Multi-channel micro-nano metal sintering pressure head pressure detection system and method

Abstract

The invention relates to the field of pressure head pressure detection, in particular to a multichannel micro-nano metal sintering pressure head pressure detection system and method. The system comprises a plurality of pressure sensor groups, each pressure sensor group is provided with a plurality of pressure sensors, and each pressure sensor is used for detecting the pressure of a pressure head of the micro-nano metal sintering mold; the temperature sensor is used for detecting the temperature of the environment where the pressure sensor is located; the voltage acquisition unit is used for acquiring power supply bus voltage of the pressure sensor; and the controller is respectively connected with the pressure sensor group, the temperature sensor and the voltage acquisition unit and is used for compensating signals output by the pressure sensors based on the environment temperature and the voltage of the power supply bus to obtain a pressure value of the pressure head. The collected pressure of each pressure head is compensated in combination with the temperature of the environment where the pressure sensor is located and the voltage of the power supply bus, and the problem that high-precision, high-accuracy and high-stability detection cannot be conducted on each pressure head in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of pressure head detection, and specifically to a multi-channel micro / nano metal sintering pressure head detection system and method. Background Technology

[0002] Micro-nano metal sintering technology, with its excellent thermal and electrical conductivity and high-temperature service reliability, has become a key interconnect technology for the packaging of power modules such as silicon carbide and gallium nitride. In this process, a sintering mold is used to reliably connect the power chip and the substrate through a sintering layer of nano-metal particles (such as nano-silver and nano-copper) under pressure and heating conditions.

[0003] To meet the high-efficiency requirements of multi-chip parallel packaging, micro / nano metal sintering molds typically integrate multiple independent pressure head units, forming a pressure head array. During the sintering process, each pressure head unit must apply precise and uniform pressure to the corresponding chip to ensure consistent density and uniform thickness of the sintered layer, thereby guaranteeing the overall electrothermal performance and long-term reliability of the module.

[0004] Currently, most sintering equipment on the market uses an overall pressure detection and control method. That is, a single total force sensor detects the total pressure applied to the entire mold, and the pressurization mechanism is controlled through total pressure feedback. This method cannot obtain the actual pressure value of individual pressure head units. When a pressure head becomes blocked due to particulate contamination, mechanical jamming, or other reasons, or when overpressure or underpressure occurs in individual pressure heads due to differences in chip thickness tolerances or substrate flatness, the system cannot detect and identify this in real time. This directly leads to poor consistency in product sintering quality, and in severe cases, may cause hidden defects such as chip cracking or voids in the sintered layer, and these defects are difficult to trace.

[0005] Therefore, it is necessary to detect multiple pressures separately. Existing technologies include solutions that configure an independent pressure sensor for each pressure head unit. However, these solutions generally use passive resistive pressure sensors. Although the signal acquisition principle of such sensors is relatively simple and the cost is low, they exhibit significant drawbacks in practical applications: First, the micro-nano metal sintering process is harsh, involving high temperatures (typically above 200°C to 300°C) and frequent heating and cooling cycles. Passive resistive sensors have a high temperature coefficient of resistance, making them susceptible to temperature drift and leading to a significant decrease in measurement accuracy. Second, the output signal of such sensors is weak, requiring sophisticated signal conditioning circuitry, and long-distance transmission of multiple signals is prone to noise interference, further reducing the accuracy and stability of pressure detection.

[0006] Therefore, how to achieve independent pressure detection of multi-head units in micro / nano metal sintering molds while ensuring high precision and high stability of the detection system is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a multi-channel micro-nano metal sintering pressure head pressure detection system. It combines the ambient temperature of the pressure sensor and the power supply voltage to compensate for the pressure of each pressure head, thus solving the problem that the prior art cannot perform high-precision, high-accuracy and high-stability detection of each pressure head.

[0008] To solve the above-mentioned technical problems, the technical solution of the present invention is: a multi-channel micro / nano metal sintering pressure head detection system, comprising: Multiple pressure sensor groups, each pressure sensor group having multiple pressure sensors, each pressure sensor being used to detect the pressure of a pressure head of a micro / nano metal sintering mold; Temperature sensor is used to detect the ambient temperature of the pressure sensor. The voltage acquisition unit is used to acquire the power supply bus voltage of the pressure sensor; wherein, the power supply outside the environment where the pressure sensor is located is connected to the power supply bus located inside the environment where the pressure sensor is located through the wire, and the power supply bus is connected to each pressure sensor. The controller is connected to the pressure sensor group, temperature sensor and voltage acquisition unit respectively. It is used to compensate the signal output by the pressure sensor based on the ambient temperature and the power supply bus voltage to obtain the pressure value of the pressure head.

