Power management circuit and power equipment

Abstract

The utility model is suitable for the technical field of power supply equipment, and provides a power supply management circuit and power supply equipment, and the power supply management circuit comprises a first voltage dividing unit, a second voltage dividing unit, a first switch unit and a resistor unit. The first voltage dividing unit is electrically connected with the second voltage dividing unit, the first switch unit and the output end of the voltage conversion module, and the first switch unit is electrically connected with the resistor unit. When the resistance value of the load is larger than or equal to the first preset resistance value and smaller than the second preset resistance value, the first voltage dividing unit is used for converting the first output voltage of the output end of the voltage conversion module into the first voltage and transmitting the first voltage to the second voltage dividing unit and the first switch unit. The second voltage dividing unit is used for converting the first voltage into the voltage required by the load, and the first switch unit is used for conducting according to the first voltage, so that the resistor unit is connected with the output end of the voltage conversion module, and the problem that the voltage ripple output by the power supply equipment is relatively large when the light load is accessed is effectively avoided.

Description

Technical Field

[0001] The present application belongs to the technical field of power supply equipment, and in particular, relates to a power management circuit and a power supply equipment. Background Art

[0002] Traditional power supply devices with secondary windings have a major defect, that is, the voltage stabilization feedback mechanism can only be derived from the main winding, which makes it difficult to suppress the ripple of the secondary winding. Especially when connected to a light load, the current provided by the power supply device is small, which may cause the operating frequency of the switching element in the power supply device to change. In order to maintain a stable output voltage, the power supply device may increase the switching frequency, thereby increasing the switching action, causing the ripple of the secondary winding to increase exponentially. Therefore, the existing power management circuit has the problem of large output voltage ripple when connected to a light load. Utility Model Content

[0003] The embodiments of the present application provide a power management circuit and a power supply device, which can solve the problem of large ripple in the existing power management circuit when connected to a light load.

[0004] In a first aspect, an embodiment of the present application provides a power management circuit, including a first voltage dividing unit, a second voltage dividing unit, a first switch unit and a resistor unit; the first voltage dividing unit is electrically connected to the second voltage dividing unit, the first switch unit and an output end of a voltage conversion module respectively, the first switch unit is grounded through the resistor unit, and the second voltage dividing unit is used to be electrically connected to a load;

[0005] When the resistance of the load is greater than or equal to the first preset resistance and the resistance of the load is less than the second preset resistance, the first voltage divider unit is used to convert the first output voltage of the output end of the voltage conversion module into a first voltage, and transmit the first voltage to the second voltage divider unit and the first switch unit respectively, the second voltage divider unit is used to convert the first voltage into the voltage required by the load, and the first switch unit is used to be turned on according to the first voltage to connect the resistance unit to the output end of the voltage conversion module.

[0006] In a possible implementation of the first aspect, the first voltage dividing unit includes a first resistor, a first end of the first resistor is electrically connected to the output end of the voltage conversion module and the first switch unit, and a second end of the first resistor is electrically connected to the first switch unit and the second voltage dividing unit.

[0007] In a possible implementation manner of the first aspect, the second voltage dividing unit includes a second resistor, a first end of the second resistor is electrically connected to the first switch unit and the first voltage dividing unit respectively, and a second end of the second resistor is used to be electrically connected to the load.

[0008] In a possible implementation of the first aspect, the first switching unit includes a first transistor, the base of the first transistor is electrically connected to the first voltage dividing unit and the second voltage dividing unit respectively, the collector of the first transistor is electrically connected to the resistance unit, and the emitter of the first transistor is used to be electrically connected to the output end of the voltage conversion module.

[0009] In a possible implementation of the first aspect, the first switching unit also includes a third resistor and a fourth resistor, the first end of the third resistor is electrically connected to the emitter of the first transistor and the output end of the voltage conversion module, respectively, the second end of the third resistor is electrically connected to the first end of the fourth resistor and the base of the first transistor, and the second end of the fourth resistor is electrically connected to the first voltage divider unit and the second voltage divider unit, respectively.

[0010] In a possible implementation manner of the first aspect, the resistance unit includes a fifth resistor, a first end of the fifth resistor is electrically connected to the first switch unit, and a second end of the fifth resistor is grounded.

[0011] In a possible implementation manner of the first aspect, the power management circuit further includes a third voltage dividing unit, a fourth voltage dividing unit, and a second switch unit, the second switch unit being electrically connected to the first voltage dividing unit, the second voltage dividing unit, the third voltage dividing unit, the fourth voltage dividing unit, the first switch unit, and an output end of the voltage conversion module, respectively, and the fourth voltage dividing unit being electrically connected to the third voltage dividing unit and the load, respectively;

[0012] When the resistance of the load is greater than or equal to the third preset resistance and the resistance of the load is less than the fourth preset resistance, the third voltage divider unit is used to convert the first output voltage into a second voltage, and transmit the second voltage to the fourth voltage divider unit and the second switch unit respectively, the fourth voltage divider unit is used to convert the second voltage into the voltage required by the load, the second switch unit is used to be turned on according to the second voltage, and output the second output voltage to the first switch unit, and the first switch unit is used to be turned off according to the second output voltage, so that the resistance unit is disconnected from the output end of the voltage conversion module.

