A contact detection device for ac impedance testing

Abstract

The utility model provides a contact detection device for alternating current impedance test, including contact detection signal generation module and frequency division module, the first end of contact detection signal generation module and the first end of frequency division module are connected. The utility model has the beneficial effect as follows, the core purpose of the present application is to realize the precise contact detection without interference through frequency separation and difference detection technology. Through the injection 400kHz high frequency sine wave signal, the signal crosstalk between contact detection and impedance measurement is completely eliminated, the differential alternating current amplification module is used in combination rectifier filter circuit, common mode noise is effectively inhibited and the anti -interference ability is promoted, through the real -time monitoring each test line loop's signal state, the specific terminal of contact bad is positioned accurately, finally the direct current level signal is exported to the ARM treater through the buffer, realizes the online real -time diagnosis in full variable frequency test process, thereby solves the technical problem of contact reliability determination in mOmega level low impedance measurement.

Description

Technical Field

[0001] This invention relates to a contact testing device for AC impedance testing, belonging to the field of lithium battery impedance testing technology. Background Technology

[0002] In the field of lithium battery impedance testing, existing contact detection technologies have significant limitations. The DC voltage drop method in existing technologies applies DC current, which can induce electrode polarization and thermoelectric effects, causing the measured contact resistance value to deviate from the actual value. Simultaneously, the DC signal may induce unnecessary electrochemical reactions within the battery, affecting the integrity of the test. Another method, low-frequency AC injection (typically using 1kHz), can alleviate the polarization problem, but its operating frequency band overlaps with the mainstream lithium battery impedance testing frequency band (0.1-1050Hz), causing interference between the contact detection signal and the main measurement signal, resulting in distorted impedance spectrum data. Utility Model Content

[0003] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a contact detection device for AC impedance testing.

[0004] To achieve the above objectives, this utility model is implemented through the following technical solution:

[0005] A contact detection device for AC impedance testing includes a contact detection signal generation module and a frequency division module. The first end of the contact detection signal generation module is connected to the first end of the frequency division module. The second end of the contact detection signal generation module and the second end of the frequency division module are respectively connected to the first end of a rectification / filtering module and the first end of a differential sampling module. The second end of the differential sampling module is connected to the second end of the rectification / filtering module. The third end of the rectification / filtering module is connected to the first end of an amplification module. The second end of the amplification module is connected to a processor.

[0006] Furthermore, the contact detection signal generation module includes a Schmitt trigger IC2. The first pin of the Schmitt trigger IC2 is connected to one end of capacitor C2 and resistor R5, respectively. The other end of capacitor C2 is grounded. The other end of resistor R5 is connected to the second pin of the Schmitt trigger IC2 and the frequency divider module, respectively. The fourteenth pin and the seventh pin of the Schmitt trigger IC2 are connected to the power supply voltage and ground, respectively.

[0007] Furthermore, the frequency divider module includes a frequency divider IC4. The first pin of frequency divider IC4 is connected to one end of resistor R5. The fourth and fifth pins of frequency divider IC4 are connected to one end of resistor R12 and one end of resistor R18, respectively. The other end of resistor R12 is connected to the third and fifth pins of Schmitt trigger IC2, respectively. The fourth and sixth pins of Schmitt trigger IC2 are connected to interface P1 and one end of capacitor C4, respectively. The other end of capacitor C4 is connected to one end of resistor R8 and resistor R9, respectively. The other end of resistor R8 is grounded. The other end of resistor R9 is connected to the fourth pin of capacitor C3 and inductor L1, respectively. The other end of capacitor C3 is grounded. The third pin of inductor L1 is grounded. The second and first pins of inductor L1 are connected to the SENSE port and one end of resistor R10, respectively. The other end of resistor R10 is connected to one end of capacitor C5. The other end of capacitor C5 is connected to the DRIVE- port. The other end of resistor R18 is connected to pin 13 of Schmitt trigger IC2. Pin 12 of Schmitt trigger IC2 is connected to pins 9 and 11 respectively. Pins 8 and 10 of Schmitt trigger IC2 are connected to interface P2 and one end of capacitor C8. The other end of capacitor C8 is connected to one end of resistor R20 and one end of resistor R13 respectively. The other end of resistor R20 is grounded. The other end of resistor R13 is connected to one end of capacitor C10 and one pin of inductor L2 respectively. The other end of capacitor C10 is grounded. Pins 3 and 4 of inductor L2 are connected to the SENSE+ port and one end of resistor R14 respectively. The other end of resistor R14 is connected to one end of capacitor C9. The other end of capacitor C9 is connected to the DRIVE+ port. Pin 2 of inductor L2 is grounded.

[0008] Furthermore, pin 14 of frequency divider IC4 is connected to the power supply voltage, while pins 2, 12, and 13 of frequency divider IC4 are all grounded.

