Power supply circuit, circuit board and electronic equipment

Abstract

The invention discloses a power supply circuit, a circuit board and electronic equipment, and the circuit comprises a first power supply circuit which is connected with a first power supply, and when the first power supply circuit is switched on, the output voltage of the first power supply circuit is approximately equal to the output voltage of the first power supply; the second power supply circuit is connected with a second power supply, and when the second power supply circuit is switched on, the second power supply circuit adjusts the output voltage of the second power supply to preset voltage; and the control circuit is respectively connected with the first power supply circuit and the second power supply circuit, and the control circuit responds to the access condition of the first power supply and controls the on-off state of the second power supply circuit. According to the technical scheme provided by the invention, the dual power supplies can be automatically switched.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic circuits, in particular to a power supply circuit, a circuit board and an electronic device. BACKGROUND

[0002] During the development and debugging stage of a product, test equipment such as a debugging adapter board can help a technician to verify whether the function and performance of the product meet the expectations, and when the product malfunctions, the test equipment can help the technician to locate the source of the problem, so the test equipment is an indispensable part of ensuring the quality, performance and reliability of the product.

[0003] However, the existing test equipment usually only provides one power input port, so when testing some small power equipment, the technician needs to introduce an additional external power supply to power the equipment. This means that the technician often needs to carry a bunch of power cords and other equipment when performing testing work, which is very inconvenient to use. SUMMARY

[0004] The purpose of the present application is to provide a power supply circuit, a circuit board and an electronic device, which can automatically switch between dual power supplies.

[0005] To achieve the above purpose, the present application provides a power supply circuit in one aspect, comprising: a first power supply circuit connected with a first power supply, and when the first power supply circuit is turned on, the output voltage of the first power supply circuit is approximately equal to the output voltage of the first power supply; a second power supply circuit connected with a second power supply, and when the second power supply circuit is turned on, the second power supply circuit adjusts the output voltage of the second power supply to a preset voltage; a control circuit connected with the first power supply circuit and the second power supply circuit respectively, the control circuit controls the on-off state of the second power supply circuit in response to the access condition of the first power supply.

[0006] To achieve the above purpose, the present application further provides a circuit board in another aspect, comprising the power supply circuit as described above.

[0007] To achieve the above purpose, the present application further provides an electronic device in another aspect, comprising the power supply circuit as described above, and a circuit load connected with the voltage output end of the power supply circuit.

[0008] It can be seen that the technical scheme provided in the application, the power supply circuit includes a first power supply circuit and a second power supply circuit, the first power supply circuit is connected with a first power supply, and the second power supply circuit is connected with a second power supply, so that two external power supplies can be connected on one test equipment. Meanwhile, the control circuit is arranged between the first power supply circuit and the second power supply circuit, the control circuit can control the on-off state of the second power supply circuit according to the connection state of the first power supply. When the first power supply is connected to the first power supply circuit, the control circuit can automatically disconnect the second power supply circuit, so that the test equipment can be powered by the first power supply. When the first power supply is not connected to the first power supply circuit, the control circuit can keep the second power supply circuit in the on state, so that the test equipment can be powered by the second power supply. The technical scheme provided in the application can automatically switch between dual power supplies to adapt to different power consumption of external devices. BRIEF DESCRIPTION OF DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0010] Figure 1 is a structural schematic block diagram of the power supply circuit provided by an embodiment of the present application;

[0011] Figure 2 is a circuit diagram of the power supply circuit provided by an embodiment of the present application;

[0012] Figure 3 is a structural schematic diagram of the power supply circuit provided by an embodiment of the present application;

[0013] Figure 4 is a structural schematic diagram of the circuit board provided by an embodiment of the present application;

[0014] Figure 5 is a structural schematic diagram of the electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0015] In order to facilitate understanding of the present application, the present application will be described in more detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to illustrate and explain the embodiments of the present application, and are not used to limit the embodiments of the present application. The embodiments described in the present application are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0016] The following description refers to the accompanying drawings. Unless otherwise indicated, same or similar elements in different drawings are denoted with the same or similar reference numerals. In the description of the present application, the terms "first", "second", "third", etc. are used only to distinguish similar objects, and do not necessarily indicate a specific order or sequence, nor can they be understood as indicating or implying relative importance. The above terms can be understood according to the specific meaning in the present application by those of ordinary skill in the art. In addition, in the description of the present application, unless otherwise stated, when an element is described as "connected" to another element, it can be directly connected to the other element, or one or more intervening elements can be present. "Multiple" means two or more. "And / or" describes the relationship between the associated objects, indicating that there can be three relationships, for example, A and / or B can represent the three cases of A alone, A and B together, and B alone. The character " / " generally represents an "or" relationship between the associated objects.