[0013] In a possible implementation of the first aspect, the third voltage divider unit includes a sixth resistor, a first end of the sixth resistor is electrically connected to the second switch unit and the output end of the voltage conversion module, respectively, and a second end of the sixth resistor is electrically connected to the fourth voltage divider unit and the second switch unit, respectively.

[0014] In a possible implementation of the first aspect, the fourth voltage dividing unit includes a seventh resistor, a first end of the seventh resistor is electrically connected to the third voltage dividing unit and the second switch unit respectively, and a second end of the seventh resistor is used to be electrically connected to the load.

[0015] In a possible implementation of the first aspect, the second switch unit includes a first switch tube, a gate of the first switch tube is electrically connected to the third voltage divider unit and the fourth voltage divider unit, a source of the first switch tube is electrically connected to the third voltage divider unit and the output end of the voltage conversion module, and a drain of the first switch tube is electrically connected to the first voltage divider unit, the second voltage divider unit and the first switch unit.

[0016] In a second aspect, an embodiment of the present application provides a power supply device, comprising a voltage conversion module and a plurality of power management circuits described in any one of the first aspects, wherein the plurality of power management circuits are electrically connected to a plurality of output terminals of the voltage conversion module.

[0017] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0018] The power management circuit provided by the embodiment of the present application includes a first voltage dividing unit, a second voltage dividing unit, a first switch unit and a resistor unit. When the resistance of the load is greater than or equal to the first preset resistance and the resistance of the load is less than the second preset resistance, that is, the power management circuit is connected to a light load, the first voltage dividing unit can convert the first output voltage of the output end of the voltage conversion module into a first voltage, and transmit the first voltage to the second voltage dividing unit and the first switch unit. The second voltage dividing unit converts the first voltage and converts the first voltage into a voltage required by the load so as to supply power to the load. The first switch unit is turned on according to the first voltage to connect the resistor unit to the output end of the voltage conversion module. It can be seen that the power management circuit provided by the embodiment of the present application, when connected to a light load, connects the resistor unit to the output end of the voltage conversion module through the conduction of the first switch unit. Since the resistor unit has a certain resistance, connecting the resistor unit to the output end of the voltage conversion module is equivalent to connecting a dummy load with a certain resistance to the output end of the voltage conversion module, thereby effectively avoiding the problem of large voltage ripple output by the power supply device when connected to a light load. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 It is a circuit connection diagram of an existing power supply device;

[0021] Figure 2 is a principle block diagram of a power management circuit provided in an embodiment of the present application;

[0022] Figure 3 is a circuit connection diagram of a power management circuit provided in an embodiment of the present application;

[0023] Figure 4 is a principle block diagram of a power management circuit provided by another embodiment of the present application;

[0024] Figure 5 It is a circuit connection diagram of four groups of power management circuits provided in one embodiment of the present application;

[0025] Figure 6 This is a test circuit connection diagram of a power management circuit provided in an embodiment of the present application;

[0026] Figure 7 is a schematic diagram of a voltage waveform provided by an embodiment of the present application;

[0027] Figure 8 This is a principle block diagram of a power supply device provided in one embodiment of the present application.

[0028] In the figure: 10, power management circuit; 101, first voltage dividing unit; 102, second voltage dividing unit; 103, first switch unit; 104, resistance unit; 105, third voltage dividing unit; 106, fourth voltage dividing unit; 107, second switch unit; 108, first filter unit; 109, second filter unit; 20, voltage conversion module; 30, load. DETAILED DESCRIPTION

[0029] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0030] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0031] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0032] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0033] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0034] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0035] like Figure 1 As shown, the traditional power supply device with a secondary winding has a major defect, that is, the voltage stabilization feedback mechanism can only be derived from the main winding, which makes it difficult to suppress the ripple of the secondary winding. Especially when connected to a light load, the current provided by the power supply device is small, which may cause the operating frequency of the switching element in the power supply device to change. In order to maintain a stable output voltage, the power supply device may increase the switching frequency, thereby increasing the switching action, causing the ripple of the secondary winding to increase exponentially. Therefore, the existing power management circuit has the problem of large output voltage ripple when connected to a light load.

