Power supply circuit for short circuit detection

Abstract

The utility model relates to the technical field of circuit detection, and discloses a power supply circuit for short circuit detection. The power supply circuit comprises a single-chip microcomputer, a constant current source circuit, a voltage detection circuit, a direct current power supply circuit and a product to be detected. The input end of the constant current source circuit is connected with an external power supply and a first output port of the single-chip microcomputer. The output end of the constant current source circuit is connected with the input end of the voltage detection circuit and a product to be detected. The output end of the voltage detection circuit is connected with the detection input port of the single-chip microcomputer. The input end of the direct-current power supply circuit is connected with the external power supply and the second output port of the single-chip microcomputer, and the output end of the direct-current power supply circuit is connected with the to-be-tested product. According to the application, an existing open-short circuit detection mode is simplified, whether the power supply impedance is short-circuited or not can be detected firstly when the high-density PCBA and the chip are powered on for the first time, judgment and preliminary screening of the open-short circuit of the power supply are realized, and meanwhile, the situation that short-circuit ignition or burning of test equipment or burning of a to-be-tested product occurs after direct power-on due to short circuit is avoided.

Description

Technical Field

[0001] This application relates to the technical field of circuit testing, and in particular to a power supply circuit for short-circuit detection. Background Technology

[0002] In the PCBA product manufacturing process, each product must undergo an initial power-on operation after manufacturing to check its functionality. Detecting power short circuits is a critical task. In industry practice, open and short circuit tests for PCBA products are typically performed using AOT (Aspect-Oriented Inspection) or ICT (Information and Technology) equipment; however, for chip products, expensive ATE (Automatic Test Equipment) equipment is required for this test.

[0003] Currently available testing technologies have many problems. For example, optical inspection and X-ray inspection use expensive equipment and have limited accuracy. They rely solely on visual recognition and lack electrical signal detection, making it difficult to accurately measure and eliminate abnormalities such as short circuits and open circuits. In-circuit flying probe testing (ICT) works by having probes contact test points on the PCBA, offering advantages such as high accuracy and comprehensive signal coverage. However, it has specific requirements for the size of test points, making it impossible to design high-density PCBAs and chips with pre-reserved test points. While automated chip testing (ATE) can perform full-function chip inspection and has good operability, its equipment is extremely expensive and its testing efficiency is low, making it unable to meet the production capacity requirements of mass production.

[0004] Therefore, the testing methods commonly used in these industries are generally expensive. In particular, for SSD products, due to their small size and high component density, there is simply no extra space to reserve test points, so ICT testing cannot be used. Utility Model Content

[0005] The technical problem to be solved by this application is to provide a power supply circuit for short circuit detection, which simplifies the existing open and short circuit detection methods. It can realize the detection of whether the power supply impedance is short-circuited when high-density PCBA and chips are powered on for the first time, realize the judgment and initial screening of power supply open and short circuits, and at the same time avoid the situation that short circuit fire or burnout of test equipment or product under test will occur after powering on directly with a short circuit.

[0006] To address the aforementioned issues, this application provides a power supply circuit for short-circuit detection, comprising a microcontroller, a constant current source circuit, a voltage detection circuit, a DC power supply circuit, and a device under test (DUT). The input terminal of the constant current source circuit is connected to an external power supply and the first output port of the microcontroller, respectively. The output terminal of the constant current source circuit is connected to the input terminal of the voltage detection circuit and the DUT. The output terminal of the voltage detection circuit is connected to the detection input port of the microcontroller. The input terminal of the DC power supply circuit is connected to an external power supply and the second output port of the microcontroller, respectively. The output terminal of the DC power supply circuit is connected to the DUT.

[0007] Preferably, the constant current source circuit includes a power switch and a constant current source. The input terminal of the power switch is connected to an external power supply and the first output port of the microcontroller, respectively. The output terminal of the power switch is connected to the positive terminal of the constant current source, and the negative terminal of the constant current source is connected to the input terminal of the voltage detection circuit and the product under test.

[0008] Preferably, the DC power supply circuit includes a DC power supply, the input terminal of which is connected to an external power supply and the second output port of the microcontroller, and the output terminal of which is connected to the product under test.

[0009] Preferably, the DC power supply circuit further includes a first capacitor, the two ends of which are respectively connected to an external power supply and ground.

[0010] Preferably, the DC power supply circuit further includes a first inductor, the two ends of which are respectively connected to the output terminal of the DC power supply and the product under test.

