A leakage current detection circuit

Abstract

This invention discloses a leakage current detection circuit. The leakage current detection circuit includes: an amplification module electrically connected to the device under test (DUT), the amplification module including an operational amplifier (op-amp) unit and a feedback resistor matrix, the feedback resistor matrix being connected in parallel with the op-amp unit, and the op-amp unit configured to convert leakage current or noise current into an output voltage based on a target feedback resistor in the feedback resistor matrix; and an output status monitoring module connected to a reference voltage, the output status monitoring module being configured to monitor the operating status of the target feedback resistor based on the output voltage and the reference voltage. In this embodiment, the amplification module converts the leakage current of the DUT into an output voltage, and the output status monitoring module indicates the operating status of the target feedback resistor in the feedback resistor matrix of the amplification module based on the output voltage and the reference voltage, ensuring a proportional relationship between the output voltage and the leakage current, thereby improving the accuracy of leakage current detection.

Description

Technical Field

[0001] This utility model relates to the field of electronic technology, and in particular to a leakage current detection circuit. Background Technology

[0002] Leakage current refers to the unexpected current flowing through the interior or surface of an electronic device when a certain voltage is applied across its terminals. It is an important parameter for measuring device performance and reliability, and is especially crucial in low-power, high-precision circuit design.

[0003] In existing technologies, device leakage current is often detected using transimpedance amplifiers. Among them, the transimpedance amplifier (TIA) is a special amplifier structure that is mainly used to convert weak current signals into voltage signals.

[0004] However, when the feedback resistor of the transimpedance amplifier is not selected properly, the output voltage of the transimpedance amplifier will exhibit saturation distortion, which will also lead to deviations in the detection of device leakage current. Utility Model Content

[0005] This invention provides a leakage current detection circuit to improve the accuracy of leakage current detection in devices.

[0006] The leakage current detection circuit includes: an amplification module and an output status monitoring module; The amplification module is electrically connected to the device under test. The amplification module includes an operational amplifier unit and a feedback resistor matrix. The feedback resistor matrix is ​​connected between the first input terminal and the output terminal of the operational amplifier unit. The operational amplifier unit is configured to convert the leakage current or the noise current into an output voltage based on the target feedback resistor in the feedback resistor matrix. The output status monitoring module is connected to a reference voltage and is connected to the output terminal of the operational amplifier unit. The output status monitoring module is configured to monitor the operating status of the target feedback resistor based on the output voltage and the reference voltage.

[0007] Optionally, the operational amplifier unit includes: an operational amplifier and a feedback capacitor; The first terminal of the operational amplifier is connected to the device under test, the second terminal of the operational amplifier is grounded, the third terminal of the operational amplifier is connected to the output status monitoring module, the power supply terminal of the operational amplifier is connected to a first power supply voltage, the ground terminal of the operational amplifier is grounded, and the feedback capacitor is connected between the first terminal and the third terminal of the operational amplifier.

[0008] Optionally, the operational amplifier unit further includes: circuit protection devices; The first terminal of the circuit protection device is connected to the third terminal of the operational amplifier, and the second terminal of the circuit protection device is grounded.

[0009] Optionally, the feedback resistor matrix includes: a feedback switch and multiple feedback resistors; The feedback switch has multiple input terminals. The first terminal of each feedback resistor is connected to the first terminal of the operational amplifier unit. The second terminal of each feedback resistor is connected to each input terminal of the feedback switch in a corresponding manner. The output terminal of the feedback switch is connected to the third terminal of the operational amplifier unit. Each feedback resistor corresponds to a different leakage current level or noise current level.

[0010] Optionally, the feedback resistor matrix includes: a plurality of feedback switches and a plurality of feedback resistors; Each of the feedback switches and each of the feedback resistors are connected in a one-to-one correspondence to form multiple feedback branches, and each of the feedback branches is connected between the first terminal and the third terminal of the operational amplifier unit; wherein, each of the feedback resistors corresponds to a different leakage current level or noise current level.

[0011] Optionally, the resistance values ​​of each of the feedback resistors are in a proportional relationship.

[0012] Optionally, the leakage current detection circuit further includes: a switching module; The amplification module is connected to the device under test (DUT) via the switching module. The switching module is configured to remain on when leakage current of the DUT is detected, and to remain off when noise current of the amplification module is detected.