[0036] For example, Figure 1Actual tests of the power management circuit in the power supply equipment showed that when the main winding load was 5-100%, the secondary winding ripple was 100mVpp@18V; when the main winding load was <5%, the switch tube of the switching power supply was at a smaller duty cycle, and with the introduction of voltage stabilization feedback regulation, the ripple of the secondary winding would increase to nearly 3000mVpp@18V, seriously affecting the stability of its back-end circuit.

[0037] Based on the above problems, the power management circuit provided by the embodiment of the present application includes a first voltage dividing unit, a second voltage dividing unit, a first switch unit and a resistor unit. When the resistance of the load is greater than or equal to the first preset resistance and the resistance of the load is less than the second preset resistance, that is, the power management circuit is connected to a light load, the first voltage dividing unit can convert the first output voltage of the output end of the voltage conversion module into a first voltage, and transmit the first voltage to the second voltage dividing unit and the first switch unit. The second voltage dividing unit converts the first voltage and converts the first voltage into a voltage required by the load so as to supply power to the load. The first switch unit is turned on according to the first voltage to connect the resistor unit to the output end of the voltage conversion module. It can be seen that the power management circuit provided by the embodiment of the present application, when connected to a light load, connects the resistor unit to the output end of the voltage conversion module through the conduction of the first switch unit. Since the resistor unit has a certain resistance, connecting the resistor unit to the output end of the voltage conversion module is equivalent to connecting a dummy load with a certain resistance to the output end of the voltage conversion module, thereby effectively avoiding the problem of large voltage ripple output by the power supply device when connected to a light load.

[0038] In order to illustrate the technical solution described in this application, a specific embodiment is provided below for illustration.

[0039] Figure 2 FIG. 1 shows a functional block diagram of a power management circuit 10 provided in an embodiment of the present application. Figure 2 As shown, the power management circuit 10 includes a first voltage dividing unit 101, a second voltage dividing unit 102, a first switch unit 103 and a resistor unit 104. The first voltage dividing unit 101 is electrically connected to the second voltage dividing unit 102, the first switch unit 103 and the output end of the voltage conversion module 20 respectively, the first switch unit 103 is grounded through the resistor unit 104, and the second voltage dividing unit 102 is used to be electrically connected to the load 30.

[0040] Specifically, when the resistance of the load 30 is greater than or equal to the first preset resistance and the resistance of the load 30 is less than the second preset resistance, that is, the power management circuit 10 is connected to a light load, the first voltage divider unit 101 can convert the first output voltage output from the output end of the voltage conversion module 20 into a first voltage, and transmit the first voltage to the second voltage divider unit 102 and the first switch unit 103 respectively. The second voltage divider unit 102 converts the first voltage and converts the first voltage into the voltage required by the load 30 so as to supply power to the load 30. The first switch unit 103 is turned on according to the first voltage, so that the resistor unit 104 is connected to the output end of the voltage conversion module 20. It can be seen that the power management circuit 10 provided in the embodiment of the present application, when connected to a light load, is connected to the output end of the voltage conversion module 20 by turning on the first switch unit 103. Since the resistor unit 104 has a certain resistance value, connecting the resistor unit 104 to the output end of the voltage conversion module 20 is equivalent to connecting a dummy load 30 with a certain resistance value to the output end of the voltage conversion module 20, thereby effectively avoiding the problem of large voltage ripple output by the power management circuit 10 when connected to a light load.

[0041] It should be noted that the connection of the dummy load 30 can remove the ripple of the voltage output by the power supply device. Specifically, the dummy load 30 is usually a large resistor, which can provide a stable current path, making the current and voltage output by the power supply device more stable, thereby reducing the voltage ripple output by the power supply device. At the same time, by connecting a dummy load 30, high-frequency noise can be filtered out through the dummy load 30, thereby reducing the voltage ripple output by the power supply device. In addition, in some cases, the dummy load 30 can also simulate the characteristics of the real load 30, allowing the power supply device to be tested and adjusted under different load 30 conditions to ensure that the performance of the power supply device is stable under different load 30 conditions, thereby facilitating the measurement and evaluation of the performance of the power supply device.

[0042] For example, the designer may set the first output voltage outputted from the output end of the voltage conversion module 20 according to actual conditions. For example, the first output voltage may be set to 18V.

[0043] In one embodiment of the present application, Figure 3 As shown, the first voltage dividing unit 101 includes a first resistor R1, a first end of the first resistor R1 is electrically connected to the output end of the voltage conversion module 20 and the first switch unit 103, and a second end of the first resistor R1 is electrically connected to the first switch unit 103 and the second voltage dividing unit 102.

[0044] Specifically, the first resistor R1 is connected in series between the output end of the voltage conversion module 20 and the second voltage dividing unit 102, and the first resistor R1 and the second voltage dividing unit 102 are both connected in series between the output end of the voltage conversion module 20 and the load 30. Therefore, the first resistor R1 and the second voltage dividing unit 102 are both used for voltage division, and the voltage (first voltage) at the second end of the first resistor R1 is equal to the first output voltage minus the voltage drop of the first resistor R1.

