Constant power reference modulation circuit, control device and chip, power supply device and method

Abstract

The present application discloses a constant power reference modulation circuit, a control device and a chip, a power supply device and a method. The constant power reference modulation circuit is configured in a power supply device, and the constant power reference modulation circuit includes a first sampling terminal and a reference modulation unit. The first sampling terminal is used to receive a first sampling signal reflecting the load voltage; the reference modulation unit is coupled to the first sampling terminal and is used to convert the first sampling signal into a constant power reference signal; wherein the constant power reference signal changes in the opposite direction to the change of the first sampling signal; under the action of the constant power reference signal, the power supply output by the power supply device is maintained at a stable power.

Description

Technical Field

[0001] The present application relates to the field of control circuit technology, and in particular to a constant power reference modulation circuit, a control device and chip, a power supply device and method. Background Art

[0002] A switching power supply is a device used to convert electrical energy. It can convert the AC power provided by the power grid into various DC outputs to power the load. Due to its advantages such as fewer peripheral system components, low cost, simple structure, and low standby power consumption, it is widely used in power adapters for various loads and other occasions.

[0003] However, technological advancements have led to higher demands on the functionality provided by loads, forcing switching power supplies to offer diversified output power supply methods to accommodate these needs. For example, mobile electronic devices are rapidly evolving, evolving from standard charging methods to fast charging. This technological advancement, coupled with the inherent technical advancements in mobile devices, has placed higher demands on the technology of the switching power supplies they support. While requiring switching power supplies to meet the load's power requirements, they must also be designed to provide power to the load in a manner that avoids damage or energy waste. Summary of the Invention

[0004] In view of the problem that the above-mentioned related technologies cannot reasonably provide a suitable load power supply method according to the power supply requirements of the load, resulting in energy waste or load damage, the purpose of this application is to provide a constant power reference modulation circuit, control device and chip, power supply device and method.

[0005] To achieve the above-mentioned purpose and other related purposes, the first aspect of the present application discloses a constant power reference modulation circuit, which is configured in a power supply device. The constant power reference modulation circuit includes a first sampling end, which is used to receive a first sampling signal reflecting the load voltage; a reference modulation unit, coupled to the first sampling end, is used to convert the first sampling signal into a constant power reference signal; wherein the constant power reference signal changes in the opposite direction to the change of the first sampling signal; under the action of the constant power reference signal, the power supply power output by the power supply device is maintained at a stable power.

[0006] In certain embodiments disclosed in the first aspect of the present application, the constant power reference signal and the first sampling signal have a multi-segment change relationship in opposite directions; wherein the product of the constant power reference signal and the first sampling signal corresponding to each segment endpoint is a fixed value.

[0007] In certain embodiments disclosed in the first aspect of the present application, the constant power reference signal and the first sampling signal are in an opposite multi-segment linear relationship.

[0008] In certain embodiments disclosed in the first aspect of the present application, it further includes: a demagnetization sampling unit, coupled between the first sampling end and the reference modulation unit, for outputting the first sampling signal to the reference modulation unit when it is detected that the power conversion circuit in the power supply device is in the demagnetization stage.

[0009] In certain embodiments disclosed in the first aspect of the present application, the demagnetization sampling unit includes: a demagnetization detection circuit, coupled to the first sampling end, for detecting the first sampling signal to output a demagnetization detection signal when the power conversion circuit is in a demagnetization stage; and a demagnetization sampling circuit, coupled to the demagnetization detection circuit, for outputting the first sampling signal upon receiving the demagnetization detection signal.

[0010] In certain embodiments disclosed in the first aspect of the present application, the reference modulation unit includes: a constant power reference generation circuit, for outputting a constant power reference signal based on a reference signal output by a reference power supply; a signal adjustment circuit, coupled to the first sampling end and the constant power reference generation circuit, and receiving at least one threshold signal, for adjusting the circuit characteristics of the constant power reference generation circuit according to the signal change of the first sampling signal relative to the threshold signal, so that the output constant power reference signal changes in the opposite direction to the change of the first sampling signal.

[0011] In certain embodiments disclosed in the first aspect of the present application, the signal conditioning circuit includes: a current branch connected to the constant power reference generation circuit; at least one current conversion circuit, wherein one input terminal of the current conversion circuit receives the first sampling signal, another input terminal receives the threshold signal, and an output terminal is coupled to the current branch and configured to adjust the current signal in the current branch based on a signal difference between the first sampling signal and the threshold signal. Different current conversion circuits receive different threshold signals.

[0012] In certain embodiments disclosed in the first aspect of the present application, the signal conditioning circuit includes at least two current conversion circuits, and the signal conditioning circuit also includes: at least one current limiting circuit, which is coupled to one of the current conversion circuits and is used to limit the current signal output by the current conversion circuit coupled thereto to a fixed current signal when it determines that the first sampling signal reaches a threshold signal received by the other current conversion circuit, so that the current signal in the current branch changes with the current signal output by the other current conversion circuit.

[0013] In certain embodiments disclosed in the first aspect of the present application, the at least two current conversion circuits are a first current conversion circuit and a second current conversion circuit, and the current limiting circuit includes: a first selection circuit, one input end of which receives the first sampling signal, the other input end receives the second threshold signal, and an output end coupled to the first current conversion circuit, for outputting the first sampling signal or the second threshold signal; wherein, the first current conversion circuit outputs the fixed current signal based on the signal difference between the second threshold signal and the first threshold signal, and the fixed current signal and the current signal output by the second current conversion circuit based on the signal difference between the first sampling signal and the second threshold signal are merged into the current signal in the current branch; wherein, the first threshold signal corresponds to the threshold signal received by the first current conversion circuit, and the second threshold signal corresponds to the threshold signal received by the second current conversion circuit.

[0014] In certain embodiments disclosed in the first aspect of the present application, the constant power reference generating circuit includes an output resistor, one end of the output resistor is used to obtain the reference signal, and the other end is coupled to the signal conditioning circuit for outputting the constant power reference signal.

[0015] According to a second aspect of the present application, a control device for a switching device is disclosed. The control device includes: a second sampling terminal for obtaining a second sampling signal reflecting a peak current of a power conversion circuit; wherein the power conversion circuit is coupled to the switching device; a third sampling terminal for obtaining a third sampling signal reflecting a load current; a constant power reference signal generation unit, coupled to the second sampling terminal, comprising any of the constant power reference modulation circuits disclosed in the first aspect of the present application, and configured to output a constant power reference signal based on the second sampling signal and the constant power reference signal; a mode selection unit, coupled to the third sampling terminal and the constant power reference generation unit, configured to selectively output the constant power reference signal or the third sampling signal as a constant voltage reference signal; and a switch control unit, coupled to the mode selection unit, configured to control the switching device under the action of the constant voltage reference signal so that the power supply voltage output by the power conversion circuit is maintained at a stable voltage, or to control the switching device under the action of the constant power reference signal so that the power supply power output by the power conversion circuit is maintained at a stable power.

[0016] In certain embodiments disclosed in the second aspect of the present application, the constant power reference signal and the first sampling signal have a multi-segment change relationship that is opposite to each other, and the supply power output by the power conversion circuit corresponding to each segment endpoint is maintained at the stable power.

[0017] In certain embodiments disclosed in the second aspect of the present application, the mode selection unit includes: a comparison circuit, coupled to the third sampling end and the constant power reference signal generation unit, for outputting a high-level signal when determining that the third sampling signal is less than a first load threshold so that the constant power reference signal is forced to be the high-level signal; a selection circuit, coupled to the third sampling end and the constant power reference signal generation unit, for selectively outputting the constant power reference signal or outputting the third sampling signal as a constant voltage reference signal based on the size relationship of the received signal.

[0018] In certain embodiments disclosed in the second aspect of the present application, the mode selection unit also receives a constant current reference signal for selectively outputting the constant current reference signal. Under the action of the constant current reference signal, the power supply current output by the power conversion circuit is maintained at a stable current.

[0019] In certain embodiments disclosed in the second aspect of the present application, the switch control unit includes: a shutdown detection circuit, coupled to the mode selection unit and the second sampling end, for outputting a shutdown signal when it determines that the second sampling signal reaches one of the reference signals output by the mode selection unit to turn off the switching device.

[0020] In certain embodiments disclosed in the second aspect of the present application, the switch control unit further includes: a conduction detection circuit, configured to output a conduction signal to turn on the switch device.

[0021] In certain embodiments disclosed in the second aspect of the present application, the switch control unit further includes:

[0022] The driving circuit is coupled to the on-detection circuit and the off-detection circuit, and is configured to output a driving signal based on the on-signal and the off-signal to control the on or off state of the switching device.

[0023] The third aspect of the present application discloses a power supply device, comprising: a rectifier circuit for receiving an external drive signal to output a rectified signal; a filter circuit coupled to the rectifier circuit for filtering the rectified signal to output a filtered signal; a control device as described in any one of the second aspects of the present application, for outputting a drive signal based on a first sampling signal, a second sampling signal, and a third sampling signal; a switching device, a control end of which is coupled to the control device, for turning on or off based on the drive signal; a power conversion circuit coupled to the switching device and the filter circuit, for performing energy conversion on the filtered signal based on the turning on or off of the switching device to output constant voltage power supply or constant power power supply to a load; a sampling circuit coupled to the control device and the power conversion circuit, for sampling electrical signals reflecting the load voltage, load current, and peak current of the power conversion circuit to output the first sampling signal, the third sampling signal, and the second sampling signal to the control device.

[0024] The fourth aspect of the present application discloses a constant power reference modulation method, comprising the following steps: receiving a first sampling signal reflecting a load voltage; converting the first sampling signal into a constant power reference signal; wherein the constant power reference signal changes in the opposite direction to the change of the first sampling signal.

[0025] In certain embodiments of the fourth aspect of the present application, the constant power reference signal and the first sampling signal have a multi-segment change relationship that is opposite to each other; wherein the product of the constant power reference signal and the first sampling signal corresponding to each segment endpoint is a fixed value.

[0026] In certain embodiments of the fourth aspect of the present application, the constant power reference signal and the first sampling signal are in an opposite multi-segment linear relationship.

[0027] The fifth aspect of the present application discloses a control method for a switching device, comprising the following steps: obtaining a second sampling signal reflecting a peak current of a power conversion circuit and a third sampling signal reflecting a load current; wherein the power conversion circuit is coupled to the switching device; converting the first sampling signal into the constant power reference signal using any of the constant power reference modulation methods disclosed in the fourth aspect of the present application; outputting a constant power reference signal based on the second sampling signal and the constant power reference signal; selectively outputting the constant power reference signal or outputting the third sampling signal as a constant voltage reference signal; controlling the switching device under the action of the constant voltage reference signal so that the power supply voltage output by the power conversion circuit is maintained at a stable voltage, or controlling the switching device under the action of the constant power reference signal so that the power supply power output by the power conversion circuit is maintained at a stable power.

