Four-wire power supply with self-detection function

Abstract

A four-wire power supply with a self-detection function comprises a power supply output unit; a load detection unit; the compensation voltage difference detection unit is used for respectively acquiring the voltage of the first output end and the first sensing end, or respectively acquiring the voltage of the second output end and the second sensing end; when the compensation voltage difference is larger than or equal to the compensation threshold value, the compensation voltage difference detection unit outputs a first signal through the output end. And the processing unit is used for controlling the power supply output unit to adjust the power supply voltage of the power supply output unit when the first signal is received, so that the adjusted compensation voltage difference between the first output end and the first sensing end or between the second sensing end and the second output end is smaller than a compensation threshold value. The adjusted compensation voltage difference is smaller than the compensation threshold value, so that the power supply voltage of the power supply output unit is limited, the to-be-tested equipment cannot be burnt out due to large power supply voltage after normal wiring, and the use safety is improved.

Description

Technical Field

[0001] The present application relates to the technical field of power supply, and in particular to a four-wire power supply with a self-detection function. Background Art

[0002] When a power supply is supplying power to a load, it is usually hoped that the voltage across the load reaches the rated value output by the power supply as much as possible. Since the power supply needs to be connected to the load through a cable, and the line resistance of the cable will divide the voltage, the voltage across the load is usually lower than the rated value output by the power supply.

[0003] For the above problems, the current technical solution is usually to make the power supply have Kelvin four-wire function (sense function), that is, its power output terminals V+ and V- output voltage through two cables, and its remote sensing terminals S+ and S- detect the voltage across the load through two cables, so that the output of the power output terminals V+ and V- can be adjusted based on the voltage detected by the remote sensing terminals S+ and S-, so that the voltage across the load can reach the rated value.

[0004] However, when there is a poor connection between the power output terminal V+ or V-, and the remote sensing terminal S+ or S-, even if the power output line outputs the maximum voltage, the load voltage detected by the remote sensing terminals S+ and S- may not reach the rated value, and if the wiring is accidentally connected back to normal at this time, the maximum output voltage may burn out the load device. Therefore, a new technical solution is needed. Utility Model Content

[0005] The main technical problem solved by this application is that poor wiring may cause the device under test to burn out.

[0006] According to the first aspect, an embodiment provides a four-wire power supply with a self-detection function, comprising:

[0007] A power supply output unit, having a first output end and a second output end, wherein the first output end and the second output end are respectively connected to two ends of a load through cables, and the power supply output unit is used to supply power to the load through the first output end and the second output end;

[0008] A load detection unit, comprising a first sensing end and a second sensing end, wherein the first sensing end and the second sensing end are respectively connected to two ends of the load through cables, and the load detection unit is used to detect the voltage of the load through the first sensing end and the second sensing end; a first resistor is connected between the first sensing end and the first output end, and a second resistor is connected between the second sensing end and the second output end;

[0009] at least one compensation voltage difference detection unit, the compensation voltage difference detection unit having a first input terminal, a second input terminal and an output terminal, when the power output unit supplies power to the load, the first input terminal and the second input terminal are used to respectively obtain the voltage of the first output terminal and the first sensing terminal, or respectively obtain the voltage of the second output terminal and the second sensing terminal; and when the compensation voltage difference between the first output terminal and the first sensing terminal or between the second sensing terminal and the second output terminal is greater than or equal to a compensation threshold, the compensation voltage difference detection unit outputs a first signal from its output terminal;

[0010] A processing unit is used to control the power supply output unit to adjust the power supply voltage of the power supply output unit when receiving the first signal output by the compensation voltage difference detection unit, so that the adjusted compensation voltage difference between the first output terminal and the first sensing terminal or between the second sensing terminal and the second output terminal is less than the compensation threshold.

[0011] In some embodiments, the compensation voltage difference detection unit includes:

[0012] A detection module, configured to be turned on when a first preset voltage drop is reached between the first end and the second end, and output the first signal through the third end;

[0013] A voltage drop module is connected in series with the first end and / or the second end of the detection module, and the two ends of the series connection respectively obtain the voltage of the first output end and the first sensing end, or respectively obtain the voltage of the second output end and the second sensing end;

[0014] The voltage drop module is used to be turned on when the detection module is turned on, and to generate a second preset voltage drop between its first end and the second end, and the sum of the first preset voltage drop and the second preset voltage drop is equal to the compensation threshold.