[0045] For example, the designer may set the resistance value of the first resistor R1 according to actual conditions. For example, the resistance value of the first resistor R1 may be set to 8.2Ω.

[0046] In one embodiment of the present application, Figure 3 As shown, the second voltage dividing unit 102 includes a second resistor R2 , a first end of the second resistor R2 is electrically connected to the first switch unit 103 and the first voltage dividing unit 101 , respectively, and a second end of the second resistor R2 is electrically connected to the load 30 .

[0047] Specifically, the second resistor R2 is connected in series between the first resistor R1 and the load 30, and the first resistor R1 and the second resistor R2 are both connected in series between the output end of the voltage conversion module 20 and the load 30. Therefore, the second resistor R2 has the same function as the first resistor R1, and is also used for voltage division. The voltage at the first end of the second resistor R2 (the first voltage) is equal to the voltage at the second end of the first resistor R1, and the voltage at the second end of the second resistor R2 (the voltage required by the load 30) is equal to the difference obtained by subtracting the first voltage from the first output voltage minus the voltage drop of the second resistor R2.

[0048] For example, the designer may set the resistance value of the second resistor R2 according to actual conditions. For example, the resistance value of the second resistor R2 may be set to 7.5Ω.

[0049] In one embodiment of the present application, Figure 3 As shown, the first switch unit 103 includes a first transistor VT1, the base of the first transistor VT1 is electrically connected to the first voltage divider unit 101 and the second voltage divider unit 102 respectively, the collector of the first transistor VT1 is electrically connected to the resistance unit 104, and the emitter of the first transistor VT1 is used to be electrically connected to the output end of the voltage conversion module 20.

[0050] Specifically, the first transistor VT1, as a switching device, can be turned on or off according to the voltage difference between the base and the emitter of the first transistor VT1. When the resistance of the load 30 is greater than or equal to the first preset resistance and the resistance of the load 30 is less than the second preset resistance, that is, the power management circuit 10 is connected to a light load, the current flowing through the first resistor R1 will produce a voltage drop. The voltage drop of the first resistor R1 reaches the turn-on voltage of the first transistor VT1, thereby turning on the first transistor VT1, connecting the resistor unit 104 and the output end of the voltage conversion module 20, thereby effectively avoiding the problem of large voltage ripple output by the power management circuit 10 when the light load is connected.

[0051] It should be noted that if the power management circuit 10 is connected to a heavy load, no load or full load, the first transistor VT1 is in a cut-off state, and the resistor unit 104 is disconnected from the output end of the voltage conversion module 20. At this time, it means that the ripple requirement of the connected load 30 can be met without connecting a dummy load 30 with a certain resistance value, that is, the ripple is less than 100mVpp@18V.

[0052] Exemplarily, the designer may set the type and model of the first transistor VT1 according to actual conditions. For example, the type of the first transistor VT1 may be set to be a PNP type, and the model of the first transistor VT1 may be set to be 2N3906.

[0053] In one embodiment of the present application, Figure 3 As shown, the first switch unit 103 also includes a third resistor R3 and a fourth resistor R4, the first end of the third resistor R3 is electrically connected to the emitter of the first transistor VT1 and the output end of the voltage conversion module 20, respectively, the second end of the third resistor R3 is electrically connected to the first end of the fourth resistor R4 and the base of the first transistor VT1, and the second end of the fourth resistor R4 is electrically connected to the first voltage divider unit 101 and the second voltage divider unit 102, respectively.

[0054] Specifically, the third resistor R3 and the fourth resistor R4 are both used as current limiting resistors of the first transistor VT1, and are used to limit the current flowing into the base to prevent the first transistor VT1 from being damaged due to overcurrent. At the same time, the third resistor R3 and the fourth resistor R4 are also used to provide a base bias current, which can control the opening and closing speed of the first transistor VT1, as well as its stability under different load conditions.

[0055] For example, the designer may set the resistance value of the third resistor R3 and the resistance value of the fourth resistor R4 according to actual conditions. For example, the resistance value of the third resistor R3 may be set to 100 kΩ, and the resistance value of the fourth resistor R4 may be set to 30 Ω.

[0056] In one embodiment of the present application, Figure 3As shown, the resistance unit 104 includes a fifth resistor R5, a first end of the fifth resistor R5 is electrically connected to the first switch unit 103, and a second end of the fifth resistor R5 is grounded.

[0057] Specifically, the fifth resistor R5 as a dummy load 30 can provide a stable current path, making the current and voltage output by the power supply device more stable, thereby reducing the voltage ripple output by the power supply device. At the same time, by connecting the fifth resistor R5, high-frequency noise can be filtered out through the dummy load 30, thereby reducing the voltage ripple output by the power supply device.