[0028] In certain embodiments of the fifth aspect of the present application, the following steps are also included: obtaining a constant current reference signal; selectively outputting the constant current reference signal, and under the action of the constant current reference signal, the power supply current output by the power conversion circuit is maintained at a stable current.

[0029] The sixth aspect of the present application discloses a control chip, which is packaged with any constant power reference modulation circuit disclosed in the first aspect of the present application, or is packaged with any control device disclosed in the second aspect of the present application.

[0030] To sum up, the constant power reference modulation circuit, control device and chip, power supply device and method disclosed in this application can provide different power supplies according to different load capacities, so that when powering the load, the load can quickly be in the high-power power supply stage, thereby improving energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The specific features of the invention involved in this application are shown in the appended claims. The features and advantages of the invention involved in this application can be better understood by referring to the exemplary embodiments described in detail below and the accompanying drawings. A brief description of the drawings is as follows:

[0032] Figure 1 Shown is a circuit block diagram of a power supply device in one embodiment of the present application.

[0033] Figure 2 FIG. 1 is a schematic diagram showing the circuit structure of a rectifier circuit in one embodiment of the present application.

[0034] Figure 3 FIG. 1 is a schematic diagram showing the circuit structure of a filter circuit in one embodiment of the present application.

[0035] Figure 4 Shown is a circuit block diagram of a power conversion device in one embodiment of the present application.

[0036] Figure 5 FIG. 1 is a schematic diagram showing the circuit structure of a power conversion device in one embodiment of the present application.

[0037] Figure 6 Shown is a circuit block diagram of a control device in one embodiment of the present application.

[0038] Figure 7 Shown is a circuit block diagram of a constant power reference generation unit in one embodiment of the present application.

[0039] Figure 8 Schematic diagram showing the input and output relationship of the reference modulation unit in one embodiment of the present application.

[0040] Figure 9Schematic diagram showing the input and output relationship of a reference modulation unit in another embodiment of the present application.

[0041] Figure 10 Shown is a circuit block diagram of a reference modulation unit in one embodiment of the present application.

[0042] Figure 11 FIG. 1 is a schematic diagram showing the circuit structure of a constant power reference generating circuit in one embodiment of the present application.

[0043] Figure 12 FIG. 1 is a schematic diagram showing the circuit structure of a constant power reference generating circuit in another embodiment of the present application.

[0044] Figure 13 Shown is a circuit block diagram of a signal conditioning circuit in one embodiment of the present application.

[0045] Figure 14 Shown is a circuit block diagram of a signal conditioning circuit in another embodiment of the present application.

[0046] Figure 15 Shown is a schematic diagram of the input and output relationship of a signal conditioning circuit in another embodiment of the present application.

[0047] Figure 16 Shown is a circuit block diagram of a constant power reference modulation circuit in one embodiment of the present application.

[0048] Figure 17 FIG. 1 is a schematic diagram showing the circuit structure of a demagnetization sampling unit in one embodiment of the present application.

[0049] Figure 18 Shown is a circuit block diagram of a mode selection unit in one embodiment of the present application.

[0050] Figure 19 Shown is a circuit block diagram of a switch control unit in one embodiment of the present application.

[0051] Figure 20 Shown is a schematic diagram of a power supply device outputting power to a load in one embodiment of the present application DETAILED DESCRIPTION

[0052] The following describes the implementation of the present application through specific embodiments. People familiar with this technology can easily understand other advantages and effects of the present application from the contents disclosed in this specification.

[0053] In the following description, reference is made to the accompanying drawings, which describe several embodiments of the present application. It should be understood that other embodiments may also be used, and that mechanical, structural, electrical, and operational changes may be made without departing from the spirit and scope of the present disclosure. The following detailed description should not be considered restrictive, and the scope of the embodiments of the present application is limited only by the claims of the published patents. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application. Spatially related terms, such as "upper", "lower", "left", "right", "below", "below", "lower", "above", "upper", etc., may be used in the text to illustrate the relationship between one element or feature shown in the figure and another element or feature.

[0054] Although in some instances the terms first, second, etc. are used herein to describe various elements or parameters, these elements or parameters should not be limited by these terms. These terms are only used to distinguish one element or parameter from another element or parameter. For example, the first sampling signal can be referred to as the second sampling signal, and similarly, the second sampling signal can be referred to as the first sampling signal without departing from the scope of the various described embodiments. The first sampling signal and the second sampling signal are both describing a sampling signal, but unless the context clearly indicates otherwise, they are not the same sampling signal. Similar situations also include a first current conversion circuit and a second current conversion circuit, or a first threshold signal and a second threshold signal.

[0055] Furthermore, as used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context indicates otherwise. It should be further understood that the terms "comprise", "include" indicate the presence of the described features, steps, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Thus, "A, B, or C" or "A, B, and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B, and C". Exceptions to this definition occur only when the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0056] In addition, it should be noted that in order to clearly illustrate the various inventive features disclosed in this application, this document describes each embodiment as follows in the form of multiple embodiments, but this does not mean that each embodiment can only be implemented alone. Those skilled in the art can design feasible implementation examples together according to their needs, or simply replace the replaceable components / modules in different embodiments according to design requirements. In other words, the implementation methods taught in this case are not limited to the aspects described in the following embodiments, but also include the replacement and permutation and combination of each embodiment / component / module when feasible, which is described in advance.

[0057] To power a wide range of loads, including electronic terminals, displays, servers, mobile devices, and various instruments and meters, switching power supplies typically convert AC power from the grid into a DC output suitable for these loads. Due to factors such as the relationship between the load's electrical characteristics and changes in the power supply signal, and / or the relationship between changes in the load's required charge and the required power signal, switching power supplies must provide a variety of power supply modes. For example, in the case of LED devices, temperature rise causes a sharp change in current. Therefore, switching power supplies must be designed with power adapters capable of both constant current and constant voltage modes to prevent overcurrent in the LED device, which can affect its lifespan. For another example, for electronic devices that include batteries, in order to achieve fast charging of the electronic devices, the charger including the switching power supply is designed to provide a constant current power supply mode and a constant voltage power supply mode. In the initial stage, the electronic device is quickly charged with a large current provided by the constant current power supply mode to the charging cutoff threshold of the first stage (generally set to 70% of the total battery capacity), and then constant voltage charging is performed according to the voltage corresponding to the charging cutoff threshold until the current decays below the charging cutoff threshold of the second stage (generally set to 100% of the total battery capacity).

[0058] However, as the battery capacity of electronic devices continues to increase and the demand for charging speeds increases, the power requirements for chargers are also increasing. Although it is possible to increase the power by further increasing the charging current, this approach is not advisable due to the limitations of charging cables and costs. Another way to increase the power is to increase the charging voltage. In this case, the charger output voltage is higher. If the charging current allowed by the charging cable is still used, the power output of the charger will be far higher than the battery's requirements, resulting in energy waste. In addition, this also increases the size and cost of the charger.

[0059] In view of this, in a possible implementation, the present application provides a power supply device, which can output constant voltage power supply or constant power supply to the load, thereby meeting the load with constant power supply requirements. Furthermore, when the power supply device is used to power the load, the output current can be flexibly adjusted according to the output voltage of the power supply device, so that the load is quickly in a high-power power supply stage, thereby improving energy utilization.

[0060] See also Figure 1 , which shows a circuit block diagram of a power supply device according to one embodiment of the present application. As shown, the power supply device 10 includes a rectifier circuit 11, a filter circuit 12, and a power conversion device 13. The rectifier circuit 11 is coupled to a first pin P_11 and a second pin P_12. The filter circuit 12 is coupled to the rectifier circuit 11 via a first rectifier output terminal P_13 and a second rectifier output terminal P_14. The power conversion device 13 is coupled to the filter circuit 12 via a first filter output terminal P_15 and a second filter output terminal P_16.

[0061] The rectifier circuit 11 receives an external drive signal via a first pin P_11 and a second pin P_12, and is configured to rectify the external drive signal to output a rectified signal. The external drive signal may be, for example, an AC signal output from a utility grid or a DC signal output from an emergency power supply. The rectifier circuit 11 may be, for example, a full-wave rectifier circuit or a half-wave rectifier circuit constructed using electronic components such as diodes.

[0062] See also Figure 2 , which is a schematic diagram of the circuit structure of a rectifier circuit in one embodiment of the present application. As shown in the figure, the rectifier circuit 11 includes diodes D1 to D4. The anode of diode D1 is coupled to the first pin P_11, and the cathode is coupled to the cathode of diode D2. The cathode of diode D2 is coupled to the first rectifier output terminal P_13, and the anode is coupled to the cathode of diode D3. The cathode of diode D3 is coupled to the second pin P_12, and the anode is coupled to the second rectifier output terminal P_14. The anode of diode D4 is coupled to the second rectifier output terminal P_14, and the cathode is coupled to the first pin P_11.

[0063] When the signals received by the first pin P_11 and the second pin P_12 are AC signals, the operation of the rectifier circuit 11 is described as follows. When the AC signal is in the positive half-wave, the AC signal flows in through the first pin P_11, diode D1, and the first rectifier output terminal P_13, and then flows out through the second rectifier output terminal P_14, diode D3, and the second pin P_12. When the AC signal is in the negative half-wave, the AC signal flows in through the second pin P_12, diode D2, and the first rectifier output terminal P_13, and then flows out through the second rectifier output terminal P_14, diode D4, and the first pin P_11. Therefore, regardless of whether the AC signal is in the positive or negative half-wave, the positive electrode of the rectified signal from the rectifier circuit 11 is located at the first rectifier output terminal P_13, and the negative electrode is located at the second rectifier output terminal P_14. Based on the above operation description, the rectified signal output by the rectifier circuit 11 is a full-wave rectified signal.

[0064] When the first and second pins P_11 and P_12 are coupled to a DC power source and receive a DC signal, the operation of the rectifier circuit 11 is described as follows. When the first pin P_11 is coupled to the positive terminal of the DC power source and the second pin P_12 is coupled to the negative terminal of the DC power source, the DC signal flows sequentially through the first pin P_11, diode D1, and the first rectifier output terminal P_13, and then flows out sequentially through the second rectifier output terminal P_14, diode D3, and the second pin P_12. When the first pin P_11 is coupled to the negative terminal of the DC power source and the second pin P_12 is coupled to the positive terminal of the DC power source, the DC signal flows sequentially through the second pin P_12, diode D2, and the first rectifier output terminal P_13, and then flows out sequentially through the second rectifier output terminal P_14, diode D4, and the first pin P_11. Similarly, regardless of how the DC signal is input through the first pin P_11 and the second pin P_12, the positive electrode of the rectified signal from the rectifier circuit 11 is always located at the first rectifier output terminal P_13, and the negative electrode is always located at the second rectifier output terminal P_14. Therefore, in this embodiment, the rectifier circuit 11 can correctly output the rectified signal regardless of whether the received signal is an AC signal or a DC signal.