[0015] In some embodiments, the detection module includes a coupled driving module and an isolation module; the driving module is used to turn on when a first preset voltage drop is reached between its first end and the second end, and the isolation module is used to respond to the driving module turning on and outputting the isolated first signal.

[0016] In some embodiments, the detection module is an optical coupler or a relay, and the optical coupler or the relay is turned on when a first preset voltage drop is reached between the first end and the second end thereof, and the third end of the optical coupler or the relay outputs a first signal;

[0017] The optocoupler or relay is cut off when the voltage drop between its first end and the second end is lower than the first preset voltage drop, and causes the third end of the optocoupler or the relay to output a second signal; when the first signal is at a low level, the second signal is at a high level, and when the first signal is at a high level, the second signal is at a low level.

[0018] In some embodiments, the voltage drop module includes at least one voltage drop device, each of which is connected in series with the first end and / or the second end of the detection module, and is turned on when the detection module is turned on to generate a third voltage drop, and the sum of each of the third voltage drops is equal to the second preset voltage drop.

[0019] In some embodiments, the voltage drop module includes a resistor device and at least one voltage drop device;

[0020] The detection module is used to generate a first current when it is turned on, and the resistance device is connected in series with the first end or the second end of the detection module and generates a fourth voltage drop when the first current is on;

[0021] Each of the voltage drop devices is connected in series with the first end and / or the second end of the detection module, and is turned on when the detection module is turned on to generate a third voltage drop. The sum of the fourth voltage drop and each of the third voltage drops is equal to the second preset voltage drop.

[0022] In some embodiments, the voltage drop device is a forward diode or a reverse Zener diode, the forward diode is used to generate the third voltage drop when forward conducting, and the reverse Zener diode is used to generate the third voltage drop when reverse conducting;

[0023] The at least one voltage drop device includes at least one forward diode, or includes at least one reverse Zener diode, or includes at least one forward diode and at least one reverse Zener diode.

[0024] In some embodiments, the voltage drop module includes a resistor device, the detection module is used to generate a first current when turned on, the resistor device is connected in series with the first end or the second end of the detection module, and generates the second preset voltage drop when the first current is applied.

[0025] In some embodiments, the compensation voltage difference detection unit has two, wherein the first input terminal and the second input terminal of one of the compensation voltage difference detection units are used to respectively obtain the voltages of the first output terminal and the first sensing terminal, and the first input terminal and the second input terminal of the other compensation voltage difference detection unit are used to respectively obtain the voltages of the second output terminal and the second sensing terminal.

[0026] In some embodiments, the output ends of the two compensation voltage difference detection units are connected to form an output node, so that when either of the two compensation voltage difference detection units outputs the first signal, the output node outputs the first signal, and the processing unit is used to receive the first signal output by the output node.

[0027] According to the four-wire power supply with self-detection function of the above embodiment, when there is a poor wiring situation, and the compensation voltage difference between the first output terminal and the first sensing terminal or the second output terminal and the second sensing terminal is normal and greater than the compensation threshold, the compensation voltage difference detection unit outputs a first signal to enable the processing unit to adjust the supply voltage of the power supply output unit. Since the adjusted compensation voltage difference is less than the compensation threshold, the supply voltage of the power supply output unit is limited, so that after the wiring is normal, the device under test will not be burned due to the large supply voltage, thereby improving the safety of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the structure of a four-wire power supply with a self-detection function according to an embodiment;

[0029] Figure 2 A circuit diagram of a four-wire power supply with a self-detection function according to an embodiment;

[0030] Figure 3 is a circuit diagram of a compensation voltage difference detection unit according to an embodiment;

[0031] Figure 4 FIG. 4 is a circuit diagram of a compensation voltage difference detection unit according to another embodiment. DETAILED DESCRIPTION

[0032] The present application is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are intended to enable the present application to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, and methods. In some cases, some operations related to the present application are not shown or described in the specification, in order to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0033] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0034] The serial numbers of the components in this document, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0035] In the current technical solution, when the power output terminal V+ or V-, and the remote sensing terminal S+ or S- are poorly wired, the line resistance of the cable will increase, resulting in a greater voltage drop, making the voltage across the load far less than the rated voltage. At this time, the power supply will increase the output voltage according to the detected voltage across the load, and it is possible that when the power output line outputs the maximum voltage, the detected load voltage still cannot reach the rated value. If the wiring is accidentally connected normally at this time, the maximum output voltage may burn out the load equipment.