[0058] For example, the designer may set the resistance value of the fifth resistor R5 according to actual conditions. For example, the resistance value of the fifth resistor R5 may be set to 510Ω.

[0059] Figure 1 Although the power management circuit 10 in the power supply device shown has added dummy load 30 resistors R21, R22, R23 and R24, and the resistance value of each dummy load 30 resistor is 4.7 kΩ, the effect on the ripple is not obvious. If the resistance value of the dummy load 30 resistor is further reduced, it will cause waste of power supply energy and cause serious heating of the whole machine, which cannot meet the safety regulations and standby energy efficiency requirements.

[0060] In response to the above problems, Figure 4 As shown, the power management circuit 10 provided in the embodiment of the present application also includes a third voltage dividing unit 105, a fourth voltage dividing unit 106 and a second switch unit 107. The second switch unit 107 is electrically connected to the first voltage dividing unit 101, the second voltage dividing unit 102, the third voltage dividing unit 105, the fourth voltage dividing unit 106, the first switch unit 103 and the output end of the voltage conversion module 20, respectively, and the fourth voltage dividing unit 106 is electrically connected to the third voltage dividing unit 105 and the load 30, respectively.

[0061] Specifically, when the resistance of the load 30 is greater than or equal to the third preset resistance and the resistance of the load 30 is less than the fourth preset resistance, that is, the power management circuit 10 is connected to a heavy load or a full load, the third voltage divider unit 105 can convert the first output voltage into a second voltage, and transmit the second voltage to the fourth voltage divider unit 106 and the second switch unit 107 respectively. The fourth voltage divider unit 106 converts the second voltage and converts the second voltage into a voltage required by the load 30 so as to supply power to the load 30. The second switch unit 107 is turned on according to the second voltage and outputs the second output voltage to the first switch unit 103. The first switch unit 103 is turned off according to the second output voltage, so that the connection between the resistor unit 104 and the output end of the voltage conversion module 20 is disconnected. It can be seen that the power management circuit 10 provided in the embodiment of the present application, when connected to a heavy load or a full load, connects the first end and the second end of the first voltage divider unit 101 through the conduction of the second unit, that is, the first voltage divider unit 101 is short-circuited. At this time, the voltage difference between the base and the emitter of the first transistor VT1 in the first switch unit 103 is less than the turn-on voltage, so that the first transistor VT1 is disconnected, thereby disconnecting the resistance unit 104 from the output end of the voltage conversion module 20. The power supply device does not need to supply power to the dummy load 30, but is only used to supply power to the load 30, which will not cause excessive energy waste, save energy consumption and reduce the temperature of the whole machine.

[0062] It should be noted that the fourth preset resistance value may be equal to the first preset resistance value.

[0063] In one embodiment of the present application, Figure 3 As shown, the third voltage dividing unit 105 includes a sixth resistor R6, a first end of the sixth resistor R6 is electrically connected to the second switch unit 107 and the output end of the voltage conversion module 20, and a second end of the sixth resistor R6 is electrically connected to the fourth voltage dividing unit 106 and the second switch unit 107.

[0064] Specifically, the sixth resistor R6 is connected in series between the output end of the voltage conversion module 20 and the fourth voltage dividing unit 106, and the sixth resistor R6 and the fourth voltage dividing unit 106 are both connected in series between the output end of the voltage conversion module 20 and the load 30. Therefore, the sixth resistor R6 and the fourth voltage dividing unit 106 are both used for voltage division, and the voltage (second voltage) at the second end of the sixth resistor R6 is equal to the first output voltage minus the voltage drop of the sixth resistor R6.

[0065] For example, the designer may set the resistance value of the sixth resistor R6 according to actual conditions. For example, the resistance value of the first resistor R1 may be set to 100 kΩ.

[0066] In one embodiment of the present application, Figure 3As shown, the fourth voltage dividing unit 106 includes a seventh resistor R7 , a first end of the seventh resistor R7 is electrically connected to the third voltage dividing unit 105 and the second switch unit 107 , and a second end of the seventh resistor R7 is electrically connected to the load 30 .

[0067] Specifically, the seventh resistor R7 is connected in series between the sixth resistor R6 and the load 30, and the sixth resistor R6 and the seventh resistor R7 are both connected in series between the output end of the voltage conversion module 20 and the load 30. Therefore, the seventh resistor R7 and the sixth resistor R6 have the same function and are also used for voltage division, the voltage (the second voltage) of the first end of the seventh resistor R7 is equal to the voltage of the second end of the sixth resistor R6, and the voltage (the voltage required by the load 30) of the second end of the seventh resistor R7 is equal to the difference obtained by subtracting the second voltage from the first output voltage minus the voltage drop of the seventh resistor R7.