[0011] Preferably, the DC power supply circuit further includes a first resistor and a second resistor, one end of the first resistor is connected to the first inductor, the other end of the first resistor is connected to the output terminal of the DC power supply and one end of the second resistor, and the other end of the second resistor is grounded.

[0012] Preferably, the DC power supply circuit further includes a second capacitor, one end of which is connected to the first inductor and the external output voltage, and the other end of which is grounded.

[0013] Preferably, the power switch is a PMOS.

[0014] Compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0015] When the product under test (DUT) is first connected to the power supply circuit, after the power supply circuit is turned on, the first output port of the microcontroller opens, thereby connecting the constant current source circuit, while the second output port of the microcontroller closes, and the DC power supply circuit is in a state of no power output. At this time, the constant current source circuit starts working, providing a constant 1mA current to the DUT. Typically, the normal resistance to ground of the DUT is 50Ω-2KΩ, and a voltage drop of 50mV-2V occurs when current flows through a normal product. By detecting the external power supply voltage through the microcontroller, the resistance to ground of the product can be calculated using U / 1mA. If a short circuit occurs, the detection input port of the microcontroller will detect 0V; if an open circuit occurs, the detection input port of the microcontroller will detect the voltage value of the external power supply.

[0016] Using the above detection methods, the microcontroller can determine whether the product under test (DUT) is abnormal. If an abnormality is detected, the constant current source circuit is shut down, and the microcontroller's second output port remains in a state where the DC power supply circuit is off, thus protecting the DUT and the DC power supply circuit from being burned out by overcurrent. If a normal condition is detected, the constant current source circuit is shut down, the microcontroller's second output port is opened, the DC power supply circuit provides power, and the DUT begins normal operation. This application simplifies existing open / short circuit detection methods, enabling high-density PCBAs and chips to detect whether the power supply impedance is short-circuited upon first power-on, achieving initial screening for open / short circuits, and also avoiding situations where short circuits lead to fires, burnout of test equipment, or burnout of the DUT after direct power-on. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The circuit structure diagram of the power supply circuit for short circuit detection provided in the embodiments of this application is shown.

[0019] Explanation of reference numerals in the attached diagram: U1, microcontroller; U2, constant current source; U3, DC power supply; U4, product under test; Q1, power switch; C1, first capacitor; C2, second capacitor; R1, first resistor; R2, second resistor; L1, first inductor. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0022] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0023] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0024] Please refer to Figure 1 This application provides a power supply circuit for short-circuit detection, which can be used to perform open and short-circuit detection on high-density PCBAs and chips. The power supply circuit includes a microcontroller U1, a constant current source circuit, a voltage detection circuit, a DC power supply circuit, and a device under test (DUT) U4.

[0025] Specifically, the input terminals of the constant current source circuit are connected to the external power supply and the first output port (i.e., the second pin of the microcontroller U1), respectively. The output terminal of the constant current source circuit is connected to the input terminal of the voltage detection circuit and the product under test (U4). The output terminal of the voltage detection circuit is connected to the detection input port (i.e., the third pin of the microcontroller U1). The input terminals of the DC power supply circuit are connected to the external power supply and the second output port (i.e., the fourth pin of the microcontroller U1), respectively. The output terminal of the DC power supply circuit is connected to the product under test (U4). In this embodiment, the voltage detection circuit is connected to the detection input port of the microcontroller U1 through the output terminal of the constant current source circuit.

[0026] Here, when the product under test (U4) is first connected to the power supply circuit, after the power supply circuit starts running, the first output port of the microcontroller U1 opens, thereby connecting the constant current source circuit, and the second output port of the microcontroller U1 closes, so the DC power supply circuit is in a state of no power output. At this time, the constant current source circuit starts working, providing a constant 1mA current to the product under test (U4). Normally, the resistance to ground of the product under test (U4) is 50Ω-2KΩ, and a voltage drop of 50mV-2V occurs when current flows through a normal product. By detecting the external power supply voltage through the microcontroller U1, the product's resistance to ground can be calculated using U / 1mA. If a short circuit occurs, the detection input port of the microcontroller U1 will detect 0V; if an open circuit occurs, the detection input port of the microcontroller U1 will detect the voltage value of the external power supply.