[0036] In some embodiments, a four-wire power supply with a self-detection function is provided, which is used to supply power to a load, for example, to provide a rated voltage to the load, and can also detect the voltage across the load. When the voltage is lower than the rated voltage, the supply voltage can be increased so that the voltage across the load reaches the rated voltage. At the same time, the compensation voltage difference between the load voltage and the supply voltage can be detected, and the supply voltage can be adjusted when the compensation voltage difference is greater than or equal to the compensation threshold, so as to avoid burning out the load device when the wiring is accidentally connected normally. Please refer to Figure 1 The four-wire power supply with self-detection function includes a power supply output unit 10, a load detection unit 20, at least one compensation voltage difference detection unit 30 and a processing unit 40, which are described in detail below.

[0037] Please refer to Figure 1 and Figure 2 , the power supply output unit 10 is used to supply power to the load. In some embodiments, the power supply output unit 10 has a first output terminal V+ and a second output terminal V-, and the first output terminal V+ and the second output terminal V- can be connected to the two ends of the load through cables, respectively, and supply power to the load. Among them, the cable resistance corresponding to the first output terminal V+ and the second output terminal V- can be regarded as the resistor RV1 and the resistor RV2, respectively. In some embodiments, the power supply output unit 10 can be a power supply such as a switching power supply, a DC power supply, etc.

[0038] Please refer to Figure 2, the load detection unit 20 is used to detect the voltage of the load. In some embodiments, the load detection unit 20 has a first sensing terminal S+ and a second sensing terminal S-, and the first sensing terminal S+ and the second sensing terminal S- can be connected to the two ends of the load through cables, respectively, so as to detect the voltage of the load. Among them, the cable resistance corresponding to the first sensing terminal S+ and the second sensing terminal S- can be regarded as resistor RS1 and resistor RS2, respectively. In some embodiments, the load detection unit 20 can collect the voltage of the load based on a voltage acquisition circuit, for example, the voltage acquisition circuit can be implemented based on an operational amplifier, wherein the first input terminal V_readback+ of the voltage acquisition circuit is used to connect the first sensing terminal S+, and the second input terminal V_readback- of the voltage acquisition circuit is used to connect the second sensing terminal S-, so as to collect the voltage across the load. In some embodiments, a first resistor RVS1 is also connected between the first sensing terminal S+ and the first output terminal V+, and a second resistor RVS2 is also connected between the second sensing terminal S- and the second output terminal V-.

[0039] The compensation voltage difference detection unit 30 is used to detect the compensation voltage difference between the first output terminal V+ and the first sensing terminal S+, or to detect the compensation voltage difference between the second sensing terminal S- and the second output terminal V-. In some embodiments, the compensation voltage difference detection unit 30 has a first input terminal, a second input terminal and an output terminal, wherein the first input terminal and the second input terminal are used to obtain the voltage of the first output terminal V+ and the first sensing terminal S+, respectively, or to obtain the voltage of the second output terminal V- and the second sensing terminal S-, respectively. When the compensation voltage difference between the first output terminal V+ and the first sensing terminal S+ is greater than or equal to the compensation threshold, or when the compensation voltage difference between the second sensing terminal S- and the second output terminal V- is greater than or equal to the compensation threshold, the compensation voltage difference detection unit 30 outputs a first signal from its output terminal, for example, the first signal is a low level or a high level.

[0040] In some embodiments, the compensation voltage difference detection unit 30 includes a detection module and a voltage drop module. The detection module has a first end, a second end and a third end. The detection module is used to turn on when a first preset voltage drop is reached between the first end and the second end, and output a low level or a high level from the third end. The voltage drop module is connected in series with the first end and / or the second end of the detection module, and the two ends after the series connection respectively obtain the voltage of the first output end V+ and the first sensing end S+, or respectively obtain the voltage of the second output end V- and the second sensing end S-. When the detection module is turned on, the voltage drop module is also turned on accordingly, and a second preset voltage drop is generated between the first end and the second end of the voltage drop module, and the sum of the first preset voltage drop and the second preset voltage drop is equal to the compensation threshold. In this embodiment, the detection module needs to be turned on and output a low level or a high level under the condition of the first preset voltage drop, and the voltage drop module is turned on accordingly when the detection module is turned on, and a second preset voltage drop is generated. Therefore, if you want to compensate for the voltage difference detection unit 30 outputting a low level or a high level, the compensation voltage difference between the first output terminal V+ and the first sensing terminal S+ needs to be greater than or equal to the compensation threshold, or the compensation voltage difference between the second sensing terminal S- and the second output terminal V- needs to be greater than or equal to the compensation threshold, so that the detection module and the voltage drop module connected in series are both turned on.