[0068] Exemplarily, the designer may set the resistance value of the seventh resistor R7 according to actual conditions. For example, the resistance value of the seventh resistor R7 may be set to 100 kΩ.

[0069] In one embodiment of the present application, Figure 3 As shown, the second switch unit 107 includes a first switch tube Q1, the gate of the first switch tube Q1 is electrically connected to the third voltage dividing unit 105 and the fourth voltage dividing unit 106 respectively, the source of the first switch tube Q1 is electrically connected to the third voltage dividing unit 105 and the output end of the voltage conversion module 20 respectively, and the drain of the first switch tube Q1 is electrically connected to the first voltage dividing unit 101, the second voltage dividing unit 102 and the first switch unit 103 respectively.

[0070] Specifically, the first switch tube Q1, as a switch device, can be turned on or off according to the difference between the gate voltage and the source voltage of the first switch tube Q1. When the resistance of the load 30 is greater than or equal to the third preset resistance and the resistance of the load 30 is less than the fourth preset resistance, that is, when the load 30 is connected to a heavy load or a full load, the current flowing through the sixth resistor R6 will generate a voltage drop. The voltage drop of the sixth resistor R6 reaches the turn-on voltage of the first switch tube Q1, so that the first switch tube Q1 is turned on, and the first end and the second end of the first voltage divider unit 101 are connected, that is, the first voltage divider unit 101 is short-circuited. At this time, the voltage difference between the base and the emitter of the first transistor VT1 is less than the turn-on voltage, so that the first transistor VT1 is disconnected, so that the resistor unit 104 is disconnected from the output end of the voltage conversion module 20, and the power supply device does not need to supply power to the dummy load 30, but is only used to supply power to the load 30, which will not cause excessive energy waste, save energy consumption and reduce the temperature of the whole machine.

[0071] It should be noted that, if the power management circuit 10 is connected to a light load or no load, the first switch tube Q1 is in a cut-off state, and the first end and the second end of the first voltage divider unit 101 are disconnected.

[0072] For example, the designer may set the type and model of the first switch tube Q1 according to actual conditions. For example, the type of the first switch tube Q1 may be set to a P-type MOS tube, and the model of the first switch tube Q1 may be set to PMXB75UPE.

[0073] In one embodiment of the present application, Figure 3 As shown, the power management circuit 10 also includes a first filtering unit 108 and a second filtering unit 109. The first filtering unit 108 is electrically connected to the output end of the voltage conversion module 20, and the second filtering unit 109 is electrically connected to the second voltage dividing unit 102, the fourth voltage dividing unit 106 and the load 30 respectively.

[0074] Specifically, the first filter unit 108 is used to filter out the high-frequency noise signal in the first output voltage outputted from the output end of the voltage conversion module 20, so as to make the first output voltage more stable. The second filter unit 109 is used to smooth the voltage waveform required by the load 30, reduce the voltage ripple, and provide a more stable voltage for the load 30.

[0075] In one embodiment of the present application, Figure 3 As shown, the first filtering unit 108 includes a first capacitor C1 and a second capacitor C2, the first end of the first capacitor C1 and the first end of the second capacitor C2 are both electrically connected to the output end of the voltage conversion module 20, and the second end of the first capacitor C1 and the second end of the second capacitor C2 are both grounded.

[0076] Specifically, the first capacitor C1 and the second capacitor C2 are both used to filter out high-frequency noise signals in the first output voltage outputted from the output end of the voltage conversion module 20 , so as to make the first output voltage more stable.

[0077] For example, the designer may set the capacitance value of the first capacitor C1 and the capacitance value of the second capacitor C2 according to actual conditions. For example, the capacitance value of the first capacitor C1 may be set to 10uF, and the capacitance value of the second capacitor C2 may be set to 0.1uF.

[0078] In one embodiment of the present application, Figure 3 As shown, the second filtering unit 109 includes a third capacitor C3 and a fourth capacitor C4, a first end of the third capacitor C3 and a first end of the fourth capacitor C4 are electrically connected to the second voltage dividing unit 102, and a second end of the third capacitor C3 and a second end of the fourth capacitor C4 are grounded.

[0079] Specifically, the third capacitor C3 and the fourth capacitor C4 are both used to smooth the voltage waveform required by the load 30 , reduce the voltage ripple, and provide a more stable voltage for the load 30 .

[0080] Exemplarily, the designer may set the capacitance value of the third capacitor C3 and the capacitance value of the fourth capacitor C4 according to actual conditions. For example, the capacitance value of the third capacitor C3 may be set to 10uF, and the capacitance value of the fourth capacitor C4 may be set to 0.1uF.