[0017] During the development and debugging stage of a product, test equipment such as a debugging adapter can help technicians verify whether the functions and performance of the product meet expectations, and when the product fails, the test equipment can help technicians locate the source of the problem, so the test equipment is an indispensable part of ensuring product quality, performance and reliability.

[0018] However, the existing test equipment usually only provides one power input port, does not set up the remaining power input ports, and the power input port position is fixed and unchangeable, so when testing some small power devices, technicians need to introduce additional external power supplies to power the devices. This means that technicians often need to carry a bunch of power cords and other equipment when performing testing work, which is very inconvenient to use. At the same time, the power input port lacks a protection circuit or an indication status light, and the lack of a protection circuit can increase the risk of damage to the device, and the lack of an indication status light makes it impossible for technicians to intuitively understand the working state of the device. These problems make the existing test equipment inconvenient to use, reducing research and development efficiency and production efficiency.

[0019] Therefore, how to improve the power supply circuit of the test equipment so that it can flexibly switch between multiple power supplies according to the needs of different test scenarios has become a topic that needs to be addressed in the field.

[0020] The application provides a power supply circuit, a circuit board and an electronic device. The power supply circuit provides two power input ports, each of which can be connected to an external power supply. When the power supply circuit is connected to only one external power supply, it can directly use the external power supply to supply power externally. When the power supply circuit is connected to two external power supplies at the same time, it can perform dual protection and automatically switch between the two power supplies. The power supply circuit retains the external power supply port, can be compatible with high-power test scenarios, and the power driving is not limited. At the same time, the power supply circuit has an automatic power switching function, which can avoid danger caused by mixed use of multiple power supplies, and can preferentially select a high-power power supply to supply power externally in the case of sufficient power supply conditions.

[0021] Figure 1 The power supply circuit provided by an embodiment of the application has a structural schematic block diagram. The power supply circuit can be applied to test equipment such as an interface adapter board, an expansion dock, and a signal converter. Using the power supply circuit, the test equipment can supply power to any circuit module or device such as an audio and video device, a computer motherboard, a network device, and a control chip.

[0022] The power supply circuit includes a first power supply circuit 100, a second power supply circuit 200, and a control circuit 300. The first power supply circuit 100 has a power input port and can be connected to a first power supply. The second power supply circuit 200 also has a power input port and can be connected to a second power supply. The first power supply circuit 100 and the second power supply circuit 200 are connected and share a voltage output port VCC_OUT to simplify the structure of the test equipment. In actual application, the first power supply can be a 12V direct-current power supply, and the second power supply can be a USB power supply.

[0023] When the first power supply is connected to the first power supply circuit 100 and the first power supply circuit 100 is in a conduction state, the first power supply circuit 100 receives a voltage from the first power supply and outputs the voltage to other circuit parts. At the same time, the first power supply circuit 100 is configured such that the voltage output by the first power supply circuit 100 is very close to the voltage directly output by the first power supply, that is, the output voltage of the first power supply circuit 100 is approximately equal to the output voltage of the first power supply. Specifically, a low-resistance element can be used to configure the first power supply circuit 100.

[0024] When the second power supply is connected to the second power supply circuit 200 and the second power supply circuit 200 is in a conduction state, the second power supply circuit 200 receives a voltage from the second power supply and adjusts the output voltage of the second power supply to a preset voltage. Specifically, the second power supply circuit 200 can use a voltage converter to adjust the output voltage of the second power supply, or configure resistors, capacitors and other elements to adjust the output voltage of the second power supply.