[0041] In some embodiments, the detection module includes a driving module and an isolation module, and the driving module and the isolation module are coupled to each other. The driving module is used to turn on when a first preset voltage drop is reached between the first end and the second end thereof, and the isolation module is used to respond to the driving module turning on and output an isolated low level or high level. In this embodiment, the detection module outputs an isolated low level or high level based on the response of the isolation module to the driving module, so that the signal output by the detection module is isolated from other signals, thereby avoiding signal interference.

[0042] Please refer to Figure 3 and Figure 4 In some embodiments, the detection module is an optocoupler U1, which is turned on when a first preset voltage drop is reached between the first end and the second end thereof, and generates a first current, and at the same time makes the third end and the fourth end of the optocoupler U1 turned on, so as to output a low level based on the third end of the optocoupler U1. For example, the third end of the optocoupler U1 is connected to a high level through a pull-up resistor R3, and the fourth end of the optocoupler U1 is grounded. The optocoupler U1 is turned on when a first preset voltage drop is reached between the first end and the second end thereof, and makes the fourth end of the optocoupler U1 pull down the voltage of its third end, so that the third end of the optocoupler U1 outputs a low level. On the contrary, the optocoupler U1 is turned off when the voltage between the first end and the second end thereof is lower than the first preset voltage drop, so that the third end of the optocoupler U1 is pulled up by the pull-up resistor R3 to output a high level.

[0043] In some embodiments, the detection module is a relay, and the coil end of the relay is turned on when the voltage between the first end and the second end reaches a first preset voltage drop, and generates a first current, and at the same time, the third end of the relay, that is, the contact end of the relay is closed or disconnected, thereby outputting a low level or a high level based on the contact end of the relay. For example, when the contact end of the relay is used to input a high level, the relay is turned on when the voltage between the first end and the second end reaches a first preset voltage drop, and the third end of the relay outputs a high level. Conversely, the relay is turned off when the voltage between the first end and the second end is lower than the first preset voltage drop, and the contact end of the relay is disconnected, thereby outputting a low level.

[0044] In some embodiments, the voltage drop module includes at least one voltage drop device, each of which is connected in series with the first end and / or the second end of the detection module, for example, each of the voltage drop devices is connected in series with the first end of the detection module, or is connected in series with the second end of the detection module, or part of the voltage drop devices is connected in series with the first end of the detection module, and the other part of the voltage drop devices is connected in series with the second end of the detection module. The voltage drop devices are used to be turned on respectively when the detection module is turned on, and respectively generate a third voltage drop, and the sum of each third voltage drop is equal to the second preset voltage drop. In this embodiment, the voltage drop device is turned on when the detection module is turned on, and generates a relatively fixed third voltage drop, and the second preset voltage drop can be obtained based on the third voltage drop generated by each voltage drop device.

[0045] Please refer to Figure 3 and Figure 4 In some embodiments, the voltage drop device is a forward diode or a reverse Zener diode. The forward diode is used to generate a third voltage drop when conducting in the forward direction, for example, the positive electrode of the forward diode is connected to the first output terminal V+, so as to achieve forward conduction of the forward diode. The reverse Zener diode is used to generate a third voltage drop when conducting in the reverse direction, for example, the negative electrode of the reverse Zener diode is connected to the first output terminal V+, so as to achieve reverse conduction of the reverse Zener diode. In some embodiments, at least one voltage drop device includes at least one forward diode, or includes at least one reverse Zener diode, or includes at least one forward diode and at least one reverse Zener diode.

[0046] In some embodiments, the voltage drop module includes a resistor device, which is connected in series with the first end or the second end of the detection module. Since the detection module generates a first current when it is turned on, the resistance of the resistor device is selected as needed, so that the resistor device can generate a second preset voltage drop based on the first current. For example, the resistor device can be a resistor or an adjustable resistor.

