Chip type integrated leakage current detection method and device

Abstract

The invention relates to a chip type integrated leakage current detection method and device, and the method comprises the steps: enabling a first line body and a second line body to be led into an input loop and an output loop of a target chip through a chip packaging lead frame, and enabling the first line body and the second line body to form a loop through an external power supply; a plurality of magnetic sensing units with the same number and symmetrical positions are respectively arranged on the first line body and the second line body; measuring magnetic field data of a plurality of preset positions through the plurality of magnetic sensing units; and calculating the leakage current of the target chip based on the magnetic field data of the plurality of preset positions. According to the invention, through the design of the chip lead frame, the wire body is introduced into the chip, and the magnetic field is measured through the magnetic sensitive sensing unit, so that miniaturization and integration of chip electric leakage measurement are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of chip detection, and in particular relates to a method and device for chip-type integrated leakage current detection. Background Art

[0002] The increasing demand for electricity has led to the rapid development of the power industry, and the scale of various household appliances has also become increasingly rich, such as certain types of laptops, microwave ovens, washing machines, etc. How to ensure the safety of household electricity use is an important issue. At present, direct current is increasingly used in household and industrial equipment. The causes of leakage include unqualified secondary circuit insulation materials, or disrepair, serious aging, equipment damage defects, secondary circuits and equipment dampness, water ingress, etc. The DC system is also a major cause of DC leakage, and is generally used in water conservancy, thermal power plants, various substations, etc.

[0003] Leakage current detection can be done in many ways, such as fluxgate, Hall, magnetoresistive module, etc. The fluxgate method requires high permeability soft magnetic core and complex circuit detection circuit to achieve, which is characterized by large size and high cost. Hall and magnetoresistive module use closed-loop mode, although the structure and current complexity are reduced to a certain extent, but still relatively high. The patent of this invention measures the leakage current of the loop by detecting the difference signal of the input circuit and the output circuit through a highly sensitive magnetoresistive probe, which has the characteristics of small size and high integration.

[0004] At present, the mainstream leakage current sensors are mainly measured through modularization. The principle is mainly to shield the external magnetic field interference through the form of flux gate or shielding ring, and measure the current difference between the current entering and returning in the loop. This method can accurately measure the current, but there are problems such as large size and complex process, and it is subject to various restrictions in use. The present invention proposes a chip-type integrated leakage current detection method to address this pain point. . Summary of the invention

[0005] In order to solve the problems of large size and complex process of existing leakage current sensors, a first aspect of the present invention provides a chip-type integrated leakage current detection method, including: introducing a first wire body and a second wire body into an input circuit and an output circuit of a target chip respectively through a chip packaging lead frame, wherein the first wire body and the second wire body form a circuit through an external power supply; arranging a plurality of magnetic sensitive sensing units of the same number and symmetrically positioned relative to the center of the chip on the input circuit and the output circuit respectively; measuring magnetic field data of a plurality of preset positions through the plurality of magnetic sensitive sensing units; and calculating the leakage current of the target chip based on the magnetic field data of the plurality of preset positions. In some embodiments of the present invention, the arrangement of a plurality of magnetic sensitive sensing units of the same number and symmetrically positioned relative to the center of the chip on the input loop and the output loop includes: two groups of magnetic sensitive sensing units are arranged on the input loop and the output loop, respectively, and the position of each magnetic sensitive sensing unit on the first line body is symmetrical relative to the center of the chip with respect to the corresponding magnetic sensitive sensing unit on the second line body.

[0006] Furthermore, the two magnetically sensitive sensing units of the first wire body and the two magnetically sensitive sensing units of the second wire body form a Wheatstone bridge.

[0007] In some embodiments of the present invention, calculating the leakage current of the target chip based on the magnetic field data of the multiple preset positions includes: calculating the resistance of each magnetic sensitive sensing unit based on the magnetic field data of the multiple preset positions; calculating the voltage of the input loop and the output loop respectively according to the resistance of all magnetic sensitive sensing units; and calculating the leakage current of the target chip based on the voltage of the input loop and the output loop.

[0008] Furthermore, the voltage of the input circuit is expressed as: , in, V out+ Indicates the voltage of the input circuit. R 0 represents the resistance of each magnetic sensitive sensor unit under zero magnetic field. A tmr represents the magnetic susceptibility coefficient, I in and I return They represent the current of the input circuit and the current of the output circuit respectively. V cc Indicates the voltage of the external power supply.

[0009] Further, the voltage of the output circuit is expressed as:

[0010]

[0011] in, V out- Indicates the voltage of the output circuit. R 0 represents the resistance of each magnetic sensitive sensor unit under zero magnetic field. A tmr represents the magnetic susceptibility coefficient, I in and I return They represent the current of the input circuit and the current of the output circuit respectively. V cc Indicates the voltage of the external power supply.