[0065] The filter circuit 12 receives the rectified signal output by the first rectified output terminal P_13 and the second rectified output terminal P_14, and is configured to filter the rectified signal to output a filtered signal. The filter circuit 12 may be a π-type filter circuit, an LC-type filter circuit, an RC-type filter circuit, an LCπ-type filter circuit, an RCπ-type filter circuit, or the like, and this application does not limit this.

[0066] See also Figure 3, which is a schematic diagram of the circuit structure of a filter circuit in one embodiment of the present application. As shown in the figure, the filter circuit 12 includes a filter capacitor C1. One end of the filter capacitor C1 is coupled to the first rectifier output terminal P_13 and the first filter output terminal P_15, and the other end is coupled to the second rectifier output terminal P_14 and the second filter output terminal P_16. The filter capacitor C1 performs low-pass filtering on the rectified signal output by the first rectifier output terminal P_13 and the second rectifier output terminal P_14 to remove high-frequency components in the rectified signal to form a filtered signal, which is then output by the first filter output terminal P_15 and the second filter output terminal P_16.

[0067] The power conversion device is used to output different power supplies to the load based on the filtered signal and the power supply condition on the load side, such as constant voltage power supply or constant power power supply.

[0068] See also Figure 4 , which shows a circuit block diagram of a power conversion device in one embodiment of the present application. As shown in the figure, the power conversion device 13 includes a control device 20, a switching device 30, a sampling circuit 50, and a power conversion circuit 40. The control device 20 is coupled to the control terminal of the switching device 30 and is configured to output a drive signal based on a first sampling signal, a second sampling signal, and a third sampling signal to control the on / off state of the switching device 30. The power conversion circuit 40 is coupled to the switching device 30 and is coupled to a first filter output terminal P_15 and a second filter output terminal P_16 to receive the filtered signal. Based on the on / off state of the switching device 30, the power conversion circuit 40 converts the filtered signal into energy, thereby outputting a constant voltage supply to the load via its first power output terminal P_17 and second power output terminal P_17 when the load current is less than a first preset current, a constant power supply to the load when the load current is greater than the first preset current and less than a second preset current, and a constant current supply to the load when the load current reaches the second preset current. The sampling circuit 50 is coupled to the power conversion circuit 40 and the control device 20 and is configured to respectively sample the load voltage, the load current, and the peak current of the power conversion circuit, thereby correspondingly outputting a first sampling signal reflecting the load voltage, a third sampling signal reflecting the load current, and a second sampling signal reflecting the peak current of the power conversion circuit to the control device 20.

[0069] The switching device refers to a three-terminal controllable device that can be controlled to turn on or off by a driving signal. The three-terminal controllable device includes a control terminal, a first terminal, and a second terminal. The control terminal controls the conduction or disconnection between the first terminal and the second terminal based on the received driving signal. The three-terminal controllable device includes a controllable transistor, which can be exemplified by a metal-oxide-semiconductor field-effect transistor (MOSFET) or a bipolar junction transistor (BJT).

[0070] The power conversion circuit refers to a DC-DC converter circuit that can convert electric energy based on the conduction and shutdown of a switching device to convert a received DC power into another DC power, wherein the one and the other DC power represent that the electric energy characteristics of the two DC powers are different, for example, the current amplitude, voltage amplitude, or power value are different. In a specific embodiment, the power conversion circuit includes an isolated or non-isolated DC-DC converter circuit. The non-isolated DC-DC converter circuit includes but is not limited to a Buck circuit, a Boost circuit, a Cuk circuit, a Sepic circuit, or a Zata circuit. The isolated DC-DC converter circuit includes but is not limited to a forward circuit or a flyback circuit.

[0071] The sampling circuit is coupled between the power conversion circuit and the control device to output the three sampling signals. In this embodiment, the sampling circuit includes a first sampling circuit, a second sampling circuit, and a third sampling circuit.

[0072] The first sampling circuit utilizes components such as inductive devices, shunt and voltage divider devices that can obtain electrical signals of the load voltage to obtain electrical signals reflecting the load voltage output by the power conversion circuit, thereby outputting a first sampling signal. For example, the first sampling circuit is arranged between the two output terminals of the power conversion circuit and has an output terminal for outputting the first sampling signal. The first sampling circuit includes a plurality of resistive devices connected in series, such as a plurality of series resistors. For another example, the first sampling circuit is coupled to an inductive device of the power conversion circuit to sense the electrical energy output by the power conversion circuit and has an output terminal for outputting the first sampling signal. The first sampling circuit includes an inductor and a resistor connected to the inductor.

[0073] The second sampling signal utilizes components such as resistors and capacitors to acquire an electrical signal reflecting the peak current of the power conversion circuit, thereby outputting the second sampling signal. For example, the second sampling circuit is connected in series with the circuit where the switching device resides and has an output terminal for outputting the second sampling signal. The second sampling signal includes a resistor, etc., and is used to sample the peak current of the power conversion circuit when the switching device is turned on, thereby outputting the second sampling signal.

[0074] The third sampling circuit utilizes sampling devices such as an inductive device, a photoelectric conversion device, a current shunt and voltage divider device, etc. to obtain an electrical signal reflecting the load current output by the power conversion circuit, thereby outputting a third sampling signal. For example, the third sampling circuit is disposed between two output terminals of the power conversion circuit and has an output terminal for outputting the third sampling signal. The third sampling circuit includes, for example, a photoelectric conversion device.

[0075] Each sampling circuit can select an appropriate circuit structure based on the type of power conversion circuit configured, and the structural form of the sampling circuit in this application is not limited. For example, the sampling circuit may share some circuit components, and the sampling circuit may also include a sampling control circuit, which controls the sampling timing and utilizes some shared circuit components to output different sampling signals.

[0076] The following Figure 5 The power conversion device shown in FIG. 1 is used as an example to illustrate its working principle. The specific circuit and working principle of the control device will be described later. Figures 6 to 19 See . Figure 5, shows a schematic diagram of the circuit structure of a power conversion device in one embodiment of the present application. As shown in the figure, the power conversion device 13 includes a control device 20, a switching device 30, a sampling circuit 50, and a power conversion circuit 40. The control device 20 includes a control chip 21 and peripheral circuits adapted to the control chip 21. Since the peripheral circuits may vary depending on the specific embodiment and the circuit modules encapsulated within the control chip 21, they are only provided here as an example, and the peripheral circuits of the control device 20 mentioned in subsequent embodiments will not be described again. The control chip 21 includes a power supply terminal Vcc, a ground terminal Gnd, a first sampling terminal Det, a second sampling terminal Cs, a third sampling terminal Fb, and an output terminal Drv. The power supply terminal Vcc is coupled to a peripheral power supply circuit composed of a resistor R3 and a capacitor C3 to obtain power supply. Specifically, one end of the resistor R3 is coupled to the first filter output terminal P_15, and the other end is coupled to one end of the capacitor C3 and coupled to the power supply terminal Vcc. The other end of the capacitor C3 is coupled to the second filter output terminal P_16. The ground terminal Gnd is connected to the second filter output terminal P_16. The first sampling terminal Det, the second sampling terminal Cs, and the third sampling terminal Fb are connected to the sampling circuit 50. The output terminal Drv is connected to the control terminal of the switch device 30.

[0077] The power conversion circuit 40 includes a transformer T, a diode D5, and an output capacitor C2. The transformer T is a flyback transformer, which includes a primary winding Np and a secondary winding Ns. The opposite-name end of the primary winding Np is coupled to the first filter output terminal P_15, and the same-name end is coupled to the first end of the switching device 30. The opposite-name end of the secondary winding Ns is coupled to the second power output terminal P_18, and the same-name end is coupled to the anode of the diode D5. The cathode of the diode D5 is coupled to the first power output terminal P_17. The output capacitor C2 is connected in parallel between the first power output terminal and the second power output terminal to stabilize the output power signal.

[0078] The sampling circuit 50 includes a first sampling circuit 51, a second sampling circuit 52, and a third sampling circuit 53. The first sampling circuit 51 includes an auxiliary winding Na wound around the primary side of the transformer T, a diode D6, a resistor R1, and a resistor R2. The common-signal terminal of the auxiliary winding Na is coupled to the anode of the diode D6, and the opposite-signal terminal is coupled to the second filter output terminal P_16. The cathode of the diode D6 is coupled to the other end of the resistor R3. Resistors R1 and R2 are connected in series between the common-signal terminal of the auxiliary winding Na and the second filter output terminal P_16. The connecting end of resistors R1 and R2 is coupled to the first sampling terminal Det of the control chip 21. The second sampling circuit 52 includes resistors R4 and R5, and a capacitor C4. One end of resistor R4 is connected to one end of resistor R5 and to the second end of the switch device 30, and the other end is coupled to the second filter output terminal P_16. The other end of resistor R5 is connected to the second sampling terminal Cs of the control chip 21. Capacitor C4 may be omitted as appropriate and is connected between the other end of resistor R5 and the second filter output terminal P_16. The third sampling circuit 53 includes an output resistor R6, a light-emitting diode D7, a phototransistor Q1 (the light-emitting diode D7 and the phototransistor Q1 may also be collectively referred to as an optocoupler), and a Zener diode D8. One end of the output resistor R6 is coupled to the first power output terminal P_17, and the other end is coupled to the anode of the light-emitting diode D7. The cathode of the light-emitting diode D7 is coupled to the cathode of the Zener diode D8, and the anode of the Zener diode D8 is connected to the second power output terminal P_18. The phototransistor Q1 is connected between the first filter output terminal P_16 and the third sampling terminal Fb of the control chip 21. In this embodiment, the first sampling circuit 51 samples the load voltage on the primary side and feeds back a first sampling signal to the control device 20. Thus, the third sampling circuit 52, by providing an optocoupler on the secondary side, can feed back a third sampling signal to the control device 20, reflecting the load current. This sampling circuit has a simple circuit structure and reduces the cost of the power supply device.

