Isolation resistor detection circuit

Abstract

The utility model relates to the technical field of resistance detection, and discloses an isolation resistance detection circuit, which comprises a reference power supply circuit, a parallel resistance circuit and an isolation test circuit, the first end of the parallel resistance circuit is connected with the first end of a resistor to be tested in a high-voltage power supply circuit, the isolation test circuit and the reference power supply circuit, and the second end of the parallel resistance circuit is connected with the second end of the resistor to be tested, the isolation test circuit and the reference power supply circuit; wherein the isolation test circuit is used for detecting the resistance value of the resistor to be tested. According to the invention, resistance detection in the high-voltage power supply circuit is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of resistance detection, in particular to an isolation resistance detection circuit. Background Art

[0002] With the development of society, high-voltage power supply circuits are being used more and more in various fields, which also puts forward higher requirements on the detection of resistance values ​​in high-voltage power supply circuits.

[0003] The detection circuit of the buffer resistor value in the traditional high-voltage power supply circuit is to connect the standard voltage and the standard resistor in series with the measured resistor, and detect the voltage across the measured resistor through the MCU (Microcontroller Unit). This resistor value detection circuit has a great defect. The measured resistor needs to share the same ground with the MCU. When the measured resistor is installed in the main loop of the high-voltage power supply circuit, it is easy to cause damage to the MCU. Therefore, a new resistor value detection circuit is urgently needed to realize resistance detection in the high-voltage power supply circuit. Utility Model Content

[0004] The main purpose of the utility model is to provide an isolation resistance detection circuit and device, aiming at solving the problem of how to realize resistance detection in a high-voltage power supply circuit.

[0005] To achieve the above object, the utility model provides an isolation resistance detection circuit, which includes a reference power supply circuit, a parallel resistance circuit and an isolation test circuit;

[0006] The first end of the parallel resistance circuit is respectively connected to the first end of the resistor to be measured in the high-voltage power supply circuit, the isolation test circuit and the reference power supply circuit, and the second end of the parallel resistance circuit is respectively connected to the second end of the resistor to be measured, the isolation test circuit and the reference power supply circuit;

[0007] Wherein, the isolation test circuit is used to detect the resistance value of the resistor to be tested.

[0008] Optionally, the parallel resistance circuit includes a parallel resistor, the first end of the parallel resistor is respectively connected to the first end of the resistor to be measured, the isolation test circuit and the reference power supply circuit, and the second end of the parallel resistor is respectively connected to the second end of the resistor to be measured, the isolation test circuit and the reference power supply circuit.

[0009] Optionally, the reference power supply circuit includes an isolated reference power supply, a first end of the isolated reference power supply is connected to a first end of the parallel resistor, and a second end of the isolated reference power supply is connected to a second end of the parallel resistor.

[0010] Optionally, the reference power supply circuit also includes a voltage-dividing resistor, a first end of the voltage-dividing resistor is connected to the first end of the parallel resistor, a second end of the voltage-dividing resistor is connected to the first end of the isolated reference power supply, and a second end of the isolated reference power supply is connected to the second end of the parallel resistor, or, the second end of the voltage-dividing resistor is connected to the second end of the parallel resistor, the first end of the voltage-dividing resistor is connected to the second end of the isolated reference power supply, and the first end of the isolated reference power supply is connected to the first end of the parallel resistor.

[0011] Optionally, the isolation resistor detection circuit also includes a control switch, wherein the first end of the control switch is connected to the first end of the parallel resistor, and the second end of the control switch is connected to the first end of the resistor to be measured, or the first end of the control switch is connected to the second end of the parallel resistor, and the second end of the control switch is connected to the second end of the resistor to be measured.

[0012] Optionally, the control switch includes a relay switch.

[0013] Optionally, the isolation test circuit includes a micro-control chip, and an input end of the micro-control chip is connected to the first end of the parallel resistor and the second end of the parallel resistor.

[0014] Optionally, the isolation test circuit also includes an isolation amplifier and an operational amplifier, the first input terminal of the isolation amplifier is connected to the first end of the parallel resistor, the second input terminal of the isolation amplifier is connected to the second end of the parallel resistor, the output terminal of the isolation amplifier is connected to the input terminal of the operational amplifier, and the output terminal of the operational amplifier is connected to the input terminal of the microcontrol chip.