[0027] Using the above detection method, microcontroller U1 can determine whether the product under test (U4) is abnormal. If it is determined to be abnormal, the constant current source circuit is turned off, and the second output port of microcontroller U1 remains in a state where the DC power supply circuit is turned off, thereby protecting the product under test U4 and the DC power supply circuit from being burned out by overcurrent. If it is determined to be normal, the constant current source circuit is turned off, the second output port of microcontroller U1 is turned on, the DC power supply circuit provides power, and the product under test U4 begins to operate normally. This application simplifies the existing open and short circuit detection methods, enabling high-density PCBAs and chips to detect whether the power supply impedance is short-circuited during the first power-on, realizing the judgment and initial screening of power supply open and short circuits, and also avoiding situations where short circuits directly cause fires or burn out the test equipment or the product under test U4 after power-on.

[0028] In one specific embodiment, the constant current source circuit includes a power switch Q1 and a constant current source U2. The input terminal of the power switch Q1 is connected to an external power supply and the first output port of the microcontroller U1, respectively. The output terminal of the power switch Q1 is connected to the positive terminal of the constant current source U2, and the negative terminal of the constant current source U2 is connected to the input terminal of the voltage detection circuit and the product under test U4.

[0029] The state of power switch Q1 is controlled by microcontroller U1. When the first output port of microcontroller U1 is open, power switch Q1 is turned on, connecting the constant current source circuit and enabling the external power supply to power the constant current source circuit, thus providing the power basis for subsequent testing. When microcontroller U1 determines that the product under test U4 is abnormal and the constant current source circuit needs to be shut down, it controls power switch Q1 to turn off through the first output port, cutting off the connection between the constant current source circuit and the external power supply, stopping the supply of constant current to the product under test U4, thus providing protection.

[0030] The constant current source U2 provides a stable current to the product under test (U4). By detecting the voltage drop across U4 under this constant current, the product's resistance to ground can be calculated, thereby determining whether the product has any abnormalities such as short circuits or open circuits. Without the constant current source U2 providing a stable current, it is impossible to accurately determine the resistance state of U4 through voltage detection and calculation, and therefore it is impossible to effectively detect problems such as short circuits. In this embodiment, the constant current is 1mA; in other embodiments, the constant current can be set to other values.

[0031] Furthermore, in this embodiment, the power switch Q1 is a PMOS. PMOS is simple and convenient to control as a high-side switch. In the on-state, PMOS has low on-resistance, resulting in lower power loss when the constant current source circuit is on, reducing energy waste and improving circuit efficiency. Additionally, PMOS has a certain reverse voltage withstand capability. Voltage fluctuations or reverse voltages may occur in the circuit; PMOS can withstand these reverse voltages to a certain extent, preventing damage to the constant current source circuit and the subsequent device under test U4, thus enhancing circuit stability and reliability.

[0032] In one specific embodiment, the DC power supply circuit includes a DC power supply U3. The input terminal of the DC power supply U3 (i.e., the third pin of the DC power supply U3) is connected to an external power supply and the second output port of the microcontroller U1, respectively. The output terminal of the DC power supply U3 (i.e., the second pin of the DC power supply U3) is connected to the product under test U4. When the constant current source circuit detects that the product under test U4 is normal, the microcontroller U1 controls the second output port to open, enabling the DC power supply U3 to operate and provide the power required for the normal operation of the product under test U4. When an abnormality is detected in the product under test U4, the microcontroller U1 maintains the state of the second output port of the DC power supply U3 being closed, avoiding overcurrent and other problems that may be caused by connecting an abnormal product to the DC power supply U3, protecting the product under test U4 and the entire power supply circuit, and preventing damage to circuit components or even safety accidents due to abnormal conditions.

[0033] In the entire power supply circuit's workflow, the constant current source circuit is used for short-circuit detection in the initial stage, while the DC power supply U3 takes over after the detection is complete and the product is functioning normally, providing a continuous and stable high-current output power supply to the product. This coordination achieves an orderly switch from detection to normal power supply, enabling the circuit to not only perform open and short-circuit detection on the product but also ensure the normal operation of the product after the detection passes, effectively improving the circuit's practicality and reliability.

[0034] In one specific embodiment, the DC power supply circuit further includes a first capacitor C1, the two ends of which are respectively connected to an external power supply and ground.

[0035] External power supplies may experience voltage fluctuations or noise. The first capacitor, C1, smooths the power supply voltage and filters out high-frequency noise components, providing a stable and clean DC voltage for the device under test (DUT), U4. During circuit operation, when the external power supply experiences a momentary voltage drop or a sudden change in load current, the first capacitor, C1, releases its stored charge, temporarily providing additional current to the DUT, U4. This buffering effect prevents the DUT from malfunctioning due to momentary power fluctuations, enhancing the circuit's anti-interference capability and stability.