[0079] Figure 5The working principle of the power supply device shown is as follows: When the switching device 30 is turned on, the primary winding Np of the transformer T stores energy, and the second sampling circuit 52 obtains the current flowing through the switching device 30 to output a second sampling signal reflecting the peak current of the transformer T to the second sampling terminal Cs. When the switching device 30 is turned off, the energy in the transformer T is released to the third sampling circuit 53 and supplied to the load side through the secondary winding Ns and the diode D5, and a first sampling signal reflecting the load voltage is output to the first sampling terminal Det through the first sampling circuit 51. In the third sampling circuit 53, the light-emitting diode D7 in the third sampling circuit 53 is used to detect the load current to emit a light intensity that changes positively with the current intensity. For example, when the load current is large, its luminous brightness is high, and thus it is sensed by the phototransistor Q1 and converted into a third sampling signal reflecting the load current to the third sampling terminal Fb. Thus, the control device 20 generates a drive signal for controlling the on or off timing of the switching device 30 by detecting and processing the first sampling signal, the second sampling signal, and the third sampling signal and / or performing signal modulation and other processing based on the sampling signals, and outputs it to the switching device 30, so as to change the energy storage and release timing of the power conversion circuit 40 to supply the power required by the load to the load.

[0080] Specifically, please refer to Figure 20 , which shows a schematic diagram of the power supply device outputting power to the load in an embodiment of the present application. Among them, the abscissa I represents the output current, and the ordinate V represents the output voltage. During the control process of the control device 20, it uses the first sampling signal, the second sampling signal, and the third sampling signal to control the switching device 30 to make the power conversion circuit 40 output constant voltage power supply, constant power power supply, or constant current power supply. Further, in the case of a light load on the load, such as Figure 20 in the stage where the load current I < I1, the control device 20 controls the switching device 30 to turn off based on the second sampling signal and the first sampling signal, and controls the switching device 30 to turn on based on at least one of the first sampling signal, the second sampling signal, and the third sampling signal or a fixed PWM pulse signal, so as to make the power conversion circuit 40 output constant voltage power supply. In the case of a heavy load on the load, such as Figure 20 in the stage where the load current I > I1, the control device 20 controls the switching device 30 to turn off based on the second sampling signal and the third sampling signal, and controls the switching device 30 to turn on based on at least one of the first sampling signal, the second sampling signal, and the third sampling signal or a fixed PWM pulse signal, so as to make the power conversion circuit 40 output constant power power supply. In the case of an extremely heavy load on the load, such as Figure 20During the load current I>I2 stage, the control device 20 controls the switching device 30 to turn off based on the second sampling signal, and controls the switching device 30 to turn on based on at least one of the first sampling signal, the second sampling signal, and the third sampling signal, or a fixed PWM pulse signal, thereby causing the power conversion circuit 40 to output a constant current supply. Taking a mobile electronic device as an example, during the initial charging phase, the battery stores a small amount of charge, the load is heavily loaded, and the charging current is greater than I1 but less than I2. The power supply device then charges the battery using a constant power supply mode. The battery's stored charge continuously increases, and the charging current continuously decreases. When the battery is charged to approximately 70% of its total capacity, the charging current decreases to less than I1, and the power supply device then charges the battery using a constant voltage supply mode.

[0081] The following combination Figures 6 to 19 For a detailed description of the circuit architecture and working principle of the control device, please refer to Figure 6, which is a circuit block diagram of a control device in one embodiment of the present application. As shown in the figure, the control device 40 includes a first sampling terminal P_41, a second sampling terminal P_42, a third sampling terminal P_43, and an output terminal P_44. The first sampling terminal P_41 is used to obtain the aforementioned first sampling signal, the second sampling terminal P_42 is used to obtain the aforementioned second sampling signal, the third sampling terminal P_43 is used to obtain the aforementioned third sampling signal, and the output terminal P_44 is used to output the driving signal. The control device 40 also includes a constant power reference generation unit 41, a mode selection unit 42, and a switch control unit 43. The constant power reference generation unit 41 is coupled to the first sampling terminal P_41 and the second sampling terminal P_42, and is used to generate a constant power reference signal based on the first sampling signal and the second sampling signal, and output it to the mode selection unit 42 via its output terminal P_45. The mode selection unit 42 is connected to the output terminal P_45 and the third sampling terminal P_43 of the constant power reference generation unit 41, and receives a constant current reference signal Cc_com. It is configured to selectively output the constant power reference signal, the constant current reference signal Cc_com, or the third sampling signal as a constant voltage reference signal, and output the signal to the switch control unit 43 via its output terminal P_46. The switch control unit 43 is connected to the output terminal P_46 and the second sampling terminal P_42 of the mode selection unit 42, and is configured to output a driving signal based on the signal output by the mode selection unit 42 and the second sampling signal to control the conduction or shutdown of the switching device, thereby causing the power conversion circuit to output power in the corresponding mode. Specifically, the switching device is controlled under the action of the constant voltage reference signal to maintain the power supply voltage output by the power conversion circuit at a stable voltage, or the switching device is controlled under the action of the constant current reference signal to maintain the power supply current output by the power conversion circuit at a stable current, or the switching device is controlled under the action of the constant power reference signal to maintain the power supply output by the power conversion circuit at a stable power level. It should be noted that, in some embodiments, the mode selection unit 42 may not receive the constant current reference signal Cc_com. In this case, the mode selection unit 42 does not output the constant current reference signal Cc_com.

[0082] See also Figure 7, which is a circuit block diagram of a constant power reference generation unit in one embodiment of the present application. As shown in the figure, the constant power reference generation unit 41 includes a constant power reference modulation circuit 60 and a constant power reference generation circuit 411. The constant power reference modulation circuit 60 is connected to the first sampling terminal P_41 to receive the first sampling signal, and is used to convert the first sampling signal into a constant power reference signal and output it through its output terminal P_61. The constant power reference generation circuit 411 is connected to the second sampling terminal P_42 and the output terminal P_61 of the constant power reference modulation circuit 60 to receive the second sampling signal and the constant power reference signal and generate a constant power reference signal, which is output to the subsequent circuit through the output terminal P_45. It should be noted that in actual applications, the constant power reference generation circuit 411 may include an integration circuit, which integrates the first sampling signal and the constant power reference signal to generate the constant power reference signal.

[0083] The constant power reference modulation circuit 60 includes a reference modulation unit, which is coupled to the first sampling end to obtain a first sampling signal and convert it into a constant power reference signal. Since the first sampling signal can reflect the load voltage, the constant power reference signal converted by the reference modulation unit in the present application reflects the load current that should be achieved in order to output constant power under the current load voltage. In other words, the constant power reference signal will change in the opposite direction with the change of the first sampling signal. For example, when the load voltage increases, the first sampling signal will also increase, and the constant power reference signal generated by the reference modulation unit will decrease, so that when the load voltage changes, the control device adjusts the load current based on the constant power reference signal to achieve constant power output of the power supply device.

[0084] In some embodiments, if the first sampling signal changes, the product of the constant power reference signal generated by the reference modulation unit and the corresponding first sampling signal remains unchanged, and both are a fixed value (the fixed value corresponds to the preset desired constant power value, which will not be described in detail later). Figure 8 , which is a schematic diagram showing the input-output relationship of the reference modulation unit in one embodiment of the present application, wherein the horizontal axis Vdet represents the first sampling signal, and the vertical axis Cp_ref represents the constant power reference signal. When the load voltage increases, the first sampling signal Vdet also increases, and the constant power reference signal Cp_ref generated by the reference modulation unit decreases, and Figure 8 The product of the horizontal and vertical coordinates corresponding to each point on the curve is a fixed value, so that the control device adjusts the load current based on the currently generated constant power reference signal to achieve the power output by the power supply device to maintain a stable power.

[0085] In other embodiments, if the first sampling signal changes, the constant power reference signal converted by the reference modulation unit changes in the opposite direction to the change of the first sampling signal. Under certain discrete signal values ​​of the preset first sampling signal, the product of the corresponding constant power reference signal and the first sampling signal remains unchanged, that is, a fixed value (also called a stable value, which reflects the preset desired constant power and will not be described in detail later). In other words, the constant power reference signal and the first sampling signal have a multi-segment change relationship in the opposite direction, and the product of the constant power reference signal and the first sampling signal corresponding to the endpoints of each segment is a fixed value. Please refer to Figure 9 , which is a schematic diagram showing the input and output relationship of the reference modulation unit in another embodiment of the present application, Figure 9 In the example, the constant power reference signal and the first sampling signal are in an opposite multi-segment linear relationship. The horizontal axis Vdet represents the first sampling signal, and the vertical axis Cp_ref represents the constant power reference signal. When the load voltage increases, the first sampling signal Vdet will also increase, and the constant power reference signal Cp_ref generated by the reference modulation unit will decrease. Figure 8 The difference is, Figure 9 In the image shown, only the product of the horizontal and vertical coordinates corresponding to the endpoints of each line segment is a fixed value, such as point A, point B, and point C, so that the control device adjusts the load current based on the currently generated constant power reference signal to achieve that the power supply output by the power supply device is maintained at a stable power.

[0086] It should be noted that, due to the influence of the adjustment accuracy of the control device and the modulation accuracy of the reference modulation unit, the power output by the power supply device is maintained at a stable power. This does not mean that the power output by the power supply device does not change at all, but rather that the power output by the power supply device is allowed to fluctuate around a stable power, but the overall trend is to maintain a stable power. For example, the reference modulation unit can make the constant power reference signal and the first sampling signal appear as follows: Figure 8 The curve shown is due to Figure 8 The product of the constant power reference signal and the first sampling signal corresponding to any point in the constant power reference signal is a fixed value. The control device adjusts the load current based on the constant power reference signal so that the power output by the power supply device is stable. Even if there is a deviation, it is mainly due to the adjustment accuracy of the control device. The deviation is generally small or even non-existent. For another example, the reference modulation unit can make the constant power reference signal and the first sampling signal appear as follows: Figure 9 The curve shown is due to Figure 9In the example, only the product of the constant power reference signal corresponding to each line segment endpoint and the first sampling signal is a fixed value. Then, when the constant power reference signal is present, the control device adjusts the load current based on the constant power reference signal in the linear region of the line segment, which will cause the power output by the power supply device to be slightly higher than the power supply power (i.e., stable power) obtained based on the constant power signal at the line segment endpoint. At this time, the deviation of the power output by the power supply device relative to the stable power is mainly affected by the design principle of the reference modulation unit itself. Figure 9 The more segmented lines there are in the image shown, the smaller the deviation will be. However, it should be noted that whether Figure 8 still Figure 9 The idea of ​​converting the constant power reference signal shown is that any deviations can be designed to be within the allowable range. Therefore, unless otherwise specified in the following description of this application, slight changes in the output power during the constant power stage will be regarded as maintaining a stable power.

[0087] See also Figure 10 , which is a circuit block diagram of a reference modulation unit in one embodiment of the present application. As shown in the figure, the reference modulation unit 61 includes a signal conditioning circuit 62 and a constant power reference generation circuit 63. The output terminal of the constant power reference generation circuit 63, namely the output terminal P_61 of the constant power reference modulation circuit, is used to output a constant power reference signal based on a reference signal output by a reference power supply. The signal conditioning circuit 62 is coupled to the first sampling terminal P_41 and is connected to the constant power reference generation circuit 63. It is used to adjust the circuit characteristics of the constant power reference generation circuit 63 according to changes in the first sampling signal, so that the output constant power reference signal changes inversely with changes in the first sampling signal.

