of the buck circuit and the output voltage of the loop compensation circuit, and to control the turn-off of a switching transistor of the buck circuit based on the relationship between the output voltage and the input current, and the turn-on duty cycle of the switching transistor is directly proportional to the ratio of the output voltage to the average value of the input current. In this application, the turn-on duty cycle of the buck switching transistor is set to be directly proportional to the ratio of the output voltage of the loop compensation circuit to the average input current, thereby achieving power factor adjustment and eliminating the need for an input voltage sampling register and a corresponding multiplier.

Description

[Technical Field]

[0001] This application claims priority to Chinese Patent Application No. 202311116746.4, entitled "CONTROL MODULE AND ADAPTER," filed with the State Intellectual Property Office of China on August 30, 2023, and is incorporated herein by reference in its entirety.

[0002] This application relates to the field of electronics, and more particularly to control modules and adapters. [Background technology]

[0003] With the development of supercharging technology, the power required to charge terminal devices becomes increasingly higher, reaching the hectowatt level. Due to standard restrictions on harmonic injection in the power grid, power supplies above 75W require the addition of a power factor correction (PFC) circuit to reduce the harmonics injected into the power grid by the device. To reduce peak power and conduction losses, high-power PFC circuits typically operate in continuous conduction mode (CCM). To reduce switch losses, medium / low-power PFC circuits typically operate in critical conduction mode (CRM).

[0004] The traditional control method for buck PFC in constant frequency CCM is the average current control method. After being sampled using voltage divider resistors R1 and R2, the input bus voltage is multiplied by the output voltage of the voltage feedback loop to obtain the current command Iref. After the current feedback loop performs an operation on the current command and the input current sampling voltage, a modulated wave is obtained. By comparing it with a constant frequency sawtooth wave, the modulated wave generates a control signal for the switching transistor. It can be seen that in the control system, a high-voltage resistor network is needed to sample the bus voltage, and a multiplier needs to be added to multiply the instantaneous input voltage by the output of the feedback circuit to obtain the target average current value.

[0005] However, in the current control method, multiple high-voltage resistors need to be added outside the control system to sample the bus voltage to achieve the tracking function, and multipliers need to be added inside the control system to process the signals, resulting in a large system layout area and high standby power consumption. Summary of the Invention

[0006] This application provides a control module and adapter for omitting the input voltage sampling register and corresponding multiplier, thereby reducing system layout area and standby power consumption.

[0007] According to a first aspect, this application provides a control module that can be utilized in a device power supply, such as a terminal device adapter, a base station power supply, or a server power supply. The control module is configured to determine an input current of a buck circuit and an output voltage of a loop compensation circuit, the control module being further configured to control the turn-off of a switching transistor of the buck circuit based on a relationship between the output voltage and the input current, wherein a turn-on duty cycle of the switching transistor is directly proportional to a quotient of the output voltage and an average value of the input current.

[0008] For example, the relationship between the output voltage and the output current may be understood as the relationship between the output voltage and the voltage of a capacitor after the capacitor has been charged with the output current or a current proportional to the output current.

[0009] This application provides a control mode for PFC operating in constant frequency CCM, in which the turn-on duty cycle of the switching transistor is set to be directly proportional to the ratio of the output voltage of the loop compensation circuit to the average input current, thereby achieving power factor correction and eliminating the input voltage sampling register and corresponding multiplier.

[0010] In a possible implementation, the input current tracks the input voltage of the buck circuit.

[0011] In a possible implementation, the average value of the input current is the average value of the input current over all switching periods.

[0012] In a possible implementation, the control module includes a current source and a capacitor, the current source configured to output a current proportional to an average value of the input current, the capacitor configured to charge based on the current output by the current source when the switching transistor is turned on, and the control module is particularly configured to control the turn-off of the switching transistor when the voltage of the capacitor reaches the output voltage.

[0013] In the above scheme, the capacitor is charged using a current proportional to the average input current, and the voltage of the capacitor (for example, the voltage is a sawtooth wave) is compared with the output voltage of the feedback circuit. When the voltage of the capacitor exceeds the output voltage of the feedback circuit, the PFC switching transistor is turned off, thereby realizing the ratio calculation function without a divider.