[0009] Furthermore, the differential sampling module includes operational amplifier IC7B. The non-inverting input of operational amplifier IC7B is connected to one end of resistor R23. The other end of resistor R23 is connected to one end of capacitor C11 and one end of resistor R27. The other end of capacitor C11 is connected to the DRIVE+ port. The other end of resistor R27 is grounded. The inverting input of operational amplifier IC7B is connected to one end of resistor R26 and one end of resistor R28. The other end of resistor R28 is connected to... The outputs of operational amplifier IC7B are all connected to one end of resistor 24R24. The other end of resistor 24R24 is connected to one end of resistor 25R25 and the non-inverting input of operational amplifier IC8B. The other end of resistor 25R25 is grounded. The inverting input of operational amplifier IC8B is connected to one end of resistor 30R30. One end of resistor 30R30 is connected to one end of resistor 31R31. The other end of resistor 31R31 is connected to voltage 3V3 and one end of resistor 32R32. The output of 8B is also connected to voltage 3V3. The other end of resistor 32R32 is connected to the inverting input of operational amplifier 9IC9B and one end of resistor 37R37. The other end of resistor 37R37 is connected to voltage 4V4. The non-inverting input of operational amplifier 9IC9B is grounded. The output of operational amplifier 9IC9B is connected to voltage 4V4. The other end of resistor 30R30 is connected to one end of resistor 29R29 and the output of operational amplifier 11IC11B. The other end of resistor 29R29 is connected to operational amplifier 11IC11B. The non-inverting input of C11B is connected to one end of capacitor C12. The other end of capacitor C12 is connected to one end of resistor R26. The inverting input of IC11B is connected to one end of resistor R33 and ground. The other end of resistor R33 is connected to one end of capacitor R13 and one end of resistor R38. The other end of resistor R38 is grounded. The other end of capacitor R13 is connected to the SENSE+ port.

[0010] Furthermore, the differential sampling module also includes operational amplifier IC1B. The non-inverting input of operational amplifier IC1B is connected to one end of resistor R1. The other end of resistor R1 is connected to one end of capacitor C1 and one end of resistor R6. The other end of capacitor C1 is connected to the DRIVE port. The other end of resistor R6 is grounded. The inverting input of operational amplifier IC1B is connected to one end of resistor R4 and one end of resistor R7. The other end of resistor R7 and the output of operational amplifier IC1B are connected to one end of resistor R2. The other end of resistor R2 is connected to one end of resistor R3 and the non-inverting input of operational amplifier IC3B. The other end of resistor R3 is grounded. The inverting input of operational amplifier IC3B is connected to one end of resistor R15. Resistor R15 is connected to one end of resistor R16. The other end of resistor R16 is connected to voltage V1 and one end of resistor R17. The output of operational amplifier IC3B is also connected to... The three-phase V3 is connected. The other end of resistor 17R17 is connected to the inverting input of operational amplifier 5 IC5B and one end of resistor 21R21. The other end of resistor 21R21 is connected to voltage 2 V2. The non-inverting input of operational amplifier 3 IC3B is grounded. The output of operational amplifier 3 IC3B is connected to voltage 2 V2. The other end of resistor 15R15 is connected to one end of resistor 11R11 and the output of operational amplifier 6 IC6B. The other end of resistor 11R11 is connected to the non-inverting input of operational amplifier 6 IC6B. The non-inverting input of operational amplifier 6 IC6B is also connected to one end of capacitor 6 C6. The other end of capacitor 6 C6 is connected to one end of resistor 4R4. The inverting input of operational amplifier 6 IC6B is connected to one end of resistor 19R19 and grounded. The other end of resistor 19R19 is connected to one end of capacitor 7 R7 and one end of resistor 22R22. The other end of resistor 22R22 is grounded. The other end of capacitor 7 R7 is connected to the SENSE port.

[0011] Furthermore, the rectifier / filter module includes a dual analog switch IC10. The fifteenth pin of the dual analog switch IC10 is connected to one end of the thirty-fourth resistor R34. The other end of the thirty-fourth resistor R34 is connected to one end of the fourteenth capacitor C14 and one end of the thirty-fifth resistor R35. The other end of the fourteenth capacitor C14 is grounded. The other end of the thirty-fifth resistor R35 is connected to one end of the fifteenth capacitor C15 and one end of the thirty-sixth resistor R36. The other end of the fifteenth capacitor C15 is grounded. The other end of the thirty-sixth resistor R36 is connected to one end of the sixteenth capacitor C16 and one end of the voltage V5. The other end of the sixteenth capacitor C16 is grounded.

