Voltage acquisition circuit, bipolar direct current power supply and voltage acquisition method

Abstract

This application discloses a voltage acquisition circuit, a bipolar DC power supply, and a voltage acquisition method. By setting a near-end sampling unit and a far-end sampling unit, the near-end voltage of the bipolar DC power supply output port and the far-end voltage of the load power supply port are respectively acquired. The difference between the two is calculated using a subtractor, and the difference is compared with the positive voltage compensation voltage by a first comparator. The comparison result is output to the switching unit through a first diode. At the same time, the difference is compared with the negative voltage compensation voltage by a second comparator. The comparison result is output to the switching unit through a second diode, causing the switching unit to switch on and off states to output an abnormal comparison voltage. The control unit intelligently selects to call the far-end voltage (normal) or the near-end voltage (abnormal) according to the level of the abnormal comparison voltage. Thus, under both positive and negative voltage output conditions of the bipolar DC power supply, the abnormality of the far-end sampling can be reliably identified.

Description

Technical Field

[0001] This application relates to the technical field of power supply equipment, and in particular to voltage acquisition circuits, bipolar DC power supplies, and voltage acquisition methods. Background Technology

[0002] When a DC regulated power supply supplies power to a load, there is a voltage difference between the output port of the DC regulated power supply and the port of the device under test due to line loss on the output line, which reduces the accuracy of the DC regulated power supply. To solve this problem, the sampling point of the output port is moved to the input port of the load, which is called remote sampling.

[0003] Existing DC regulated power supplies with remote induction sampling have the following drawbacks: 1. When the sampling line falls off, it can cause an open circuit in the constant voltage closed loop, potentially resulting in an open-circuit voltage higher than the required voltage, leading to breakdown or damage to the tested object, or even causing electric shock or fire hazards. 2. When the remote sampling line is reversed, it may burn out the instrument or cause inaccurate sampling voltage, again resulting in an open-circuit voltage higher than the required voltage, which can also lead to breakdown or damage to the tested object, or even causing electric shock or fire hazards. 3. The DC regulated power supply cannot detect when the remote sampling line falls off or is reversed. However, a bipolar DC power supply is a type of power supply that can output both positive voltage and positive current, as well as negative voltage and negative current, operating in the first and third quadrants. Its compensation method differs from that of common unipolar DC power supplies. When the bipolar DC power supply outputs a positive voltage, the current flow direction is as follows... Figure 1 As shown, the output is the same as that of a common DC power supply; when the bipolar DC power supply outputs a negative voltage, the current flow direction is as follows. Figure 2 As shown.

[0004] like Figure 1 and Figure 2As shown, Ulc is the proximal voltage, Urm is the distal voltage, and R0 is the cable resistance. Due to the existence of R0 on the cable, Urm will be slightly less than Ulc, and there will be a small phase difference. In the prior art, the Chinese patent application with the application number CN202311725089.3 discloses a near-end and far-end voltage acquisition circuit for preventing reverse connection and disconnection and a DC regulated power supply, and the Chinese patent application with the application number CN202411611015.1 discloses a voltage acquisition circuit and a power supply device. However, these two methods are only applicable to the case of positive voltage and positive current, and are not applicable to the case of negative voltage and negative current output by the bipolar DC regulated power supply. Currently, there is also a common method of separately sampling the distal voltage and the proximal voltage with two ADCs, calculating the effective value of Ulc - Urm (denoted as |Ulc - Urm|rms), and judging according to the compensation voltage Ucom set by the user to perform distal inductive sampling recognition. If |Ulc - Urm|rms > Ucom, it is judged that the distal inductive sampling is abnormal, and the control loop of the DC power supply calls the sampling data of the proximal end; if |Ulc - Urm|rms < Ucom, it is judged that the distal inductive sampling is normal, and the control loop of the DC power supply calls the sampling data of the distal end. However, this method requires two ADCs for separate sampling, resulting in a higher cost, and the control chip needs to communicate with the two ADCs, which will occupy the algorithm resources of the control chip. Summary of the Invention

[0005] This application aims to propose a voltage acquisition circuit, a bipolar DC power supply, and a voltage acquisition method, which can identify the disconnection of distal inductive sampling and the reverse connection of distal inductive sampling under the conditions of negative voltage and negative current of the bipolar DC power supply.

[0006] In a first aspect, an embodiment of this application provides a voltage acquisition circuit, which is applied to a bipolar DC power supply. The bipolar DC power supply is used to supply power to a load. The voltage acquisition circuit includes: A proximal sampling unit, having a proximal voltage output terminal, a proximal abnormality detection terminal, and a proximal voltage sampling terminal connected to the output port of the bipolar DC power supply; A distal sampling unit, having a distal voltage output terminal, a distal abnormality detection terminal, and a distal voltage sampling terminal connected to the power supply port of the load; An analog-to-digital conversion unit, connected to the proximal voltage output terminal and the distal voltage output terminal respectively; A subtractor, having a subtraction output terminal, a first subtraction input terminal connected to the proximal abnormality detection terminal, and a second subtraction input terminal connected to the distal abnormality detection terminal; The comparison unit includes a first comparator, a second comparator, a positive voltage compensation unit, a negative voltage compensation unit, a first diode, a second diode, and a switching unit. The non-inverting input of the first comparator is connected to the positive voltage compensation unit, and the inverting input of the first comparator is connected to the subtraction output. The non-inverting input of the second comparator is connected to the subtraction output, and the inverting input of the second comparator is connected to the negative voltage compensation unit. The cathode of the first diode is connected to the output of the first comparator, and the anode of the first diode is connected to the input of the switching unit. The cathode of the second diode is connected to the output of the second comparator, and the anode of the second diode is connected to the input of the switching unit. When the input of the switching unit is low, the output of the switching unit is high. The control unit has a control signal output terminal connected to the output terminal of the switching unit and a near-end sampling input terminal and a far-end sampling input terminal connected to the analog-to-digital conversion unit. The control unit is used to receive the near-end voltage and far-end voltage output by the analog-to-digital conversion unit, as well as the abnormal comparison voltage output by the switching unit. If the abnormal comparison voltage is low, it is determined that the far-end sensing sampling is normal, and the far-end voltage is called. If the abnormal comparison voltage is high, it is determined that the far-end sensing sampling is abnormal, and the near-end voltage is called.