[0015] Optionally, the input end of the operational amplifier includes a first op amp input end and a second op amp input end, the output end of the isolation amplifier includes a first isolation output end and a second isolation output end, the first op amp input end is connected to the first isolation output end, and the second op amp input end is connected to the second isolation output end.

[0016] Optionally, the isolation ground port of the isolation amplifier is connected to the chip ground port of the micro-control chip.

[0017] The present application provides an isolation resistance detection circuit, which includes an isolation resistance detection circuit including a reference power supply circuit, a parallel resistance circuit and an isolation test circuit; the first end of the parallel resistance circuit is respectively connected to the first end of the resistance to be measured in the high-voltage power supply circuit, the isolation test circuit and the reference power supply circuit, and the second end of the parallel resistance circuit is respectively connected to the second end of the resistance to be measured, the isolation test circuit and the reference power supply circuit; wherein the isolation test circuit is used to detect the resistance value of the resistance to be measured. By connecting the reference power supply circuit, the parallel resistance circuit and the isolation test circuit, and then detecting the resistance value of the resistance to be measured by the isolation test circuit, the resistance to be measured in the prior art is avoided. When the resistance to be measured is installed in the main circuit of the high-voltage power supply circuit, it is easy to cause the MCU to be damaged. This isolation resistance detection circuit can avoid direct MCU measurement causing MCU damage, and then can realize resistance detection in the high-voltage power supply circuit while ensuring the safety of the MCU. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of the isolation resistance detection circuit of the utility model;

[0019] Figure 2 A circuit connection diagram of a commonly used resistance detection circuit;

[0020] Figure 3 It is a circuit diagram of a commonly used high voltage power supply circuit;

[0021] Figure 4 It is a circuit connection schematic diagram of the isolation resistance detection circuit of the utility model;

[0022] Figure 5 This is another circuit connection schematic diagram of the isolation resistance detection circuit of the utility model.

[0023] Description of Figure Numbers:

[0024] Label name Label name 100 Resistance to be measured 10 Parallel resistor circuit 20 Reference power supply circuit 30 Isolation test circuit K1 High voltage switch K2 Control switch C1 capacitance DC High voltage power supply VRef Isolated Reference Power Supply R1 Resistance to be measured R2 Parallel resistance R3 Voltage Divider Resistors M1 Isolation Amplifiers M2 Operational Amplifier U1 Microcontroller chip G1 Isolated ground port G2 Chip ground port VinP The first input of the isolation amplifier VinN The second input of the isolation amplifier VCC Standard voltage

[0025] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0026] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0029] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] In addition, in this application, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0031] The utility model provides an isolation resistance detection circuit, referring to Figure 1 A structural schematic diagram of an isolation resistance detection circuit, the isolation resistance detection circuit includes a reference power supply circuit 20, a parallel resistance circuit 10 and an isolation test circuit 30;

[0032] The first end of the parallel resistance circuit 10 is respectively connected to the first end of the resistor to be measured 100 in the high-voltage power supply circuit, the isolation test circuit 30 and the reference power supply circuit 20, and the second end of the parallel resistance circuit 10 is respectively connected to the second end of the resistor to be measured 100, the isolation test circuit 30 and the reference power supply circuit 20;

[0033] The isolation test circuit 30 is used to detect the resistance value of the resistor to be tested 100 .

[0034] For example, in a supercapacitor charger development project (it can also be other resistors fixed on the power supply side of the circuit, and it is not easy to remove the resistor to detect the resistance value), the buffer resistor needs to be tested before buffering to prevent the resistor from short-circuiting or opening the circuit and causing equipment damage or abnormal charging. Figure 2 , Figure 2 This is a circuit connection diagram of a commonly used resistance detection circuit. Through the standard voltage Vcc and the standard resistor R4, it is connected in series with the resistor R1 to be tested, and the voltage across the resistor R1 to be tested is tested, so as to calculate the resistance value of R1. However, it can be seen from the figure that the resistor R1 to be tested needs to share the same ground with the MCU. When the resistor R1 to be tested is installed in the power main circuit (high-voltage power supply side), it is easy to cause damage to the MCU. Further, refer to Figure 3 , Figure 3 This is a circuit diagram of a commonly used high-voltage power supply circuit. The equivalent circuit of a supercapacitor charging application is as follows Figure 3 As shown, before the high-voltage switch K1 is closed, the resistance R1 to be measured needs to be detected to ensure that the resistance R1 to be measured is not short-circuited and has an open-circuit fault. However, when charging starts (the high-voltage switch K1 is not closed), the voltage across the capacitor C1 is 0, and the voltage across the resistance R1 to be measured is approximately the DC voltage of the high-voltage power supply. And the resistance R1 to be measured is connected in the power circuit, thereby causing the problem of MCU damage. Based on the above problems, the technical solution of the present application is proposed to realize a circuit for isolating and measuring the resistance value of the resistance R1 to be measured before the high-voltage switch K1 is closed.