[0088] The constant power reference generation circuit receives the reference signal output by the reference power supply, and converts the reference signal into a constant power reference signal according to the circuit characteristics adjusted by the signal conditioning circuit. The circuit characteristics may be, for example, the current, voltage, impedance, etc. of the constant power reference generation circuit. The reference power supply may be the power supply of the control device, and the reference signal output by it may be, for example, the voltage signal output by the power supply after voltage division by the voltage divider circuit, or may be the electrical signal directly output by the power supply, but the present invention is not limited thereto. In some embodiments, the reference power supply may also be a constant voltage source preset in the control device, and the electrical signal output by it is the reference signal. In other embodiments, the reference power supply may also be a ground terminal, and the reference signal is a ground signal.

[0089] See also Figure 11, which is a schematic diagram of the circuit structure of the constant power reference generating circuit in one embodiment of the present application. As shown in the figure, the constant power generating circuit 63 includes a buffer Buf and an output resistor R7. The input end of the buffer Buf is used to receive the reference signal Ref, and the output end is connected to one end of the output resistor R7. The other end of the output resistor R7 is used to be connected to the signal conditioning circuit 62 to change the circuit characteristics of the constant power generating circuit 63 under the action of the signal conditioning circuit 62. The other end of the output resistor R7 also serves as the output end P_61 of the constant power reference modulation circuit, which is used to output the constant power reference signal Cp_ref. Specifically, in this embodiment, Cp_ref=Ref–R7*I7, where I7 is the current corresponding to the current flowing through R7, which is not shown in the figure. The current value is adjusted by the signal conditioning circuit 62. When the first sampling signal received by the signal conditioning circuit 62 changes, I7 also changes accordingly, so that the constant power reference signal Cp_ref also changes, and changes in the opposite direction to I7, that is, the constant power reference signal can change in the opposite direction to the change of the first sampling signal. It should be noted that Figure 11 The buffer Buf in the illustrated embodiment may be omitted as appropriate and is not an essential component.

[0090] See also Figure 12 , shows a circuit structure diagram of a constant power reference generation circuit in another embodiment of the present application. As shown in the figure, the constant power generation circuit 63 includes an output resistor R8. One end of the output resistor R8 receives the reference signal Gnd, and the other end of the output resistor R8 is connected to the signal conditioning circuit 62 to change the circuit characteristics of the constant power generation circuit 63 under the action of the signal conditioning circuit 62. The other end of the output resistor R8 also serves as the output end P_61 of the constant power reference modulation circuit, which is used to output the constant power reference signal Cp_ref. Specifically, in this embodiment, Cp_ref = Vcc-R8*I8, where I8 is the current flowing through R8, and Vcc is the total power supply of the circuit where the signal conditioning circuit 62 and the constant power generation circuit 63 are located (not shown in the figure). I8 is adjusted by the signal conditioning circuit 62. When the first sampling signal received by the signal conditioning circuit 62 changes, I8 also changes accordingly, so that the constant power reference signal Cp_ref also changes, and the change is opposite to I8, that is, the constant power reference signal can change in the opposite direction to the change of the first sampling signal.

[0091] like Figure 11 and Figure 12As shown, the signal conditioning circuit 62 is connected to the constant power reference generation circuit 63 to adjust the current characteristics of the constant power reference generation circuit 63. Specifically, based on the first sampling signal received by the first sampling terminal P_41, the signal conditioning circuit 62 outputs a current that varies inversely with the first sampling signal. This current enters the constant power reference generation circuit 63, thereby causing the current characteristics of the constant power reference generation circuit 63 to vary inversely with the first sampling signal. It should be noted that if the constant power reference generation circuit 63 adopts other circuit architectures, the signal conditioning circuit 62 will also make adaptive adjustments to change the voltage or impedance characteristics of the constant power reference generation circuit 63. It is sufficient that the constant power reference signal output by the constant power reference generation circuit 63 varies inversely with changes in the first sampling signal.

[0092] In some embodiments, the curve of converting the first sampling signal into the constant power reference signal by the reference modulation unit can be as follows: Figure 8 In view of this, in some embodiments, the signal conditioning circuit 62 adjusts the current characteristics (eg, Figure 11 I7 and Figure 12 The curve of I8) can also be similar to Figure 8 , that is, on the input-output relationship diagram corresponding to the signal conditioning circuit 62, as the first sampling signal increases, the current signal in the constant power reference generation circuit 63 adjusted by the signal conditioning circuit 62 will decrease, and the product of the first sampling signal and the current signal in the constant power reference generation circuit 63 corresponding to each point on the input-output relationship curve is a fixed value, so that the reference modulation unit can achieve the following Figure 8 The input-output relationship diagram shown.

[0093] In other embodiments, the curve of converting the first sampling signal into the constant power reference signal by the reference modulation unit can be as follows: Figure 9 In view of this, in other embodiments, the signal conditioning circuit 62 adjusts the current characteristics (eg, Figure 11 I7 and Figure 12 The input-output relationship of I8) can also be similar to Figure 9 , that is, in the input-output relationship corresponding to the signal conditioning circuit 62, as the first sampling signal increases, the current signal in the constant power reference generating circuit 63 adjusted by the signal conditioning circuit 62 will decrease linearly in multiple segments, and the product of the first sampling signal corresponding to the endpoints of each line segment in the input-output relationship and the current signal in the constant power reference generating circuit 63 is a certain value, so that the reference modulation unit can achieve the following Figure 9 The input-output relationship diagram shown.

[0094] Specifically, in some other embodiments described above, the signal conditioning circuit 62 receives at least one threshold signal and adjusts the current characteristics of the constant power reference circuit based on the signal change of the first sampling signal relative to the threshold signal. Each threshold signal corresponds to the first sampling signal corresponding to the endpoint of each line segment in the input-output relationship of the signal conditioning circuit 62. These threshold signals can be preset by those skilled in the art based on actual needs, or randomly selected and determined within the allowable range of the first sampling signal, without limitation herein. In the example of receiving a single threshold signal, the current output by the signal conditioning circuit 62 exhibits a first linear relationship with the first sampling signal that varies inversely. In the example of receiving a first threshold signal and a second threshold signal, the current output by the signal conditioning circuit 62 exhibits a first linear relationship with the first sampling signal that varies inversely during the period between the first threshold signal and the second threshold signal, and exhibits a second linear relationship with the first sampling signal that varies inversely during the period above the second threshold signal. In the example of receiving multiple threshold signals greater than two, the current signal output by the signal conditioning circuit 62 exhibits a multi-segment linear relationship with the first sampling signal that varies inversely, with each threshold signal as an endpoint.

[0095] See also Figure 13 , which shows a circuit block diagram of a signal conditioning circuit in one embodiment of the present application. As shown in the figure, the signal conditioning circuit 62 includes a current branch P_63 and a current conversion circuit 621. The current branch P_63 is used to connect to the constant power reference generation circuit 63 to change the current signal of the constant power reference generation circuit using the current signal in the current branch P_63. One input terminal of the current conversion circuit 621 is connected to the first sampling terminal P_41 to receive the first sampling signal, and the other input terminal receives the threshold signal Thr. The output terminal is coupled to the current branch P_63 and is used to adjust the current signal in the current branch P_63 based on the signal difference between the first sampling signal and the threshold signal Thr.

[0096] In another embodiment, the signal conditioning circuit includes a current branch, at least two current conversion circuits, and at least one current limiting circuit. The following uses two current conversion circuits and one current limiting circuit as an example to describe the circuit architecture and working principle of a signal conditioning circuit containing multiple current conversion circuits and current limiting circuits. Figure 14, shows a circuit block diagram of a signal conditioning circuit in another embodiment of the present application. As shown, the signal conditioning circuit 62 includes a current branch P_63, a first current conversion circuit 621a, a second current conversion circuit 621b, and a first current limiting circuit 622a. The first current limiting circuit 622a is coupled between one input terminal of the first current conversion circuit 621a and the first sampling terminal P_41. The other input terminal of the first current conversion circuit 621a receives the first threshold signal Thr1, and the output terminal is coupled to the current branch P_63. The second current conversion circuit 621b has one input terminal coupled to the first sampling terminal P_41 to receive the first sampling signal, another input terminal receives the second threshold signal Thr2, and an output terminal is coupled to the current branch P_63. The first current conversion circuit 621a is configured to adjust the current signal in the current branch P_63 based on the signal difference between the first sampling signal and the first threshold signal Thr1, while the first sampling signal is between the first threshold signal Thr1 and the second threshold signal Thr2. The second current conversion circuit 621b is configured to adjust the current signal in the current branch P_63 based on the signal difference between the first sampling signal and the second threshold signal Thr2 after the first sampling signal reaches the second threshold signal Thr2. The first current limiting circuit 622a is configured to limit the current outputted from the output terminal of the first current conversion circuit 621a to a fixed current signal when it determines that the first sampling signal reaches the second threshold signal Thr2, thereby causing the current signal in the current branch P_63 to change in accordance with the current signal outputted from the output terminal of the second current conversion circuit 621b.

[0097] The first current limiting circuit 622a includes a first selection circuit (not shown), one input of which is connected to the first sampling terminal P_41 to receive the first sampling signal, another input of which receives the second threshold signal Thr2, and an output of which is coupled to the first current conversion circuit 621a for outputting the first sampling signal or the second threshold signal Thr2. In an embodiment, the first selection circuit is, for example, a min-max circuit. Thus, before the first sampling signal reaches the second threshold signal Thr2, the min-max circuit outputs the first sampling signal to the first current conversion circuit 621a. After the first sampling signal reaches the second threshold signal Thr2, the min-max circuit outputs the second threshold signal Thr2 to the first current conversion circuit 621a. Thus, the first current conversion circuit 621a outputs the fixed current signal based on the signal difference between the second threshold signal Thr2 and the first threshold signal Thr2.

[0098] Each current conversion circuit includes a voltage-to-current converter, wherein the positive input of the voltage-to-current converter is connected to the output of the first selection circuit, the negative input receives a corresponding threshold signal, and the output is connected to the current branch P_63. When the signal at the positive input is greater than the signal at the negative input, the voltage-to-current converter can output a current signal that is linearly related to the difference between the signals received at the positive and negative inputs based on the difference between the signals received at the positive and negative inputs. Given that the threshold signal is a constant signal, the current signal output by the voltage-to-current converter exhibits a linear relationship that changes inversely with the first sampling signal. Each voltage-to-current converter is configured to output a current signal that exhibits a different linear relationship based on the difference between the signals at the two inputs. In an embodiment, the voltage-to-current converter can be implemented using an operational amplifier, configured with external resistors of varying sizes to enable the operational amplifier to output a current signal that exhibits a different linear relationship based on the difference between the signals at the two inputs. Alternatively, the voltage-to-current converter can be constructed using an operational amplifier and transistors. This application is not limited to this embodiment; any circuit structure that can achieve the aforementioned functions falls within the scope of protection of this application.