[0012] According to a second aspect of the present invention, a chip-type integrated leakage current detection device is provided, comprising: an introduction module for introducing a first wire body and a second wire body into an input circuit and an output circuit of a target chip respectively through a chip package lead frame, wherein the first wire body and the second wire body form a circuit through an external power supply; an arrangement module for arranging a plurality of magnetic sensitive sensing units of the same number and symmetrically positioned relative to the center of the chip on the input circuit and the output circuit respectively; a measurement module for measuring magnetic field data of a plurality of preset positions through the plurality of magnetic sensitive sensing units; and calculating the leakage current of the target chip based on the magnetic field data of the plurality of preset positions.

[0013] The beneficial effects of the present invention are: The present invention introduces the current loops of the input loop and the output loop into the lead frame of the chip respectively. Since the two lead frames have a symmetrical structure, multiple magnetic sensitive units are placed at symmetrical positions of the structure. When there is leakage in the loop, a magnetic field gradient will be generated at the symmetrical positions of the structure. The magnetic field difference at these positions is measured by a high-sensitivity magnetic unit, and the magnitude of the leakage current in the system can be measured. The present invention has the characteristics of small size, high sensitivity, and strong resistance to external interference of the entire leakage sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of a basic flow chart of a chip-type integrated leakage current detection method in some embodiments of the present invention; Figure 2 A schematic diagram of the circuit principle of a chip-type integrated leakage current detection method in some embodiments of the present invention; Figure 3 A schematic diagram of a typical chip configuration structure in some embodiments of the present invention; Figure 4 A diagram showing the relationship between the magnetic field magnitude and the current difference at the measuring point of the magnetoresistive sensor in some embodiments of the present invention; Figure 5 Schematic diagram of chip packaging in some embodiments of the present invention; Figure 6 It is a schematic diagram of the structure of a chip-type integrated leakage current detection device in some embodiments of the present invention. DETAILED DESCRIPTION

[0015] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0016] refer to Figures 1 to 3In a first aspect of the present invention, a method for detecting leakage current of a chip-type integrated circuit is provided, comprising: S100. Introducing a first wire body and a second wire body into an input circuit and an output circuit of a target chip respectively through a chip package lead frame, wherein the first wire body and the second wire body form a circuit through an external power supply; S200. Arranging a plurality of magnetic sensitive sensing units of the same number and symmetrically positioned relative to the center of the chip on the input circuit and the output circuit respectively; S300. Measuring magnetic field data of a plurality of preset positions through the plurality of magnetic sensitive sensing units; S400. Calculating the leakage current of the target chip based on the magnetic field data of the plurality of preset positions.

[0017] It should be noted that each magnetic sensor includes multiple or multiple groups of magnetic sensing units, and each or multiple groups of magnetic sensing units can be divided into multiple smaller magnetic sensing units.

[0018] In step S100 of some embodiments of the present invention, the first wire body and the second wire body are respectively introduced into the input loop and the output loop of the target chip through the chip packaging lead frame, wherein the first wire body and the second wire body form a loop through an external power supply; specifically, the current of the input loop (wire body 1) and the output loop (wire body 2) are introduced into the interior of the chip through the chip packaging lead frame, and when the current passes through wire body 1 and wire body 2, the magnetic field at the positions of B1 and B1 is measured by a tunneling magnetoresistive sensor, and the size of the chip leakage current is calculated by the size of the magnetic field.

[0019] In step S200 of some embodiments of the present invention, the arrangement of multiple magnetic sensing units of the same number and symmetric relative to the center of the chip on the input loop and the output loop includes: arranging two groups of magnetic sensing units on the input loop and the output loop, and the positions of each magnetic sensing unit on the first wire body and the corresponding magnetic sensing unit on the second wire body are symmetric relative to the center of the chip. The magnetic sensing unit is a tunneling magnetoresistance effect sensor. The magnetic sensor is composed of a Wheatstone bridge structure inside; by designing a frame structure for introducing current with wire bodies 1 and 2, it has a symmetrical structure inside; during the packaging process, the four bridges on the bridge arms of the magnetic sensing are placed under the two frames respectively. When the monitored load system has no leakage current, the current flowing through the package lead frame is the same, the magnetic field generated is also the same, the Wheatstone bridge is in a balanced state, and the sensor has no output. When the detected load has leakage current, the magnetic field generated by the package lead frame is different in size, resulting in the bridge no longer being balanced, and the bridge has a differential signal output, and the intensity of the output signal is linearly related to the difference in the input current of the signal.