[0012] Furthermore, the rectifier / filter module includes a dual-channel analog switch IC10. The first, second, third, and fifth pins of the dual-channel analog switch IC10 are connected to voltage 4 (V4), voltage 3 (V3), voltage 2 (V2), and voltage 1 (V1), respectively. The seventh, eleventh, twelfth, thirteenth, and fourteenth pins of the dual-channel analog switch IC10 are grounded. The tenth and ninth pins of the dual-channel analog switch IC10 are connected to interface 1 (P1) and interface 2 (P2), respectively.

[0013] Furthermore, the amplification module includes operational amplifier 13IC13B. The non-inverting input of operational amplifier 13IC13B is connected to voltage 5V5. The inverting input of operational amplifier 13IC13B is connected to one end of resistor 47R47 and one end of resistor 46R46, respectively. The other end of resistor 47R47 is grounded. The other end of resistor 46R46 and the output of operational amplifier 13IC13B are connected to the inverting input of operational amplifier 12IC12B. The non-inverting input of operational amplifier 12IC12B is connected to one end of resistor 42R42, one end of resistor 43R43, and one end of resistor 45R45, respectively. The other end of resistor 45R45 is connected to the power supply voltage. The other end of resistor 43R43 is grounded. The other end of resistor 42R42 and the output of operational amplifier 12IC12B are connected to one end of resistor 44R44 and the ARM-21 pin of the ARM chip. The other end of resistor 44R44 is connected to the power supply voltage.

[0014] Furthermore, the amplification module also includes operational amplifier IC15B. The non-inverting input of operational amplifier IC15B is connected to voltage 6V6. The inverting input of operational amplifier IC15B is connected to one end of resistor R53 and one end of resistor R52, respectively. The other end of resistor R53 is grounded. The other end of resistor R52 and the output of operational amplifier IC15B are connected to the inverting input of operational amplifier IC14B. The non-inverting input of operational amplifier IC14B is connected to one end of resistor R48, one end of resistor R49, and one end of resistor R51, respectively. The other end of resistor R51 is connected to the power supply voltage. The other end of resistor R49 is grounded. The other end of resistor R48 and the output of operational amplifier IC14B are connected to one end of resistor R50 and the ARM-22 pin of the ARM chip. The other end of resistor R50 is connected to the power supply voltage.

[0015] The beneficial effects of this utility model are:

[0016] This invention generates a contact detection signal through a contact detection signal generation module and a frequency division module. If the contact detection is abnormal, the contact detection signal will become a high level after passing through a differential sampling, rectification module, and filtering and amplification module, and will be sent to the ARM, which will then recognize the contact detection as abnormal. If the contact detection is successful (i.e., the SENCE and DRIVE terminals are in normal contact), the signal sent to the differential sampling module is 0V, and will become a low level after passing through the differential sampling, rectification module, and filtering and amplification module, which will then recognize the contact detection as normal.

[0017] This invention injects a sinusoidal AC contact detection signal at a specific frequency (e.g., 30kHz) and uses a differential AC amplification module for sampling processing. This allows for precise location of which test line (DRIVE+, DRIVE-, SENSE+, SENSE-) has a poor contact. Its frequency separation design (detection signal is much higher than the main measurement frequency band by 0.1-1050Hz) combined with differential amplification technology effectively suppresses environmental noise and common-mode interference, thereby achieving interference-free real-time monitoring and accurate judgment in full-frequency conversion testing scenarios.

[0018] This invention uses high-frequency AC signal injection and differential detection technology to determine contact reliability. By generating a 400kHz sine wave contact detection signal (far higher than the main measurement frequency band of 0.1-1050Hz), combined with sampling and processing by the differential amplification module, it can accurately locate which two sets of test lines among DRIVE+, DRIVE-, SENSE+, and SENSE- have poor contact.

[0019] This invention provides a complete technical solution through frequency separation design to avoid signal crosstalk, differential AC amplification module to suppress common-mode interference, rectifier and filter circuit to convert AC signal to DC level output, and ARM processor to achieve real-time online diagnosis.

[0020] This invention generates a high-frequency square wave using a Schmitt trigger and a frequency divider, and converts it into a sine wave via a bandpass filter; a differential sampling module extracts the signal through capacitor DC blocking and a symmetrical amplification structure; an analog switch-controlled rectification mechanism converts the sine wave into a DC level, and finally outputs a judgment signal to the processor through a hysteresis comparator, forming a complete technical protection system.

[0021] Compared to the DC voltage drop method and the low-frequency AC injection scheme, this invention completely solves the problems of signal interference and measurement inaccuracy. The DC method causes distortion in contact resistance measurements due to electrode polarization and thermoelectric effects, while the low-frequency AC method (e.g., 1kHz) overlaps with the main measurement frequency band, causing impedance spectrum data crosstalk. This invention, however, completely separates the frequency bands using a 400kHz high-frequency detection signal, ensuring that contact detection and main measurement do not interfere with each other, eliminating the source of error at its root. Furthermore, the signal sent to the processor is a high / low level signal, facilitating software processing and identification. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in 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.