[0081] In one embodiment of the present application, Figure 3 As shown, the power management circuit 10 further includes an eighth resistor R8, a first end of the eighth resistor R8 is used to be electrically connected to the output end of the voltage conversion module 20, and a second end of the eighth resistor R8 is grounded.

[0082] Specifically, the eighth resistor R8 is connected between the output terminal of the voltage conversion module 20 and the ground, and is used to limit the current between the output terminal of the voltage conversion module 20 and the ground, so as to protect the power management circuit 10 from being damaged by excessive current in the case of overload or short circuit. At the same time, the eighth resistor R8 also provides a safe grounding path to protect personal safety.

[0083] Exemplarily, the designer may set the resistance value of the eighth resistor R8 according to actual conditions. For example, the resistance value of the eighth resistor R8 may be set to 1 kΩ.

[0084] It should be noted that if Figure 3 As shown, the load 30 includes a tenth resistor R10 with an adjustable resistance and a ninth resistor R9 with a fixed resistance. The adjustable range of the resistance of the tenth resistor R10 is set to 0-200Ω, and the fixed resistance of the ninth resistor R9 is set to 75Ω. If the resistance of the tenth resistor R10 is 0, that is, the total resistance of the load 30 is 75Ω, combined with the resistance values ​​of the above resistors, it can be calculated that the current flowing into the load 30 is approximately 240mA, and at this time, the power management circuit 10 can be connected to more loads 30 or full load. If the resistance of the tenth resistor R10 is adjusted to a certain value, the power management circuit 10 can be connected to a light load. If the resistance of the tenth resistor R10 is 200Ω, that is, the total resistance of the load 30 is 275Ω, combined with the resistance values ​​of the above resistors, it can be calculated that the current flowing into the load 30 is approximately 65mA, and at this time, the power management circuit 10 can be connected to no load.

[0085] It should be noted that if Figure 5 As shown, similar to the circuit connection diagram of the existing power supply device, the power management circuit 10 provided in the embodiment of the present application also requires four groups.

[0086] It should be noted that if Figure 6As shown, taking one of the power management circuits 10 as an example, a voltage and current monitoring device XWM1 and a four-channel oscilloscope XSC1 are added, wherein the voltage and current monitoring device XWM1 is used to monitor the current parameters and voltage parameters in the power management circuit 10, and the four-channel oscilloscope XSC1 is used to monitor the voltage waveforms at the four points A, B, C and D. As the total resistance of the load 30 changes, the voltage waveforms at the four points A, B, C and D are monitored as shown in FIG. Figure 7 shown.

[0087] The T0-T1 time period is when the power management circuit 10 is connected to no-load, that is, the resistance of the tenth resistor R10 is 200Ω, the total resistance of the load 30 is 275Ω, and the first switch unit 103 and the second switch unit 107 are both in the disconnected state. Since no ripple is required when connected to no-load, the power management circuit 10 is in the standby low power consumption mode, and the voltage change trends of the three points A, B and C in the power management circuit 10 are basically the same.

[0088] The time period T1-T2 is when the power management circuit 10 is connected to a light load, that is, the resistance of the tenth resistor R10 is less than 200Ω, the total resistance of the load 30 is less than 275Ω, the first switch unit 103 is in an on state, and the second switch unit 107 is in an off state. At this time, the resistor unit 104 is electrically connected to the output end of the voltage conversion module 20, the voltage at point D rises, and the voltage at points A, B, and C decreases to a certain extent due to the connection of the light load, and the change trends are basically the same.

[0089] During the time period T1-T2, the power management circuit 10 is connected to a large number of loads 30, that is, the resistance of the tenth resistor R10 is 0, the total resistance of the load 30 is 75Ω, the voltage at point B drops, and the second switch unit 107 is turned on, thereby increasing the voltage at point A. Since the resistance of the fourth resistor R4 is extremely small compared to the third resistor R3, the voltage change trend at point C is basically consistent with that at point A, the first switch unit 103 is disconnected, the resistor unit 104 is disconnected from the output end of the voltage conversion module 20, and the voltage at point D drops.

[0090] The time period T2-T4 is when the power management circuit 10 is connected to more loads 30 until it is fully loaded, the first switch unit 103 remains in the off state, the second switch unit 107 remains in the on state, and the voltages at points A, B, C and D remain unchanged.

[0091] like Figure 8 As shown, the present application also discloses a power supply device, including a voltage conversion module 20 and a plurality of the above-mentioned power management circuits 10, wherein the plurality of power management circuits 10 are electrically connected to the plurality of output terminals of the voltage conversion module 20. The power supply device adopts the above-mentioned power management circuit 10, which can effectively avoid the problem of large output voltage ripple when connected to a light load, and at the same time will not cause excessive energy waste, saving energy consumption while reducing the temperature of the whole machine.

