Power supply circuit and powered device

Abstract

The application discloses a power supply circuit and a power consumption device. The power supply circuit is connected between an input power supply and a capacitive load. The power supply circuit comprises a current sampling branch, a first switch branch, a second switch branch and a controller. The input power supply, the current sampling branch, the first switch branch, the second switch branch and the capacitive load are connected in series. The first switch branch is further connected with the current sampling branch and the controller. The current sampling branch is configured to generate a sampling voltage based on the current flowing through the capacitive load. The second switch branch is configured to be turned on or turned off. The first switch branch is configured to be turned off when the sampling voltage is greater than a first voltage threshold, so as to discharge the capacitive load. The first switch branch is further configured to be turned on in response to a control signal output by the controller when the sampling voltage is less than or equal to the first voltage threshold, so as to charge the capacitive load by the input power supply when the second switch branch is turned on. In this way, the inrush current can be reduced, and the risk of device damage can be reduced.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of electronic circuit, in particular to a power supply circuit and a power consuming device. BACKGROUND

[0002] In some power consuming devices, such as frequency converters, a large-capacity electrolytic capacitor needs to be connected to play a role of energy storage and voltage stabilization. In the working process of the power consuming device, after disconnecting and reconnecting the connection between the input power supply and the electrolytic capacitor (this action is referred to as hot plug), the electrolytic capacitor will quickly discharge and charge, and then a large inrush current is generated, and the risk of damage to the devices in the power consuming device is high. CONTENT OF THE UTILITY MODEL

[0003] Embodiments of the present application provide a power supply circuit and a power consuming device, which can reduce the inrush current and reduce the risk of damage to the devices.

[0004] In a first aspect, embodiments of the present application provide a power supply circuit connected between an input power supply and a capacitive load, the power supply circuit comprising a current sampling branch, a first switch branch, a second switch branch and a controller; the input power supply, the current sampling branch, the first switch branch, the second switch branch and the capacitive load are connected in series; the first switch branch is further connected with the current sampling branch and the controller; the current sampling branch is configured to generate a sampling voltage based on a current flowing through the capacitive load; the second switch branch is configured to be turned on or turned off; the first switch branch is configured to be turned off when the sampling voltage is greater than a first voltage threshold, so as to discharge the capacitive load; the first switch branch is further configured to be turned on in response to a control signal output by the controller when the sampling voltage is less than or equal to the first voltage threshold, so as to charge the capacitive load by the input power supply when the second switch branch is turned on.

[0005] In one or more embodiments, the first switch branch comprises a first switch module and a second switch module; the first switch module is connected with the current sampling branch, and the second switch module is connected with the first switch module and the controller, and is connected between the current sampling branch and the second switch branch; the first switch module is configured to be turned on when the sampling voltage is greater than the first voltage threshold, and to be turned off when the sampling voltage is less than or equal to the first voltage threshold; the second switch module is configured to be turned off when the first switch module is turned on, and to be turned on in response to the control signal when the first switch module is turned off, so as to charge the capacitive load by the input power supply when the second switch branch is turned on.

[0006] In one or more embodiments, the first switching module includes a first switching unit and a second switching unit; the first switching unit is connected to an input power supply, a current sampling branch, and a second switching unit, respectively, and the second switching unit is connected to a second switching module; the first switching unit is configured to turn on when the sampled voltage is greater than a first voltage threshold to establish a connection between the input power supply and the second switching unit, and to turn off when the sampled voltage is less than or equal to the first voltage threshold to disconnect the connection between the input power supply and the second switching unit; the second switching unit is configured to turn on when it is connected to the input power supply and turn off when it is not connected to the input power supply, wherein the turning on of the second switching unit corresponds to the turning on of the first switching module, and the turning off of the second switching unit corresponds to the turning off of the first switching module.

[0007] In one or more embodiments, the first switching unit includes a first resistor and a first switching transistor; the first end of the first resistor is connected to the second end of the current sampling branch and the second switching module respectively, the second end of the first resistor is connected to the control terminal of the first switching transistor, the first end of the first switching transistor is connected to the first end of the current sampling branch and the input power supply respectively, and the second end of the first switching transistor is connected to the second switching unit.