[0023] Figure 1 This is a schematic block diagram of a contact detection device for AC impedance testing according to the present invention.

[0024] Figure 2 This is a circuit diagram of the contact detection signal generation module and frequency division module of a contact detection device for AC impedance testing according to the present invention.

[0025] Figure 3 This invention relates to a differential sampling module circuit for a contact detection device used for AC impedance testing. Figure 1 ;

[0026] Figure 4 This invention relates to a differential sampling module circuit for a contact detection device used for AC impedance testing. Figure 2 ;

[0027] Figure 5 This is a circuit diagram of the rectifier / filter module of a contact detection device for AC impedance testing according to the present invention.

[0028] Figure 6 This invention relates to an amplification module circuit for a contact detection device used for AC impedance testing. Figure 1 ;

[0029] Figure 7 This invention relates to an amplification module circuit for a contact detection device used for AC impedance testing. Figure 2 . Detailed Implementation

[0030] The technical solutions of the present utility model 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 utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] Please see Figure 1This utility model provides a contact detection device for AC impedance testing, including a contact detection signal generation module and a frequency division module. The first end of the contact detection signal generation module and the first end of the frequency division module are connected. The second end of the contact detection signal generation module and the second end of the frequency division module are respectively connected to the first end of the rectification / filtering module and the first end of the differential sampling module. The second end of the differential sampling module is connected to the second end of the rectification / filtering module. The third end of the rectification / filtering module is connected to the first end of the amplification module. The second end of the amplification module is connected to the processor.

[0032] See Figure 2The contact detection signal generation module includes a Schmitt trigger IC2. The first pin of Schmitt trigger IC2 is connected to one end of capacitor C2 and resistor R5, respectively. The other end of capacitor C2 is grounded. The other end of resistor R5 is connected to the second pin of Schmitt trigger IC2 and the frequency divider module. The fourteenth and seventh pins of Schmitt trigger IC2 are connected to the power supply voltage and ground, respectively. The frequency divider module includes a frequency divider IC4. The first pin of frequency divider IC4 is connected to one end of resistor R5, and the fourth and fifth pins of frequency divider IC4 are connected to resistor R12, respectively. One end of the resistor is connected to one end of resistor 18R18. The other end of resistor 12R12 is connected to the third and fifth pins of Schmitt trigger IC2, respectively. The fourth and sixth pins of Schmitt trigger IC2 are connected to interface P1 and one end of capacitor C4, respectively. The other end of capacitor C4 is connected to one end of resistors R8 and R9, respectively. The other end of resistor R8 is grounded. The other end of resistor R9 is connected to the fourth pin of capacitor C3 and inductor L1, respectively. The other end of capacitor C3 is grounded. The third pin of inductor L1 is grounded. The second and first pins of inductor L1 are connected to... Connect the resistor to the SENSE port and one end of resistor R10. Connect the other end of resistor R10 to one end of capacitor C5. Connect the other end of capacitor C5 to the DRIVE port. Connect the other end of resistor R18 to pin 13 of Schmitt trigger IC2. Connect pin 12 of Schmitt trigger IC2 to pins 9 and 11 respectively. Connect pins 8 and 10 of Schmitt trigger IC2 to interface P2 and one end of capacitor C8. Connect the other end of capacitor C8 to one end of resistor R20 and one end of resistor R13 respectively. The other end of resistor R20 is grounded. The other end of resistor R13 is connected to one end of capacitor C10 and the first pin of inductor L2. The other end of capacitor C10 is grounded. The third and fourth pins of inductor L2 are connected to the SENSE+ port and one end of resistor R14. The other end of resistor R14 is connected to one end of capacitor C9. The other end of capacitor C9 is connected to the DRIVE+ port. The second pin of inductor L2 is grounded. The fourteenth pin of frequency divider IC4 is connected to the power supply voltage. The second, twelfth, and thirteenth pins of frequency divider IC4 are all grounded.A 400kHz square wave signal is generated by combining Schmitt trigger IC2, resistor R5, and capacitor C2. A 200kHz square wave signal is generated by frequency divider IC4. The 200kHz and 100kHz square wave signals are then converted into 200kHz and 100kHz sine wave signals by a bandpass filter composed of capacitor C4, resistor R8, resistor R9, capacitor C3 / C8, resistor R13, resistor R20, and capacitor C10. The 200kHz and 100kHz sine wave signals are then fed into the DRIVE- and SENSE- ports and the DRIVE+ and SENSE+ ports, respectively, by common-mode inductor L1 / L2. If the DRIVE+ and SENSE+ ports have an abnormal connection (i.e., an open circuit or high impedance between them), a 200kHz sine wave signal will exist between them. If the DRIVE+ and SENSE+ ports have a normal connection (i.e., near short circuit), there will be almost no voltage difference between them. The signal between the DRIVE- and SENSE- ports is similar.