[0035] In this embodiment, on the one hand, the resistance value test of the resistor to be measured 100 is completed through the parallel resistance circuit 10 and the isolation test circuit 30, thereby avoiding the situation where the MCU is directly damaged by the common ground with the resistor to be measured R1 installed in the power main circuit, thereby ensuring the safety of the test. On the other hand, the parallel resistance circuit 10 and the resistor to be measured 100 are powered by the reference power supply circuit 20, and then the voltage across the isolation test circuit 30 and the resistor to be measured 100 (also across the parallel resistance circuit 10) is used to determine the resistance value of the resistor to be measured 100 to complete the detection of the resistor to be measured 100.

[0036] The present embodiment provides an isolation resistance detection circuit, which includes a reference power supply circuit, a parallel resistance circuit and an isolation test circuit; the first end of the parallel resistance circuit is respectively connected to the first end of the resistance to be measured in the high-voltage power supply circuit, the isolation test circuit and the reference power supply circuit, and the second end of the parallel resistance circuit is respectively connected to the second end of the resistance to be measured, the isolation test circuit and the reference power supply circuit; wherein the isolation test circuit is used to detect the resistance value of the resistance to be measured. By connecting the reference power supply circuit, the parallel resistance circuit and the isolation test circuit, and then detecting the resistance value of the resistance to be measured by the isolation test circuit, the problem that the resistance to be measured needs to be grounded with the MCU in the prior art is avoided, and when the resistance to be measured is installed in the main power circuit, the phenomenon that the MCU is easily damaged occurs. This isolation resistance detection circuit can avoid the MCU from being damaged by direct MCU measurement, and thus can realize resistance detection in the high-voltage power supply circuit while ensuring the safety of the MCU.

[0037] Further, in another embodiment of the isolation resistance detection circuit of the present application, referring to Figure 4 , Figure 4 This is a circuit connection diagram of the isolation resistor detection circuit of the utility model, the parallel resistor circuit 10 includes a parallel resistor R2, the first end of the parallel resistor R2 is respectively connected to the first end of the resistor to be measured 100, the isolation test circuit 30 and the reference power supply circuit 20, and the second end of the parallel resistor R2 is respectively connected to the second end of the resistor to be measured 100, the isolation test circuit 30 and the reference power supply circuit 20.

[0038] Exemplarily, the parallel resistor circuit 10 includes a parallel resistor R2 which may be composed of multiple resistors. By connecting the parallel resistor R2 in parallel with the resistor to be measured 100 (the resistor to be measured R1 in the figure, and the resistor to be measured R1 will be described later), and then testing the voltage value at both ends through the isolation test circuit 30, the resistance value of the isolated resistor to be measured R1 can be measured. The role of the parallel resistor R2 is to avoid being directly connected to the resistor to be measured R1 through the isolation test circuit 30, thereby damaging the hardware in the isolation test circuit 30.

[0039] Specifically, the reference power supply circuit 20 includes an isolated reference power supply VRef, a first end of the isolated reference power supply VRef is connected to a first end of the parallel resistor R2, and a second end of the isolated reference power supply VRef is connected to a second end of the parallel resistor R2.

[0040] Exemplarily, the isolated reference power supply VRef provides a test power supply for the entire isolation resistance detection circuit, and then the voltage divider resistor R3, the parallel resistor R2 and the resistor to be measured R1 are powered based on the power supply, and then the voltage of the parallel resistor R2 (which is now connected in parallel with the resistor to be measured R1) is collected to achieve the measurement of the resistance value of the resistor to be measured R1.

[0041] Specifically, the reference power supply circuit also includes a voltage-dividing resistor R3, a first end of the voltage-dividing resistor R3 is connected to the first end of the parallel resistor R2, a second end of the voltage-dividing resistor R3 is connected to the first end of the isolated reference power supply VRef, and a second end of the isolated reference power supply VRef is connected to the second end of the parallel resistor R2, or, the second end of the voltage-dividing resistor R3 is connected to the second end of the parallel resistor R2, a first end of the voltage-dividing resistor R3 is connected to the second end of the isolated reference power supply VRef, and a first end of the isolated reference power supply VRef is connected to the first end of the parallel resistor R2.