[0099] See also Figure 15 , which is a schematic diagram of the input-output relationship of the signal conditioning circuit in another embodiment of the present application. As shown in the figure, the horizontal axis represents the first sampling signal Vdet, and the vertical axis represents the current I in the current branch P_63, wherein the first threshold signal Thr1 and the second threshold signal Thr2 correspond to the first sampling signals Vdet1 and Vdet2 corresponding to points D and F, respectively.

[0100] The following combination Figure 15 and targeting Figure 14 The working process of the signal conditioning circuit 62 described in each embodiment is explained as follows: During the period when the first sampling signal is less than the second threshold signal Thr2, the first current limiting circuit 622a receives the first sampling signal via the first sampling terminal P_41. When the minimum circuit determines that the first sampling signal is less than the second threshold signal Thr2, it outputs the first sampling signal to the first current conversion circuit 621a. The current signal output by the voltage-to-current converter in the first current conversion circuit 621a has a first linear relationship with the first sampling signal that changes inversely. At this time, since the first sampling signal received by the positive input terminal of the voltage-to-current converter in the second current conversion circuit 621b is less than the second threshold signal Thr2 received by the negative input terminal, the second current conversion circuit 621b is in a dormant state and does not output a current signal. The current in the current branch P_63 is determined only by the current signal output by the first current conversion circuit 621a. That is, the current in the current branch P_63 has a first linear relationship with the first sampling signal that changes inversely (as shown in FIG. 1 ). Figure 15(The line segment between DF in FIG. 1 ) During the period when the first sampling signal is greater than the second threshold signal Thr2, the first current limiting circuit 622a receives the first sampling signal via the first sampling terminal P_41. When the minimum circuit therein determines that the first sampling signal is greater than the second threshold signal Thr2, it outputs the second threshold signal Thr2 to the first current conversion circuit 621a. The current signal output by the voltage-to-current converter in the first current conversion circuit 621a is a fixed current signal. At this time, because the first sampling signal received at the positive input terminal of the voltage-to-current converter in the second current conversion circuit 621b is greater than the second threshold signal Thr2 received at the negative input terminal, the voltage-to-current converter in the second current conversion circuit 621b is able to output a current signal having a first linear relationship that varies inversely with the first sampling signal. That is, the fixed current signal output by the first current conversion circuit 621a and the current signal output by the second current conversion circuit 621b are combined into the current signal in the current branch, but the change of the current in the current branch P_63 is determined only by the current signal output by the second current conversion circuit 621b. That is, the current in the current branch P_63 and the first sampling signal have a second linear relationship in which the change is inversely proportional (as shown in FIG. Figure 15 The line segment after F in ).

[0101] It should be stated first that Figure 14 and Figure 15 This is just an example, and does not mean that the current conversion circuit in the signal conditioning circuit can only be set to two, and the current limiting circuit can only be set to one. In actual application, Figure 14 The connection method shown continues to add current conversion circuits and current limiting circuits. For example, the information conditioning circuit also includes a third current conversion circuit and a second current limiting circuit. One input end of the third current conversion circuit is connected to the first sampling end P_41, and the other input end receives the third threshold signal. The second current limiting circuit is connected between the first sampling end P_41 and the second current conversion circuit 621a, and so on. Its working principle is also similar to Figure 14 Similar, I will not go into details here.

[0102] It should be noted that the reference modulation unit in each of the aforementioned embodiments converts the first sampling signal reflecting the load change into a constant power reference signal. Figure 5 As can be seen from the illustrated embodiment, the power conversion circuit releases energy to the load side and the third sampling circuit to supply power to the load side only when the switching device is disconnected. In other words, during the energy storage phase (or excitation phase) of the power conversion circuit, the signal output by the third sampling circuit cannot reflect the load voltage. Only during the energy release phase (or demagnetization phase) of the power conversion circuit can the third sampling signal output by the third sampling circuit reflect the load voltage.

[0103] In view of this, in some embodiments, see Figure 16 , which is a circuit block diagram of a constant power reference modulation circuit according to one embodiment of the present application. As shown in the figure, the constant power reference modulation circuit 60 includes, in addition to the reference modulation unit 61 described in any of the aforementioned embodiments, a demagnetization sampling unit 64. The demagnetization sampling unit 64 is coupled between the first sampling terminal P_41 and the reference modulation unit 61. Upon detecting that the power conversion circuit is in the demagnetization phase, the demagnetization sampling unit 64 outputs the first sampling signal to the reference modulation unit 61 via its output terminal P_62. The reference modulation unit 61 then processes the first sampling signal using the circuit architecture and principles described in the aforementioned embodiments.

[0104] See also Figure 17 , which is a schematic diagram of the circuit structure of the demagnetization sampling unit in one embodiment of the present application. As shown in the figure, the demagnetization sampling unit 64 includes a demagnetization detection circuit 641 and a demagnetization sampling circuit 642. The demagnetization detection circuit 641 is coupled to the first sampling terminal P_41, and is used to detect the first sampling signal to output a demagnetization detection signal when the power conversion circuit is in the demagnetization stage. The demagnetization sampling circuit 642 is coupled to the first sampling terminal P_41 at one end and to the demagnetization detection circuit 641 at the other end, and is used to output the first sampling signal by conducting the line between the first sampling terminal P_41 and the output terminal P_62 of the demagnetization sampling unit 64 when receiving the demagnetization detection signal. In an embodiment, the demagnetization detection circuit 641 may include a comparison circuit, which compares the first sampling signal with a preset threshold to determine whether the first sampling signal at this time can reflect the load voltage, that is, whether the power conversion circuit is in the demagnetization stage. The demagnetization sampling circuit 642 may be as follows Figure 17 The circuit shown includes a switch S1 and a resistor R9, which are connected in series between the first sampling terminal P_41 and the output terminal P_62 of the demagnetization sampling unit 64. The switch S1 can be turned on by the demagnetization detection signal, thereby outputting the first sampling signal from the output terminal P_62.

[0105] Present as Figure 6 As shown in FIG, the constant power reference generating unit 41 in the control device 40 adopts the following Figures 7 to 17 The circuit architecture and working principle shown in each embodiment described herein output a constant power reference signal to the mode selection unit 42. The function of the mode selection unit 42 and the connection method in the control device 40 can be found in the embodiment described herein. Figure 6 The description in , will not be repeated here.

[0106] See also Figure 18, which shows a circuit block diagram of a mode selection unit in one embodiment of the present application. As shown, the mode selection unit 42 includes a comparison circuit 421 and a selection circuit 422. The comparison circuit 421 is coupled to the third sampling terminal P_43 and connected to the output terminal P_45 of the constant power reference signal generation unit. The comparison circuit 421 is configured to output a high-level signal when determining that the third sampling signal output by the third sampling terminal P_43 is less than the first load threshold value load1, thereby forcing the constant power reference signal output by the output terminal P_45 to a high-level signal. The selection circuit 422 is coupled to the third sampling terminal P_43 to receive the third sampling small signal and connected to the output terminal P_45 of the constant power reference signal generation unit to receive the constant power reference signal. The selection circuit 422 also receives the constant current reference signal Cc_com and is configured to selectively output the constant power reference signal, the constant current reference signal Cc_com, or the third sampling signal as a constant voltage reference signal based on the magnitude of the received signals.

[0107] The comparison circuit 421 includes a comparator 4211 and a switch 4212. The comparator 4211 has a positive input connected to the third sampling terminal P_43 to receive a third sampling signal, a negative input receiving a first load threshold value load1, and an output connected to the control terminal of the switch 4212. The first terminal of the switch 4212 is connected to a power supply Vcc, and the second terminal is connected to the output terminal P_45. The comparator 4211 outputs a low-level signal when the third sampling signal is less than the first load threshold value load1. The switch 4212 is, for example, a P-type transistor. When its control terminal receives a low-level signal, it turns on, thereby allowing the power supply Vcc to be fed into the control terminal P_45 of the output terminal, forcing the constant power reference signal to a high-level signal. It should be noted that the selection and connection method of the comparator 4211 and the switch 4212 can be adaptively adjusted, and this application is not limited thereto.

[0108] against Figure 4 It can be seen from the description that the power supply device outputs different power supplies under different load capacities. Specifically, when the load current is less than the first preset current, it outputs constant voltage power to the load; when the load current is greater than the first preset current and less than the second preset current, it outputs constant power to the load; when the load current reaches the second preset current, it outputs constant current power to the load, and the first preset current is less than the second preset current. In view of this, Figure 18The first load threshold value load1 corresponds to a first preset current, and the constant current reference signal Cc_com corresponds to a second preset current. The selection circuit 422 includes a minimum circuit, which selects and outputs the minimum of the received constant power reference signal, the third sampling signal, and the constant current reference signal. Specifically, the third sampling signal reflects the load current. When the load current is less than the first preset current, the third sampling signal is less than both the constant current reference signal Cc_com and the first load threshold value load1. As a result, the comparison circuit 421 is turned on, allowing the power supply Vcc to be supplied to the output terminal P_45, thereby maximizing the signal flowing into the minimum circuit at the output terminal P_45. Furthermore, the minimum circuit selects the third sampling signal as the constant voltage power supply reference signal and outputs it to the subsequent circuit, thereby enabling the power supply device to output a constant voltage power supply to the load when the load current is less than the first preset current. As the load current increases to the maximum current that can be provided under the constant voltage power supply, that is, when it increases to exceed the first preset current but has not yet reached the second preset current, the third sampling signal is less than the constant current reference signal Cc_com and greater than the first load threshold value load1, thereby disconnecting the comparison circuit 421 so that the output terminal P_45 outputs a constant power reference signal that flows into the minimum circuit. The minimum circuit selects the constant power reference signal and outputs it to the subsequent circuit, so that the power supply device can output constant power to the load during the period when the load current is greater than the first preset current and less than the second preset current. When the load current continues to increase to the maximum output current, that is, when it increases to the second preset current, at this time, the load voltage is very low, so that the constant power reference signal output by the output terminal P_45 reaches a maximum, so that the minimum circuit selects the constant current reference signal Cc_com and outputs it to the subsequent circuit, so that the power supply device can output constant current to the load during the period when the load current reaches the second preset current.