[0007] Secondly, embodiments of this application provide a bipolar DC power supply, including the voltage acquisition circuit described in the first aspect embodiment above.

[0008] Thirdly, embodiments of this application provide a voltage acquisition method applied to the bipolar DC power supply described in the second aspect embodiment above, the voltage acquisition method comprising: Receive the near-end voltage and far-end voltage output by the analog-to-digital conversion unit, and the abnormal comparison voltage output by the switching unit; If the abnormal comparison voltage is low, it is determined that the remote sensing sampling is normal, and the remote voltage is called. If the abnormal comparison voltage is high, it is determined that the remote sensing sampling is abnormal, and the near-end voltage is invoked.

[0009] Fourthly, embodiments of this application provide an electronic device, which includes a processor and a memory storing computer program instructions; When the processor executes the computer program, it implements the voltage acquisition method as described in the third aspect embodiment above.

[0010] Fifthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions for performing the voltage acquisition method as described in the third aspect of the embodiments above.

[0011] The voltage acquisition circuit, bipolar DC power supply, and voltage acquisition method of this application embodiment acquire the near-end voltage of the bipolar DC power supply output port and the far-end voltage of the load power supply port by setting a near-end sampling unit and a far-end sampling unit, respectively. A subtractor calculates the difference between the two, and a first comparator compares the positive voltage compensation voltage with this difference. The comparison result is output to the switching unit via a first diode. Simultaneously, a second comparator compares the difference with the negative voltage compensation voltage, and the comparison result is output to the switching unit via a second diode. This causes the switching unit to switch on / off states to output an abnormal comparison voltage. The control unit can determine whether the far-end induction sampling is abnormal based on the level of the abnormal comparison voltage. Thus, it can reliably identify far-end sampling anomalies under both positive and negative voltage output conditions of the bipolar DC power supply. Furthermore, through the coordinated operation of the near-end negative rectification circuit, the far-end negative rectification circuit, the maximum value circuit, and the ADC unit, it achieves the acquisition of far-end voltage when far-end sampling is normal and automatic switching to near-end voltage when abnormal. Only one ADC unit is used, reducing cost and minimizing the algorithm resource usage of the control unit. In addition, by setting four sets of calibration parameters, corresponding to different transmission paths and logical relationships of positive and negative voltages at the far end and near end respectively, the errors caused by path differences and different logic for taking the absolute value of positive and negative voltages are effectively eliminated.

[0012] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. Attached Figure Description

[0013] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of near-end sampling and far-end sampling when a bipolar DC power supply outputs a positive voltage to power a load according to an embodiment of this application; Figure 2 This is a schematic diagram of near-end sampling and far-end sampling when a bipolar DC power supply outputs a negative voltage to power a load according to an embodiment of this application; Figure 3 This is an electrical schematic diagram of a voltage acquisition circuit according to an embodiment of this application; Figure 4 This is a flowchart of a voltage acquisition method according to an embodiment of this application.

[0014] Figure label: Subtractor 100; Comparison Unit 200; Control unit 300; Near-end negative rectifier circuit 410, far-end negative rectifier circuit 420, maximum value circuit 430, ADC unit 440; First sampling unit 510, first signal attenuation unit 520; Second sampling unit 610, second signal attenuation unit 620. Detailed Implementation

[0015] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0016] In the description of this application, the use of terms such as "first," "second," etc., is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0017] In the description of this application, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0018] In the description of this application, it should be noted that, unless otherwise explicitly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0019] The following will combine Figures 1 to 4 The voltage acquisition circuit of the embodiments of this application will be clearly and completely described. Obviously, the embodiments described below are some embodiments of this application, not all embodiments.

[0020] refer to Figures 1 to 4 , Figure 1 This is a schematic diagram of near-end sampling and far-end sampling when a bipolar DC power supply outputs a positive voltage to power a load according to an embodiment of this application; Figure 2 This is a schematic diagram of near-end sampling and far-end sampling when a bipolar DC power supply outputs a negative voltage to power a load according to an embodiment of this application; Figure 3 This is an electrical schematic diagram of a voltage acquisition circuit according to an embodiment of this application; Figure 4This is a flowchart of a voltage acquisition method according to an embodiment of this application.

[0021] According to a first aspect embodiment of the present application, a voltage acquisition circuit is applied to a bipolar DC power supply used to supply power to a load. The voltage acquisition circuit includes a near-end sampling unit, a far-end sampling unit, an analog-to-digital conversion unit, a subtractor 100, a comparison unit 200, and a control unit 300.

[0022] The near-end sampling unit has a near-end voltage output terminal, a near-end anomaly detection terminal, and a near-end voltage sampling terminal connected to the output port of a bipolar DC power supply; The remote sampling unit has a remote voltage output terminal, a remote anomaly detection terminal, and a remote voltage sampling terminal connected to the power supply port of the load; The analog-to-digital conversion unit is connected to the near-end voltage output terminal and the far-end voltage output terminal, respectively. Subtractor 100 has a subtraction output terminal, a first subtraction input terminal connected to a near-end anomaly detection terminal, and a second subtraction input terminal connected to a far-end anomaly detection terminal; The comparison unit 200 includes a first comparator IC8, a second comparator IC9, a positive voltage compensation unit, a negative voltage compensation unit, a first diode D9, a second diode D10, and a switching unit. The non-inverting input of the first comparator IC8 is connected to the positive voltage compensation unit, and the inverting input of the first comparator IC8 is connected to the subtraction output. The non-inverting input of the second comparator IC9 is connected to the subtraction output, and the inverting input of the second comparator IC9 is connected to the negative voltage compensation unit. The cathode of the first diode D9 is connected to the output of the first comparator IC8, and the anode of the first diode D9 is connected to the input of the switching unit. The cathode of the second diode D10 is connected to the output of the second comparator IC9, and the anode of the second diode D10 is connected to the input of the switching unit. When the input of the switching unit is low, the output of the switching unit is high. The control unit 300 has a control signal output terminal connected to the output terminal of the switching unit and a near-end sampling input terminal and a far-end sampling input terminal connected to the analog-to-digital conversion unit. The control unit 300 is used to receive the near-end voltage and far-end voltage output by the analog-to-digital conversion unit, as well as the abnormal comparison voltage output by the switching unit. If the abnormal comparison voltage is low, it is determined that the far-end sensing sampling is normal and the far-end voltage is called. If the abnormal comparison voltage is high, it is determined that the far-end sensing sampling is abnormal and the near-end voltage is called.