[0013] Optionally, the output status monitoring module includes: a first indicator circuit and a second indicator circuit; The first terminal of the first indicator circuit is connected to the operational amplifier unit, and the second terminal of the first indicator circuit receives the reference voltage. The first indicator circuit is configured to indicate that the working state of the target feedback resistor is a normal detection state based on the output voltage and the reference voltage. The first terminal of the second indicator circuit is connected to the second terminal of the first indicator circuit, and the second terminal of the second indicator circuit is connected to the first terminal of the first indicator circuit. The second indicator circuit is configured to indicate that the operating state of the target feedback resistor is an abnormal detection state based on the output voltage and the reference voltage.

[0014] Optionally, the first indicating circuit includes: a first comparator, a first switching transistor, and a first light-emitting diode; The first terminal of the first comparator is connected to the operational amplifier unit, the second terminal of the first comparator receives the reference voltage, the power supply terminal of the first comparator is connected to the first power supply voltage, the ground terminal of the first comparator is grounded, the third terminal of the first comparator is connected to the control terminal of the first switching transistor, the input terminal of the first switching transistor is connected to the cathode of the first light-emitting diode, the anode of the first light-emitting diode is connected to the second power supply voltage, and the output terminal of the first switching transistor is grounded. The second indicator circuit includes: a second comparator, a second switching transistor, and a second light-emitting diode; The first terminal of the second comparator is connected to the second terminal of the first comparator, the second terminal of the second comparator is connected to the first terminal of the first comparator, the power supply terminal of the second comparator is connected to the first power supply voltage, the ground terminal of the second comparator is grounded, the third terminal of the second comparator is connected to the control terminal of the second switching transistor, the input terminal of the second switching transistor is connected to the cathode of the second light-emitting diode, the anode of the second light-emitting diode is connected to the second power supply voltage, and the output terminal of the second switching transistor is grounded.

[0015] Optionally, the light-emitting color of the first light-emitting diode is different from the light-emitting color of the second light-emitting diode.

[0016] The amplification module of this utility model converts the leakage current of the device under test into a voltage, i.e., an output voltage. The output status monitoring module indicates the working status of the target feedback resistor in the feedback resistor matrix of the amplification module based on the output voltage and the reference voltage, so as to ensure that there is a proportional relationship between the output voltage and the leakage current, thereby improving the detection accuracy of the device leakage current.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a leakage current detection circuit provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of another leakage current detection circuit provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of another leakage current detection circuit provided in this embodiment of the present invention; Figure 4 This is a schematic diagram of another leakage current detection circuit provided in this embodiment of the present invention; Figure 5 This is a schematic diagram of another leakage current detection circuit provided in this embodiment of the present invention; Figure 6 This is a schematic diagram of another leakage current detection circuit provided in this embodiment of the present invention; Figure 7 This is a schematic diagram of a power generation circuit provided in an embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] This utility model embodiment provides a leakage current detection circuit. This leakage current detection circuit is suitable for detecting leakage current in electronic devices. In this embodiment, the amplification module converts the leakage current of the device under test into a voltage, i.e., an output voltage. The output status monitoring module indicates whether the feedback resistor selected by the feedback resistor matrix of the amplification module is suitable based on the output voltage and a reference voltage, ensuring a proportional relationship between the output voltage and the leakage current, thereby improving the accuracy of leakage current detection. Figure 1 This is a schematic diagram of a leakage current detection circuit provided in an embodiment of this utility model. (Refer to...) Figure 1The leakage current detection circuit includes an amplification module 140 and an output status monitoring module 150.

[0023] Amplification module 140 is electrically connected to device under test 20. Amplification module 140 includes operational amplifier unit 141 and feedback resistor matrix 142. Feedback resistor matrix 142 is connected between the first input terminal and the output terminal of operational amplifier unit 141. Operational amplifier unit 141 is configured to convert leakage current or noise current into output voltage Vout based on the target feedback resistor in feedback resistor matrix 142. Output status monitoring module 150 is connected to reference voltage Vref. Output status monitoring module 150 is connected to the output terminal of operational amplifier unit 141. Output status monitoring module 150 is configured to monitor the operating status of target feedback resistor based on output voltage Vout and reference voltage Vref.

[0024] Specifically, in application, the device under test (DUT) 20 and the operational amplifier unit 141 need to be connected to the test power supply 10 to form a circuit. The test power supply 10 provides the DC power required for the DUT 20 during leakage current detection. The DUT 20 and the test power supply 10 can be connected via the first test probe 110, and the DUT 20 and the first input terminal of the operational amplifier unit 141 can be connected via the second test probe 120. The second input terminal of the operational amplifier unit 141 is connected to the test power supply 10.