[0109] It should be noted that Figure 18 This is just an example of a mode selection unit. In actual applications, Figure 18On the basis of the circuit structure shown, the mode selection unit 42 can also omit the comparison circuit 421, and the selection circuit 422 receives the third sampling signal, the constant power reference signal, and the constant current reference signal Cc_com, for selectively outputting the constant power reference signal, or outputting the constant current reference signal Cc_com, or outputting the third sampling signal as a constant voltage reference signal based on the size relationship of the received signal. The selection circuit 422 includes a small circuit, which selects the smallest of the received constant power reference signal, the third sampling signal, and the constant current reference signal to be output. When the load is light (such as when the load current is less than the first preset current), the third sampling signal reflecting the load current is the smallest, and the small circuit selects the third sampling signal as the constant voltage power supply reference signal and outputs it to the subsequent circuit. When the load is heavy (such as when the load current is greater than the first preset current), the third sampling signal increases, and the constant power reference signal is the smallest at this time. The constant power reference signal output by the small circuit is output to the subsequent circuit. When the load is overloaded (such as the load current is greater than the second preset current), the load voltage is low and the constant power reference signal is high. Therefore, when the load current continues to increase to the maximum output current, that is, when it increases to the second preset current, the load voltage is very low, so the constant current reference signal Cc_com is minimum, and the small circuit selects the constant current reference signal Cc_com and outputs it to the subsequent circuit.

[0110] Present as Figure 6 As shown in FIG, the mode selection unit 42 in the control device 40 adopts Figure 18 The circuit architecture and working principle shown in the various embodiments described herein output signals to the switch control unit 43. The function of the switch control unit 43 and the connection method in the control device 40 can be found in the Figure 6 The description in , will not be repeated here.

[0111] See also Figure 19 , which is a circuit block diagram of a switch control unit in one embodiment of the present application. As shown in the figure, the switch control unit 43 includes a shutdown detection circuit 431, a conduction detection circuit 432, and a drive circuit 433. One input end of the shutdown detection circuit 431 is coupled to the output end P_46 of the mode selection unit, and the other input end is coupled to the second sampling end P_42 to receive the second sampling signal, which is used to output a shutdown signal to the drive circuit 433 when the second sampling signal reaches one of the reference signals output by the output end P_46 of the mode selection unit. The conduction detection circuit 432 is used to output a conduction signal to the drive circuit 433. The input end of the drive circuit 433 is connected to the shutdown detection circuit 431 and the conduction detection circuit 432, and the output end is the output end P_44 of the control device, which is used to be connected to the switching device (such as Figure 4The switch device 30 in the embodiment of the present invention is configured such that the driver circuit 433 outputs a drive signal based on the on-signal and the off-signal to control the on or off state of the switch device. The off-signal detection circuit 431 includes a comparator (not shown), the positive input of the comparator being connected to the second sampling terminal P_43 and the negative input being connected to the output terminal P_46 of the mode selection unit. The comparator achieves the above-mentioned function by comparing the second sampling signal with the reference signal output by the output terminal P_46. The on-signal detection circuit 432 may be, for example, a PWM generation circuit, with the rising edge of the PWM pulse signal output by the PWM generation circuit serving as the on-signal to the driver circuit 433. The on-signal detection circuit 432 may also employ the same architecture as the on-signal detection circuit in a control device implementing switch control using a PFM control method. Here, the input of the on-signal detection circuit 432 is required to be coupled to at least one of the first sampling terminal, the second sampling terminal, and the third sampling terminal, thereby outputting the on-signal to the driver circuit 433 based on the acquired signal. The driver circuit 433 may include, but is not limited to, a switch, a power supply, a trigger, a timer, a selector, an AND gate, or a NOT gate, depending on control requirements and control logic, and this application does not impose any restrictions thereon. Furthermore, depending on circuit partitioning and design considerations, only the off-state detection circuit 431 may serve as the switch control unit 43, or at least one of the on-state detection circuit 432 and the driver circuit 433 may serve together with the off-state detection circuit 431 as the switch control unit 43.

[0112] The following combination Figures 1 to 20The working principle of the power supply device proposed in this application is described. The external drive signal is rectified by the rectifier circuit and output to the filter circuit, thereby outputting the filtered signal to the power conversion circuit. Under different load capacities, the power conversion circuit outputs different types of power supplies based on the on or off of the switch device controlled by the control device. Specifically, the sampling circuit outputs a first sampling signal reflecting the load voltage, a second sampling signal reflecting the peak current of the power conversion circuit, and a third sampling signal reflecting the load current to the control device. When the load current is small (such as less than the first preset current), the mode selection unit in the control device selects to output a constant voltage reference signal to the switch control unit, and the switch control unit controls the shutdown timing of the switch device based on the constant voltage reference signal, so that the power supply voltage output by the power conversion circuit is maintained at a stable voltage (also known as output constant voltage power supply). As the load current continues to increase, when it increases to the first preset current but has not yet reached the second preset current, the mode selection unit in the control device selects to output a constant power reference signal to the switch control unit, and the switch control unit controls the shutdown timing of the switch device based on the constant power reference signal, so that the power supply power output by the power conversion circuit is maintained at a stable power (also known as output constant power power supply). When the load current continues to increase to the second preset current, the mode selection unit in the control device selects to output a constant current reference signal to the switch control unit. The switch control unit controls the shutdown timing of the switch device based on the constant current reference signal, so that the power supply current output by the power conversion circuit is maintained at a stable current (also called output constant current power supply), which is the second preset current.

[0113] The present application also discloses a control chip, which is packaged with a constant power reference modulation circuit as described in any of the above embodiments, or a control device as described in any of the above embodiments. The control chip also includes a plurality of pins. In one embodiment, the chip is packaged with the reference modulation unit and the demagnetization sampling unit as described above, and the plurality of pins include a first pin for receiving a first sampling signal reflecting the load voltage, a second pin for outputting a constant power reference signal, a third pin for obtaining a chip power supply, and a fourth pin for grounding. In another embodiment, the chip is packaged with the constant power reference generation unit, the mode selection unit, and the switch control unit as described above, and the plurality of pins include a first pin for receiving a first sampling signal reflecting the load voltage, a second pin for receiving a second sampling signal reflecting the peak current of the power conversion circuit, a third pin for receiving a third sampling signal reflecting the load current, a fourth pin for outputting a drive signal, a fifth pin for obtaining a chip power supply, and a sixth pin for grounding. For the modules and circuits in each embodiment, please refer to the aforementioned description for Figures 6 to 19 The description will not be repeated here.

[0114] The present application also discloses a constant power reference modulation method, comprising the following steps: step S11 and step S12. The constant power reference modulation method can be performed by the aforementioned constant power reference modulation circuit, or other constant power reference modulation circuits capable of performing the modulation method.

[0115] In step S11 , a first sampling signal reflecting a load voltage is received.

[0116] Here, the constant power reference modulation circuit obtains a first sampling signal reflecting the load voltage by coupling with the sampling circuit. The constant power reference modulation circuit may obtain the first sampling signal by, for example, obtaining the first sampling signal by electrical connection, obtaining the first sampling signal by optical coupling, or obtaining the first sampling signal by inductive sensing.

[0117] by Figures 7 to 17 For example, the constant power reference modulation circuit receives the first sampling signal via the first sampling terminal. For the specific circuit structure and acquisition method, please refer to the description of Figures 5 to 17 The description is not repeated here.

[0118] In step S12, the first sampling signal is converted into a constant power reference signal; wherein the constant power reference signal changes inversely with changes in the first sampling signal.

[0119] The constant power reference modulation circuit converts the first sampling signal into a constant power reference signal. For example, the constant power reference signal outputted by the constant power reference signal exhibits a multi-segment variation relationship opposite to the first sampling signal, where the product of the constant power reference signal and the first sampling signal corresponding to each segment endpoint is a fixed value, and each segment variation relationship is, for example, a linear relationship. In an embodiment, the constant power reference modulation circuit adjusts its circuit characteristics based on signal variations of the first sampling signal relative to at least one threshold signal, such that the output constant power reference signal varies inversely with variations in the first sampling signal. The circuit characteristics include electrical characteristics such as resistance, current, and voltage.

[0120] by Figures 7 to 17 As an example, the constant power reference modulation circuit adopts Figures 7 to 17 Any embodiment and the circuit structure and working principle shown in the description thereof execute step S21. For details, please refer to Figures 7 to 17 The description is not repeated here.

[0121] The present application also discloses a control method for a switching device, comprising steps S21, S22, S23, and S24. The control method can be executed by the aforementioned control device, or other control circuits capable of executing the control method.

[0122] In step S21, a second sampling signal reflecting a peak current of a power conversion circuit and a third sampling signal reflecting a load current are obtained, wherein the power conversion circuit is coupled to the switching device.

[0123] Here, by coupling with the sampling circuit, the control device obtains a second sampling signal reflecting the peak current of a power conversion circuit and a third sampling signal reflecting the load current. Examples of how the control device obtains the second sampling signal include: obtaining the second sampling signal via electrical connection, obtaining the second sampling signal via resistance, or obtaining the second sampling signal via inductive sensing. Examples of how the control device obtains the third sampling signal include: obtaining the third sampling signal via electrical connection, obtaining the second sampling signal via photoelectric sensing, or obtaining the third sampling signal via inductive sensing.

[0124] by Figure 5 and Figure 6 As an example of the embodiment and its description, the control device obtains the second sampling signal and the third sampling signal through its second sampling terminal and the third sampling terminal. For specific acquisition methods, please refer to the Figure 5 and Figure 6 The description is not repeated here.

[0125] In step S22, the first sampling signal is converted into a constant power reference signal.

[0126] Here, the constant power reference modulation circuit in the control device adopts the constant power reference modulation method disclosed above in this application (such as step S11 and step S12). Please refer to the above description for details and will not be repeated here.

[0127] In step S23 , a constant power reference signal is output based on the second sampling signal and the constant power reference signal.

[0128] Here, the control device may output a constant power reference signal based on the second sampling signal and the constant power reference signal via a constant power reference generation unit therein. In some embodiments, the constant power reference generation unit integrates the first sampling signal and the constant power reference signal to generate the constant power reference signal.

[0129] by Figures 7 to 17 As an example of the embodiment and description shown, the constant power reference generating unit in the control device adopts Figures 7 to 17 Any embodiment and the circuit structure and working principle shown in the description thereof execute step S23. For details, please refer to Figures 7 to 17 The description is not repeated here.

[0130] In some embodiments, step S25 is further included before step S24. In step S25, a constant current reference signal is obtained.

[0131] Here, the mode selection unit in the control device obtains the constant current reference signal. Figure 6 and Figure 18 As an example of the embodiment and its description, the mode selection unit in the control device obtains the constant current reference signal. For its circuit architecture and the process of executing step S25, please refer to Figure 6 and Figure 18 The embodiments and their descriptions are shown and will not be repeated here.