[0023] The voltage acquisition circuit of this application embodiment acquires the near-end voltage of the bipolar DC power supply output port and the far-end voltage of the load power supply port by setting a near-end sampling unit and a far-end sampling unit, respectively. The difference between the two is calculated by a subtractor 100, and the difference is compared with the positive voltage compensation voltage by a first comparator. The comparison result is output to the switching unit through a first diode. At the same time, the difference is compared with the negative voltage compensation voltage by a second comparator. The comparison result is output to the switching unit through a second diode, so that the switching unit switches the on / off state to output an abnormal comparison voltage. The control unit 300 intelligently selects to call the far-end voltage (normal) or the near-end voltage (abnormal) according to the level of the abnormal comparison voltage, so that the far-end sampling abnormality can be reliably identified under both positive and negative voltage output conditions of the bipolar DC power supply.

[0024] In some embodiments of this application, reference is made to Figure 3 The near-end sampling unit includes a first sampling unit 510 and a first signal attenuation unit 520, and the far-end sampling unit includes a second sampling unit 610 and a second signal attenuation unit 620.

[0025] The first sampling unit 510 has its input terminal connected to the output port of the bipolar DC power supply. The first signal attenuation unit 520 has its input terminal connected to the output terminal of the first sampling unit 510, and its output terminal connected to the analog-to-digital conversion unit and the first subtraction input terminal, respectively. The second sampling unit 610 has its input terminal connected to the power supply port of the load. The second signal attenuation unit 620 has its input terminal connected to the output terminal of the second sampling unit 610, and its output terminal connected to the analog-to-digital conversion unit and the second subtraction input terminal, respectively.

[0026] The first sampling unit 510 is used to initially acquire the voltage at the output port of the bipolar DC power supply, obtaining the raw near-end voltage signal. The first signal attenuation unit 520 attenuates the near-end voltage signal output by the first sampling unit 510, adjusting it to a voltage range that can be adapted to by the subtractor 100 and the ADC unit 440, thus preventing damage to subsequent circuit components due to excessively high input voltage. Similarly, the second sampling unit 610 is responsible for acquiring the far-end voltage signal at the load power supply port, and the second signal attenuation unit 620 attenuates the acquired far-end voltage signal to meet the input requirements of the subtractor 100 and the ADC unit 440. Figure 3In this diagram, Ulc1 is the near-end voltage Ulc after signal attenuation, and Urm1 is the far-end voltage Urm after signal attenuation. The ADC unit 440 converts the attenuated analog near-end voltage signal or analog far-end voltage signal into a digital signal and transmits the digital signal to the control unit 300 so that the control unit 300 can perform subsequent numerical calculations and judgments.

[0027] Through this structural design, the near-end sampling unit and the far-end sampling unit can accurately and reliably sample the voltage at the output terminal and the load terminal of the bipolar DC power supply, respectively, and provide the sampling results to the control unit 300 in digital form, laying a solid data foundation for the control unit 300 to accurately determine the remote sensing sampling status.

[0028] In some embodiments of this application, reference is made to Figure 3 The subtractor 100 includes resistors R19, R21, R22, and R23, and operational amplifier IC7. The resistance values ​​of resistors R19, R21, R22, and R23 are equal, so that the voltage output by operational amplifier IC7 is U7 = Ulc1 - Urm1.

[0029] In some embodiments of this application, reference is made to Figure 3 Both the positive and negative voltage compensation units employ voltage divider circuits. The positive voltage compensation unit includes resistors R17 and R18, with U8 being the positive voltage compensation voltage, obtained by dividing the positive power supply VCC through resistors R17 and R18. The negative voltage compensation unit includes resistors R24 and R25, with U9 being the negative voltage compensation voltage, obtained by dividing the negative power supply -VCC through resistors R24 and R25.

[0030] It should be noted that the positive voltage compensation voltage and the negative voltage compensation voltage are set according to the actual situation, which is equivalent to the compensation voltage Ucom mentioned in the background art. The specific setting principle is the prior art known to those skilled in the art, and will not be elaborated here.

[0031] In some embodiments of this application, if the compensation voltage for the positive voltage of the allowed line is Ucom_h, the compensation voltage for the negative voltage is Ucom_n, and the ratio of the first signal attenuation unit 520 and the second signal attenuation unit 620 is k, then the values ​​of U8 and U9 are respectively: U8=Ucom_h×k=VCC×R17 / (R17+R18), U9=Ucom_n×k=-VCC×R24 / (R24+R25).

[0032] In some embodiments of this application, reference is made to Figure 3The switching unit includes a current-limiting resistor R6, a pull-up resistor R5, a switching transistor Q1, and a pull-down resistor R10.

[0033] A current-limiting resistor R6 is used, with one end of the current-limiting resistor R6 connected to the positive terminals of the first diode and the second diode, respectively. Pull-up resistor R5, one end of pull-up resistor R5 is connected to the other end of current limiting resistor R6, and the other end of pull-up resistor R5 is connected to power supply VCC. The base of the switching transistor Q1 is connected to the other end of the current limiting resistor R6 and one end of the pull-up resistor R5, respectively. The emitter of the switching transistor Q1 is connected to the other end of the pull-up resistor R5 and the power supply VCC, respectively. Pull-down resistor R10, one end of which is connected to the collector of switching transistor Q1 and control unit 300 respectively, and the other end of pull-down resistor R10 is connected to reference ground GND.

[0034] The switching transistor Q1 is a PNP transistor. The outputs of the first comparator IC8 and the second comparator IC9 control the switching on and off of the switching transistor Q1 through the first diode D9 and the second diode D10. The output values ​​of the first comparator IC8 are U8-U7, and the output values ​​of the second comparator IC9 are U7-U9. When the remote sensing sampling is normal, U12 is high, the switching transistor Q1 is off, and the abnormal comparison voltage U10 is low; when the remote sensing sampling is abnormal (reverse connection or disconnection), U12 is low, the switching transistor Q1 is on, and the abnormal comparison voltage U10 is high.

[0035] In some embodiments of this application, reference is made to Figure 3 The comparison unit 200 also includes a third diode D7 and a fourth diode D8. The cathode of the third diode D7 is connected to the output terminal of the first comparator IC8, and the cathode of the fourth diode D8 is connected to the output terminal of the second comparator IC9. The analog-to-digital conversion unit includes a near-end negative rectifier circuit 410, a far-end negative rectifier circuit 420, a maximum value circuit 430, and an ADC unit 440.