[0008] In one or more embodiments, the second switching unit includes a second resistor and a second switching transistor; the first end of the second resistor is connected to the first switching unit, the second end of the second resistor is connected to the control terminal of the second switching transistor, the first end of the second switching transistor is grounded, and the second end of the second switching transistor is connected to the second switching module.

[0009] In one or more embodiments, the second switching module includes a third switching unit and a fourth switching unit; the third switching unit is connected to the first switching module, the controller, and the fourth switching unit, respectively, and the fourth switching unit is connected between the current sampling branch and the second switching branch; the third switching unit is configured to turn off when the first switching module is turned on, and to turn on in response to a control signal when the first switching module is turned off; the fourth switching unit is configured to turn off when the third switching unit is turned off to discharge the capacitive load, and to turn on when the third switching unit is turned on to charge the capacitive load with the input power supply when the second switching branch is turned on.

[0010] In one or more embodiments, the third switching unit includes a third resistor, a fourth resistor, and a third switching transistor; the first end of the third resistor is connected to the controller, the second end of the third resistor is connected to the first end of the fourth resistor, the first switching module, and the control terminal of the third switching transistor, respectively, the second end of the fourth resistor and the first end of the third switching transistor are both grounded, and the second end of the third switching transistor is connected to the fourth switching unit.

[0011] In one or more embodiments, the fourth switching unit includes a fifth resistor, a sixth resistor, a first capacitor, and a fourth switching transistor; the first end of the fifth resistor is connected to the third switching unit, the second end of the fifth resistor is connected to the first end of the sixth resistor, the first end of the first capacitor, and the control end of the fourth switching transistor, the second end of the sixth resistor is connected to the current sampling branch, the second end of the first capacitor, and the first end of the fourth switching transistor, and the second end of the fourth switching transistor is connected to the second switching branch.

[0012] In one or more embodiments, the current sampling branch includes a sampling resistor; the first end of the sampling resistor is connected to the input power supply and the first switching branch respectively, and the second end of the sampling resistor is connected to the second switching branch through the first switching branch.

[0013] Secondly, embodiments of this application provide an electrical device, including a capacitive load and a power supply circuit as described above; the power supply circuit is connected between the input power supply and the capacitive load.

[0014] The beneficial effects of this application are as follows: The power supply circuit of this embodiment is connected between the input power supply and the capacitive load. The power supply circuit includes a current sampling branch, a first switching branch, a second switching branch, and a controller. The input power supply, the current sampling branch, the first switching branch, the second switching branch, and the capacitive load are connected in series in sequence. The first switching branch is also connected to the current sampling branch and the controller. The current sampling branch generates a sampling voltage based on the current flowing through the capacitive load. When the power supply circuit is started, if the sampling voltage is less than or equal to a first voltage threshold, the controller outputs a control signal to turn on the first switching branch. At the same time, the second switching branch also turns on, and the input power supply supplies power to the capacitive load through the current sampling branch, the first switching branch, and the second switching branch. In this case, if the second switching branch is turned off and then on again, it corresponds to hot-swapping operation. At this time, when the second switch branch is turned on, the capacitive load will be charged quickly, resulting in a large inrush current. This current flows through the current sampling branch, causing the sampling voltage to be greater than the first voltage threshold, and the first switch branch is turned off. After that, the sampling voltage is lower than the first voltage threshold again, and the first switch branch is turned on. Then, if the inrush current is still large, the sampling voltage will be greater than the first voltage threshold, and the first switch branch will be turned off. ... The above process is repeated continuously, eventually limiting the inrush current to a small range, thereby achieving the purpose of reducing the inrush current and helping to reduce the risk of device damage. Attached Figure Description

[0015] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are not intended to limit the embodiments, and elements having the same reference numerals in the drawings are designated as similar elements.

[0016] Figure 1This is a schematic diagram of the power supply circuit provided in the embodiments of this application. Figure 1 ; Figure 2 This is a schematic diagram of the power supply circuit provided in the embodiments of this application. Figure 2 ; Figure 3 This is a schematic diagram of the power supply circuit provided in the embodiments of this application. Figure 3 ; Figure 4 This is a schematic diagram of the power supply circuit provided in the embodiments of this application. Figure 4 ; Figure 5 This is a schematic diagram of the power supply circuit provided in the embodiments of this application. Figure 5 ; Figure 6 This is a schematic diagram of the power supply circuit provided in the embodiments of this application. Figure 6 . Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0018] It should be noted that when an element is described as "connected" to another element, it can be directly connected to the other element, or there can be one or more intermediate elements between them.