[0033] See Figures 3-4The differential sampling module includes operational amplifier IC7B. The non-inverting input of operational amplifier IC7B is connected to one end of resistor R23 (23 R23). The other end of resistor R23 is connected to one end of capacitor C11 (11) and one end of resistor R27 (27 R27). The other end of capacitor C11 is connected to the DRIVE+ port. The other end of resistor R27 is grounded. The inverting input of operational amplifier IC7B is connected to one end of resistor R26 (26 R26) and one end of resistor R28 (28 R28). The other end of resistor R28 and the output of operational amplifier IC7B are both connected to one end of resistor R24 ​​(24 R24). The other end of resistor R24 ​​is connected to one end of resistor R25 (25 R25) and one end of operational amplifier IC7B (8). The non-inverting input of IC8B is connected, and the other end of resistor 25R25 is grounded. The inverting input of operational amplifier IC8B is connected to one end of resistor 30R30. One end of resistor 30R30 is connected to one end of resistor 31R31. The other end of resistor 31R31 is connected to voltage 3V3 and one end of resistor 32R32. The output of operational amplifier IC8B is also connected to voltage 3V3. The other end of resistor 32R32 is connected to the inverting input of operational amplifier IC9B and one end of resistor 37R37. The other end of resistor 37R37 is connected to voltage 4V4. The non-inverting input of operational amplifier IC9B is grounded, and the output of operational amplifier IC9B is connected to voltage 4V4. The connection is as follows: the other end of resistor 30R30 is connected to one end of resistor 29R29 and the output terminal of operational amplifier 11IC11B. The other end of resistor 29R29 is connected to the non-inverting input terminal of operational amplifier 11IC11B. The non-inverting input terminal of operational amplifier 11IC11B is also connected to one end of capacitor 12C12. The other end of capacitor 12C12 is connected to one end of resistor 26R26. The inverting input terminal of operational amplifier 11IC11B is connected to one end of resistor 33R33 and ground. The other end of resistor 33R33 is connected to one end of capacitor 13R13 and one end of resistor 38R38. The other end of resistor 38R38 is grounded. The other end of capacitor 13R13 is connected to S... The ENSE+ port is connected. The differential sampling module also includes operational amplifier IC1B. The non-inverting input of operational amplifier IC1B is connected to one end of resistor R1. The other end of resistor R1 is connected to one end of capacitor C1 and one end of resistor R6. The other end of capacitor C1 is connected to the DRIVE- port. The other end of resistor R6 is grounded. The inverting input of operational amplifier IC1B is connected to one end of resistor R4 and one end of resistor R7. The other end of resistor R7 and the output of operational amplifier IC1B are connected to one end of resistor R2. The other end of resistor R2 is connected to one end of resistor R3 and the non-inverting input of operational amplifier IC3B. The other end of resistor R3 is grounded.The inverting input of operational amplifier IC3B is connected to one end of resistor 15R15. Resistor 15R15 is connected to one end of resistor 16R16. The other end of resistor 16R16 is connected to one end of voltage 1 (V1) and resistor 17R17. The output of operational amplifier IC3B is also connected to voltage 3 (V3). The other end of resistor 17R17 is connected to the inverting input of operational amplifier IC5B and one end of resistor 21R21. The other end of resistor 21R21 is connected to voltage 2 (V2). The non-inverting input of operational amplifier IC3B is grounded. The output of operational amplifier IC3B is connected to voltage V2. The other end of resistor R15 is connected to one end of resistor R11 and the output of operational amplifier IC6B. The other end of resistor R11 is connected to the non-inverting input of operational amplifier IC6B. The non-inverting input of operational amplifier IC6B is also connected to one end of capacitor C6. The other end of capacitor C6 is connected to one end of resistor R4. The inverting input of operational amplifier IC6B is connected to one end of resistor R19 and ground. The other end of resistor R19... The terminals are connected to one end of capacitor 7R7 and one end of resistor 22R22 respectively. The other end of resistor 22R22 is grounded, and the other end of capacitor 7R7 is connected to the SENSE- port. The signal between the DRIVE+ port and the SENSE+ port is DC blocked by capacitors 11C11 and 13C13, allowing only the AC signal to be sampled in. This signal then passes through resistors 27R27, 23R23, 26R26, 38R38, 33R33, 28R28, 29R29, and 24R24. A differential amplifier circuit composed of resistors R25 (25), R30 (30), R31 (31), C12 (12), and operational amplifiers IC7B (7), IC11B (11), and IC8B (8) amplifies the voltage to V3. This V3 voltage is then amplified by an inverting amplifier composed of IC9B (9), R32 (32), and R37 (37) to obtain voltage V4, which is the inverse of V3. Similarly, the DRIVE-port and SENSE-port are differentially amplified through capacitor blocking to obtain voltage V1 and voltage V2, which is the inverse of voltage V1. Voltages V1 and V3 are amplified signals from the sampled contact detection sinusoidal signal. Voltages V2 and V4 are signals opposite to voltages V1 and V3, used for subsequent rectification.