[0036] The input terminal of the near-end negative rectifier circuit 410 is connected to the near-end voltage output terminal. The input terminal of the remote negative rectifier circuit 420 is connected to the remote voltage output terminal. The maximum value circuit 430 has a comparison output terminal, a first comparison input terminal connected to the output terminal of the near-end negative rectifier circuit 410, and a second comparison input terminal connected to the output terminal of the far-end negative rectifier circuit 420, the positive terminal of the third diode D7, and the positive terminal of the fourth diode D8, respectively. ADC unit 440, the input terminal of ADC unit 440 is connected to the comparison output terminal, and the output terminal of ADC unit 440 is connected to the control unit 300.

[0037] The near-end negative rectifier circuit 410 includes a first near-end resistor R3, a first near-end operational amplifier IC1, a first near-end diode D2, a second near-end diode D3, a second near-end resistor R7, a third near-end resistor R2, a second near-end operational amplifier IC2, a fourth near-end resistor R8, and a fifth near-end resistor R9.

[0038] The first near-end resistor R3, one end of which is connected to the near-end voltage output terminal; The first near-end operational amplifier IC1 has its non-inverting input connected to reference ground and its inverting input connected to the other end of the first near-end resistor R3. The positive terminal of the first near-end diode D2 is connected to the output terminal of the first near-end operational amplifier IC1. The positive terminal of the second near-end diode D3 is connected to the other end of the first near-end resistor R3 and the inverting input terminal of the first near-end operational amplifier IC1, respectively. The negative terminal of the second near-end diode D3 is connected to the output terminal of the first near-end operational amplifier IC1 and the positive terminal of the first near-end diode D2, respectively. The second near-end resistor R7 has one end connected to the other end of the first near-end resistor R3 and the inverting input terminal of the first near-end operational amplifier IC1, and the other end of the second near-end resistor R7 is connected to the cathode of the first near-end diode D2. The third near-end resistor R2, one end of which is connected to the cathode of the first near-end diode D2 and the other end of the second near-end resistor R7. The second near-end operational amplifier IC2 has its non-inverting input connected to reference ground GND, its inverting input connected to the other end of the third near-end resistor R2, and its output connected to the first comparator input. The fourth near-end resistor R8 has one end connected to the near-end voltage output terminal and one end of the first near-end resistor R3, and the other end of the fourth near-end resistor R8 is connected to the other end of the third near-end resistor R2 and the inverting input terminal of the second near-end operational amplifier IC2. The fifth near-end resistor R9 has one end connected to the other end of the fourth near-end resistor R8, the other end of the third near-end resistor R2, and the inverting input of the second near-end operational amplifier IC2. The other end of the fifth near-end resistor R9 is connected to the output of the second near-end operational amplifier IC2 and the first comparator input.

[0039] The remote negative rectifier circuit 420 includes a first remote resistor R12, a first remote operational amplifier IC4, a first remote diode D5, a second remote diode D6, a second remote resistor R14, a third remote resistor R11, a second remote operational amplifier IC5, a fourth remote resistor R15, and a fifth remote resistor R16.

[0040] The first remote resistor R12, one end of which is connected to the remote voltage output terminal; The first remote operational amplifier IC4 has its non-inverting input connected to reference ground GND, and its inverting input connected to the other end of the first remote resistor R12. The positive terminal of the first far-end diode D5 is connected to the output terminal of the first far-end operational amplifier IC4. The positive terminal of the second far-end diode D6 is connected to the other end of the first far-end resistor R12 and the inverting input terminal of the first far-end operational amplifier IC4, respectively. The negative terminal of the second far-end diode D6 is connected to the output terminal of the first far-end operational amplifier IC4 and the positive terminal of the first far-end diode D5, respectively. The second remote resistor R14 has one end connected to the other end of the first remote resistor R12 and the inverting input terminal of the first remote operational amplifier IC4, and the other end of the second remote resistor R14 is connected to the negative terminal of the first remote diode D5. The third remote resistor R11 is connected at one end to the negative terminal of the first remote diode D5 and the other end of the second remote resistor R14. The second remote operational amplifier IC5 has its non-inverting input connected to reference ground GND, its inverting input connected to the other end of the third remote resistor R11, and its output connected to the second comparator input. The fourth remote resistor R15 is connected to the remote voltage output terminal and one end of the first remote resistor R12, respectively. The other end of the fourth remote resistor R15 is connected to the other end of the third remote resistor R11 and the inverting input terminal of the second remote operational amplifier IC5. The fifth remote resistor R16 has one end connected to the other end of the fourth remote resistor R15, the other end of the third remote resistor R11, and the inverting input of the second remote operational amplifier IC5. The other end of the fifth remote resistor R16 is connected to the output and the second comparator input of the second remote operational amplifier IC5.

[0041] The maximum value circuit 430 includes a first maximum value operational amplifier IC3, a first maximum value diode D1, a first maximum value resistor R20, a second maximum value operational amplifier IC6, a second maximum value diode D4, a second maximum value resistor R1, a third maximum value operational amplifier IC10, and a third maximum value resistor R4.

[0042] The first maximum value operational amplifier IC3 has its non-inverting input terminal connected to the output terminal of the near-end negative rectifier circuit 410. The first maximum value diode D1 has its positive terminal connected to the output terminal of the first maximum value operational amplifier IC3, and its negative terminal connected to the inverting input terminal of the first maximum value operational amplifier IC3. The first maximum value resistor R20 has one end connected to the output terminal of the remote negative rectifier circuit 420, and the other end connected to the positive terminal of the third diode D7 and the positive terminal of the fourth diode D8, respectively. The second maximum value operational amplifier IC6 has its non-inverting input terminal connected to the other end of the first maximum value resistor R20, the positive terminal of the third diode D7, and the positive terminal of the fourth diode D8, respectively. The positive terminal of the second maximum value diode D4 is connected to the output terminal of the second maximum value operational amplifier IC6, and the negative terminal of the second maximum value diode D4 is connected to the inverting input terminal of the second maximum value operational amplifier IC6, the negative terminal of the first maximum value diode D1, and the inverting input terminal of the first maximum value operational amplifier IC3. The second maximum value resistor R1 has one end connected to the cathode of the first maximum value diode D1, the inverting input terminal of the first maximum value operational amplifier IC3, the cathode of the second maximum value diode D4, and the inverting input terminal of the second maximum value operational amplifier IC6, respectively. The third maximum value operational amplifier IC10 has its non-inverting input connected to reference ground GND, its inverting input connected to the other end of the second maximum value resistor R1, and its output connected to the input of ADC unit 440. The third maximum resistance R4, one end of the third maximum resistance R4 is respectively connected to the other end of the second maximum resistance R1 and the inverting input terminal of the third maximum operational amplifier IC10, and the other end of the third maximum resistance R4 is respectively connected to the output terminal of the third maximum operational amplifier IC10 and the input terminal of the ADC unit 440.