[0025] When the operational amplifier unit 141 of the amplification module 140 is connected to the device under test 20, the DC power supplied by the test power supply 10 is output to the first input terminal of the operational amplifier unit 141 through the device under test 20. The operational amplifier unit 141 converts the leakage current into an output voltage Vout based on the target feedback resistor in the feedback resistor matrix 142. It should be noted that the feedback resistor matrix 141 is composed of multiple feedback resistors, and the target feedback resistor is the feedback resistor currently connected to the operational amplifier unit 141 within the feedback resistor matrix 141. The magnitude of the output voltage Vout output by the operational amplifier unit 141 is related to the resistance value of the target feedback resistor and the current input to the operational amplifier unit 141, and the product of the resistance value of the target feedback resistor and the current input to the operational amplifier unit 141 is the output voltage Vout of the operational amplifier unit 141. Among these, due to the inherent characteristics of the operational amplifier unit 141, the output voltage Vout of the operational amplifier unit 141 has a maximum value, that is, the operational amplifier unit 141 has a maximum output voltage. When the product of the target feedback resistor and the current of the input operational amplifier unit 141 is less than the maximum output voltage of the operational amplifier unit 141, the relationship between the leakage current of the device under test 20, the target feedback resistor, and the output voltage of the operational amplifier unit 141 is as follows: Ileakage = (-Vout) / Rf; Where Ileakage is the leakage current of the device under test 20; Vout is the output voltage of the operational amplifier unit; and Rf is the resistance value of the target feedback resistor.

[0026] For example, the output voltage Vout of the operational amplifier unit 141 can be obtained from the voltage between the first input terminal and the output terminal of the operational amplifier unit 141. The leakage current of the device under test 20 can be obtained by combining the output voltage Vout of the operational amplifier unit 141 with the target feedback resistor.

[0027] Since the leakage current of the device under test 20 is a stable value, when detecting the leakage current of the device under test 20, the larger the value of the target feedback resistor, the larger the output voltage Vout output by the operational amplifier unit 141; conversely, the smaller the value of the target feedback resistor, the smaller the output voltage Vout output by the operational amplifier unit 141.

[0028] When the product of the target feedback resistor and the current of the input operational amplifier unit 141 is greater than the maximum output voltage of the operational amplifier unit 141, the output voltage Vout of the operational amplifier unit 141 is the same as the maximum output voltage due to the limitation of the maximum output voltage of the operational amplifier unit 141. That is, the output voltage Vout of the operational amplifier unit 141 is no longer correlated with the resistance of the target feedback resistor and the current of the input operational amplifier unit 141.

[0029] Therefore, when detecting the leakage current of the device under test 20, it is necessary to determine the operating state of the target feedback resistor in the feedback resistor matrix 142 to ensure that the output voltage Vout of the operational amplifier unit 141 is correlated with the resistance value of the target feedback resistor in the feedback resistor matrix 142 and the current input to the operational amplifier unit 141. The operating state of the target feedback resistor can be determined by the output voltage Vout of the operational amplifier unit 141.

[0030] The output status monitoring module 150 acquires the output voltage Vout of the operational amplifier unit 141 and compares it with the reference voltage Vref. The reference voltage Vref is a pre-set voltage value used to determine the operating state of the target feedback resistor. The reference voltage Vref should be less than the maximum output voltage of the operational amplifier unit 141. In practical applications, the specific value of the reference voltage Vref can be set according to actual needs; this embodiment does not impose any restrictions on this.

[0031] When the output voltage Vout is less than the reference voltage Vref, the output status monitoring module 150 indicates that the target feedback resistor is in a normal detection state. At this time, the operational amplifier unit 141 operates in the linear region, meaning that the output voltage Vout of the operational amplifier unit 141 has a linear relationship with the leakage current of the device under test 20. The leakage current of the device under test 20 can be calculated using the output voltage Vout and the resistance value of the target feedback resistor. When the output voltage Vout is greater than or equal to the reference voltage Vref, the output status monitoring module 150 indicates that the target feedback resistor is in an abnormal detection state. At this time, the operational amplifier unit 141 operates in the non-linear region, meaning that the output voltage Vout of the operational amplifier unit 141 has a non-linear relationship with the leakage current of the device under test 20. The leakage current of the device under test 20 cannot be calculated using the output voltage Vout and the resistance value of the target feedback resistor. For example, the output status monitoring module 150 can indicate the operating state of the target feedback resistor through sound, light, or text display; this embodiment does not limit this.