[0047] In some embodiments, the voltage drop module may include the above-mentioned resistor and at least one of the above-mentioned voltage drop devices, wherein the resistor is used to generate the fourth voltage drop, each voltage drop device is used to generate a third voltage drop, and the sum of the fourth voltage drop and each third voltage drop is equal to the second preset voltage drop. Figure 3 In some embodiments, the positive electrode of the diode D1 is connected to the first output terminal V+, the negative electrode of the diode D1 is connected in series with the resistor R1 and then connected to the first end of the optocoupler U1, and the second end of the optocoupler U1 is connected to the first sensing terminal S+. At this time, the compensation threshold Vth=Vd+Iu*R+Vu, wherein Vu is the on-state voltage of the optocoupler U1, i.e., the first preset voltage drop, Iu is the first current of the optocoupler U1 at the on-state voltage, R is the resistance value of the resistor R1, Iu*R is the fourth voltage drop of the resistor R1, Vd is the forward voltage drop of the diode D1, i.e., the third voltage drop, Vd+Iu*R is the total voltage drop of the diode D1 plus the resistor R1, i.e., the second preset voltage drop. When the compensation voltage difference between the first output terminal V+ and the second output terminal V- exceeds the compensation threshold, the third end of the optocoupler U1 outputs the first signal (Vout_Enable). Please refer to Figure 4 In some embodiments, the diode D1 may be replaced with a Zener diode D2, and the cathode of the Zener diode D2 is connected to the first output terminal V+, and the anode of the Zener diode D2 is connected in series with the resistor R1 and then connected to the first end of the optocoupler U1.

[0048] The processing unit 40 can adjust the output size of the power supply output unit 10, and can also adjust the output size of the power supply output unit 10 according to the load voltage detected by the load detection unit 20, so as to compensate for the load voltage. In some embodiments, the processing unit 40 is also used to control the adjustment of the power supply voltage of the power supply output unit when receiving the first signal, such as reducing the voltage of the first output terminal V+ so that the adjusted compensation voltage difference between the first output terminal V+ and the first sensing terminal S+ does not exceed the compensation threshold, such as increasing the voltage of the second output terminal V- so that the adjusted compensation voltage difference between the second sensing terminal S- and the second output terminal V- does not exceed the compensation threshold. In some embodiments, the processing unit 40 is also used to control the alarm unit to issue an alarm when receiving the first signal.

[0049] In some embodiments, there are two compensation voltage difference detection units 30, wherein the first input terminal and the second input terminal of one compensation voltage difference detection unit 30 are used to obtain the voltage of the first output terminal V+ and the first sensing terminal S+ respectively, and the first input terminal and the second input terminal of the other compensation voltage difference detection unit 30 are used to obtain the voltage of the second output terminal V- and the second sensing terminal S- respectively. In some embodiments, the output terminals of the two compensation voltage difference detection units 30 are connected to form an output node, so that when any one of the two compensation voltage difference detection units 30 outputs the first signal, the output node outputs the first signal, and the processing unit 40 is used to receive the first signal output by the output node.

[0050] The above is some description of the four-wire power supply with a self-detection function. The following is a specific description of the process of compensating for voltage difference limitation of the four-wire power supply with a self-detection function.

[0051] When the first sensing terminal S+ or the second sensing terminal S- has poor wiring or is disconnected, the line resistance of the cable between the first sensing terminal S+ or the second sensing terminal S- and the load is large, so that the voltage between the first sensing terminal S+ and the second sensing terminal S- is significantly less than the rated value. At this time, the processing unit 40 will increase the voltage between the first output terminal V+ and the second output terminal V-, so that the voltage between the first sensing terminal S+ and the second sensing terminal S- reaches the rated value. Therefore, the voltage between the first output terminal V+ and the second output terminal V- is relatively high, which can easily damage the device under test.

[0052] When the first output terminal V+ or the second output terminal V- is poorly wired or disconnected, the first resistor RVS1 and the second resistor RVS2 have large resistance values, so that the voltage between the first output terminal V+ and the second output terminal V- is mainly on the first resistor RVS1 or the second resistor RVS2, resulting in that even if the maximum voltage is reached between the first output terminal V+ and the second output terminal V-, the first sensing terminal S+ cannot reach the rated voltage. At this time, if the wiring is accidentally connected back, it will easily damage the device under test.