[0014] In a possible implementation, the control module is configured to control the switching transistor to be turned on when the inductor current of the inductor of the buck circuit crosses zero, or to control the switching transistor to be turned on after a preset fixed duration based on a constant frequency pulse.

[0015] In a possible implementation, the buck circuit further includes an auxiliary winding connected to the inductor, and the control module is configured to determine a zero-crossing point of the current in the inductor by detecting a voltage on the auxiliary winding.

[0016] In a possible implementation, the control module is configured to perform an OR operation on the constant frequency pulse and a zero-crossing signal of the inductor current of the inductor of the buck circuit, and control the turn-on of the switching transistor based on the operation result.

[0017] In the above scheme, the turn-on signal for the PFC switching transistor is obtained by performing an OR operation between the constant frequency pulse and the zero-crossing signal of the PFC auxiliary winding, thereby enabling smooth switching between CRM mode and CCM mode.

[0018] In a possible implementation, the input current is the current of a sampling resistor of the buck circuit.

[0019] According to a second aspect, the application provides an adapter including a power factor correcting PFC circuit, the PFC circuit including a rectifier bridge and a buck circuit, and a control module in any implementation of the first aspect.

[0020] In a possible implementation, the PFC circuit further includes an auxiliary winding connected to the inductor.

[0021] According to a third aspect, there is provided a control method, the method comprising the steps of determining an input current of a buck circuit and an output voltage of a loop compensation circuit, and controlling turn-off of a switching transistor of the buck circuit based on a relationship between the output voltage and the input current, wherein a turn-on duty cycle of the switching transistor is directly proportional to a ratio of an average value of the output voltage and the input current.

[0022] In a possible implementation, the input current tracks the input voltage of the buck circuit.

[0023] In a possible implementation, the average value of the input voltage is the average value of the input current over all switching periods.

[0024] In a possible implementation, the step of controlling the turn-off of the switching transistor of the buck circuit based on the relationship between the output voltage and the input current includes the steps of outputting a current proportional to an average value of the input current through a current source, charging a capacitor based on the current output by the current source when the switching transistor is turned on, and controlling the turn-off of the switching transistor when the voltage of the capacitor reaches the output voltage.

[0025] In a possible implementation, the method further comprises a step of controlling the switching transistor to be turned on when the inductor current of the inductor of the buck circuit crosses zero, or controlling the switching transistor to be turned on after a preset fixed duration based on a constant frequency pulse.

[0026] In a possible implementation, the buck circuit further includes an auxiliary winding connected to the inductor, and the method further includes determining a zero-crossing point of the current in the inductor by detecting the current in the auxiliary winding.

[0027] In a possible implementation, the method further includes performing an OR operation between the constant frequency pulse and a zero-crossing signal of the inductor current of the inductor of the buck circuit, and controlling the turn-on of the switching transistor based on the operation result.

[0028] In a possible implementation, the input current is the current of a sampling resistor of the buck circuit. [Brief explanation of the drawings]

[0029] [Figure 1A] 1 is a schematic diagram of a PFC circuit. [Figure 1B] 1 is a schematic diagram of a PFC circuit. [Figure 2] 10 is a waveform diagram showing a case where the PFC circuit operates with a high voltage input overload. [Figure 3] 10 is a waveform diagram showing a case where the PFC circuit operates with a low voltage input overload. [Figure 4] 1 is a schematic diagram of a PFC circuit. [Figure 5] 1 is a schematic flow chart of a control method according to an embodiment of the present application. [Figure 6] FIG. 1 is a schematic diagram of a PFC circuit according to an embodiment of the present application. [Figure 7] FIG. 1 is a schematic diagram of a PFC circuit according to an embodiment of the present application. [Figure 8] FIG. 10 is a waveform diagram in the case where a low input voltage is overloaded. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings in the embodiments of the present invention. The terms used in the embodiments of the present invention are only used to describe specific embodiments of the present invention, and are not intended to limit the present invention.

[0031] The following describes embodiments of this application with reference to the accompanying drawings. Those skilled in the art can understand that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of this application can also be applied to similar technical problems.