[0032] In this embodiment of the invention, the amplification module 140 converts the leakage current of the device under test 20 into a voltage, namely the output voltage Vout. The output status monitoring module 150 indicates the working status of the target feedback resistor in the feedback resistor matrix 142 of the amplification module 140 based on the output voltage Vout and the reference voltage Vref, so as to ensure that the output voltage Vout and the leakage current are proportional, thereby improving the detection accuracy of the device leakage current.

[0033] It should be noted that because the operational amplifier unit 141 itself has a noise current, the leakage current obtained according to the above formula when detecting the leakage current of the device under test 20 includes a certain amount of noise. The noise current of the operational amplifier unit 141 is essentially its bias current. In practical applications, since the noise current of the operational amplifier unit 141 is small, it can be ignored when detecting the leakage current of the device under test 20. However, in scenarios requiring high accuracy in detecting the leakage current of the device under test 20, the noise current of the operational amplifier unit 141 must be subtracted from the leakage current obtained according to the above formula.

[0034] When the connection between the operational amplifier unit 141 of the amplification module 140 and the device under test 20 is turned off, the operational amplifier unit 141 converts its own noise current into an output voltage Vout based on the target feedback resistor in the feedback resistor matrix 141. Similarly, the magnitude of the output voltage Vout of the operational amplifier unit 141 is related to the resistance value of the target feedback resistor in the feedback resistor matrix 142 and the noise current of the operational amplifier unit 141 itself. The product of the resistance value of the target feedback resistor and the noise current of the operational amplifier unit 141 is the output voltage Vout of the operational amplifier unit 141. When the product of the resistance value of the target feedback resistor and the current of the operational amplifier unit 141 is less than the maximum output voltage of the operational amplifier unit 141, the relationship between the noise current of the operational amplifier unit 141, the target feedback resistor, and the output voltage of the operational amplifier unit 141 is as follows: Inoise = (-Vout) / Rf; Where Inoise is the noise current of the operational amplifier unit 141 itself; Vout is the output voltage of the operational amplifier unit; and Rf is the resistance value of the target feedback resistor.

[0035] Provided that the output voltage Vout of the operational amplifier unit 141 is correlated with the resistance value of the target feedback resistor in the feedback resistor matrix 142 and the noise current of the operational amplifier unit 141 itself, the noise current of the operational amplifier unit 141 can be obtained based on the output voltage of the operational amplifier unit 141 and the target feedback resistor.

[0036] Figure 2 This is a schematic diagram of another leakage current detection circuit provided in an embodiment of the present invention. Optionally, based on the above embodiments, refer to... Figure 2 The leakage current detection circuit also includes a switching module 130.

[0037] Amplification module 140 is connected to device under test (DUT) 20 via switching module 130. Switching module 130 is configured to remain on during leakage current detection of DUT 20 and off during noise current detection of amplification module 140. Switching module 130 controls the connection between DUT 20 and operational amplifier unit 141 in amplification module 140. When switching module 130 is on, the connection between DUT 20 and operational amplifier unit 141 is established, and the leakage current detection circuit detects the leakage current of DUT 20. When switching module 130 is off, the connection between DUT 20 and operational amplifier unit 141 is severed, and the leakage current detection circuit detects the noise current of operational amplifier unit 141. For example, switching module 130 can be a mechanical switch. The leakage current detection method of DUT 20 and the noise current detection method of operational amplifier unit 141 are described above and will not be repeated here.

[0038] Figure 3 This is a schematic diagram of another leakage current detection circuit provided by an embodiment of the present invention. Optionally, based on the above embodiments, refer to... Figure 3 The operational amplifier unit 141 includes: operational amplifier U1 and feedback capacitor Cf.

[0039] The first terminal of operational amplifier U1 is connected to the device under test 20, the second terminal of operational amplifier U1 is grounded, the third terminal of operational amplifier U1 is connected to the output status monitoring module 150, the power supply terminal of operational amplifier U1 is connected to the first power supply voltage VCC1, the ground terminal of operational amplifier U1 is grounded, and the feedback capacitor Cf is connected between the first and third terminals of operational amplifier U1. It should be noted that in practical applications, the second terminal of operational amplifier U1 is also connected to the test power supply 10 to form a loop.