[0053] In this regard, the compensation voltage difference detection unit 30 can obtain the voltage of the first sensing terminal S+ and the first output terminal V+ respectively, and output a first signal to the processing unit 40 when the compensation voltage difference between the two exceeds the compensation threshold, so as to adjust the supply voltage of the power supply output unit, thereby avoiding damage to the device under test. And the range of the compensation voltage difference is limited based on the compensation threshold, so that the output of the power supply is safer. The limiting process of the compensation voltage difference between the second output terminal V- and the second sensing terminal S- is the same as the above process, and will not be repeated here. In this embodiment, two-wire compensation of the compensation voltage difference can be performed through the first output terminal V+ and the second output terminal V-, respectively, and the compensation voltage difference is limited to a certain range. In some embodiments, when the cable is too thin, too long or too poor, resulting in a large compensation voltage difference, there is a risk of overheating and fire during operation. The present application can also adjust the supply voltage of the power supply output unit to avoid the risk of overheating and fire.

[0054] It can be seen from the above that the four-wire power supply with a self-detection function can monitor the compensation voltage difference in real time during output, and adjust the output when the compensation voltage difference exceeds the threshold, so that the compensation voltage difference is within a certain range, and the first output terminal V+ and the second output terminal V- can adjust the compensation voltage difference. It can be seen from the above that when monitoring the compensation voltage difference, the detection is directly performed based on hardware such as the detection module and the voltage drop module, so the structure is simple, the response speed is fast, and the stability is good. And based on the different performance or different quantity of different hardware, the compensation threshold can be adjusted to adapt to application scenarios with different voltages, currents and different cables.

[0055] In some embodiments, the four-wire power supply with a self-detection function further includes an overvoltage protection unit. The overvoltage protection unit is used to perform overvoltage protection when the voltage difference between the second output terminal V- and the second output terminal V- exceeds a threshold.

[0056] In some embodiments, the overvoltage protection unit includes an overvoltage detection module and a feedback protection module. Among them, the overvoltage detection module is used to detect the voltage difference between the first output terminal V+ and the second output terminal V-, and when the voltage difference exceeds the threshold, the first output terminal V+ and the second output terminal V- are short-circuited. The feedback protection module is used to output a feedback signal based on the short-circuit current between the first output terminal V+ and the second output terminal V-, and output a first feedback signal when the short-circuit current is greater than the threshold, otherwise it outputs a second feedback signal, and the processing unit 40 adjusts the voltage of the first output terminal V+ and the second output terminal V- based on the first feedback signal, so that the short-circuit current is less than the threshold. In this embodiment, the short-circuit response speed of the overvoltage detection module is fast, so that overvoltage protection can be effectively performed. In some embodiments, the overvoltage detection module can be connected in series with a thyristor between the first output terminal V+ and the second output terminal V-, and the voltage difference between the first output terminal V+ and the second output terminal V- is detected, and the thyristor is driven to conduct when the voltage difference exceeds the threshold. Thereby, the first output terminal V+ and the second output terminal V- are short-circuited. In some embodiments, the feedback protection module can obtain the voltage across the short-circuit current collection resistor, amplify the voltage and compare it with a reference voltage. When the amplified voltage is greater than the reference voltage, it means that the short-circuit current is greater than the threshold value, and the feedback protection module outputs a first feedback signal. The first feedback signal can be output after being isolated by an optocoupler to indicate that the circuit is in an overvoltage protection state.

[0057] From the above, it can be seen that the four-wire power supply with self-detection function can also continuously short-circuit and limit the short-circuit current to protect the power supply and the device under test when the output is over-voltage, with fast response, simple and stable.

[0058] The above specific examples are used to illustrate the present application, which is only used to help understand the present application and is not intended to limit the present application. For technicians in the technical field to which the present application belongs, they can also make some simple deductions, deformations or substitutions based on the ideas of the present application.

Claims

1. A four-wire power supply with a self-detection function, characterized in that: include: A power supply output unit, having a first output end and a second output end, wherein the first output end and the second output end are respectively connected to two ends of a load through cables, and the power supply output unit is used to supply power to the load through the first output end and the second output end; A load detection unit, comprising a first sensing end and a second sensing end, wherein the first sensing end and the second sensing end are respectively connected to two ends of the load through cables, and the load detection unit is used to detect the voltage of the load through the first sensing end and the second sensing end; A first resistor is connected between the first sensing end and the first output end, and a second resistor is connected between the second sensing end and the second output end; at least one compensation voltage difference detection unit, the compensation voltage difference detection unit having a first input terminal, a second input terminal and an output terminal, when the power output unit supplies power to the load, the first input terminal and the second input terminal are used to respectively obtain the voltage of the first output terminal and the first sensing terminal, or respectively obtain the voltage of the second output terminal and the second sensing terminal; When the compensation voltage difference between the first output terminal and the first sensing terminal or between the second sensing terminal and the second output terminal is greater than or equal to a compensation threshold, the compensation voltage difference detection unit outputs a first signal from its output terminal; A processing unit is used to control the power supply output unit to adjust the power supply voltage of the power supply output unit when receiving the first signal output by the compensation voltage difference detection unit, so that the adjusted compensation voltage difference between the first output terminal and the first sensing terminal or between the second sensing terminal and the second output terminal is less than the compensation threshold.