[0019] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0020] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a power supply circuit provided in an embodiment of this application. Figure 1 As shown, the power supply circuit 100 is connected between the input power supply 200 and the capacitive load 300. The power supply circuit 100 includes a current sampling branch 10, a first switching branch 20, a second switching branch 30, and a controller 40. The input power supply 200, the current sampling branch 10, the first switching branch 20, the second switching branch 30, and the capacitive load 300 are connected in series. The first switching branch 20 is also connected to the current sampling branch 10 and the controller 40.

[0021] Specifically, the current sampling branch 10 is configured to generate a sampling voltage based on the current flowing through the capacitive load 300. The second switching branch 30 is configured to be turned on or off. The first switching branch 20 is configured to be turned off when the sampling voltage is greater than a first voltage threshold, so as to discharge the capacitive load 300. The first switching branch 20 is also configured to be turned on in response to a control signal output by the controller 40 when the sampling voltage is less than or equal to the first voltage threshold, so as to charge the capacitive load 300 by the input power supply 200 when the second switching branch 30 is turned on. Herein, the first voltage threshold is a preset voltage value, which can be set based on the actual application scenario. This application embodiment does not impose specific limitations on this. However, it should be noted that when a hot-plugging operation occurs, it will cause the sampling voltage to exceed the first voltage threshold.

[0022] In practical applications, when the power supply circuit 100 starts, if the sampled voltage is less than or equal to the first voltage threshold, the controller 40 outputs a control signal to turn on the first switch branch 20. Simultaneously, the second switch branch 30 also turns on, and the input power supply 200 supplies power to the capacitive load 300 through the current sampling branch 10, the first switch branch 20, and the second switch branch 30. In this case, if the second switch branch 30 is turned off (understandably, after the second switch branch 30 is turned off, the capacitive load 300 will quickly discharge to the electrical load connected to it; for example, when the power supply circuit 100 is used in a frequency converter, the capacitive load 300 will quickly discharge to the motor connected to it), and then turned on again, it corresponds to hot-swapping operation. At this time, when the second switch branch 30 is turned on, the capacitive load 300 will be rapidly charged, resulting in a large inrush current. This current flows through the current sampling branch 10, causing the sampling voltage to be greater than the first voltage threshold. The first switch branch 20 is then turned off, breaking the charging circuit for the capacitive load 300, and the current drops to zero. When the sampling voltage is again less than the first voltage threshold, the first switch branch is turned on, and the charging circuit for the capacitive load 300 is reconnected. If the inrush current is still large enough to make the sampling voltage greater than the first voltage threshold, the first switch branch is turned off. This process is repeated continuously, ultimately limiting the inrush current to a small range, thereby reducing the inrush current and mitigating the risk of damage to components in the power supply circuit 100.

[0023] In some embodiments, such as Figure 2 As shown, the first switch branch 20 includes a first switch module 21 and a second switch module 22. The first switch module 21 is connected to the current sampling branch 10, and the second switch module 22 is connected to the first switch module 21 and the controller 40, respectively, and is connected between the current sampling branch 10 and the second switch branch 30.

[0024] Specifically, the first switch module 21 is configured to turn on when the sampled voltage is greater than a first voltage threshold, and to turn off when the sampled voltage is less than or equal to the first voltage threshold. The second switch module 22 is configured to turn off when the first switch module 21 is turned on, and to turn on in response to a control signal when the first switch module 21 is turned off, so as to charge the capacitive load 300 by the input power supply 200 when the second switch branch 30 is turned on.

[0025] In practical applications, when the power supply circuit 100 is started, if the sampled voltage is less than or equal to the first voltage threshold, the first switch module 21 is turned off. At the same time, the controller 40 outputs a control signal to turn on the second switch module 22. Simultaneously, the second switch branch 30 is also turned on. The input power supply 200 supplies power to the capacitive load 300 through the current sampling branch 10, the second switch module 22, and the second switch branch 30. In this scenario, after hot-swapping, when the second switch branch 30 is turned on, the capacitive load 300 is rapidly charged, resulting in a large inrush current. This current flows through the current sampling branch 10, causing the sampling voltage to exceed the first voltage threshold. The first switch module 21 then turns on, causing the second switch module 22 to turn off, thus breaking the charging circuit for the capacitive load 300 and reducing the current to zero. When the sampling voltage falls below the first voltage threshold again, the first switch module 21 turns off. Simultaneously, because the controller 40 maintains its output control signal, the second switch module 22 turns on, reconnecting the charging circuit for the capacitive load 300. If the inrush current remains large enough to exceed the first voltage threshold, the first switch module 21 turns on, causing the second switch module 22 to turn off; and so on. This process is repeated continuously, ultimately limiting the inrush current to a small range, thereby reducing the inrush current and mitigating the risk of damage to components in the power supply circuit 100.