[0040] The feedback capacitor Cf and the target feedback resistor in the feedback resistor matrix 142 form a low-pass filter to limit the bandwidth of the operational amplifier U1, thereby reducing high-frequency noise. Optionally, continue referring to... Figure 3 The operational amplifier U1 can also be equipped with a circuit protection device 1411 at its third terminal to limit the output voltage of the operational amplifier U1, thereby preventing surges from impacting the output status monitoring module 150. The first terminal of the circuit protection device 1411 is connected to the third terminal of the operational amplifier U1, and the second terminal of the circuit protection device 1411 is grounded. For example, the circuit protection device 1411 can be a transient voltage suppressor diode (TVS).

[0041] Specifically, operational amplifier U1 exhibits virtual short and virtual open characteristics. When switch module 130 is turned on, due to the virtual open characteristic of operational amplifier U1, its input resistance is infinite, preventing the leakage current of device under test 20 from flowing into the first terminal of operational amplifier U1. At this time, operational amplifier U1 is essentially open-circuited, and the leakage current of device under test 20 flows from the target feedback resistor in feedback resistor matrix 142 to the third terminal of operational amplifier U1. Furthermore, due to the virtual short characteristic of operational amplifier U1, the voltages at the first and second terminals of operational amplifier U1 are the same and both zero. Therefore, the voltage across operational amplifier U1 is essentially a negative output voltage Vout. Since feedback resistor matrix 142 is connected in parallel with operational amplifier U1, the voltage applied across the target feedback resistor in feedback resistor matrix 142 is also a negative output voltage Vout. For example, in practical applications, a first test point HOOK1, a second test point HOOK2, and a third test point HOOK3 can be set at the first, second, and third terminals of the operational amplifier U1, respectively. The voltage across the operational amplifier U1 can be obtained by measuring the voltage between the first test point HOOK1 and the third test point HOOK3 or by measuring the voltage between the second test point HOOK2 and the third test point HOOK3.

[0042] As mentioned earlier, the input resistance of operational amplifier U1 is infinite, so the leakage current of device under test 20 cannot flow into operational amplifier U1. Operational amplifier U1 is equivalent to an open circuit. The leakage current of device under test 20 flows from the feedback resistor in feedback resistor matrix 142 to the third terminal of operational amplifier U1. Therefore, the leakage current of device under test 20 can be obtained from the voltage across the target feedback resistor in feedback resistor matrix 142 and the resistance value of the target feedback resistor.

[0043] Figure 4 This is a schematic diagram of another leakage current detection circuit provided by an embodiment of the present invention. Optionally, based on the above embodiments, refer to... Figure 4 The feedback resistor matrix 142 includes a feedback switch Sf and multiple feedback resistors Rf.

[0044] The feedback switch Sf has multiple input terminals. The first terminal of each feedback resistor Rf is connected to the first terminal of the operational amplifier unit 141. The second terminal of each feedback resistor Rf is connected to each input terminal of the feedback switch Sf in a corresponding manner. The output terminal of the feedback switch Sf is connected to the third terminal of the operational amplifier unit 141. Each feedback resistor Rf corresponds to a different leakage current level or noise current level.

[0045] Specifically, the feedback switch Sf has multiple input terminals and one output terminal. At any given time, only one input terminal and one output terminal are connected by the feedback switch Sf. That is, at any given time, only one feedback resistor Rf in the feedback resistor matrix 142 is connected to the operational amplifier unit 141. For example, the feedback switch Sf can be a rotary switch.

[0046] The feedback resistor matrix 142 is configured with multiple feedback resistors Rf with different resistance values ​​to correspond to different leakage current levels, thereby meeting the leakage current detection requirements of different devices under test 20.

[0047] Figure 5 This is a schematic diagram of another leakage current detection circuit provided by an embodiment of the present invention. Optionally, based on the above embodiments, refer to... Figure 5 The feedback resistor matrix 142 includes: multiple feedback switches Sf and multiple feedback resistors Rf; Each feedback switch Sf is connected to each feedback resistor Rf in a one-to-one correspondence to form multiple feedback branches. Each feedback branch is connected between the first and third terminals of the operational amplifier unit 141. Each feedback resistor Rf corresponds to a different leakage current level or noise current level.