[0025] The control circuit 300 is connected with the first power supply circuit 100 and the second power supply circuit 200 respectively. The control circuit 300 can monitor whether the first power supply circuit 100 is connected with the first power supply, and control the on-off state of the second power supply circuit 200 according to the connection of the first power supply. Specifically, no matter whether the second power supply is connected with the second power supply circuit 200, as long as the control circuit 300 monitors that the first power supply is connected with the first power supply circuit 100, the control circuit 300 will disconnect the second power supply circuit 200 to prevent the second power supply circuit 200 from supplying power to the outside by using the second power supply. At this time, if the operator turns on the first power supply circuit 100, the power supply circuit will supply power to the outside by using the first power supply.

[0026] When the control circuit 300 monitors that the first power supply is not connected with the first power supply circuit 100, the control circuit 300 will not interfere with the on-off state of the second power supply circuit 200. At this time, if the operator connects the second power supply with the second power supply circuit 200 and turns on the second power supply circuit 200, the power supply circuit will supply power to the outside by using the second power supply.

[0027] The power supply circuit can not only automatically switch between the first power supply and the second power supply by using the control circuit 300, but also realize the priority function, that is, in the case of sufficient power supply condition, the high-power power supply is preferentially selected to supply power to the outside.

[0028] In some embodiments, as shown in FIG. 1, the first power supply circuit 100 includes a first diode D1. Figure 3

[0029] The anode of the first diode D1 is connected with the first power supply, and the cathode of the first diode D1 is connected with the voltage output end of the second power supply circuit 200.

[0030] The first diode D1 limits the current flow direction in the first power supply circuit 100, and serves as an isolation protection function. When the second power supply circuit 200 is turned on, the first diode D1 can prevent the current in the second power supply circuit 200 from flowing from the voltage output end of the second power supply circuit 200 to the power input port of the first power supply circuit 100, so as to avoid the risk of electric shock caused by the operator accidentally touching the power input port of the first power supply circuit 100.

[0031] Further, the first power supply circuit 100 further includes a fuse R14, the first end of the fuse R14 is connected with the first power supply, the second end of the fuse R14 is connected with the anode of the first diode D1, and the voltage input end of the control circuit 300 is connected with the second end of the fuse R14. The fuse R14 can limit the current flowing through the first diode D1 to avoid damage to the first diode D1 caused by flowing through a large current.

[0032] ​Optionally, the fuse R14 can be a self-recovery fuse. When the current flowing through the fuse R14 is too large, causing the temperature of the fuse R14 to rise above a critical temperature value, the resistance value of the fuse R14 will rapidly increase, so that the current in the first power supply circuit 100 is very small, and the first power supply circuit 100 is similar to a circuit breaking state, to achieve the purpose of protecting the first diode D1. When the load of the first power supply circuit 100 returns to normal, the resistance of the fuse R14 will decrease below the normal value, and the first power supply circuit 100 returns to the conduction state.

[0033] In some embodiments, as shown in FIG. 3, the control circuit 300 includes a transistor Q2 and a field effect transistor Q1. Figure 3

[0034] The base of the transistor Q2 is connected to the anode of the first diode D1, the emitter of the transistor Q2 is connected to the gate of the field effect transistor Q1, and the collector of the transistor Q2 is grounded. The source of the field effect transistor Q1 is connected to the power input port of the second power supply circuit 200, and when the second power supply is connected to the second power supply circuit 200, the source of the field effect transistor Q1 will be connected to the second power supply. The drain of the field effect transistor Q1 is connected to the voltage regulating sub-circuit 210 in the second power supply circuit 200. When the base of the transistor Q2 has current entering, for example, when the first power supply is connected to the first power supply circuit 100, the transistor Q2 can control the field effect transistor Q1 to be turned off, thereby turning off the second power supply circuit 200.

[0035] In some embodiments, as shown in FIG. 3, the control circuit 300 further includes a current limiting resistor R19, a base resistor R21, and a source resistor R16. Figure 3

[0036] The first end of the current limiting resistor R19 is connected to the first power supply circuit 100, specifically, the first end of the current limiting resistor R19 can be connected between the second end of the fuse R14 and the anode of the first diode D1. The second end of the current limiting resistor R19 is connected to the base of the transistor Q2 and the first end of the base resistor R21, and the second end of the base resistor R21 is grounded. The first end of the source resistor R16 is connected to the source of the field effect transistor Q1, and the second end of the source resistor R16 is connected to the gate of the field effect transistor Q1.