[0009] Furthermore, the multi-channel micro-nano metal sintering pressure head pressure detection system also includes a group control unit. The controller is connected to the pressure sensor through the group control unit, so as to control the sequential power supply of each pressure sensor group and the enable control of each pressure sensor channel.

[0010] Furthermore, the group control unit includes a power group control circuit and a pressure sensor signal gating control circuit; wherein, The power supply group control circuit is connected between the power supply bus and each pressure sensor group, and is configured to enable the power supply bus to supply power to each pressure sensor group sequentially under the control of the controller. The pressure sensor signal gating control circuit is connected to the output of each pressure sensor to ensure that at most one pressure sensor signal is output at any given time.

[0011] Furthermore, the pressure sensor signal gating control circuit includes several multiplexed switches and multiple cascaded serial-to-parallel output shift registers; among them, The signal output terminal of each pressure sensor is connected to the signal input terminal of the corresponding multiplexer; Each shift register corresponds to a pressure sensor group, and all multiplexers connected to that pressure sensor group are used to ensure that all multiplexers select only one pressure sensor signal for output at any given time.

[0012] Furthermore, the power supply group control circuit includes multiple MOSFETs, each corresponding to a pressure sensor group. The source and drain of the MOSFET are connected to the power supply bus and the corresponding pressure sensor group, respectively, and the gate is connected to a parallel output pin of the corresponding shift register.

[0013] Furthermore, the group control unit also includes: The first signal conditioning circuit includes a resistor R10 connected in series between the signal output terminal HC1DS ​​of the controller and the data input terminal HC1DS ​​of the first shift register, and a capacitor C13 with one end connected to the data input terminal HC1DS ​​of the first shift register and the other end connected to ground VSS. The second signal conditioning circuit includes a resistor R12 connected in series between the clock output terminal STCP of the controller and the latch clock terminal STCP of all shift registers, and a capacitor C16 with one end connected to the latch clock terminal STCP of all shift registers and the other end connected to ground VSS. The third signal conditioning circuit includes a resistor R13 connected in series between the clock output terminal SHCP of the controller and the shift clock terminal SHCP of all shift registers, and a capacitor C18 with one end connected to the shift clock terminal SHCP of all shift registers and the other end connected to ground VSS.

[0014] Furthermore, the group control unit also includes: The transient suppression circuit includes transient suppression diodes D2, D3, and D4, which are respectively connected between the output terminals of the first signal conditioning circuit, the second signal conditioning circuit, and the third signal conditioning circuit and ground VSS.

[0015] Furthermore, the voltage acquisition unit includes a resistor divider circuit, a voltage follower circuit, and two filter circuits; among which, The two input terminals of the resistor voltage divider circuit are connected to the power supply bus and VSS ground respectively, and the output terminal is connected to the input terminal of the voltage follower circuit. A filter circuit is configured at both the input and output terminals of the voltage follower circuit.

[0016] This invention also relates to a method for detecting pressure in a multi-channel micro / nano metal sintering pressure head, the method comprising: The output signals of all pressure sensors were collected sequentially. ; The voltage of the power supply bus acquired by the voltage acquisition unit And the ambient temperature of the pressure sensor detected by the temperature sensor. ; use Calculate the pressure value of each pressure head ;in, kmn V represents the pressure calibration coefficient of the nth pressure sensor in the mth pressure sensor group. J X(T) is the power supply bus voltage recorded during pressure calibration, and X(T) is the sensor pressure offset coefficient corresponding to ambient temperature T.

[0017] Furthermore, the output signals of all pressure sensors were collected sequentially. Specifically, it includes: Step a, initialize m=1, n=1; Step b: Enable the power supply of the m-th pressure sensor group through the group control unit; Step c: Enable the signal output of the nth pressure sensor in the mth pressure sensor group through the group control unit, and after the signal stabilizes, acquire the output signal of that pressure sensor. ; Step d: Let n = n + 1, return to step c, until n is greater than the total number N of pressure sensors in the m-th pressure sensor group; Step e: Let m = m + 1, return to step b, until m is greater than the total number M of the pressure sensor groups.

[0018] By adopting the above technical solution, this invention uses an active pressure sensor (which can be a Wheatstone bridge active pressure sensor), which has higher accuracy and can more accurately detect pressure changes compared with traditional passive resistive pressure sensors. Furthermore, it also detects the ambient temperature of the pressure sensor and eliminates the influence of temperature changes on the pressure detection results by performing temperature compensation on the pressure signal, thus improving the accuracy of the detection. In addition, since the power supply line is long and will have a certain voltage drop, this invention also detects the power supply voltage of the pressure sensor and compensates for the pressure signal, further improving the accuracy of the detection.