[0032] In the specification, claims, and accompanying drawings of this application, terms such as "first" and "second" are intended to distinguish between similar objects, but do not necessarily indicate a particular order or sequence. Terms used in this manner should be understood to be interchangeable under appropriate circumstances. This is merely a mode of distinction used in the embodiments of this application when describing objects having the same attributes. In addition, the terms "comprise," "have," and any variations thereof are intended to cover a non-exclusive inclusion; thus, a process, method, system, product, or device that includes a series of units is not necessarily limited to those units, but may include other units that are not expressly listed or inherent to the process, method, product, or device.

[0033] Terms such as "substantially" and "about" are used herein as terms of approximation rather than as terms of degree and are intended to account for inherent error of measurement or calculation known to those of ordinary skill in the art. Additionally, when describing embodiments of the present invention, "may" is used to mean "one or more possible embodiments." As used herein, the terms "use," "using," and "used" may be considered synonymous with the terms "utilize," "utilizing," and "utilized," respectively. Additionally, the term "exemplary" is intended to refer to an example or illustration.

[0034] Below we explain some concepts in this application.

[0035] (1) Adapter: A device that has a voltage conversion function and supplies power to an electronic device (also called a terminal device). It is also called a charger, switch power supply adapter, charger, or power converter.

[0036] (2) Super Charger: A charger or adapter that can charge devices such as mobile phones or computers with batteries, thereby shortening the charging time. A super charger is also called a super charger or a high-speed charger.

[0037] (3) Half bridge: Refers to an electrical topology structure in which two power switching transistors alternately operate in a switch power supply to perform power transmission. The primary switch bridge is also called the primary transistor or the first switch, and the secondary switch bridge is also called the secondary transistor or the second switch.

[0038] (4) Asymmetric half bridge: means that the duty cycles for turning on the upper bridge and the lower bridge are not symmetric by 50% in the present invention.

[0039] (5) Controller IC: Refers to the control unit of the product, which performs waveform detection and action logic.

[0040] (6) Transformer: A component responsible for power transmission and voltage transformation in a switching power supply.

[0041] (7) Auxiliary winding: A winding in a transformer that does not transmit power, such as a VCC winding.

[0042] (8) Primary winding: A winding that is installed on the primary side of a transformer and is responsible for inputting voltage and current.

[0043] (9) Secondary winding: A winding installed on the secondary side of a transformer and responsible for outputting voltage and current.

[0044] FIG. 1A is a schematic diagram of a bridged Buck Power Factor Correction (Buck PFC) circuit.

[0045] As shown in Figure 1A, the bridged buck PFC circuit includes an uncontrolled rectifier circuit and a buck circuit. After passing through the uncontrolled rectifier circuit, the input AC voltage Vin is rectified into a DC voltage Vrec, and the buck circuit attenuates the fluctuating DC voltage Vrec into a stable output voltage Vo.

[0046] The waveforms for the case where the bridged-buck PFC circuit operates with a high-voltage input overload are shown in Figure 2. When the inductor current IL1 crosses zero, the switching transistor Q1 is turned on, the inductor performs excitation, and the inductor current IL1 rises. After the inductor current IL1 reaches a peak current, the switching transistor Q1 is turned off, the inductor current freewheels through the diode D1, the inductor performs deexcitation, and the inductor current IL1 decreases until it decreases to zero again. This operating mode is called CRM mode.

[0047] In addition, please refer to Figure 1B, which is a schematic diagram of a co-grounded buck circuit. It should be understood that the specific structure of the buck circuit is not limited in the embodiments of this application.

[0048] It should be appreciated that in CRM mode, the switching transistor is turned on only after the inductor current crosses zero, thereby turning on the switching transistor at zero voltage, thereby reducing switch losses.

[0049] Note that when the input voltage Vin is less than the output voltage Vo, the buck circuit cannot transfer energy from input to output, and the load is supplied with energy by the output capacitor C in Figure 1A. This time period is designated by Td in Figure 2.

[0050] FIG. 3 is a waveform diagram for the case where a bridged-buck PFC circuit operates with a low-voltage input overload.