[0043] In the above-mentioned proximal negative rectifier circuit 410, R3 = R7, R8 = R9 = 2 × R2. When Ulc1 is a positive voltage, D3 conducts forward, D2 cuts off in reverse, so U1 = 0V, U2 = -Ulc1 × R9 / R8 = -Ulc1; when Ulc1 is a negative voltage, D3 cuts off in reverse, D2 conducts forward, U1 = -Ulc1 × R7 / R3, U2 = -Ulc1 × R9 / R8 - U1 × R9 / R2 = -Ulc1 × R9 / R8 + Ulc1 × R7 / R3 × R9 / R2 = Ulc1. Therefore, U2 = -|Ulc1|.

[0044] In the above-mentioned distal negative rectifier circuit 420, R12 = R14, R15 = R16 = 2 × R11. Similarly to the proximal negative rectifier circuit 410, U4 = -|Urm1|.

[0045] In the above-mentioned maximum value circuit 430, R1 = R4. When U2 > U11, D1 conducts forward, D4 cuts off in reverse, so U5 = U2; when U2 < U11, D1 cuts off in reverse, D4 conducts forward, so U5 = U11. Therefore, U5 = MAX(U2, U11). At this time, U2 and U11 are still negative voltages. R1, R4 and IC10 form an inverter, which inverts U5 into a positive voltage U6 (here it means that relative to the signal ground, the voltage of U5 is a negative voltage, and a conventional ADC unit can only receive positive voltages, so U5 needs to be inverted into a positive voltage U6 in order to be read by the ADC unit 440).

[0046] This application first converts the near-end voltage and the far-end voltage into their negative absolute values, i.e., U2=-|Ulc1| and U4=-|Urm1|, respectively, through the near-end negative rectifier circuit 410 and the far-end negative rectifier circuit 420. Then, the maximum value circuit 430 compares the two negative absolute value signals U2 and U11 (U11 is the signal after U4 output by the far-end negative rectifier circuit 420 is transmitted through the first maximum value resistor R20) and selects the maximum value U5=MAX(U2, U11). Since a conventional ADC unit 440 typically only accepts positive voltage input, while U5 is still negative at this time, an inverter composed of R1, R4, and the third maximum operational amplifier IC10 will invert U5 to a positive voltage U6 so that the ADC unit 440 can accurately read the voltage value. Subsequently, the control unit 300 performs positive and negative voltage calibration. This allows the ADC unit 440 to receive the far-end voltage when the far-end sensing sampling is normal, and to receive the near-end voltage when the far-end sensing sampling is abnormal. Only one ADC unit 440 is used, reducing costs and minimizing the algorithm resource usage of the control unit 300.

[0047] refer to Figure 4 The workflow of this application is as follows: Step 1: The control unit 300 has four built-in calibration parameters, including remote positive voltage calibration parameters, remote negative voltage calibration parameters, near-end positive voltage calibration parameters, and near-end negative voltage calibration parameters.

[0048] Step 2: User sets the output voltage; Step 3: The control unit 300 determines the positive or negative state of the output voltage and the state of U10. When the output voltage is negative and U10 is low, the remote sensing sampling is normal. The control unit 300 receives the remote voltage sent by the ADC unit 440 and calls the remote negative voltage calibration parameters to calibrate the remote voltage. When the output voltage is negative and U10 is high, the remote sensing sampling is abnormal. The control unit 300 receives the near-end voltage sent by the ADC unit 440 and calls the near-end negative voltage calibration parameters to calibrate the near-end voltage. When the output voltage is positive and U10 is low, the remote sensing sampling is normal. The control unit 300 receives the remote voltage sent by the ADC unit 440 and calls the remote positive voltage calibration parameters to calibrate the remote voltage. When the output voltage is positive and U10 is high, the remote sensing sampling is abnormal. The control unit 300 receives the near-end voltage sent by the ADC unit 440 and calls the near-end positive voltage calibration parameters to calibrate the near-end voltage.

[0049] It should be noted that the far-end voltage is transmitted to the ADC unit 440 via the second attenuation unit, IC4, IC5, IC6, and IC10, while the near-end voltage is transmitted to the ADC unit 440 via the first attenuation unit, IC1, IC2, IC3, and IC10. Because the transmission paths are different, the total attenuation factor will have slight differences, so two sets of calibration parameters are needed for the far and near ends. Although the positive and negative voltages follow the same transmission path, the logical relationship when taking the absolute value is different, so two sets of parameters are also required. Therefore, a total of four sets of calibration parameters are needed: far-end positive voltage calibration parameters, far-end negative voltage calibration parameters, near-end positive voltage calibration parameters, and near-end negative voltage calibration parameters. The calibration parameters are related to the attenuation ratio k of the first and second attenuation units. If the voltage U6 at the front end of the ADC unit 440 is 1V, and the attenuation ratio k = 1 / 300, then the control unit 300 needs to select either a positive or negative calibration coefficient based on the user's positive or negative output settings. If positive, the 1V at the front end of the ADC unit 440 will display 300V (calibrated voltage is 1V / k = 300V). If negative, the 1V at the front end of the ADC unit 440 will display -300V (calibrated voltage is -1V / k = -300V). Since there is only one ADC unit 440, but four different scenarios exist, four different calibration parameters need to be selected based on the state of U10 and the positive / negative voltage relationship set by the user.

[0050] The following specific embodiments will be used to describe in detail the operation of the voltage acquisition circuit of this application under various conditions: The ratio k of the first attenuation unit and the second attenuation unit is 1 / 300; R3=R7=R8=R9=10kΩ; R2 = 5kΩ; R12=R14=R15=R16=10kΩ; R11 = 5kΩ; R19=R21=R22=R23=10kΩ; R1=R4=10kΩ; R17=R24=1kΩ; R18=R25=100kΩ; VCC=5V, U8=0.0495V, U9=-0.0495V.