[0034] See Figure 5The rectifier / filter module includes a dual-channel analog switch IC10. Pin 15 of the dual-channel analog switch IC10 is connected to one end of resistor R34. The other end of resistor R34 is connected to one end of capacitor C14 and one end of resistor R35. The other end of capacitor C14 is grounded. The other end of resistor R35 is connected to one end of capacitor C15 and one end of resistor R36. The other end of capacitor C15 is grounded. The other end of resistor R36 is connected to one end of capacitor C16 and one end of voltage V5. The other end of the sixteen-channel C16 is grounded. The first, second, third, and fifth pins of the dual-channel analog switch IC10 are connected to voltage 4V4, voltage 3V3, voltage 2V2, and voltage 1V1, respectively. The seventh, eleventh, twelfth, thirteenth, and fourteenth pins of the dual-channel analog switch IC10 are grounded. The tenth and ninth pins of the dual-channel analog switch IC10 are connected to interface 1P1 and interface 2P2, respectively. As a dual-channel analog switch, IC10, based on the level logic of the S2 pin, realizes the selection control between a single path in 2Y0 and 2Y1 and 2Z. If there is a sinusoidal signal between the DRIVE+ and SENSE+ ports, IC10 S2, acting as a control select pin, is connected to IC2 Y2, producing a 200kHz square wave. The 2Y0 and 2Y1 pins control this signal, representing the amplified and inverted sinusoidal signal detected by the DRIVE+ and DRIVE- ports, respectively. After being switched by the 200kHz square wave, the sine wave is converted to a swirl wave, which is then filtered into DC and fed into the amplification module through multi-stage filtering. If the signal between the DRIVE+ and SENSE+ ports is zero, it will remain zero after passing through IC2. The same logic applies to the signal between the DRIVE- and SENSE- ports.

[0035] See Figures 6-7The amplification module includes operational amplifier IC13B (13th generation). The non-inverting input of IC13B is connected to a voltage of V5. The inverting input is connected to one end of resistor R47 (47th generation) and one end of resistor R46 (46th generation). The other end of resistor R47 is grounded. The other end of resistor R46 and the output of IC13B are connected to the inverting input of operational amplifier IC12B (12th generation). The non-inverting input of IC12B is connected to one end of resistor R42 (42nd generation) and one end of resistor R43 (43rd generation). One end of resistor 45R45 is connected to the power supply voltage. The other end of resistor 45R45 is connected to ground. The other end of resistor 43R43 is grounded. The other end of resistor 42R42 and the output of operational amplifier IC12B are connected to one end of resistor 44R44 and the ARM-21 pin of the ARM chip. The other end of resistor 44R44 is connected to the power supply voltage. The amplification module also includes operational amplifier IC15B. The non-inverting input of operational amplifier IC15B is connected to voltage 6V6. The inverting input of operational amplifier IC15B is connected to resistor 53R5. One end of resistor 3 is connected to one end of resistor 52R52, and the other end of resistor 53R53 is grounded. The other end of resistor 52R52 is connected to the output of operational amplifier 15IC15B and the inverting input of operational amplifier 14IC14B. The non-inverting input of operational amplifier 14IC14B is connected to one end of resistor 48R48, one end of resistor 49R49, and one end of resistor 51R51. The other end of resistor 51R51 is connected to the supply voltage, and the other end of resistor 49R49 is grounded. The other end of resistor 48R48 is connected to operational amplifier 14IC14B. The output terminal is connected to one end of resistor 50R50 and the ARM-22 pin of the ARM chip, and the other end of resistor 50R50 is connected to the power supply voltage. The rectified and filtered signal is amplified and compared with hysteresis, and the final signal is transmitted to the ARM. The final effect is: if the DRIVE+ port and SENSE+ port have good contact and the contact detection is normal, the ARM-21 pin will receive a high-level signal. If the DRIVE+ port and SENSE+ port have poor contact and the contact detection is abnormal, the ARM-21 pin will receive a low-level signal. The processor can then determine whether the contact is good or not.

[0036] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A contact detection device for AC impedance testing, characterized in that, It includes a contact detection signal generation module and a frequency division module. The first end of the contact detection signal generation module is connected to the first end of the frequency division module. The second end of the contact detection signal generation module and the second end of the frequency division module are respectively connected to the first end of the rectification / filtering module and the first end of the differential sampling module. The second end of the differential sampling module is connected to the second end of the rectification / filtering module. The third end of the rectification / filtering module is connected to the first end of the amplification module. The second end of the amplification module is connected to the processor.