[0132] In step S24, the constant power reference signal, the constant current reference signal, or the third sampling signal is selectively output as a constant voltage reference signal; under the action of the constant voltage reference signal, the switching device is controlled so that the power supply voltage output by the power conversion circuit is maintained at a stable voltage, or under the action of the constant power reference signal, the switching device is controlled so that the power supply power output by the power conversion circuit is maintained at a stable power, and under the action of the constant current reference signal, the power supply current output by the power conversion circuit is maintained at a stable current.

[0133] Here, a mode selection unit in the control device selectively outputs the constant power reference signal, the constant current reference signal, or the third sampled signal as the constant voltage reference signal based on the magnitude relationship among the third sampled signal, the constant power reference signal, and the constant current reference signal. Specifically, the mode selection unit is further configured to output a high-level signal when it determines that the third sampled signal is less than a first load threshold, thereby forcing the received constant power reference signal to be the high-level signal, and the mode selection unit selects the minimum of the received signals for output.

[0134] by Figure 6 、 Figure 18 ,as well as Figure 19 As an example of the embodiment and its description, the mode selection unit and the switch control unit in the control device adopt Figure 6 、 Figure 18 ,as well as Figure 19 Any embodiment and the circuit structure and working principle shown in the description thereof execute step S24. For details, please refer to Figure 6 、 Figure 18 ,as well as Figure 19 The description is not repeated here.

[0135] To sum up, the constant power reference modulation circuit, control device and chip, power supply device and method disclosed in this application can provide different power supplies according to different load capacities, so that when powering the load, the load can quickly be in the high-power power supply stage, thereby improving energy utilization.

[0136] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical concepts disclosed in this application shall be covered by the claims of this application.

Claims

1. A constant power reference modulation circuit, characterized in that: Configured in a power supply device, including: A first sampling terminal, configured to receive a first sampling signal reflecting a load voltage; A reference modulation unit is coupled to the first sampling terminal and is configured to convert the first sampling signal into a constant power reference signal. The reference modulation unit includes: a constant power reference generation circuit configured to output a constant power reference signal based on a reference signal output by a reference power supply; and a signal conditioning circuit coupled to the first sampling terminal and the constant power reference generation circuit. The signal conditioning circuit receives at least one threshold signal and is configured to adjust circuit characteristics of the constant power reference generation circuit based on a signal change of the first sampling signal relative to the threshold signal, so that the output constant power reference signal changes inversely with changes in the first sampling signal. Under the action of the constant power reference signal, the power output by the power supply device is maintained at a stable power. In which, the signal conditioning circuit includes a current branch connected to the constant power reference generation circuit and at least one current conversion circuit, one input end of the current conversion circuit receives the first sampling signal, the other input end receives the threshold signal, and the output end is coupled to the current branch, and is used to adjust the current signal in the current branch based on the signal difference between the first sampling signal and the threshold signal, wherein the threshold signals received by different current conversion circuits are different.

2. The constant power reference modulation circuit according to claim 1, characterized in that: The constant power reference signal and the first sampling signal have a multi-segment variation relationship that is opposite to each other; wherein the product of the constant power reference signal and the first sampling signal corresponding to the endpoints of each segment is a fixed value.

3. The constant power reference modulation circuit according to claim 2, characterized in that: The constant power reference signal and the first sampling signal are in an opposite multi-segment linear relationship.

4. The constant power reference modulation circuit according to claim 1, characterized in that: Also includes: The demagnetization sampling unit is coupled between the first sampling end and the reference modulation unit, and is configured to output the first sampling signal to the reference modulation unit when detecting that the power conversion circuit in the power supply device is in a demagnetization stage.

5. The constant power reference modulation circuit according to claim 4, characterized in that: The demagnetization sampling unit includes: a demagnetization detection circuit, coupled to the first sampling terminal, for detecting the first sampling signal and outputting a demagnetization detection signal when the power conversion circuit is in a demagnetization stage; The demagnetization sampling circuit is coupled to the demagnetization detection circuit and is configured to output the first sampling signal when receiving the demagnetization detection signal.

6. The constant power reference modulation circuit according to claim 1, characterized in that: The signal conditioning circuit includes at least two current conversion circuits, and the signal conditioning circuit further includes: at least one current limiting circuit, the current limiting circuit being coupled to one of the current conversion circuits and configured to limit the current signal output by the coupled current conversion circuit to a fixed current signal when determining that the first sampling signal reaches a threshold signal received by the other current conversion circuit, so that the current signal in the current branch changes with the current signal output by the other current conversion circuit.

7. The constant power reference modulation circuit according to claim 6, characterized in that: The at least two current conversion circuits are a first current conversion circuit and a second current conversion circuit, and the current limiting circuit includes: a first selection circuit having one input terminal receiving the first sampling signal, another input terminal receiving the second threshold signal, and an output terminal coupled to the first current conversion circuit for outputting the first sampling signal or the second threshold signal; The first current conversion circuit outputs the fixed current signal based on the signal difference between the second threshold signal and the first threshold signal, and the fixed current signal and the current signal output by the second current conversion circuit based on the signal difference between the first sampling signal and the second threshold signal are combined into the current signal in the current branch; The first threshold signal corresponds to the threshold signal received by the first current conversion circuit, and the second threshold signal corresponds to the threshold signal received by the second current conversion circuit.

8. The constant power reference modulation circuit according to claim 1, characterized in that: The constant power reference generation circuit includes an output resistor, one end of which is used to obtain the reference signal, and the other end of which is coupled to the signal conditioning circuit to output the constant power reference signal.

9. A control device for a switching device, characterized in that: The control device comprises: a second sampling terminal for acquiring a second sampling signal reflecting a peak current of a power conversion circuit coupled to the switching device; A third sampling terminal is used to obtain a third sampling signal reflecting the load current; a constant power reference signal generating unit, coupled to the second sampling end, comprising the constant power reference modulation circuit according to any one of claims 1 to 8, configured to output a constant power reference signal based on the second sampling signal and the constant power reference signal; a mode selection unit, coupled to the third sampling terminal and the constant power reference generation unit, configured to selectively output the constant power reference signal or output the third sampling signal as a constant voltage reference signal; A switch control unit, coupled to the mode selection unit, is configured to control the switch device under the action of the constant voltage reference signal so that the supply voltage output by the power conversion circuit is maintained at a stable voltage, or to control the switch device under the action of the constant power reference signal so that the supply power output by the power conversion circuit is maintained at a stable power.

10. The control device for a switching device according to claim 9, characterized in that: The constant power reference signal and the first sampling signal have a multi-segment change relationship that is opposite to each other, and the supply power outputted by the power conversion circuit corresponding to each segment endpoint is maintained at the stable power.

11. The control device for a switching device according to claim 9, characterized in that: The mode selection unit includes: a comparison circuit, coupled to the third sampling terminal and the constant power reference signal generation unit, configured to output a high-level signal when determining that the third sampling signal is less than a first load threshold, so that the constant power reference signal is forced to be the high-level signal; The selection circuit is coupled to the third sampling terminal and the constant power reference signal generation unit, and is configured to selectively output the constant power reference signal or the third sampling signal as a constant voltage reference signal based on the magnitude relationship of the received signal.

12. The control device for a switching device according to claim 9, characterized in that: The mode selection unit further receives a constant current reference signal and is used to selectively output the constant current reference signal. Under the action of the constant current reference signal, the power supply current output by the power conversion circuit is maintained at a stable current.

13. The control device for a switching device according to claim 9, characterized in that: The switch control unit includes: The turn-off detection circuit is coupled to the mode selection unit and the second sampling terminal, and is used to output a turn-off signal when determining that the second sampling signal reaches one of the reference signals output by the mode selection unit to turn off the switch device.

14. The control device for a switching device according to claim 13, characterized in that: The switch control unit further includes: a conduction detection circuit configured to output a conduction signal to turn on the switch device.

15. The control device for a switching device according to claim 14, characterized in that: The switch control unit further includes: a driving circuit coupled to the on-detection circuit and the off-detection circuit, configured to output a driving signal based on the on-signal and the off-signal to control the on or off state of the switch device.

16. A power supply device, characterized in that: include: a rectifier circuit, configured to receive an external driving signal and output a rectified signal; a filter circuit, coupled to the rectifier circuit, for filtering the rectified signal to output a filtered signal; The control device according to any one of claims 9 to 15, configured to output a drive signal based on the first sampling signal, the second sampling signal, and the third sampling signal; a switch device, a control terminal of which is coupled to the control device and configured to be turned on or off based on the drive signal; a power conversion circuit, coupled to the switching device and the filtering circuit, for performing energy conversion on the filtered signal based on the on / off state of the switching device to output constant voltage power supply or constant power power supply to a load; The sampling circuit is coupled to the control device and the power conversion circuit, and is used to respectively sample electrical signals reflecting the load voltage, the load current, and the peak current of the power conversion circuit to correspondingly output the first sampling signal, the third sampling signal, and the second sampling signal.

17. A constant power reference modulation method, characterized in that: The constant power reference modulation circuit according to any one of claims 1 to 8 comprises the following steps: receiving a first sampling signal reflecting a load voltage; The first sampling signal is converted into a constant power reference signal; wherein the constant power reference signal changes inversely with changes in the first sampling signal.

18. The constant power reference modulation method according to claim 17, characterized in that: The constant power reference signal and the first sampling signal have a multi-segment variation relationship that is opposite to each other; wherein the product of the constant power reference signal and the first sampling signal corresponding to the endpoints of each segment is a fixed value.

19. The constant power reference modulation method according to claim 18, characterized in that: The constant power reference signal and the first sampling signal are in an opposite multi-segment linear relationship.

20. A method for controlling a switching device, characterized in that: The following steps are involved: Acquiring a second sampling signal reflecting a peak current of a power conversion circuit and a third sampling signal reflecting a load current; wherein the power conversion circuit is coupled to the switching device; The constant power reference modulation method according to any one of claims 17 to 19 is used to convert the first sampling signal into the constant power reference signal; outputting a constant power reference signal based on the second sampling signal and the constant power reference signal; selectively outputting the constant power reference signal or outputting the third sampling signal as a constant voltage reference signal; Under the action of the constant voltage reference signal, the switching device is controlled so that the power supply voltage output by the power conversion circuit is maintained at a stable voltage, or under the action of the constant power reference signal, the switching device is controlled so that the power supply power output by the power conversion circuit is maintained at a stable power.

21. The method for controlling a switching device according to claim 20, wherein: The following steps are also included: Obtaining a constant current reference signal; The constant current reference signal is selectively outputted. Under the action of the constant current reference signal, the power supply current outputted by the power conversion circuit is maintained at a stable current.

22. A control chip, characterized in that: The chip is packaged with the constant power reference modulation circuit according to any one of claims 1 to 8, or is packaged with the control device according to any one of claims 9 to 15.

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