[0051] 1. When the user outputs a positive voltage and the remote sensing and sampling are all connected: The user outputs a near-end voltage of 300V and a far-end voltage of 297V. Ulc1=300V×1 / 300=1V, Urm1=297V / 300=0.99V; U2=-|Ulc1|=-1V, U4=-|Urm1|=-0.99V; U7 = Ulc1 - Urm1 = 0.01V; At this time, the outputs of IC8 and IC9 are both VCC=5V, and D7 and D8 are reverse cutoff. The voltage of U11 is not affected by the outputs of IC8 and IC9, so U11 = U4; U5=MAX(U2,U11)=-0.99V, U6=-U5=0.99V, ADC unit 440 automatically takes the remote voltage; D9 and D10 are reverse cutoff, and the voltage of U12 is pulled to the positive power rail by VCC through R5, so Q1 is turned off. At this time, U10 is at a low level, and the control unit 300 determines that the remote sensing sampling is normal.

[0052] 2. The user outputs a positive voltage, and the remote sensing sampling is disconnected: The user outputs a near-end voltage of 300V and a far-end voltage of 297V. Ulc1 = 300V × 1 / 300 = 1V, the remote end is disconnected, so Urm1 = 0V; U2=-|Ulc1|=-1V, U4=-|Urm1|=0V; U7 = Ulc1 - Urm1 = 1V; IC9 outputs VCC, IC8 outputs -VCC, D7 and D9 conduct in the forward direction, and D8 and D10 are cut off in the reverse direction. The voltage of U11 is forcibly pulled to the negative power rail by the output of IC8 through D7, U11=-VCC; U5=MAX(U2,U11)=-1V, U6=-U5=1V, ADC unit 440 automatically takes the near-end voltage; When D9 is forward-biased, U12 is pulled to the negative power rail by the output of IC8 through D9, Q1 is turned on, and U10 is at a high level. The control unit 300 determines that the remote sensing sampling is abnormal.

[0053] 3. The user outputs a positive voltage, and the remote sensing sampling is reversed: The user outputs a near-end voltage of 300V and a far-end voltage of 297V. Ulc1 = 300V × 1 / 300 = 1V, with the far end reversed, Urm1 = -297V × 1 / 300 = -0.99V; U2=-|Ulc1|=-1V, U4=-|Urm1|=-0.99V; U7 = Ulc1 - Urm1 = 1.99V; IC9 outputs VCC, IC8 outputs -VCC, D7 and D9 conduct in the forward direction, and D8 and D10 are cut off in the reverse direction. The voltage of U11 is forcibly pulled to the negative power rail by the output of IC8 through D7, U11=-VCC; U5=MAX(U2,U11)=-1V, U6=-U5=1V, ADC unit 440 automatically takes the near-end voltage; When D9 is forward-biased, U12 is pulled to the negative power rail by the output of IC8 through D9, Q1 is turned on, and U10 is at a high level. The control unit 300 determines that the remote sensing sampling is abnormal.

[0054] 4. When the user outputs a negative voltage and the remote sensing and sampling are all connected: The user outputs a near-end voltage of -300V and a far-end voltage of -297V. Ulc1=-300V×1 / 300=-1V, Urm1=-297V / 300=-0.99V; U2=-|Ulc1|=-1V, U4=-|Urm1|=-0.99V; U7 = Ulc1 - Urm1 = -0.01V; Both IC8 and IC9 output VCC=5V, and D7 and D8 are reverse cutoff. The voltage of U11 is not affected by the outputs of IC8 and IC9, so U11 = U4; U5=MAX(U2,U11)=-0.99V, U6=-U5=0.99V, ADC unit 440 automatically takes the remote voltage; D9 and D10 are reverse cutoff, and the voltage VCC of U12 is pulled to the positive power rail through R5, so Q1 is turned off, U10 is at a low level, and the control unit 300 determines that the remote sensing sampling is normal.

[0055] 5. The user outputs a negative voltage, and the remote sensing sampling is disconnected: The user outputs a near-end voltage of -300V and a far-end voltage of -297V. Ulc1 = -300V × 1 / 300 = -1V, the remote connection is lost, so Urm1 = 0V; U2=-|Ulc1|=-1V, U4=-|Urm1|=0V; U7 = Ulc1 - Urm1 = -1V; IC8 outputs VCC, IC9 outputs -VCC, D8 and D10 are forward-biased, and D7 and D9 are reverse-biased. The voltage of U11 is forcibly pulled to the negative power rail by the output of IC9 through D8, U11=-VCC; U5=MAX(U2,U11)=-1V, U6=-U5=1V, ADC unit 440 automatically takes the near-end voltage; U12 is pulled to the negative power rail by the output of IC9 through D10, Q1 is turned on, U10 is at a high level, and the control unit 300 determines that the remote sensing sampling is abnormal.

[0056] 6. The user outputs a negative voltage, and the remote sensing sampling is reversed: The user outputs a near-end voltage of -300V and a far-end voltage of -297V. Ulc1 = -300V × 1 / 300 = -1V, the far end is reversed, so Urm1 = 297V × 1 / 300 = 0.99V; U2=-|Ulc1|=-1V, U4=-|Urm1|=-0.99V; U7 = Ulc1 - Urm1 = -1.99V; IC8 outputs VCC, IC9 outputs -VCC, D8 and D10 are forward-biased, and D7 and D9 are reverse-biased. The voltage of U11 is forcibly pulled to the negative power rail by the output of IC9 through D8, U11=-VCC; U5=MAX(U2,U11)=-1V, U6=-U5=1V, ADC unit 440 automatically takes the near-end voltage; U12 is pulled to the negative power rail by the output of IC9 through D10, Q1 is turned on, U10 is at a high level, and the control unit 300 determines that the remote sensing sampling is abnormal.

[0057] The bipolar DC power supply according to a second aspect embodiment of this application includes a voltage acquisition circuit as described in the first aspect embodiment. Since the bipolar DC power supply employs all the technical solutions of the voltage acquisition circuit described in the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated further here.