[0037] The current limiting resistor R19 can limit the current flowing through the transistor Q2 to prevent the transistor Q2 from being damaged by overcurrent. The base resistor R21 can provide a voltage drop between the base of the transistor Q2 and the power supply, thereby providing a certain bias voltage for the base of the transistor Q2. The above bias voltage can help the transistor Q2 enter the saturation state, thereby realizing current amplification, so that the transistor Q2 can be turned on under a smaller input signal. At the same time, the base resistor R21 can also play a certain shunt role, preventing the base current of the transistor Q2 from being too large, to ensure the stability of the transistor Q2.​​

[0038] The source resistor R16 can provide a certain voltage drop for the source of the field effect transistor Q1, thereby helping to control the potential difference between the source of the field effect transistor Q1 and the ground, so that the field effect transistor Q1 can enter the saturation state faster, and ultimately achieve better conduction performance. At the same time, the source resistor R16 can also play a certain shunt role to prevent the source current of the field effect transistor Q1 from being too large, so as to ensure the stability of the field effect transistor Q1.

[0039] In some embodiments, as shown in FIG. 2, the voltage input end of the voltage regulating sub-circuit 210 is connected with the drain of the field effect transistor Q1, the voltage output end of the voltage regulating sub-circuit 210 is connected with the first power supply circuit 100, and the voltage regulating sub-circuit 210 adjusts the output voltage of the second power supply to a preset voltage. Figure 3

[0040] The voltage input end of the voltage regulating sub-circuit 210 receives the voltage from the drain of the field effect transistor Q1, then adjusts the above-mentioned voltage to a preset voltage, and outputs the above-mentioned preset voltage to other circuit parts by using the voltage output end port shared with the first power supply circuit 100.

[0041] The voltage regulating sub-circuit 210 includes a capacitor module, a boost module and a filter module.

[0042] The capacitor module includes a first capacitor C9, a second capacitor C10 and a third capacitor C10, the first capacitor C9, the second capacitor C10 and the third capacitor C11 are connected in parallel, the positive poles of the first capacitor C9, the second capacitor C10 and the third capacitor C11 are connected with the drain of the field effect transistor Q1, and the negative poles of the first capacitor C9, the second capacitor C10 and the third capacitor C11 are grounded. The first capacitor C9, the second capacitor C10 and the third capacitor C10 can store electric quantity, thereby improving the output current of the circuit.

[0043] ​The boost module includes a boost chip U2, a first resistor R18, a second resistor R17, a third resistor R20, a second diode D2, and an inductor L1. The first end of the first resistor R18 is connected to the positive pole of the third capacitor C11 and the input voltage pin IN of the boost chip U2, respectively, the second end of the first resistor R18 is connected to the enable pin EN of the boost chip U2, and the first resistor R18 can limit the current size to protect the boost chip U2 from excessive current. One end of the inductor L1 is connected to the positive pole of the third capacitor C11, and the other end of the inductor L1 is connected to the anode of the second diode D2 and the switch pin of the boost chip U2, respectively. The inductor L1 can store energy to stabilize the voltage in the boost module, and the second diode D2 can prevent current from flowing from the filter module to the inductor L1. The first end of the second resistor R17 is connected to the feedback pin FB of the boost chip U2, and the second end of the second resistor R17 is connected to the cathode of the second diode D2 and the filter module, respectively. The second resistor R17 can form a feedback network with the feedback pin FB to further adjust the accuracy and stability of the output voltage. One end of the third resistor R20 is connected to the feedback pin FB of the boost chip U2, and the other end of the third resistor R20 is grounded. The third resistor R20 can prevent signal reflection to make the signal transmission more stable and reliable.