[0020] refer to Figure 4 and Figure 5 In step S400 of some embodiments of the present invention, the calculating the leakage current of the target chip based on the magnetic field data of the plurality of preset positions includes: S401. Calculating the resistance of each magnetic sensitive sensing unit based on the magnetic field data of the plurality of preset positions; Specifically, the TMR tunneling magnetoresistive grain is a highly sensitive magnetoresistive device that is sensitive to magnetic fields. Its resistance changes with the magnitude of the magnetic field. tmr =R0+S tmr *H, where R0 is the resistance at zero magnetic field, H is the magnetic field at the sensor location, and S tmr The magnetic field size H inside the chip is proportional to the current size on the package lead frame. Since the bridge leads inside the chip are configured in a symmetrical structure, the magnetic fields generated by wire 1 and wire 2 are in opposite directions. Therefore, the resistance R of TMR1 and TMR2 is r =R0+A tmr *Iin; resistance R of TMR3, TMR4 r =R0+A tmr *I return .

[0021] S402. Calculate the voltage of the input circuit and the output circuit respectively according to the resistance of all magnetic sensitive sensing units; Specifically, when current flows through the chip, the bridge output voltage of the TMR probe is: , , in, V out+ Indicates the voltage of the input circuit. V out- Indicates the voltage of the output circuit; R 0 represents the resistance of each magnetic sensitive sensor unit under zero magnetic field. A tmr represents the magnetic susceptibility coefficient, I in and i return They represent the current of the input circuit and the current of the output circuit respectively. V cc Indicates the voltage of the external power supply.

[0022] S403. Calculate the leakage current of the target chip based on the voltages of the input loop and the output loop.

[0023] Specifically, the signal output by the TMR sensor is connected to the input port of the differential amplifier of the signal processing circuit, and the differential amplifier signal The size is: ; When there is no current leakage in the monitored load system,I in =I return , the resistance of the TMR bridge will change with the bridge, but the common-mode signal of the magnetic sensor can be filtered through the differential input port of the ASIC circuit, and only the differential signal is processed, so V diff The output is zero. When there is current leakage in the system ΔI=I in -I return ;The ASIC chip amplifies the signal and then outputs it. The result is the same as ΔI Directly proportional.

[0024] Continue to refer Figure 4 , inside the chip, when the current direction on wire 1 and wire 2 passes through the lead frame, the magnetic field generated will be superimposed. When the lead frame is designed as a symmetrical structure, when there is no leakage current in the loop, the current on wire 1 and wire 2 is the same, and the magnetic field strength generated at positions B1 and B2 is equal, but the direction is opposite; when the current on wire 1 and wire 2 is different, the magnetic field magnitude in the direction of the magnetic field at position B1 / B2 is proportional to the current difference. The figure shows the relationship between the magnetic field distribution when the current is the same and the magnetic field strength at positions B1 and B2 when the current of wire 1 is 30 A and the input loop-output loop current difference. The simulation results show that if there is leakage current in the loop (that is, the current flowing through wire 1 and wire 2 is different), the magnetic field is different, and the leakage current can be measured by magnetic sensitive sensing.

[0025] Example 2 refer to Figure 6 According to a second aspect of the present invention, a chip-type integrated leakage current detection device 1 is provided, comprising: an introduction module 11, used to introduce a first wire body and a second wire body into an input circuit and an output circuit of a target chip respectively through a chip package lead frame, wherein the first wire body and the second wire body form a circuit through an external power supply; an arrangement module 12, used to arrange a plurality of magnetic sensitive sensing units of the same number and symmetrical positions relative to the center of the chip on the input circuit and the output circuit respectively; a measurement module 13, used to measure magnetic field data of a plurality of preset positions through the plurality of magnetic sensitive sensing units; and calculate the leakage current of the target chip based on the magnetic field data of the plurality of preset positions.

[0026] Furthermore, the calculation module 13 includes: a measuring unit, used to measure the magnetic field data of multiple preset positions in real time through the multiple magnetic sensor units; and a calculation unit, used to calculate the leakage current of the target chip through the magnetic field data of multiple preset positions and the resistance of each magnetic sensor unit. In one embodiment of the present invention, a chip-type integrated leakage current detection device includes: four or more groups of magnetic sensing units MR1-MR4 with consistent performance form a TMR magnetic sensing probe with a Wheatstone bridge structure and a signal conditioning ASIC chip, which are placed on a packaged lead frame in a packaged form. The currents of the current wire 1 and the wire 2 are introduced into the chip through the package frame. When the currents on the wire 1 and the wire 2 are different in magnitude, the output signal of the magnetic sensor is amplified, gain-adjusted, and zero-point-adjusted by the ASIC conditioning chip before being output.