[0051] It should be understood that when the input voltage Vin in a circuit decreases and the load remains unchanged, the input current necessarily increases if the output power needs to remain unchanged. In addition, the time Td during which power cannot be transferred from the input to the output is correspondingly extended. This further increases the peak input current. However, the increase in peak current causes a sudden increase in the conduction losses of the switch components, the losses of the inductor, and the losses of the rectifier diode, thereby causing a sudden decrease in system efficiency. That is, when the PFC circuit operates in CRM mode, the peak input current increases suddenly with a decrease in the input voltage, and the system efficiency also decreases suddenly accordingly.

[0052] Figure 4 is a block diagram of the internal signals of the PFC in CCM mode.

[0053] The traditional control method for buck PFC in constant frequency CCM is the average current control method. Figure 4 shows the internal signal block diagram of buck PFC. After being sampled using voltage divider resistors R1 and R2, the input bus voltage is multiplied by the output voltage of the voltage feedback loop to obtain the current command Iref. After the current feedback loop performs an operation on the current command and the input current sampling voltage, a modulated wave is obtained. By comparing it with a constant frequency sawtooth wave, the modulated wave generates a control signal for the switching transistor. It can be seen that in the control system, a high-voltage resistor network is needed to sample the bus voltage, and a multiplier needs to be added to multiply the instantaneous input voltage by the output of the feedback circuit to obtain the target average current value.

[0054] However, in the current control method, multiple high-voltage resistors need to be added outside the control system to sample the bus voltage and realize the tracking function, and multipliers need to be added inside the control system to process the signals, resulting in a large system layout area and high standby power consumption.

[0055] 5 is a diagram of a control method 100 according to an embodiment of the present application. The method includes the following steps:

[0056] S110: Determine the input current of the buck circuit and the output voltage of the loop compensation circuit.

[0057] In a possible implementation, as shown in FIG. 6, a buck circuit may be connected after the full-bridge circuit, and the input current of the buck circuit may represent the input current of the PFC circuit.

[0058] In a possible implementation, the input current of the buck circuit is a current proportional to the input current of the PFC circuit. In other words, the input current can represent the input current of the PFC circuit. For example, the input current of the PFC circuit may be directly used as the input current, or a current that is not the input current of the PFC circuit but can represent the input current of the PFC circuit may be used as the input current.

[0059] In a possible implementation, the turn-off of a switching transistor of the PFC circuit is controlled based on a relationship between the output voltage and a first current, where the turn-on duty cycle of the switching transistor is directly proportional to a quotient of the output voltage and an average current of an input current, the input current being a current of a sampling resistor of the buck circuit.

[0060] For example, see Figure 6. Figure 6 is a schematic diagram of a PFC circuit. After the voltage of the sampling resistor Rcs is filtered, the input current Iin can be obtained.

[0061] In a possible implementation, the output voltage of the loop compensation circuit, ie, the output voltage of the voltage regulation control loop (ie, the inner loop), may be determined.

[0062] For example, see Figure 6. The loop compensation output voltage is Vcomp.

[0063] S120: Control the turn-off of a switching transistor of a buck circuit based on the relationship between the output voltage and the input current, where the turn-on duty cycle of the switching transistor is directly proportional to the ratio of the output voltage to the average value of the input current.

[0064] The average value of the input current may be the average value of the input current over all switching periods.

[0065] In a possible implementation, the control module may include a power supply and a capacitor, wherein a current proportional to the average value of the input current may be output through the power supply, and when the switching transistor is turned on, the capacitor may be charged based on the current output by the power supply, and when the voltage of the capacitor reaches the output voltage, the turn-off of the switching transistor may be controlled.

[0066] When the switching transistor is turned on, the power supply charges the capacitor Cramp, where the power supply current value is K×Iin, where K is a coefficient. When the voltage across the capacitor Cramp reaches the loop compensation output voltage Vcomp, the switching transistor is turned off. When the next constant frequency clock signal is received, the switching transistor is turned on again. In this case, the converter operates in constant frequency CCM mode.