[0026] In some embodiments, such as Figure 3 As shown, the first switch module 21 includes a first switch unit 211 and a second switch unit 212. The first switch unit 211 is connected to the input power supply 200, the current sampling branch 10 and the second switch unit 212, respectively, and the second switch unit 212 is connected to the second switch module 22.

[0027] Specifically, the first switching unit 211 is configured to turn on when the sampled voltage is greater than a first voltage threshold to establish a connection between the input power supply 200 and the second switching unit 212, and to turn off when the sampled voltage is less than or equal to the first voltage threshold to disconnect the connection between the input power supply 200 and the second switching unit 212. The second switching unit 212 is configured to turn on when it is connected to the input power supply 200 and turn off when it is not connected to the input power supply 200, wherein the turning on of the second switching unit 212 corresponds to the turning on of the first switching module 21, and the turning off of the second switching unit 212 corresponds to the turning off of the first switching module 21.

[0028] In some embodiments, such as Figure 4 As shown, the second switch module 22 includes a third switch unit 221 and a fourth switch unit 222. The third switch unit 221 is connected to the first switch module 21, the controller 40 and the fourth switch unit 222 respectively, and the fourth switch unit 222 is connected between the current sampling branch 10 and the second switch branch 30.

[0029] Specifically, the third switching unit 221 is configured to turn off when the first switching module 21 is turned on, and to turn on in response to a control signal when the first switching module 21 is turned off. The fourth switching unit 222 is configured to turn off when the third switching unit 221 is turned off to discharge the capacitive load 300, and to turn on when the third switching unit 221 is turned on to charge the capacitive load 300 with the input power supply 200 when the second switching branch 30 is turned on.

[0030] In practical applications, when the power supply circuit 100 is started, if the sampled voltage is less than or equal to the first voltage threshold, the first switching unit 211 is turned off to disconnect the connection between the input power supply 200 and the second switching unit 212, and the second switching unit 212 is also turned off. Simultaneously, the controller 40 outputs a control signal to the third switching unit 221 to turn it on, and the fourth switching unit 222 also turns on along with the third switching unit 221. At the same time, the second switching branch 30 also turns on, and the input power supply 200 supplies power to the capacitive load 300 through the current sampling branch 10, the fourth switching unit 222, and the second switching branch 30. In this scenario, after the hot-plugging operation, when the second switching branch 30 is turned on, the capacitive load 300 is rapidly charged, resulting in a large inrush current. This current flows through the current sampling branch 10, causing the sampling voltage to exceed the first voltage threshold. The first switching unit 211 is then turned on to establish a connection between the input power supply 200 and the second switching unit 212. The second switching unit is turned on, causing the third switching unit 221 to turn off. The fourth switching unit 222 also turns off as the third switching unit 221 turns off, breaking the charging circuit for the capacitive load 300 and reducing the current to zero. The sampling voltage then falls below the first voltage threshold again, and the first switching unit... Unit 211 and the second switch unit 212 are both turned off. At the same time, since the controller 40 maintains the output control signal, the third switch unit 221 and the fourth switch unit 222 are both turned on, and the circuit for charging the capacitive load 300 is turned on. If the surge current is still large, so that the sampling voltage is greater than the first voltage threshold, the first switch unit 211 and the second switch unit 212 are both turned on, so that the third switch unit 221 and the fourth switch unit 222 are both turned off. ... The above process is repeated continuously, and finally the surge current is limited to a small range, thereby achieving the purpose of reducing the surge current and helping to reduce the risk of damage to the devices in the power supply circuit 100.