[0027] MR1~MR4 can be Hall sensors or magnetoresistive magnetic sensors (such as anisotropic magnetoresistive AMR, giant magnetoresistive GMR, tunneling magnetoresistive TMR), but they must be the same type of sensors with consistent sensitivity characteristics; wire body 1 and wire body 2 are connected to lead frame 1 and lead frame 2 respectively. When the current in lead frame 1 and lead frame 2 is different, since MR1 and MR2 are symmetrically arranged in the chip, the difference between the output signals of MR1 and MR2 is proportional to the difference in current, thereby realizing the leakage current measurement function.

[0028] In another embodiment of the present invention, the lead frame has a complex structure, and the lead frame 1 and the lead frame 2 still have a symmetrical structure, which has the effect that when there is no leakage current in the system, the magnetic fields generated by the lead frames 1 and 2 at the positions MR1 ​​and MR2 are the same in magnitude, and when leakage current is generated, the superimposed magnetic fields generated at MR1 and MR2 are different, so the magnitude of the leakage current can be measured by sensing the magnetic field magnitudes at these two positions.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A chip-type integrated leakage current detection method, characterized in that: include: Introducing the first wire body and the second wire body into the input loop and the output loop of the target chip respectively through the chip packaging lead frame, wherein the first wire body and the second wire body form a loop through an external power supply; Arranging a plurality of magnetic sensing units of the same number and symmetrically positioned relative to the center of the chip on the input circuit and the output circuit respectively; Measuring magnetic field data of multiple preset positions by using the multiple magnetic sensitive sensing units; Based on the magnetic field data of the plurality of preset positions, a leakage current of the target chip is calculated.

2. The chip-type integrated leakage current detection method according to claim 1, characterized in that: The plurality of magnetic sensing units arranged in the input circuit and the output circuit in the same number and symmetrically relative to the center of the chip include: Two groups of magnetic sensing units are arranged on the input loop and the output loop respectively, and the position of each magnetic sensing unit on the first line body and the corresponding magnetic sensing unit on the second line body are symmetrical relative to the center of the chip.

3. The chip-type integrated leakage current detection method according to claim 2, characterized in that: The two groups of magnetic sensitive sensing units of the first line body and the two magnetic sensitive sensing units of the second line body form a Wheatstone bridge.

4. The chip-type integrated leakage current detection method according to claim 1, characterized in that: The calculating the leakage current of the target chip based on the magnetic field data of the plurality of preset positions comprises: Calculating the resistance of each magnetic sensitive sensing unit based on the magnetic field data of the plurality of preset positions; According to the resistance of all magnetic sensitive sensing units, the voltage of the input circuit and the output circuit are calculated respectively; Based on the voltages of the input loop and the output loop, a leakage current of the target chip is calculated.

5. The chip-type integrated leakage current detection method according to claim 4, characterized in that: The voltage of the input circuit is expressed as: ， in, V out+ Indicates the voltage of the input circuit. R 0 represents the resistance of each magnetic sensor unit in zero magnetic field. A tmr represents the magnetic susceptibility coefficient, I in and I return They represent the current of the input circuit and the current of the output circuit respectively. V cc Indicates the voltage of the external power supply.

6. The chip-type integrated leakage current detection method according to claim 4, characterized in that: The voltage of the output circuit is expressed as: in, V out- Indicates the voltage of the output circuit. R 0 represents the resistance of each magnetic sensor unit in zero magnetic field. A tmr represents the magnetic susceptibility coefficient, I in and I return They represent the current of the input circuit and the current of the output circuit respectively. V cc Indicates the voltage of the external power supply.

7. A chip-type integrated leakage current detection device, characterized in that: include: An introduction module, used to introduce the first wire body and the second wire body into the input circuit and the output circuit of the target chip respectively through the chip packaging lead frame, wherein the first wire body and the second wire body form a circuit through an external power supply; An arrangement module, used to arrange a plurality of magnetic sensing units of the same number and symmetrically positioned relative to the center of the chip on the input loop and the output loop respectively; The measuring module is used to measure the magnetic field data of multiple preset positions through the multiple magnetic sensitive sensing units; and calculate the leakage current of the target chip based on the magnetic field data of the multiple preset positions.

8. The chip-type integrated leakage current detection device according to claim 7, characterized in that: The measuring module comprises: A measuring unit, used to measure the magnetic field data of multiple preset positions in real time through the multiple magnetic sensor units; The calculation unit is used to calculate the leakage current of the target chip through the magnetic field data of multiple preset positions and the resistance of each magnetic sensitive sensor unit.

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