[0042] Exemplarily, the reference power supply circuit also includes a voltage divider resistor R3 which may be composed of multiple resistors. The voltage divider resistor R3 can further realize voltage division with an equivalent resistor composed of a parallel resistor R2 and a resistor to be measured R1. Because the use of the voltage divider resistor R3 ensures that the collected voltage value is the voltage value of the equivalent resistor composed of the parallel resistor R2 and the resistor to be measured R1, rather than the voltage of the isolated reference power supply VRef.

[0043] Specifically, the isolation resistance detection circuit also includes a control switch K2, the first end of the control switch K2 is connected to the first end of the parallel resistor R2, and the second end of the control switch K2 is connected to the first end of the resistor to be measured R1, or the first end of the control switch K2 is connected to the second end of the parallel resistor R2, and the second end of the control switch K2 is connected to the second end of the resistor to be measured R1.

[0044] Specifically, the control switch K2 includes a relay switch.

[0045] In this embodiment, the switch K2 is controlled to perform switch control, and when the control switch K2 is pulled in, the resistor R1 to be tested is connected in parallel with the parallel resistor R2 and the voltage-dividing resistor R3 in series divides the isolated reference power supply VRef. Therefore, the resistance value of the resistor R1 to be tested can be obtained from the voltages at points AB in the figure. That is, the voltages at points AB in the figure are collected through the isolation test circuit 30 to obtain the resistance value of the resistor R1 to be tested, so as to complete the resistance test of the resistor R1 to be tested.

[0046] Further, in another embodiment of the isolation resistance detection circuit of the present application, referring to Figure 5 , Figure 5This is another circuit connection diagram of the isolation resistance detection circuit of the utility model. The isolation test circuit 30 includes a micro-control chip U1. The input end of the micro-control chip U1 is connected to the first end of the parallel resistor R2 and the second end of the parallel resistor R2.

[0047] Specifically, the isolation test circuit 30 also includes an isolation amplifier M1 and an operational amplifier M2, the first input terminal VinP of the isolation amplifier is connected to the first end of the parallel resistor R2, the second input terminal VinN of the isolation amplifier is connected to the second end of the parallel resistor R2, the output end of the isolation amplifier M1 is connected to the input end of the operational amplifier M2, and the output end of the operational amplifier M2 is connected to the input end of the microcontrol chip U1.

[0048] Specifically, the input end of the operational amplifier M2 includes a first operational amplifier input end and a second operational amplifier input end, the output end of the isolation amplifier M1 includes a first isolation output end and a second isolation output end, the first operational amplifier input end is connected to the first isolation output end, and the second operational amplifier input end is connected to the second isolation output end.

[0049] Specifically, the isolation ground port G1 of the isolation amplifier M1 is connected to the chip ground port G2 of the micro-control chip U1.

[0050] In this embodiment, the model of the isolation amplifier M1 may be AMC1301, and the operational amplifier M2 may be a common operational amplifier chip. After the collected voltage is amplified by AMC1301+ operational amplifier, the voltage value is transmitted back to the MCU, and then the resistance of the resistor R1 to be measured is calculated in the MCU. For example, the resistance values ​​of each resistor and the amplifier activation multiple are designed according to different situations. For example, the specification of the resistor R1 to be measured is 20Ω, the isolation reference power supply VRef is 2.5V, the parallel resistor R2 is 750Ω, the voltage divider resistor R3 is 75Ω, the measurement range of AMC1301 is 250mV, the amplification multiple is 8.2 times, and the operational amplifier amplification multiple is 1.616 times. According to different situations, the above resistance values, amplifier activation multiples and other parameters can also be adaptively changed.