[0067] In the above scheme, the capacitor is charged using a current proportional to the average input current, and the voltage of the capacitor (for example, the voltage is a sawtooth wave) is compared with the output voltage of the feedback circuit; when the voltage of the capacitor exceeds the output voltage of the feedback circuit, the PFC switching transistor is turned off, thereby realizing the ratio calculation function without a divider.

[0068] According to the turn-off logic of the switching transistor, the following equation can be obtained: where Ton is the turn-on time of the switching transistor.

[0069]

number

[0070] The volt-second balance equation for the inductor of a buck converter is: where Tsw is the turn-on time of the switching transistor.

[0071]

number

[0072] According to the above two formulas,

[0073]

number

[0074] It can be seen that in steady state operation, Vcomp, Vout, and Tsw are all constant values, and the capacitance value Cramp and proportionality coefficient K are also preset. It can be seen that when Vcomp×Cramp / Vout / Tsw / K is a constant value, Iin and Vin can be changed proportionally, thereby making the input current track the input voltage, i.e., realizing the power factor correction function.

[0075] This application provides a control mode for PFC operating in constant frequency CCM, in which the turn-on duty cycle of the PFC switching transistor is set to be directly proportional to the ratio of the output voltage of the voltage feedback circuit to the average input current, thereby achieving power factor correction and eliminating the input voltage sampling register and corresponding multiplier.

[0076] As shown in Figure 7, Figure 7 is a schematic diagram of a PFC that supports CRM mode. In this embodiment, the condition for turning off the switching transistor may be the same as that in CCM mode described in the above embodiment, and a condition for turning on the switching transistor at the zero crossing of the auxiliary winding is added.

[0077] Specifically, in a possible implementation, when the PFC circuit operates in CRM, the switching transistor is controlled to be turned on when the inductor current of the inductor of the PFC circuit crosses zero, or when the PFC circuit operates in critical conduction mode (CCM), the switching transistor is controlled to be turned on after a preset fixed duration based on a constant frequency pulse.

[0078] In a possible implementation, the buck circuit further includes an auxiliary winding connected to the inductor, and the zero crossing point of the current in the inductor can be determined by detecting the voltage of the auxiliary winding.

[0079] In a possible implementation, an OR operation may be performed between the constant frequency pulse and the zero crossing signal of the inductor current of the inductor of the buck circuit, and the turn-on of the switching transistor may be controlled based on the operation result.

[0080] The turn-on signal for the PFC switching transistor is obtained by performing an OR operation between a constant frequency pulse and the zero-crossing signal of the PFC auxiliary winding, which enables smooth switching between CRM mode and CCM mode.

[0081] After the switching transistor is turned off, the voltage of the auxiliary winding decreases from a positive voltage to a negative voltage. After the comparator performs a zero-crossing comparison, a turn-on signal for the switching transistor is generated. When the constant-frequency clock signal is at a low level, the de-excitation of the inductor is completed, the auxiliary winding crosses zero, and the switching transistor is turned on. In this case, the switching transistor is turned on at a valley, the switch loss is reduced, and the switching transistor operates in CRM mode. Before the inductor current decreases to zero, the constant-frequency clock signal becomes high, and the switching transistor is turned on through hard switching and operates in CCM mode. It can be understood that the control policy provided in the embodiments of this application may operate in CCM or CRM mode and has a wide range of applicability.

[0082] 8 shows waveforms in the case where a low input voltage is overloaded in this embodiment. When the peak current is relatively small, the switching transistor Q1 is turned on after the peak current decreases to zero to achieve ZVS turn-on and operate in CRM mode in order to reduce switch loss. When the peak current is relatively large, the switching transistor Q1 is turned on before the peak current decreases to zero to reduce conduction loss and operate in CCM mode.

[0083] In addition, it should be noted that the described device embodiments are merely examples. Units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, located in one location, or distributed over multiple network units. Some or all of the modules may be selected according to actual requirements to achieve the objectives of the solutions in the embodiments. In addition, in the accompanying drawings of the device embodiments provided in this application, the connection relationships between modules indicate that the modules have communication connections with each other, which may be specifically implemented as one or more communication buses or signal cables.