[0058] The voltage acquisition method according to the third aspect embodiment of this application, applied to a bipolar DC power supply as described in the second aspect embodiment above, includes: It receives the near-end voltage and far-end voltage output from the analog-to-digital conversion unit, as well as the abnormal comparison voltage output from the switching unit; If the abnormal comparison voltage is low, it is determined that the remote sensing sampling is normal, and the remote voltage is called. If the abnormal comparison voltage is high, it is determined that the remote sensing sampling is abnormal, and the near-end voltage is called.

[0059] Since the voltage acquisition method adopts all the technical solutions of the bipolar DC power supply in the above embodiments, it has at least all the beneficial effects brought about by the technical solutions in the above embodiments, and will not be repeated here.

[0060] The voltage acquisition circuit, bipolar DC power supply, and voltage acquisition method of this application embodiment acquire the near-end voltage of the bipolar DC power supply output port and the far-end voltage of the load power supply port by setting a near-end sampling unit and a far-end sampling unit, respectively. The difference between the two is calculated by a subtractor 100, and the difference is compared with the positive voltage compensation voltage by a first comparator. The comparison result is output to the switching unit through a first diode. At the same time, the difference is compared with the negative voltage compensation voltage by a second comparator. The comparison result is output to the switching unit through a second diode, so that the switching unit switches on and off to output an abnormal comparison voltage. The control unit 300 can determine whether the far-end induction sampling is abnormal based on the level of the abnormal comparison voltage. Thus, the far-end sampling abnormality can be reliably identified under both positive and negative voltage output conditions of the bipolar DC power supply. Meanwhile, through the coordinated operation of the near-end negative rectifier circuit 410, the far-end negative rectifier circuit 420, the maximum value circuit 430, and the ADC unit 440, the system achieves the acquisition of the far-end voltage when the far-end sampling is normal, and automatically switches to the near-end voltage when an anomaly occurs. This utilizes only one ADC unit 440, reducing cost and minimizing the algorithm resource usage of the control unit 300. Furthermore, by setting four sets of calibration parameters, corresponding to different transmission paths and logical relationships of the far-end positive and negative voltages and the near-end positive and negative voltages respectively, errors caused by path differences and different logic for taking the absolute values ​​of positive and negative voltages are effectively eliminated.

[0061] In addition, one embodiment of this application provides an electronic device including a processor and a memory storing computer program instructions; when the processor executes the computer program, it implements the voltage acquisition method as described in the above embodiments. The processor and the memory can be connected via a bus or other means.

[0062] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0063] The non-transient software program and instructions required to implement the voltage acquisition method of the above embodiments are stored in the memory. When executed by the processor, the voltage acquisition method of the above embodiments is executed.

[0064] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0065] Furthermore, one embodiment of this application provides a computer-readable storage medium storing computer-executable instructions that are executed by a processor or controller, such as the processor of the aforementioned electronic device, causing the processor to perform the voltage acquisition method described in the above embodiment.

[0066] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0067] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. A voltage acquisition circuit, characterized in that, An application is made in a bipolar DC power supply used to supply power to a load, and the voltage acquisition circuit includes: The near-end sampling unit has a near-end voltage output terminal, a near-end anomaly detection terminal, and a near-end voltage sampling terminal connected to the output port of the bipolar DC power supply; The remote sampling unit has a remote voltage output terminal, a remote anomaly detection terminal, and a remote voltage sampling terminal connected to the power supply port of the load; An analog-to-digital conversion unit is connected to the near-end voltage output terminal and the far-end voltage output terminal, respectively. The subtractor (100) has a subtraction output terminal, a first subtraction input terminal connected to the proximal anomaly detection terminal, and a second subtraction input terminal connected to the distal anomaly detection terminal; The comparator unit (200) includes a first comparator, a second comparator, a positive voltage compensation unit, a negative voltage compensation unit, a first diode, a second diode, and a switching unit. The non-inverting input of the first comparator is connected to the positive voltage compensation unit, and the inverting input of the first comparator is connected to the subtraction output. The non-inverting input of the second comparator is connected to the subtraction output, and the inverting input of the second comparator is connected to the negative voltage compensation unit. The cathode of the first diode is connected to the output of the first comparator, and the anode of the first diode is connected to the input of the switching unit. The cathode of the second diode is connected to the output of the second comparator, and the anode of the second diode is connected to the input of the switching unit. When the input of the switching unit is low, the output of the switching unit is high. Both the positive voltage compensation unit and the negative voltage compensation unit employ voltage divider circuits. The control unit (300) has a control signal output terminal connected to the output terminal of the switching unit and a near-end sampling input terminal and a far-end sampling input terminal connected to the analog-to-digital conversion unit. The control unit (300) is used to receive the near-end voltage and far-end voltage output by the analog-to-digital conversion unit, as well as the abnormal comparison voltage output by the switching unit. If the abnormal comparison voltage is low, it is determined that the far-end sensing sampling is normal, and the far-end voltage is called. If the abnormal comparison voltage is high, it is determined that the far-end sensing sampling is abnormal, and the near-end voltage is called.

2. The voltage acquisition circuit according to claim 1, characterized in that, The comparison unit (200) further includes a third diode and a fourth diode, the negative terminal of the third diode being connected to the output terminal of the first comparator, and the negative terminal of the fourth diode being connected to the output terminal of the second comparator; The analog-to-digital conversion unit includes: A near-end negative rectifier circuit (410) is provided, wherein the input terminal of the near-end negative rectifier circuit (410) is connected to the near-end voltage output terminal; A remote negative rectifier circuit (420) is provided, wherein the input terminal of the remote negative rectifier circuit (420) is connected to the remote voltage output terminal; The maximum value circuit (430) has a comparison output terminal, a first comparison input terminal connected to the output terminal of the near-end negative rectifier circuit (410), and a second comparison input terminal connected to the output terminal of the far-end negative rectifier circuit (420), the positive terminal of the third diode, and the positive terminal of the fourth diode, respectively. An ADC unit (440) is provided, the input of which is connected to the comparison output, and the output of which is connected to the control unit (300).