[0031] Please refer to Figure 5 , Figure 5 An exemplary circuit structure for a power supply circuit 100 is shown. For example... Figure 5 As shown, the first switching unit 10 includes a first resistor R1 and a first switching transistor Q1.

[0032] The first end of the first resistor R1 is connected to the second end of the current sampling branch 10 and the second switch module 22, respectively. The second end of the first resistor R1 is connected to the control terminal of the first switch transistor Q1. The first end of the first switch transistor Q1 is connected to the first end of the current sampling branch 10 and the input power supply 200, respectively. The second end of the first switch transistor Q1 is connected to the second switch unit 212.

[0033] In this embodiment, the first switching transistor Q1 is a PNP transistor. The base of the PNP transistor is the first terminal of the first switching transistor Q1, the emitter of the PNP transistor is the second terminal of the first switching transistor Q1, and the collector of the PNP transistor is the third terminal of the first switching transistor Q1.

[0034] In addition, the first switch Q1 can be any controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field-effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0035] In some embodiments, the second switching unit 212 includes a second resistor R2 and a second switching transistor Q2.

[0036] The first end of the second resistor R2 is connected to the first switch unit 211, the second end of the second resistor R2 is connected to the control terminal of the second switch transistor Q2, the first end of the second switch transistor Q2 is grounded to GND, and the second end of the second switch transistor Q2 is connected to the second switch module 22.

[0037] In this embodiment, the second switch Q2 is an NPN transistor. The base of the NPN transistor is the first terminal of the second switch Q2, the emitter of the NPN transistor is the second terminal of the second switch Q2, and the collector of the NPN transistor is the third terminal of the second switch Q2.

[0038] In addition, the second switch Q2 can be any controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field-effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0039] In some embodiments, the third switching unit 221 includes a third resistor R3, a fourth resistor R4, and a third switching transistor Q3.

[0040] The first end of the third resistor R3 is connected to the controller 40. The second end of the third resistor R3 is connected to the first end of the fourth resistor R4, the first switch module 21, and the control terminal of the third switch transistor Q3. The second end of the fourth resistor R4 and the first end of the third switch transistor Q3 are both grounded to GND. The second end of the third switch transistor Q3 is connected to the fourth switch unit 222.

[0041] In this embodiment, the third switch Q3 is an NPN transistor. The base of the NPN transistor is the first terminal of the third switch Q3, the emitter of the NPN transistor is the second terminal of the third switch Q3, and the collector of the NPN transistor is the third terminal of the third switch Q3.

[0042] In addition, the third switch Q3 can be any controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field-effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0043] In some embodiments, the fourth switching unit 222 includes a fifth resistor R5, a sixth resistor R6, a first capacitor C1, and a fourth switching transistor Q4.

[0044] The first end of the fifth resistor R5 is connected to the third switch unit 221. The second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6, the first end of the first capacitor C1, and the control terminal of the fourth switch Q4. The second end of the sixth resistor R6 is connected to the current sampling branch 10, the second end of the first capacitor C1, and the first end of the fourth switch Q4. The second end of the fourth switch Q4 is connected to the second switch branch 30.

[0045] When the third switch Q3 is turned on, the input power supply 200 charges the first capacitor C1 after being divided by the fifth resistor R5 and the sixth resistor R6, so as to form a soft-start circuit for the fourth switch Q4, so that the fourth switch Q4 is turned on slowly.

[0046] In this embodiment, the fourth switch Q4 is a PMOS transistor. The gate of the PMOS transistor is the first terminal of the fourth switch Q4, the source of the PMOS transistor is the second terminal of the fourth switch Q4, and the drain of the PMOS transistor is the third terminal of the fourth switch Q4.

[0047] In addition, the fourth switch Q4 can be any controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field-effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0048] In some embodiments, the current sampling branch 10 includes a sampling resistor RS1.

[0049] The first terminal of the sampling resistor RS1 is connected to the input power supply 200 and the first switch branch 20, respectively. The second terminal of the sampling resistor RS1 is connected to the second switch branch 30 through the first switch branch 20. When current flows through the sampling resistor RS1, the voltage across the sampling resistor RS1 is the sampling voltage in the above embodiment.

[0050] In some embodiments, the second switch branch 30 includes a button S1. The button S1 is connected between the fourth switch unit 222 and the capacitive load 300.