[0036] In one specific embodiment, the DC power supply circuit further includes a first inductor L1, the two ends of which are respectively connected to the output terminal of the DC power supply U3 and the product under test U4.

[0037] The first inductor L1 has the characteristic of passing DC and blocking AC, which can effectively block the high-frequency AC components in the DC voltage output by the external power supply, making the DC power supply U3 output smoother and purer, reducing noise interference to the product, and ensuring the stability of product performance. The first inductor L1 is often paired with the first capacitor C1 to form an LC filter circuit. The capacitor mainly filters high-frequency signals, while the inductor filters low-frequency signals. The two working together can significantly improve the filtering effect and create a more stable power supply environment for the product under test U4.

[0038] In one specific embodiment, the DC power supply circuit further includes a first resistor R1 and a second resistor R2. One end of the first resistor R1 is connected to the first inductor L1, and the other end of the first resistor R1 is connected to the output terminal of the DC power supply U3 (i.e., the fifth pin of the DC power supply U3) and one end of the second resistor R2. The other end of the second resistor R2 is grounded.

[0039] The first resistor R1 and the second resistor R2 are connected in series in the circuit. According to the voltage division principle of series resistors, they can distribute the voltage output by the DC power supply U3 in a certain proportion. When the output voltage of the DC power supply U3 is constant, appropriately increasing the resistance value can reduce the current in the circuit, preventing damage to the product under test U4 or other circuit components due to excessive current, thus protecting the circuit.

[0040] In one specific embodiment, the DC power supply circuit further includes a second capacitor C2, one end of which is connected to the first inductor L1 and the external output voltage, and the other end of the second capacitor C2 is grounded.

[0041] In a DC power supply circuit, the external power supply may contain minor voltage fluctuations or AC components. The second capacitor C2 can bypass these AC components to ground, making the DC voltage output to the device under test (DUT) U4 smoother and more stable, reducing voltage ripple, and providing a clean DC power supply U3 for DUT U4. This helps improve the stability and reliability of DUT U4's operation. Furthermore, when the output voltage of the DC power supply U3 experiences momentary fluctuations or load changes causing changes in current demand, the second capacitor C2 can release or store charge, acting as a buffer to maintain relative voltage stability and prevent sudden, large voltage drops or rises, thus protecting DUT U4 from voltage surges.

[0042] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A power supply circuit for short-circuit detection, characterized in that: This includes microcontrollers, constant current source circuits, voltage detection circuits, DC power supply circuits, and the product under test; The input terminal of the constant current source circuit is connected to the external power supply and the first output port of the microcontroller, respectively, and the output terminal of the constant current source circuit is connected to the input terminal of the voltage detection circuit and the product under test. The output of the voltage detection circuit is connected to the detection input port of the microcontroller; The input terminals of the DC power supply circuit are connected to an external power supply and the second output port of the microcontroller, respectively, and the output terminals of the DC power supply circuit are connected to the product under test.

2. The power supply circuit for short-circuit detection according to claim 1, characterized in that, The constant current source circuit includes a power switch and a constant current source. The input terminal of the power switch is connected to an external power supply and the first output port of the microcontroller, respectively. The output terminal of the power switch is connected to the positive terminal of the constant current source, and the negative terminal of the constant current source is connected to the input terminal of the voltage detection circuit and the product under test.

3. A power supply circuit for short-circuit detection according to claim 1, characterized in that, The DC power supply circuit includes a DC power supply. The input terminal of the DC power supply is connected to an external power supply and the second output port of the microcontroller, respectively. The output terminal of the DC power supply is connected to the product under test.

4. A power supply circuit for short-circuit detection according to claim 3, characterized in that, The DC power supply circuit also includes a first capacitor, the two ends of which are connected to an external power supply and the ground, respectively.

5. A power supply circuit for short-circuit detection according to claim 3, characterized in that, The DC power supply circuit also includes a first inductor, the two ends of which are respectively connected to the output terminal of the DC power supply and the product under test.

6. A power supply circuit for short-circuit detection according to claim 5, characterized in that, The DC power supply circuit further includes a first resistor and a second resistor. One end of the first resistor is connected to the first inductor, and the other end of the first resistor is connected to the output terminal of the DC power supply and one end of the second resistor. The other end of the second resistor is grounded.

7. A power supply circuit for short-circuit detection according to claim 5, characterized in that, The DC power supply circuit also includes a second capacitor, one end of which is connected to the first inductor and the external output voltage, and the other end of which is grounded.

8. A power supply circuit for short-circuit detection according to claim 2, characterized in that, The power switch is a PMOS.

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