[0044] The filter module includes a fourth capacitor C12, a fifth capacitor C13, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, and a ninth capacitor EA1, wherein the ninth capacitor EA1 is a solid-state electrolytic capacitor. The fourth capacitor C12, the fifth capacitor C13, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8, and the ninth capacitor EA1 are connected in parallel, and the positive poles of the fourth capacitor C12, the fifth capacitor C13, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8, and the ninth capacitor EA1 are connected to the cathode of the second diode D2 and the first power supply circuit 100, respectively, and the negative poles of the fourth capacitor C12, the fifth capacitor C13, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8, and the ninth capacitor EA1 are grounded. The fourth capacitor C12, the fifth capacitor C13, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8, and the ninth capacitor EA1 can filter the current output by the boost module to improve the stability of the current.

[0045] In some embodiments, as shown in FIG. 1A, Figure 3 The first power supply circuit 100 includes a switch SW5.

[0046] The switch SW5 controls the conduction or disconnection of the first power supply circuit 100, and the voltage output end of the second power supply circuit 200 is connected to the common end of the switch SW5. The voltage output port VCC_OUT shared by the first power supply circuit 100 and the second power supply circuit 200 can be arranged on the switching end side of the switch SW5.

[0047] In some embodiments, as shown in Figure 3 The power supply circuit further includes a first indication circuit, a second indication circuit, a third indication circuit and a fourth indication circuit.

[0048] The first indication circuit is connected between the second power supply and the control circuit 300, and indicates whether the second power supply circuit 200 is connected to the second power supply. The first indication circuit includes a first current-limiting resistor R9 and a light-emitting diode LED1, wherein one end of the first current-limiting resistor R9 is connected to the first end of the source resistor R16, the other end of the first current-limiting resistor R9 is connected to the anode of the light-emitting diode LED1, and the cathode of the light-emitting diode LED1 is grounded.

[0049] The second indication circuit is connected to the second power supply circuit 200 and is arranged after the control circuit 300, and indicates the on-off state of the second power supply circuit 200. The second indication circuit includes a second current-limiting resistor R11 and a light-emitting diode LED2, wherein one end of the second current-limiting resistor R11 is connected to the drain of the field effect transistor Q1, the other end of the second current-limiting resistor R11 is connected to the anode of the light-emitting diode LED2, and the cathode of the light-emitting diode LED2 is grounded.

[0050] The third indication circuit is connected to the first power supply circuit 100, and indicates whether the first power supply circuit 100 is connected to the first power supply. The third indication circuit includes a third current-limiting resistor R12 and a light-emitting diode LED3, wherein one end of the third current-limiting resistor R12 is connected to the first end of the fuse R14, the other end of the third current-limiting resistor R12 is connected to the anode of the light-emitting diode LED3, and the cathode of the light-emitting diode LED3 is grounded.

[0051] The fourth indication circuit is connected to the switching end of the switch SW5, and indicates whether there is a state of power supply by the first power supply circuit 100 or the second power supply circuit 200 after the switch SW5. The fourth indication circuit includes a fourth current-limiting resistor R8 and a light-emitting diode LED4, wherein one end of the fourth current-limiting resistor R8 is connected to the switching end of the switch SW5, the other end of the fourth current-limiting resistor R8 is connected to the anode of the light-emitting diode LED4, and the cathode of the light-emitting diode LED4 is grounded. When the first power supply circuit 100 is connected to the first power supply, or when the second power supply circuit 200 is connected to the second power supply, if the switch SW5 is turned on, the light-emitting diode LED4 will be lit. In other words, after the switch SW5 is turned on, no matter whether the power supply circuit supplies power to the outside through the first power supply circuit 100 or through the second power supply circuit 200, the light-emitting diode LED4 will be lit.

[0052] The working principle of the power supply circuit will be introduced below by taking a debugging tool integrated with the above power supply circuit as an example in a specific application scenario.

[0053] See also Figure 2 and Figure 3 ,This debugging tool contains two power input ports, namely power input port 1 and power input port 2. ,This debugging tool has multiple application scenarios.

[0054] Application scenario 1: The power input port 2 of the debugging tool is connected to the USB port of the computer, while the power input port 1 of the debugging tool is not connected to a power source.

[0055] When the debugging tool is plugged into a computer's USB port, indicator light 1 will light up, indicating that the USB port is powered normally. That is, power input port 2 is enabled, and the debugging tool can obtain normal power from the computer's USB port. At the same time, indicator light 2 will automatically light up, indicating that the debugging tool has automatically recognized that there is no external power supply at power input port 1 in the current state. The power supply circuit then automatically activates the internal boost module to provide power, converting the low voltage from the USB port into the higher voltage required for powering the external device. After that, just turn on the switch, and the debugging tool will power the external device and communicate.