[0051] For example, after the collected voltage value Vout is determined, the resistance value of the resistor to be measured R1 can be determined, and the calculation basis is as follows:

[0052] The resistance value of the parallel resistor R2 and the resistor to be measured R1 is set to Rx, and the voltage Vout collected by the ADC port of the MCU is:

[0053]

[0054] Wherein, Gain is the product of the amplification factors of the isolation amplifier M1 and the operational amplifier M2, Vref is the voltage value of the isolation reference power supply VRef, and R3 is the resistance value of the voltage divider resistor R3. Then, the following transformation can be performed to obtain:

[0055]

[0056] Finally, according to the principle of resistor parallel connection, the resistance value of the resistor R1 to be measured can be further obtained as:

[0057]

[0058] That is, after the entire voltage value Vout is collected, the resistance value of the resistor to be measured R1 can be determined, thereby avoiding the phenomenon that the measured resistor is installed in the power main circuit and easily causes damage to the MCU, and the detection of the resistor to be measured R1 can be achieved through simple devices.

[0059] In addition, the present application also provides an isolation resistance detection device, which includes the above-mentioned isolation resistance detection circuit.

[0060] The above description is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. All equivalent structural changes made by using the contents of the present application specification and drawings under the technical concept of the present application, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present application.

Claims

1. An isolation resistance detection circuit, characterized in that: The isolation resistance detection circuit includes a reference power supply circuit, a parallel resistance circuit and an isolation test circuit; The first end of the parallel resistance circuit is respectively connected to the first end of the resistor to be measured in the high-voltage power supply circuit, the isolation test circuit and the reference power supply circuit, and the second end of the parallel resistance circuit is respectively connected to the second end of the resistor to be measured, the isolation test circuit and the reference power supply circuit; Wherein, the isolation test circuit is used to detect the resistance value of the resistor to be tested.

2. The isolation resistance detection circuit as claimed in claim 1, characterized in that: The parallel resistance circuit includes a parallel resistor, a first end of the parallel resistor is respectively connected to the first end of the resistor to be measured, the isolation test circuit and the reference power supply circuit, and a second end of the parallel resistor is respectively connected to the second end of the resistor to be measured, the isolation test circuit and the reference power supply circuit.

3. The isolation resistance detection circuit as claimed in claim 2, characterized in that: The reference power supply circuit includes an isolated reference power supply, a first end of the isolated reference power supply is connected to a first end of the parallel resistor, and a second end of the isolated reference power supply is connected to a second end of the parallel resistor.

4. The isolation resistance detection circuit as claimed in claim 3, characterized in that: The reference power supply circuit also includes a voltage-dividing resistor, a first end of the voltage-dividing resistor is connected to the first end of the parallel resistor, a second end of the voltage-dividing resistor is connected to the first end of the isolated reference power supply, and the second end of the isolated reference power supply is connected to the second end of the parallel resistor, or, the second end of the voltage-dividing resistor is connected to the second end of the parallel resistor, the first end of the voltage-dividing resistor is connected to the second end of the isolated reference power supply, and the first end of the isolated reference power supply is connected to the first end of the parallel resistor.

5. The isolation resistance detection circuit as claimed in claim 2, characterized in that: The isolation resistor detection circuit also includes a control switch, wherein the first end of the control switch is connected to the first end of the parallel resistor, and the second end of the control switch is connected to the first end of the resistor to be measured, or the first end of the control switch is connected to the second end of the parallel resistor, and the second end of the control switch is connected to the second end of the resistor to be measured.

6. The isolation resistance detection circuit as claimed in claim 5, characterized in that: The control switch includes a relay switch.

7. The isolation resistance detection circuit as claimed in claim 2, characterized in that: The isolation test circuit comprises a micro-control chip, and an input end of the micro-control chip is connected to a first end of the parallel resistor and a second end of the parallel resistor.

8. The isolation resistance detection circuit as claimed in claim 7, characterized in that: The isolation test circuit also includes an isolation amplifier and an operational amplifier, the first input end of the isolation amplifier is connected to the first end of the parallel resistor, the second input end of the isolation amplifier is connected to the second end of the parallel resistor, the output end of the isolation amplifier is connected to the input end of the operational amplifier, and the output end of the operational amplifier is connected to the input end of the microcontrol chip.

9. The isolation resistance detection circuit as claimed in claim 8, characterized in that: The input end of the operational amplifier includes a first operational amplifier input end and a second operational amplifier input end, the output end of the isolation amplifier includes a first isolation output end and a second isolation output end, the first operational amplifier input end is connected to the first isolation output end, and the second operational amplifier input end is connected to the second isolation output end.

10. The isolation resistance detection circuit as claimed in claim 9, characterized in that: The isolation ground port of the isolation amplifier is connected to the chip ground port of the micro-control chip.

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