[0084] Based on the above implementation description, those skilled in the art can clearly understand that this application can be implemented using software in addition to required general hardware, or using dedicated hardware including dedicated integrated circuits, dedicated CPUs, dedicated memories, and dedicated components. Generally, any function performed by a computer program can be easily implemented using corresponding hardware. Furthermore, the specific hardware structure used to implement the same function may take various forms, such as an analog circuit, a digital circuit, or a dedicated circuit. However, as far as this application is concerned, software program implementation is a preferred implementation in most cases. Based on this understanding, the technical solution of this application may essentially, or a part that contributes to the prior art, be implemented in the form of a software product. The computer software product is stored in a readable storage medium such as a computer floppy disk, USB flash drive, removable hard disk, ROM, RAM, magnetic disk, or optical disk, and includes several instructions for instructing a computer device (which may be a personal computer, a training device, or a network device) to perform the methods described in the embodiments of this application.

[0085] All or part of the above embodiments may be implemented by software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, all or part of the embodiments may be implemented in the form of a computer program product.

[0086] A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions according to the embodiments of this application are generated, in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from a computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, computer, training device, or data center to another website, computer, training device, or data center via wired (e.g., coaxial cable, fiber optics, or digital subscriber line (DSL)) or wireless (e.g., infrared, radio wave, or microwave) transmission. The computer-readable storage medium may be any available medium accessible by a computer or may be a data storage device, such as a training device or data center, that integrates one or more available media. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, or a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)).

Claims

1. A control module comprising: the control module is configured to determine an input current of a buck circuit and an output voltage of a loop compensation circuit; The control module is further configured to control a turn-off of a switching transistor of the buck circuit based on a relationship between the output voltage and the input current, wherein a turn-on duty cycle of the switching transistor is directly proportional to a ratio of the output voltage to an average value of the input current.

2. the average value of the input current is the average value of the input current over all switching periods; The control module of claim 1 .

3. the control module includes a current source and a capacitor; the current source is configured to output a current proportional to the average value of the input current; The capacitor is configured to charge based on the current output by the current source when the switching transistor is turned on; the control module is particularly configured to control the turning off of the switching transistor when the voltage of the capacitor reaches the output voltage; 3. A control module according to claim 1 or 2.

4. The control module Controlling the switching transistor to be turned on when the inductor current of the inductor of the buck circuit crosses zero, or The switching transistor is controlled to be turned on after a predetermined fixed duration based on a constant frequency pulse. It is configured as follows: A control module according to any one of claims 1 to 3.

5. the buck circuit further includes an auxiliary winding connected to the inductor, and the control module is configured to determine a zero-crossing point of the current in the inductor by detecting a voltage of the auxiliary winding. The control module of claim 4 .

6. The control module is configured to perform an OR operation between the constant frequency pulse and a zero-cross signal of the inductor current of the inductor of the buck circuit, and control turning on of the switching transistor based on the operation result. A control module according to any one of claims 1 to 5.

7. The input current is the current of the sampling resistor of the buck circuit. A control module according to any one of claims 1 to 6.

8. a power factor correcting PFC circuit, the PFC circuit including a rectifier bridge and a buck circuit; The control module according to any one of claims 1 to 7. Includes adapter.

9. the buck circuit further includes an auxiliary winding connected to the inductor.

9. The adapter of claim 8.

10. 1. A control method, the method comprising: determining an input current of the buck circuit and an output voltage of the loop compensation circuit; controlling the turn-off of a switching transistor of the buck circuit based on a relationship between the output voltage and the input current, wherein a turn-on duty cycle of the switching transistor is directly proportional to a ratio of the output voltage to an average value of the input current; A control method comprising:

11. the average value of the input current is the average value of the input current over all switching periods; The method of claim 10.

12. controlling the turn-off of a switching transistor of the buck circuit based on a relationship between the output voltage and the input current; outputting a current proportional to the average value of the input current through a current source; charging a capacitor based on the current output by the current source when the switching transistor is turned on; controlling the turning off of the switching transistor when the voltage of the capacitor reaches the output voltage; Including, 12. The method according to claim 10 or 11.

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