[0048] Specifically, only one feedback switch Sf is turned on at any given time, thereby connecting the feedback resistor Rf connected to it to the operational amplifier unit 141. For example, each feedback switch Sf can be a mechanical switch. The feedback resistor matrix 142 is configured with multiple feedback resistors Rf of different resistance values ​​to meet the leakage current detection requirements of different devices under test 20.

[0049] In practical applications, the resistance values ​​of each feedback resistor Rf can be set according to a proportional relationship, such as 10MΩ, 100MΩ, 1GΩ, 10GΩ, 100GΩ, and 1TΩ; or the resistance values ​​of each feedback resistor Rf can be set according to a non-proportional relationship, such as 10MΩ, 100MΩ, 500MΩ, 1GΩ, 2GΩ, and 3GΩ.

[0050] Figure 6 This is a schematic diagram of another leakage current detection circuit provided by an embodiment of the present invention. Optionally, based on the above embodiments, refer to... Figure 6 The output status monitoring module 150 includes: a first indicator circuit 151 and a second indicator circuit 152.

[0051] The first terminal of the first indicator circuit 151 is connected to the operational amplifier unit 141, and the second terminal of the first indicator circuit receives the reference voltage Vref. The first indicator circuit 151 is configured to indicate the normal detection state of the target feedback resistor based on the output voltage Vout and the reference voltage Vref. The first terminal of the second indicator circuit 152 is connected to the second terminal of the first indicator circuit 151, and the second terminal of the second indicator circuit 152 is connected to the first terminal of the first indicator circuit 151. The second indicator circuit 152 is configured to indicate the abnormal detection state of the target feedback resistor based on the output voltage Vout and the reference voltage Vref.

[0052] Specifically, the first indicating circuit 151 compares the output voltage Vout with the reference voltage Vref. When the output voltage Vout is less than the reference voltage Vref, the first indicating circuit 151 indicates that the target feedback resistor is in a normal detection state; when the output voltage Vout is greater than or equal to the reference voltage Vref, the first indicating circuit 151 does not provide any indication. For example, the first indicating circuit 151 can indicate the operating state of the target feedback resistor through sound, light, or text display; this embodiment does not limit this.

[0053] Similarly, the second indicator circuit 152 compares the output voltage Vout with the reference voltage Vref. When the output voltage Vout is less than the reference voltage Vref, the second indicator circuit 152 does not provide an indication; when the output voltage Vout is greater than or equal to the reference voltage Vref, the second indicator circuit 152 indicates that the target feedback resistor is in an abnormal detection state. For example, the second indicator circuit 152 can indicate the operating state of the target feedback resistor through sound, light, or text display; this embodiment does not limit this.

[0054] Based on the above embodiments, optionally, refer to... Figure 6 The first indicator circuit 151 includes: a first comparator U2, a first resistor R1, a second resistor R2, a first switch M1, a third resistor R3, and a first light-emitting diode LED1.

[0055] The first terminal of the first comparator U2 is connected to the operational amplifier unit 141. The second terminal of the first comparator U2 receives the reference voltage Vref. The power supply terminal of the first comparator U2 is connected to the first power supply voltage VCC1. The ground terminal of the first comparator U1 is grounded. The third terminal of the first comparator U2 is connected to the first terminal of the first resistor R1. The second terminal of the first resistor R1 is connected to the first terminal of the second resistor R2. The second terminal of the second resistor R2 is grounded. The second terminal of the first resistor R1 is also connected to the control terminal of the first switch M1. The input terminal of the first switch M1 is connected to the first terminal of the third resistor R3. The second terminal of the third resistor R3 is connected to the cathode of the first light-emitting diode LED1. The anode of the first light-emitting diode LED1 is connected to the second power supply voltage VCC2. The output terminal of the first switch M1 is grounded.

[0056] Continue to refer to Figure 6 The second indicator circuit 152 includes: a second comparator U3, a fourth resistor R4, a fifth resistor R5, a second switch M2, a sixth resistor R6, and a second light-emitting diode LED2.

[0057] The first terminal of the second comparator U3 is connected to the second terminal of the first comparator U2. The second terminal of the second comparator U3 is connected to the first terminal of the first comparator U2. The power supply terminal of the second comparator U3 is connected to the first power supply voltage VCC1. The ground terminal of the second comparator U3 is grounded. The third terminal of the second comparator U3 is connected to the first terminal of the fourth resistor R4. The second terminal of the fourth resistor R4 is connected to the first terminal of the fifth resistor R5. The second terminal of the fifth resistor R5 is grounded. The second terminal of the fourth resistor R4 is also connected to the control terminal of the second switch M2. The input terminal of the second switch M2 is connected to the first terminal of the sixth resistor R6. The second terminal of the sixth resistor R6 is connected to the cathode of the second light-emitting diode LED2. The anode of the second light-emitting diode LED2 is connected to the second power supply voltage VCC2. The output terminal of the second switch M2 is grounded.