2. The contact detection device for AC impedance testing according to claim 1, characterized in that, The contact detection signal generation module includes a Schmitt trigger IC2. The first pin of the Schmitt trigger IC2 is connected to one end of capacitor C2 and resistor R5 respectively. The other end of capacitor C2 is grounded. The other end of resistor R5 is connected to the second pin of the Schmitt trigger IC2 and the frequency divider module respectively. The fourteenth pin and the seventh pin of the Schmitt trigger IC2 are connected to the power supply voltage and ground respectively.

3. The contact detection device for AC impedance testing according to claim 2, characterized in that, The frequency divider module includes a frequency divider IC4. The first pin of frequency divider IC4 is connected to one end of resistor R5. The fourth and fifth pins of frequency divider IC4 are connected to one end of resistor R12 and one end of resistor R18, respectively. The other end of resistor R12 is connected to the third and fifth pins of Schmitt trigger IC2, respectively. The fourth and sixth pins of Schmitt trigger IC2 are connected to interface P1 and one end of capacitor C4, respectively. The other end of capacitor C4 is connected to one end of resistor R8 and resistor R9, respectively. The other end of resistor R8 is grounded. The other end of resistor R9 is connected to the fourth pin of capacitor C3 and inductor L1, respectively. The other end of capacitor C3 is grounded. The third pin of inductor L1 is grounded. The second and first pins of inductor L1 are connected to the SENSE port and one end of resistor R10, respectively. The other end of resistor R10 is connected to one end of capacitor C5, ... The other end of capacitor C5 is connected to the DRIVE- port. The other end of resistor R18 is connected to pin 13 of Schmitt trigger IC2. Pin 12 of Schmitt trigger IC2 is connected to pins 9 and 11 respectively. Pins 8 and 10 of Schmitt trigger IC2 are connected to interface P2 and one end of capacitor C8. The other end of capacitor C8 is connected to one end of resistor R20 and one end of resistor R13 respectively. The other end of resistor R20 is grounded. The other end of resistor R13 is connected to one end of capacitor C10 and one pin of inductor L2 respectively. The other end of capacitor C10 is grounded. Pins 3 and 4 of inductor L2 are connected to the SENSE+ port and one end of resistor R14 respectively. The other end of resistor R14 is connected to one end of capacitor C9. The other end of capacitor C9 is connected to the DRIVE+ port. Pin 2 of inductor L2 is grounded.

4. A contact detection device for AC impedance testing according to claim 3, characterized in that, Pin 14 of frequency divider IC4 is connected to the power supply voltage, while pins 2, 12, and 13 of frequency divider IC4 are grounded.

5. A contact detection device for AC impedance testing according to claim 4, characterized in that, The differential sampling module includes operational amplifier IC7B. The non-inverting input of operational amplifier IC7B is connected to one end of resistor R23 (23R23). The other end of resistor R23 is connected to one end of capacitor C11 (11) and one end of resistor R27 (27R27). The other end of capacitor C11 is connected to the DRIVE+ port. The other end of resistor R27 is grounded. The inverting input of operational amplifier IC7B is connected to one end of resistor R26 (26R26) and one end of resistor R28 (28R28). The other end of resistor R28 is connected to the operational amplifier... The output terminals of IC7B are all connected to one end of resistor 24R24. The other end of resistor 24R24 is connected to one end of resistor 25R25 and the non-inverting input terminal of operational amplifier IC8B. The other end of resistor 25R25 is grounded. The inverting input terminal of operational amplifier IC8B is connected to one end of resistor 30R30. One end of resistor 30R30 is connected to one end of resistor 31R31. The other end of resistor 31R31 is connected to V3 and one end of resistor 32R32. Operational amplifier IC8B... The output terminal is also connected to voltage 3V3. The other end of resistor 32R32 is connected to the inverting input terminal of operational amplifier 9IC9B and one end of resistor 37R37. The other end of resistor 37R37 is connected to voltage 4V4. The non-inverting input terminal of operational amplifier 9IC9B is grounded. The output terminal of operational amplifier 9IC9B is connected to voltage 4V4. The other end of resistor 30R30 is connected to one end of resistor 29R29 and the output terminal of operational amplifier 11IC11B. The other end of resistor 29R29 is connected to operational amplifier 11IC11B. The non-inverting input of IC11B is connected to one end of capacitor C12. The other end of capacitor C12 is connected to one end of resistor R26. The inverting input of IC11B is connected to one end of resistor R33 and ground. The other end of resistor R33 is connected to one end of capacitor R13 and one end of resistor R38. The other end of resistor R38 is grounded. The other end of capacitor R13 is connected to the SENSE+ port.