[0051] Specifically, when the current flowing through the sampling resistor RS1 increases, the voltage across RS1 (i.e., the sampling voltage) increases to a level greater than the turn-on threshold of the first switch Q1 (i.e., the first voltage threshold at this time is the turn-on threshold of the first switch Q1). The first switch Q1 turns on, and the input power supply 200 is input to the first terminal of the second switch Q2, causing the second switch Q2 to turn on. The first terminal of the third switch Q3 is grounded to GND through the second switch Q2. At this time, even if the controller 40 outputs a control signal, the third switch Q3 will remain off because it is grounded to GND through the second switch Q2. Consequently, the fourth switch Q4 also turns off, and the current flowing through the sampling resistor RS1 is reduced to zero.

[0052] After the fourth switch Q4 is turned off, the current flowing through the sampling resistor RS1 decreases, causing the voltage across the sampling resistor RS1 (i.e., the sampling voltage) to decrease to less than or equal to the conduction threshold of the first switch Q1. The first switch Q1 turns off, the connection between the second switch Q2 and the input power supply 200 is broken, and the second switch Q2 also turns off. A control signal (a high-level signal in this embodiment) is input to the first terminal of the third switch Q3, and the third switch Q3 turns on. Subsequently, the fifth resistor R5, the sixth resistor R6, and the first capacitor C1 form a soft-start circuit for the fourth switch Q4, allowing the fourth switch Q4 to start slowly.

[0053] Therefore, after a hot-swapping operation, when button S1 is opened and then closed again, the capacitive load 300 will be rapidly charged, generating a large inrush current. This current flows through the sampling resistor RS1, causing the sampling voltage to exceed the first voltage threshold. The first switch Q1 and the second switch Q2 will then conduct, causing the third switch Q3 and the fourth switch Q4 to turn off. The charging circuit for the capacitive load 300 is broken, and the current drops to zero. When the sampling voltage falls below the first voltage threshold again, the first switch Q1 and the second switch Q2 will turn off. Simultaneously, because the controller 40 maintains... When the output control signal is received, the third switch Q3 and the fourth switch Q4 are turned on, and the circuit for charging the capacitive load 300 is opened, increasing the current flowing through the sampling resistor RS1. If the surge current is still large, so that the sampling voltage is greater than the first voltage threshold, the first switch Q1 and the second switch Q2 are turned on, causing the third switch Q3 and the fourth switch Q4 to turn off; ...; the above process is repeated continuously, eventually limiting the surge current to a small range, thereby achieving the purpose of reducing the surge current and helping to reduce the risk of damage to the devices in the power supply circuit 100.

[0054] Secondly, limiting the surge current to a smaller range can reduce the stress on the fourth switch Q4 to some extent, thereby reducing the risk of damage to Q4. Furthermore, by limiting the surge current to a smaller range, a MOSFET with a lower rated current parameter can be selected for the fourth switch Q4, thus reducing costs.

[0055] It should be noted that, as Figure 5 The hardware structure of the power supply circuit 100 shown is only an example, and the power supply circuit 100 may have more or fewer components than those shown in the figure, may combine two or more components, or may have different component configurations. The various components shown in the figure may be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and / or application-specific integrated circuits.

[0056] For example, the power supply circuit 100 can also be applied in scenarios with multiple capacitive loads 300. In this case, the power supply circuit 100 needs to add a second switching branch 30 accordingly, that is, a one-to-one correspondence between the capacitive load 300 and the second switching branch 30. For example... Figure 6 As shown, the power supply circuit 100 is used in an application scenario with two capacitive loads 300. In this case, the power supply circuit 100 needs to include two second switching branches 30.

[0057] This application also provides an electrical device, which includes a capacitive load and a power supply circuit 100 as described in any embodiment of this application. The power supply circuit 100 is connected between the input power supply 200 and the capacitive load 300.

[0058] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

[0059] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A power supply circuit, characterized by comprising: Connected between the input power supply and the capacitive load, the power supply circuit includes a current sampling branch, a first switching branch, a second switching branch, and a controller; The input power supply, the current sampling branch, the first switch branch, the second switch branch, and the capacitive load are connected in series in sequence. The first switch branch is also connected to the current sampling branch and the controller. The current sampling branch is configured to generate a sampling voltage based on the current flowing through the capacitive load; The second switch branch is configured to be on or off; The first switch branch is configured to turn off when the sampled voltage is greater than a first voltage threshold, so as to discharge the capacitive load; The first switch branch is also configured to turn on in response to a control signal output by the controller when the sampled voltage is less than or equal to the first voltage threshold, so as to charge the capacitive load with the input power supply when the second switch branch is turned on.