[0058] Specifically, when the output voltage Vout is less than the reference voltage Vref, the first comparator U2 has a voltage output. The first switch M1 is turned on by the output voltage of the first comparator U2. At this time, the branch containing the first light-emitting diode LED1 is turned on, and LED1 lights up, thus indicating that the feedback resistor selected by the feedback resistor matrix 142 is applicable. When the output voltage Vout is greater than or equal to the reference voltage Vref, the first comparator U2 has no voltage output. At this time, the first switch M1 is turned off, the branch containing the first light-emitting diode LED1 is turned off, and LED1 is extinguished.

[0059] When the output voltage Vout is greater than or equal to the reference voltage Vref, the second comparator U3 has a voltage output. The second switch M2 is turned on by the output voltage of the second comparator U3. At this time, the branch containing the second LED2 is turned on, and the second LED2 lights up, indicating that the feedback resistor selected by the feedback resistor matrix 142 is incorrect. When the output voltage Vout is less than the reference voltage Vref, the second comparator U3 has no voltage output. At this time, the second switch M2 is turned off, the branch containing the second LED2 is turned off, and the second LED2 is off.

[0060] In practical applications, the color of the first light-emitting diode LED1 can be different from the color of the second light-emitting diode LED to clearly indicate the operating state of the target feedback resistor. For example, the first light-emitting diode LED1 can emit green light, and the second light-emitting diode LED can emit red light.

[0061] Combination Figure 6 Operational amplifier U1, first comparator U2, and second comparator U3 require a first power supply voltage VCC1 to drive them, while first light-emitting diode LED1 and second light-emitting diode LED2 require a second power supply voltage VCC2 to drive them. Optionally, the first power supply voltage VCC1, the second power supply voltage VCC2, and the reference voltage Vref can be obtained by transforming the standard voltage V1 using a power generation circuit. Figure 7 This is a schematic diagram of a power generation circuit provided in an embodiment of this utility model. (Refer to...) Figure 7 The power generation circuit includes: a first transformer chip U4, a second transformer chip U5, a third transformer chip U6, a first power inductor L1, a first power diode D1, a first power resistor R7, a second power resistor R8, a first power capacitor C1, and a second power capacitor C2.

[0062] The input terminal of the first transformer chip U4 is connected to the standard voltage V1, and the ground terminal of the first transformer chip U4 is grounded. The output terminal of the first transformer chip U4 is connected to the input terminal and the enable terminal of the second transformer chip U5. The input terminal of the second transformer chip U5 is also connected to the first terminal of the first power supply inductor L1. The second terminal of the first power supply inductor L1 is connected to the switching terminal of the second transformer chip U5. The switching terminal of the second transformer chip U5 is also connected to the anode terminal of the first power supply diode D1. The cathode terminal of the first power supply diode D1 outputs the first power supply voltage VCC1. The cathode terminal of the first power supply diode D1 is also connected to the first terminal of the first power supply resistor R7. The second end of resistor R7 is connected to the sampling terminal of the second transformer chip U5. The second end of the first power supply resistor R7 is also connected to the first end of the second power supply resistor R8. The second end of the second power supply resistor R8 is grounded. The grounding terminal of the second transformer chip U5 is grounded. The first power supply capacitor C1 is connected across the first power supply resistor R7. The second power supply capacitor C2 is connected between the cathode of the first power supply diode D1 and the second end of the second power supply resistor R8. The cathode of the first power supply diode D1 is also connected to the input terminal of the third transformer chip U6. The output terminal of the third transformer chip U6 outputs the second power supply voltage VCC2. The grounding terminal of the third transformer chip U6 is grounded.

[0063] It should be understood that the various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.

[0064] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A leakage current detection circuit characterized by comprising: include: Amplification module and output status monitoring module; The amplification module is electrically connected to the device under test. The amplification module includes an operational amplifier unit and a feedback resistor matrix. The feedback resistor matrix is ​​connected between the first input terminal and the output terminal of the operational amplifier unit. The operational amplifier unit is configured to convert the leakage current or noise current into an output voltage based on the target feedback resistor in the feedback resistor matrix. The output status monitoring module is connected to a reference voltage and is connected to the output terminal of the operational amplifier unit. The output status monitoring module is configured to monitor the operating status of the target feedback resistor based on the output voltage and the reference voltage.