6. A contact detection device for AC impedance testing according to claim 5, characterized in that, The differential sampling module also includes operational amplifier IC1B. The non-inverting input of operational amplifier IC1B is connected to one end of resistor R1. The other end of resistor R1 is connected to one end of capacitor C1 and one end of resistor R6. The other end of capacitor C1 is connected to the DRIVE port. The other end of resistor R6 is grounded. The inverting input of operational amplifier IC1B is connected to one end of resistor R4 and one end of resistor R7. The other end of resistor R7 and the output of operational amplifier IC1B are connected to one end of resistor R2. The other end of resistor R2 is connected to one end of resistor R3 and the non-inverting input of operational amplifier IC3B. The other end of resistor R3 is grounded. The inverting input of operational amplifier IC3B is connected to one end of resistor R15. Resistor R15 is connected to one end of resistor R16. The other end of resistor R16 is connected to voltage V1 and one end of resistor R17. The output of operational amplifier IC3B is also connected to voltage V1.

3. Connect the other end of resistor 17R17 to the inverting input of operational amplifier 5 IC5B and one end of resistor 21R21. The other end of resistor 21R21 is connected to voltage 2V2. The non-inverting input of operational amplifier 3 IC3B is grounded. The output of operational amplifier 3 IC3B is connected to voltage 2V2. Connect the other end of resistor 15R15 to one end of resistor 11R11 and the output of operational amplifier 6 IC6B. Connect the other end of resistor 11R11 to the non-inverting input of operational amplifier 6 IC6B. The non-inverting input of operational amplifier 6 IC6B is also connected to one end of capacitor 6C6. The other end of capacitor 6C6 is connected to one end of resistor 4R4. Connect the inverting input of operational amplifier 6 IC6B to one end of resistor 19R19 and ground. Connect the other end of resistor 19R19 to one end of capacitor 7R7 and one end of resistor 22R22. The other end of resistor 22R22 is grounded. Connect the other end of capacitor 7R7 to the SENSE port.

7. A contact detection device for AC impedance testing according to claim 6, characterized in that, The fifteenth pin of the dual-channel analog switch IC10 is connected to one end of the thirty-fourth resistor R34. The other end of the thirty-fourth resistor R34 is connected to one end of the fourteenth capacitor C14 and one end of the thirty-fifth resistor R35. The other end of the fourteenth capacitor C14 is grounded. The other end of the thirty-fifth resistor R35 is connected to one end of the fifteenth capacitor C15 and one end of the thirty-sixth resistor R36. The other end of the fifteenth capacitor C15 is grounded. The other end of the thirty-sixth resistor R36 is connected to one end of the sixteenth capacitor C16 and one end of the voltage V5. The other end of the sixteenth capacitor C16 is grounded.

8. A contact detection device for AC impedance testing according to claim 7, characterized in that, The rectifier / filter module includes a dual-channel analog switch IC10. The first, second, third, and fifth pins of the dual-channel analog switch IC10 are connected to voltage 4 (V4), voltage 3 (V3), voltage 2 (V2), and voltage 1 (V1), respectively. The seventh, eleventh, twelfth, thirteenth, and fourteenth pins of the dual-channel analog switch IC10 are grounded. The tenth and ninth pins of the dual-channel analog switch IC10 are connected to interface 1 (P1) and interface 2 (P2), respectively.

9. A contact detection device for AC impedance testing according to claim 8, characterized in that, The amplification module includes operational amplifier IC13B. The non-inverting input of operational amplifier IC13B is connected to voltage V5. The inverting input of operational amplifier IC13B is connected to one end of resistor R47 and one end of resistor R46. The other end of resistor R47 is grounded. The other end of resistor R46 and the output of operational amplifier IC13B are connected to the inverting input of operational amplifier IC12B. The non-inverting input of operational amplifier IC12B is connected to one end of resistor R42, one end of resistor R43, and one end of resistor R45. The other end of resistor R45 is connected to the power supply voltage. The other end of resistor R43 is grounded. The other end of resistor R42 and the output of operational amplifier IC12B are connected to one end of resistor R44 and the ARM-21 pin of the ARM chip. The other end of resistor R44 is connected to the power supply voltage.

10. A contact detection device for AC impedance testing according to claim 9, characterized in that, The amplification module also includes operational amplifier IC15B. The non-inverting input of operational amplifier IC15B is connected to voltage 6V6. The inverting input of operational amplifier IC15B is connected to one end of resistor 53R53 and one end of resistor 52R52, respectively. The other end of resistor 53R53 is grounded. The other end of resistor 52R52 and the output of operational amplifier IC15B are connected to the inverting input of operational amplifier IC14B. The non-inverting input of operational amplifier IC14B is connected to one end of resistor 48R48, one end of resistor 49R49, and one end of resistor 51R51, respectively. The other end of resistor 51R51 is connected to the power supply voltage. The other end of resistor 49R49 is grounded. The other end of resistor 48R48 and the output of operational amplifier IC14B are connected to one end of resistor 50R50 and the ARM-22 pin of the ARM chip. The other end of resistor 50R50 is connected to the power supply voltage.

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