3. The voltage acquisition circuit according to claim 2, characterized in that, The near-end negative rectifier circuit (410) includes: A first near-end resistor, one end of which is connected to the near-end voltage output terminal; A first near-end operational amplifier, wherein the non-inverting input of the first near-end operational amplifier is connected to a reference ground, and the inverting input of the first near-end operational amplifier is connected to the other end of the first near-end resistor; The first near-end diode, the positive terminal of which is connected to the output terminal of the first near-end operational amplifier; The positive terminal of the second near-end diode is connected to the other end of the first near-end resistor and the inverting input terminal of the first near-end operational amplifier, respectively, and the negative terminal of the second near-end diode is connected to the output terminal of the first near-end operational amplifier and the positive terminal of the first near-end diode, respectively. The second near-end resistor has one end connected to the other end of the first near-end resistor and the inverting input terminal of the first near-end operational amplifier, and the other end of the second near-end resistor is connected to the cathode of the first near-end diode. A third proximal resistor, one end of which is connected to the cathode of the first proximal diode and the other end of the second proximal resistor; The second near-end operational amplifier has its non-inverting input connected to reference ground, its inverting input connected to the other end of the third near-end resistor, and its output connected to the first comparator input. A fourth near-end resistor, one end of which is connected to the near-end voltage output terminal and one end of the first near-end resistor, and the other end of which is connected to the other end of the third near-end resistor and the inverting input terminal of the second near-end operational amplifier. The fifth near-end resistor has one end connected to the other end of the fourth near-end resistor, the other end of the third near-end resistor, and the inverting input of the second near-end operational amplifier, and the other end connected to the output of the second near-end operational amplifier and the first comparator input.

4. The voltage acquisition circuit according to claim 2, characterized in that, The remote negative rectifier circuit (420) includes: A first remote resistor, one end of which is connected to the remote voltage output terminal; A first remote operational amplifier, wherein the non-inverting input of the first remote operational amplifier is connected to a reference ground, and the inverting input of the first remote operational amplifier is connected to the other end of the first remote resistor; The first distal diode, the positive terminal of which is connected to the output terminal of the first distal operational amplifier; The positive terminal of the second far-end diode is connected to the other end of the first far-end resistor and the inverting input terminal of the first far-end operational amplifier, respectively, and the negative terminal of the second far-end diode is connected to the output terminal of the first far-end operational amplifier and the positive terminal of the first far-end diode, respectively. The second remote resistor has one end connected to the other end of the first remote resistor and the inverting input terminal of the first remote operational amplifier, and the other end of the second remote resistor is connected to the negative terminal of the first remote diode. The third remote resistor, one end of which is connected to the negative terminal of the first remote diode and the other end of the second remote resistor respectively; The second remote operational amplifier has its non-inverting input connected to reference ground, its inverting input connected to the other end of the third remote resistor, and its output connected to the second comparator input. A fourth remote resistor, one end of which is connected to the remote voltage output terminal and one end of the first remote resistor, and the other end of which is connected to the other end of the third remote resistor and the inverting input terminal of the second remote operational amplifier. The fifth far-end resistor has one end connected to the other end of the fourth far-end resistor, the other end of the third far-end resistor, and the inverting input terminal of the second far-end operational amplifier, and the other end connected to the output terminal and the second comparator input terminal of the second far-end operational amplifier.

5. The voltage acquisition circuit according to claim 2, characterized in that, The maximum value circuit (430) includes: The first maximum value operational amplifier is connected to the output of the near-end negative rectifier circuit (410). The first maximum value diode has its anode connected to the output terminal of the first maximum value operational amplifier, and its cathode connected to the inverting input terminal of the first maximum value operational amplifier. The first maximum value resistor has one end connected to the output terminal of the far-end negative rectifier circuit (420), and the other end connected to the positive terminal of the third diode and the positive terminal of the fourth diode, respectively. The second maximum value operational amplifier has its non-inverting input terminal connected to the other end of the first maximum value resistor, the positive terminal of the third diode, and the positive terminal of the fourth diode, respectively. The second maximum value diode has its positive terminal connected to the output terminal of the second maximum value operational amplifier, and its negative terminal connected to the inverting input terminal of the second maximum value operational amplifier, the negative terminal of the first maximum value diode, and the inverting input terminal of the first maximum value operational amplifier. The second maximum value resistor has one end connected to the cathode of the first maximum value diode, the inverting input terminal of the first maximum value operational amplifier, the cathode of the second maximum value diode, and the inverting input terminal of the second maximum value operational amplifier, respectively. The third maximum value operational amplifier has its non-inverting input connected to reference ground, its inverting input connected to the other end of the second maximum value resistor, and its output connected to the input of the ADC unit (440). The third maximum value resistor has one end connected to the other end of the second maximum value resistor and the inverting input terminal of the third maximum value operational amplifier, and the other end connected to the output terminal of the third maximum value operational amplifier and the input terminal of the ADC unit (440).

6. The voltage acquisition circuit according to claim 1, characterized in that, The switching unit includes: A current-limiting resistor, one end of which is connected to the positive terminal of the first diode and the positive terminal of the second diode, respectively; A pull-up resistor, one end of which is connected to the other end of the current-limiting resistor, and the other end of which is connected to the power supply. The switching transistor has its base connected to the other end of the current-limiting resistor and one end of the pull-up resistor, and its emitter connected to the other end of the pull-up resistor and the power supply. A pull-down resistor, one end of which is connected to the collector of the switching transistor and the control unit (300), and the other end of which is connected to a reference ground.

7. The voltage acquisition circuit according to claim 1, characterized in that, The proximal sampling unit includes: The first sampling unit (510) has its input terminal connected to the output port of the bipolar DC power supply. The first signal attenuation unit (520) has its input terminal connected to the output terminal of the first sampling unit (510), and its output terminal is connected to the analog-to-digital conversion unit and the first subtraction input terminal, respectively. The remote sampling unit includes: The second sampling unit (610) has its input terminal connected to the power supply port of the load. The second signal attenuation unit (620) has its input terminal connected to the output terminal of the second sampling unit (610), and its output terminal is connected to the analog-to-digital conversion unit and the second subtraction input terminal, respectively.

8. A bipolar DC power supply, characterized in that, Includes the voltage acquisition circuit as described in any one of claims 1 to 7.

9. A voltage acquisition method, characterized in that, Applied to the bipolar DC power supply as described in claim 8, the voltage acquisition method includes: Receive the near-end voltage and far-end voltage output by the analog-to-digital conversion unit, and the abnormal comparison voltage output by the switching unit; If the abnormal comparison voltage is low, it is determined that the remote sensing sampling is normal, and the remote voltage is called. If the abnormal comparison voltage is high, it is determined that the remote sensing sampling is abnormal, and the near-end voltage is invoked.

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