[0092] Since the processing and functions implemented by the power supply device in this embodiment basically correspond to the embodiments, principles and examples of the aforementioned power management circuit, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0093] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A power management circuit, characterized in that: It includes a first voltage dividing unit, a second voltage dividing unit, a first switch unit and a resistance unit; the first voltage dividing unit is electrically connected to the second voltage dividing unit, the first switch unit and the output end of the voltage conversion module respectively, the first switch unit is grounded through the resistance unit, and the second voltage dividing unit is used to be electrically connected to a load; When the resistance of the load is greater than or equal to the first preset resistance and the resistance of the load is less than the second preset resistance, the first voltage divider unit is used to convert the first output voltage of the output end of the voltage conversion module into a first voltage, and transmit the first voltage to the second voltage divider unit and the first switch unit respectively, the second voltage divider unit is used to convert the first voltage into the voltage required by the load, and the first switch unit is used to be turned on according to the first voltage to connect the resistance unit to the output end of the voltage conversion module.

2. The power management circuit according to claim 1, characterized in that: The first voltage dividing unit includes a first resistor, a first end of the first resistor is electrically connected to the output end of the voltage conversion module and the first switch unit respectively, and a second end of the first resistor is electrically connected to the first switch unit and the second voltage dividing unit respectively.

3. The power management circuit according to claim 1, characterized in that: The second voltage dividing unit includes a second resistor, a first end of the second resistor is electrically connected to the first switch unit and the first voltage dividing unit respectively, and a second end of the second resistor is used to be electrically connected to the load.

4. The power management circuit according to claim 1, characterized in that: The first switch unit includes a first transistor, the base of the first transistor is electrically connected to the first voltage dividing unit and the second voltage dividing unit respectively, the collector of the first transistor is electrically connected to the resistance unit, and the emitter of the first transistor is used to be electrically connected to the output end of the voltage conversion module.

5. The power management circuit according to claim 4, characterized in that: The first switching unit also includes a third resistor and a fourth resistor, the first end of the third resistor is electrically connected to the emitter of the first transistor and the output end of the voltage conversion module, the second end of the third resistor is electrically connected to the first end of the fourth resistor and the base of the first transistor, and the second end of the fourth resistor is electrically connected to the first voltage divider unit and the second voltage divider unit.

6. The power management circuit according to claim 1, characterized in that: The resistance unit includes a fifth resistor, a first end of the fifth resistor is electrically connected to the first switch unit, and a second end of the fifth resistor is grounded.

7. The power management circuit according to any one of claims 1 to 6, characterized in that: The power management circuit further includes a third voltage dividing unit, a fourth voltage dividing unit and a second switch unit, wherein the second switch unit is electrically connected to the first voltage dividing unit, the second voltage dividing unit, the third voltage dividing unit, the fourth voltage dividing unit, the first switch unit and the output end of the voltage conversion module respectively, and the fourth voltage dividing unit is electrically connected to the third voltage dividing unit and the load respectively; When the resistance of the load is greater than or equal to the third preset resistance and the resistance of the load is less than the fourth preset resistance, the third voltage divider unit is used to convert the first output voltage into a second voltage, and transmit the second voltage to the fourth voltage divider unit and the second switch unit respectively, the fourth voltage divider unit is used to convert the second voltage into the voltage required by the load, the second switch unit is used to be turned on according to the second voltage, and output the second output voltage to the first switch unit, and the first switch unit is used to be turned off according to the second output voltage, so that the resistance unit is disconnected from the output end of the voltage conversion module.

8. The power management circuit according to claim 7, characterized in that: The third voltage-dividing unit includes a sixth resistor, a first end of the sixth resistor is electrically connected to the second switch unit and the output end of the voltage conversion module respectively, and a second end of the sixth resistor is electrically connected to the fourth voltage-dividing unit and the second switch unit respectively.

9. The power management circuit according to claim 7, characterized in that: The fourth voltage dividing unit includes a seventh resistor, a first end of the seventh resistor is electrically connected to the third voltage dividing unit and the second switch unit respectively, and a second end of the seventh resistor is used to be electrically connected to the load.

10. The power management circuit according to claim 7, characterized in that: The second switch unit includes a first switch tube, a gate of the first switch tube is electrically connected to the third voltage divider unit and the fourth voltage divider unit respectively, a source of the first switch tube is electrically connected to the third voltage divider unit and the output end of the voltage conversion module respectively, and a drain of the first switch tube is electrically connected to the first voltage divider unit, the second voltage divider unit and the first switch unit respectively.

11. A power supply device, characterized in that: It comprises a voltage conversion module and a plurality of power management circuits according to any one of claims 1 to 10, wherein the plurality of power management circuits are electrically connected to a plurality of output terminals of the voltage conversion module accordingly.

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