[0056] In this scenario, when the debugging tool is plugged into the computer's USB port, it can identify the power input status and automatically start the boost module to provide the required power to the external device and communicate, thereby realizing power supply and communication functions.

[0057] Application scenario 2: First connect the power input port 1 of the debugging tool to an external power source, and then plug the power input port 2 into the USB port of the computer.

[0058] In this scenario, power input port 1 needs to be connected to an external power source. When the external power source is connected and ready, indicator light 3 will light up, indicating that the external power source is connected and available. Next, after plugging the debugging tool's power input port 2 into a computer's USB port, indicator light 1 will light up, indicating that the current USB port is powered normally and that power input port 2 is functioning properly. Then, simply turn on the power switch, and the debugging tool will automatically supply power to the external device through power input port 1 and communicate with it.

[0059] In this scenario, the debugging tool is first connected to an external power supply and then plugged into the USB port of the computer. The debugging tool can automatically select the external power supply to provide the required power to the external device.

[0060] Application scenario three: First, plug the power input port 2 of the debugging tool into the computer USB port, and then connect the power input port 1 to the external power supply.

[0061] When the debugging tool is plugged into the USB interface of the computer, the indicator light 1 is on, indicating that the power supply of the USB interface is normal. At the same time, the indicator light 2 is also automatically turned on, indicating that the power input port 1 is not connected to the external power supply in the current state, and the debugging tool has started the internal boost module to supply power. The debugging tool can obtain power from the USB interface of the computer, and provide the required power for external devices through the internal boost module.

[0062] If an external power supply is connected to the power input port 1 at this time, the indicator light 2 will be off, and the indicator light 3 will be on, indicating that the system has automatically switched to the power input port 1 to supply power to the external device.

[0063] In this scenario, when an external power supply is connected, the debugging tool will automatically select the power supply from the power input port 1 to meet the higher power requirements of the external device.

[0064] Based on the same inventive concept, the present application also provides a circuit board, which can be seen from Figure 4 The circuit board includes the power supply circuit as described above. Wherein, the circuit board can be a single one, or can be obtained by splicing multiple circuit sub-boards. In other words, the power supply circuit can be arranged on a circuit board as a whole, or can be divided into multiple parts and arranged on different circuit sub-boards. For example, the first power supply circuit 100, the second power supply circuit 200 and the control circuit 300 can be arranged on different circuit sub-boards, and when it is necessary to realize part or all of the protection functions, the user can splice the corresponding part or all of the circuit sub-boards into a circuit board with the required power supply function. The specific technical solutions and technical effects can be referred to the description of the power supply circuit above, which will not be repeated here.

[0065] Of course, any sub-circuit can also be divided into multiple parts and arranged on different circuit sub-boards. For example, the second power supply circuit 200 can be divided into multiple parts and arranged on different circuit sub-boards. In use, the user can splice the circuit sub-boards of the second power supply circuit 200 into a circuit board with voltage regulation function.

[0066] Based on the same inventive concept, the present application also provides an electronic device, which can be seen from Figure 5 The electronic device includes the power supply circuit provided by any of the above embodiments and the circuit load connected to the voltage output end of the power supply circuit. The specific technical solutions and technical effects can be referred to the description of the power supply circuit above, which will not be repeated here.

[0067] Therefore, the technical scheme provided in the application, the power supply circuit includes a first power supply circuit and a second power supply circuit, the first power supply circuit is connected with a first power supply, and the second power supply circuit is connected with a second power supply, so that two external power supplies can be connected to one test equipment. Meanwhile, the control circuit is arranged between the first power supply circuit and the second power supply circuit, and the control circuit can control the on-off state of the second power supply circuit according to the connection state of the first power supply. When the first power supply is connected to the first power supply circuit, the control circuit can automatically disconnect the second power supply circuit, so that the test equipment can be powered by the first power supply. When the first power supply is not connected to the first power supply circuit, the control circuit can keep the second power supply circuit in the on state, so that the test equipment can be powered by the second power supply. The technical scheme provided in the application can automatically switch between dual power supplies to adapt to different power consumption of external devices.