2. The power supply circuit according to claim 1, characterized in that, The first switch branch includes a first switch module and a second switch module; The first switch module is connected to the current sampling branch, and the second switch module is connected to both the first switch module and the controller, and is connected between the current sampling branch and the second switch branch. The first switching module is configured to turn on when the sampled voltage is greater than a first voltage threshold, and to turn off when the sampled voltage is less than or equal to the first voltage threshold; The second switch module is configured to turn off when the first switch module is turned on, and to turn on in response to the control signal when the first switch module is turned off, so as to charge the capacitive load with the input power supply when the second switch branch is turned on.

3. The power supply circuit of claim 2, wherein, The first switch module includes a first switch unit and a second switch unit; The first switching unit is connected to the input power supply, the current sampling branch and the second switching unit respectively, and the second switching unit is connected to the second switching module; The first switching unit is configured to turn on when the sampled voltage is greater than a first voltage threshold to establish a connection between the input power supply and the second switching unit, and to turn off when the sampled voltage is less than or equal to the first voltage threshold to disconnect the connection between the input power supply and the second switching unit. The second switching unit is configured to be turned on when it is connected to the input power supply and turned off when it is not connected to the input power supply, wherein the second switching unit being turned on corresponds to the first switching module being turned on, and the second switching unit being turned off corresponds to the first switching module being turned off.

4. The power supply circuit according to claim 3, characterized in that, The first switching unit includes a first resistor and a first switching transistor; The first end of the first resistor is connected to the second end of the current sampling branch and the second switch module, the second end of the first resistor is connected to the control terminal of the first switch transistor, the first end of the first switch transistor is connected to the first end of the current sampling branch and the input power supply, and the second end of the first switch transistor is connected to the second switch unit.

5. The power supply circuit of claim 3, wherein, The second switching unit includes a second resistor and a second switching transistor; The first end of the second resistor is connected to the first switching unit, the second end of the second resistor is connected to the control terminal of the second switching transistor, the first end of the second switching transistor is grounded, and the second end of the second switching transistor is connected to the second switching module.

6. The power supply circuit of claim 2, wherein, The second switch module includes a third switch unit and a fourth switch unit; The third switch unit is connected to the first switch module, the controller and the fourth switch unit respectively, and the fourth switch unit is connected between the current sampling branch and the second switch branch; The third switching unit is configured to turn off when the first switching module is turned on, and to turn on in response to the control signal when the first switching module is turned off; The fourth switching unit is configured to turn off when the third switching unit is turned off to discharge the capacitive load, and to turn on when the third switching unit is turned on to charge the capacitive load with the input power supply when the second switching branch is turned on.

7. The power supply circuit of claim 6, wherein, The third switching unit includes a third resistor, a fourth resistor, and a third switching transistor; The first end of the third resistor is connected to the controller, and the second end of the third resistor is connected to the first end of the fourth resistor, the first switch module, and the control terminal of the third switch transistor. The second end of the fourth resistor and the first end of the third switch transistor are both grounded, and the second end of the third switch transistor is connected to the fourth switch unit.

8. The power supply circuit of claim 6, wherein, The fourth switching unit includes a fifth resistor, a sixth resistor, a first capacitor, and a fourth switching transistor; The first end of the fifth resistor is connected to the third switching unit. The second end of the fifth resistor is connected to the first end of the sixth resistor, the first end of the first capacitor, and the control terminal of the fourth switching transistor. The second end of the sixth resistor is connected to the current sampling branch, the second end of the first capacitor, and the first end of the fourth switching transistor. The second end of the fourth switching transistor is connected to the second switching branch.

9. The power supply circuit according to claim 1, characterized in that, The current sampling branch includes a sampling resistor; The first end of the sampling resistor is connected to the input power supply and the first switch branch respectively, and the second end of the sampling resistor is connected to the second switch branch through the first switch branch.

10. An electric device, characterized by Includes capacitive loads and power supply circuits as described in any one of claims 1-9; The power supply circuit is connected between the input power supply and the capacitive load.

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