2. The leakage current detection circuit according to claim 1, characterized by, The operational amplifier unit includes: an operational amplifier and a feedback capacitor; The first terminal of the operational amplifier is connected to the device under test, the second terminal of the operational amplifier is grounded, the third terminal of the operational amplifier is connected to the output status monitoring module, the power supply terminal of the operational amplifier is connected to a first power supply voltage, the ground terminal of the operational amplifier is grounded, and the feedback capacitor is connected between the first terminal and the third terminal of the operational amplifier.

3. The leakage current detection circuit according to claim 2, characterized by The operational amplifier unit also includes: circuit protection devices; The first terminal of the circuit protection device is connected to the third terminal of the operational amplifier, and the second terminal of the circuit protection device is grounded.

4. The leakage current detection circuit according to claim 1, characterized by, The feedback resistor matrix includes: a feedback switch and multiple feedback resistors; The feedback switch has multiple input terminals. The first terminal of each feedback resistor is connected to the first terminal of the operational amplifier unit. The second terminal of each feedback resistor is connected to each input terminal of the feedback switch in a corresponding manner. The output terminal of the feedback switch is connected to the third terminal of the operational amplifier unit. Each feedback resistor corresponds to a different leakage current level or noise current level.

5. The leakage current detection circuit according to claim 1, characterized by The feedback resistor matrix includes: multiple feedback switches and multiple feedback resistors; Each of the feedback switches and each of the feedback resistors are connected in a one-to-one correspondence to form multiple feedback branches, and each of the feedback branches is connected between the first terminal and the third terminal of the operational amplifier unit; wherein, each of the feedback resistors corresponds to a different leakage current level or noise current level.

6. The leakage current detection circuit according to any one of claims 4-5, wherein The resistance values ​​of the feedback resistors are in a proportional relationship.

7. The leakage current detection circuit according to claim 1, characterized by Also includes: Switch module; The amplification module is connected to the device under test (DUT) via the switching module. The switching module is configured to remain on when leakage current of the DUT is detected, and to remain off when noise current of the amplification module is detected.

8. The leakage current detection circuit of claim 1, wherein, The output status monitoring module includes: a first indicator circuit and a second indicator circuit; The first terminal of the first indicator circuit is connected to the operational amplifier unit, and the second terminal of the first indicator circuit receives the reference voltage. The first indicator circuit is configured to indicate that the working state of the target feedback resistor is a normal detection state based on the output voltage and the reference voltage. The first terminal of the second indicator circuit is connected to the second terminal of the first indicator circuit, and the second terminal of the second indicator circuit is connected to the first terminal of the first indicator circuit. The second indicator circuit is configured to indicate that the operating state of the target feedback resistor is an abnormal detection state based on the output voltage and the reference voltage.

9. The leakage current detection circuit according to claim 8, characterized by The first indicator circuit includes: a first comparator, a first switching transistor, and a first light-emitting diode; The first terminal of the first comparator is connected to the operational amplifier unit, the second terminal of the first comparator receives the reference voltage, the power supply terminal of the first comparator is connected to the first power supply voltage, the ground terminal of the first comparator is grounded, the third terminal of the first comparator is connected to the control terminal of the first switching transistor, the input terminal of the first switching transistor is connected to the cathode of the first light-emitting diode, the anode of the first light-emitting diode is connected to the second power supply voltage, and the output terminal of the first switching transistor is grounded. The second indicator circuit includes: a second comparator, a second switching transistor, and a second light-emitting diode; The first terminal of the second comparator is connected to the second terminal of the first comparator, the second terminal of the second comparator is connected to the first terminal of the first comparator, the power supply terminal of the second comparator is connected to the first power supply voltage, the ground terminal of the second comparator is grounded, the third terminal of the second comparator is connected to the control terminal of the second switching transistor, the input terminal of the second switching transistor is connected to the cathode of the second light-emitting diode, the anode of the second light-emitting diode is connected to the second power supply voltage, and the output terminal of the second switching transistor is grounded.

10. The leakage current detection circuit according to claim 9, characterized by The first light-emitting diode emits a different color than the second light-emitting diode.

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