[0068] Meanwhile, the power supply circuit has a boosting function, so that the operator does not need to carry multiple specifications of external power supplies, and the troublesome external power supply line is saved, and the carrying is simple. The power supply circuit retains the external power supply, can be compatible with special scenes, uses external power-off measures, and the power driving is not limited. The power supply circuit also has a priority design, in the case that the power supply condition is sufficient, the high-power power supply is preferentially selected to supply power externally, and the high-power equipment can be better supported. The power supply circuit also has a plurality of power supply indicator lights, and the operator can intuitively know the current running state of the test equipment.

[0069] The above only describes the preferred embodiments of the application, and is not used to limit the application, and any modification, equivalent replacement, improvement, etc. within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A power supply circuit, characterized by comprising: The power supply circuit comprises: a first power supply circuit connected with a first power supply, and when the first power supply circuit is turned on, the output voltage of the first power supply circuit is approximately equal to the output voltage of the first power supply; a second power supply circuit connected with a second power supply, and when the second power supply circuit is turned on, the second power supply circuit adjusts the output voltage of the second power supply to a preset voltage; a control circuit connected with the first power supply circuit and the second power supply circuit, respectively, and the control circuit controls the on-off state of the second power supply circuit in response to the connection state of the first power supply.

2. The power supply circuit of claim 1, wherein, The first power supply circuit comprises a first diode, the anode of the first diode is connected with the first power supply, and the cathode of the first diode is connected with the voltage output end of the second power supply circuit.

3. The power supply circuit of claim 2, wherein, The control circuit comprises a transistor and a field effect transistor; the base of the transistor is connected with the anode of the first diode, the emitter of the transistor is connected with the gate of the field effect transistor, and the collector of the transistor is grounded; the source of the field effect transistor is connected with the second power supply, and the drain of the field effect transistor is connected with a voltage regulating sub-circuit in the second power supply circuit.

4. The power supply circuit according to claim 3, characterized in that, The control circuit comprises a current limiting resistor, a base resistor and a source resistor; the first end of the current limiting resistor is connected with the first power supply circuit, the second end of the current limiting resistor is connected with the base of the transistor and the first end of the base resistor, and the second end of the base resistor is grounded; the first end of the source resistor is connected with the source of the field effect transistor, and the second end of the source resistor is connected with the gate of the field effect transistor.

5. The power supply circuit of claim 4, wherein, The voltage input end of the voltage regulating sub-circuit is connected with the drain of the field effect transistor, the voltage output end of the voltage regulating sub-circuit is connected with the first power supply circuit, and the voltage regulating sub-circuit adjusts the output voltage of the second power supply to the preset voltage.

6. The power supply circuit of claim 1, wherein, The first power supply circuit comprises a switch, the switch controls the on-off of the first power supply circuit, and the voltage output end of the second power supply circuit is connected with the common end of the switch.

7. The power supply circuit of claim 6, wherein, The power supply circuit comprises a first indication circuit, a second indication circuit, a third indication circuit and a fourth indication circuit; The first indication circuit is connected between the second power supply and the control circuit, and indicates whether the second power supply circuit is connected with the second power supply; The second indication circuit is connected with the second power supply circuit and arranged after the control circuit, and indicates the on-off state of the second power supply circuit; The third indication circuit is connected with the first power supply circuit, and indicates whether the first power supply circuit is connected with the first power supply; The fourth indication circuit is connected with the switching end of the switch, and indicates whether there is the first power supply circuit or the second power supply circuit after the switch.

8. The power supply circuit of claim 1, wherein, The first power supply circuit further comprises a fuse, the first end of the fuse is connected with the first power supply, the second end of the fuse is connected with the anode of the first diode, and the voltage input end of the control circuit is connected with the second end of the fuse.

9. A circuit board, characterized by The circuit board comprises the power supply circuit according to any one of claims 1-8.

10. An electronic device, comprising: The electronic device comprises the power supply circuit according to any one of claims 1-8, and a circuit load connected to the voltage output terminal of the power supply circuit.

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