2. The four-wire power supply with self-detection function as claimed in claim 1, characterized in that: The compensation voltage difference detection unit comprises: A detection module, configured to be turned on when a first preset voltage drop is reached between the first end and the second end, and output the first signal through the third end; A voltage drop module is connected in series with the first end and / or the second end of the detection module, and the two ends of the series connection respectively obtain the voltage of the first output end and the first sensing end, or respectively obtain the voltage of the second output end and the second sensing end; The voltage drop module is used to be turned on when the detection module is turned on, and to generate a second preset voltage drop between its first end and the second end, and the sum of the first preset voltage drop and the second preset voltage drop is equal to the compensation threshold.

3. The four-wire power supply with self-detection function as claimed in claim 2, characterized in that: The detection module includes a coupled driving module and an isolation module; the driving module is used to be turned on when a first preset voltage drop is reached between its first end and the second end, and the isolation module is used to respond to the driving module being turned on and outputting the isolated first signal.

4. The four-wire power supply with self-detection function as claimed in claim 3, characterized in that: The detection module is an optical coupler or a relay, which is turned on when a first preset voltage drop is reached between the first end and the second end thereof, and causes the third end of the optical coupler or the relay to output a first signal; The optocoupler or relay is cut off when the voltage drop between its first end and the second end is lower than the first preset voltage drop, and causes the third end of the optocoupler or the relay to output a second signal; when the first signal is at a low level, the second signal is at a high level, and when the first signal is at a high level, the second signal is at a low level.

5. The four-wire power supply with self-detection function as claimed in claim 2, characterized in that: The voltage drop module includes at least one voltage drop device, each of which is connected in series with the first end and / or the second end of the detection module, and is turned on when the detection module is turned on to generate a third voltage drop, and the sum of each third voltage drop is equal to the second preset voltage drop.

6. The four-wire power supply with self-detection function as claimed in claim 2, characterized in that: The voltage drop module includes a resistor device and at least one voltage drop device; The detection module is used to generate a first current when it is turned on, and the resistance device is connected in series with the first end or the second end of the detection module and generates a fourth voltage drop when the first current is on; Each of the voltage drop devices is connected in series with the first end and / or the second end of the detection module, and is turned on when the detection module is turned on to generate a third voltage drop. The sum of the fourth voltage drop and each of the third voltage drops is equal to the second preset voltage drop.

7. The four-wire power supply with self-detection function as claimed in claim 5 or 6, characterized in that: The voltage drop device is a forward diode or a reverse Zener diode, the forward diode is used to generate the third voltage drop when forward conducting, and the reverse Zener diode is used to generate the third voltage drop when reverse conducting; The at least one voltage drop device includes at least one forward diode, or includes at least one reverse Zener diode, or includes at least one forward diode and at least one reverse Zener diode.

8. The four-wire power supply with self-detection function as claimed in claim 2, characterized in that: The voltage drop module includes a resistor device. The detection module is used to generate a first current when it is turned on. The resistor device is connected in series with the first end or the second end of the detection module and generates the second preset voltage drop when the first current is on.

9. The four-wire power supply with self-detection function as claimed in claim 1, characterized in that: The compensation voltage difference detection unit has two, wherein the first input terminal and the second input terminal of one of the compensation voltage difference detection units are used to respectively obtain the voltages of the first output terminal and the first sensing terminal, and the first input terminal and the second input terminal of the other compensation voltage difference detection unit are used to respectively obtain the voltages of the second output terminal and the second sensing terminal.

10. The four-wire power supply with self-detection function as claimed in claim 9, characterized in that: The output ends of the two compensation voltage difference detection units are connected to form an output node, so that when either of the two compensation voltage difference detection units outputs the first signal, the output node outputs the first signal, and the processing unit is used to receive the first signal output by the output node.

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