[0019] Therefore, based on the active pressure sensor, this invention combines temperature and voltage compensation to achieve high-precision measurement of the pressure of each pressure head, meeting the stringent requirements of micro-nano metal sintering for pressure detection accuracy. This multi-channel precise detection capability can detect abnormalities such as pressure head blockage and overpressure in real time, enabling timely fault diagnosis and handling, thereby improving the reliability of the equipment and the yield of sintered parts. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the multi-channel micro / nano metal sintering pressure head pressure detection system of the present invention; Figure 2 This is a schematic diagram of the structure of the three signal conditioning circuits and transient suppression circuit of the group control unit of the present invention; Figure 3 This is a circuit diagram of a pressure sensor group according to the present invention; Figure 4This is a partial circuit diagram of the pressure sensor signal gating control circuit of the group control unit of the present invention; Figure 5 This is a circuit diagram of the power grouping control circuit of the grouping control unit of the present invention; Figure 6 This is a circuit diagram of the signal processing unit of the present invention; Figure 7 This is a circuit diagram of the voltage acquisition unit of the present invention; Figure 8 This is a flowchart of the multi-channel micro / nano metal sintering pressure detection method of the present invention; Figure 9 The present invention sequentially acquires the output signals of all pressure sensors. The flowchart. Detailed Implementation

[0021] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0022] like Figures 1 to 7 As shown, a multi-channel micro / nano metal sintering pressure head pressure detection system includes: Multiple pressure sensor groups, each pressure sensor group having multiple pressure sensors, each pressure sensor being used to detect the pressure of a pressure head of a micro / nano metal sintering mold; Temperature sensor is used to detect the ambient temperature of the pressure sensor. The voltage acquisition unit is used to acquire the power supply bus voltage of the pressure sensor; wherein, the power supply outside the environment where the pressure sensor is located is connected to the power supply bus located inside the environment where the pressure sensor is located through the wire, and the power supply bus is connected to each pressure sensor. The controller is connected to the pressure sensor group, temperature sensor and voltage acquisition unit respectively. It is used to compensate the signal output by the pressure sensor based on the ambient temperature and the power supply bus voltage to obtain the pressure value of the pressure head.

[0023] In practical applications, pressure sensors are mounted on the force transmission rods of each pressure head in the micro / nano metal sintering mold to detect the pressure of each pressure head. A signal board is located within the chamber housing the pressure heads, and the controller is mounted on the main board, which is located outside the chamber to prevent damage to the main board components due to high temperatures within the chamber. A temperature sensor is installed near the signal board to detect the ambient temperature around it. The signal board has interfaces for connecting the pressure and temperature sensors. The main board and signal board are connected via shielded cables; this connection method is insensitive to cable length, allowing for greater flexibility in system layout.

[0024] Once the pressure sensor signal is acquired, the signal processing unit on the motherboard processes the signal and, in conjunction with the temperature signal detected by the temperature sensor, performs temperature compensation on the pressure signal. Furthermore, the motherboard also detects the power supply voltage of the pressure sensor and compensates for voltage drops caused by long power cables, thereby obtaining an accurate pressure value. In this way, the system can achieve pressure detection from multiple sensors while ensuring detection accuracy and reliability.

[0025] In some examples, such as Figures 1 to 7 As shown, the multi-channel micro-nano metal sintering pressure head pressure detection system also includes a group control unit. The controller is connected to the pressure sensor through the group control unit, so as to control the sequential power supply of each pressure sensor group and the enable control of each pressure sensor channel.

[0026] Specifically, the controller on the motherboard uses a group control unit to select and control the signals according to the set program, so that the signals of each pressure sensor and temperature sensor can be collected in sequence.

[0027] In some examples, such as Figure 4 and Figure 5 As shown, the group control unit includes a power group control circuit and a pressure sensor signal gating control circuit; wherein, The power supply group control circuit is connected between the power supply bus and each pressure sensor group, and is configured to enable the power supply bus to supply power to each pressure sensor group sequentially under the control of the controller. The pressure sensor signal gating control circuit is connected to the output of each pressure sensor to ensure that at most one pressure sensor signal is output at any given time.

[0028] like Figure 4 As shown, the pressure sensor signal gating control circuit includes several multiplexed switches and multiple cascaded serial-to-parallel output shift registers; among them, The signal output terminal of each pressure sensor is connected to the signal input terminal of the corresponding multiplexer; Each shift register corresponds to a pressure sensor group, and all multiplexers connected to that pressure sensor group are used to ensure that all multiplexers select only one pressure sensor signal for output at any given time.

[0029] Specifically, this cascaded design allows for flexible configuration of the number of sensors according to actual needs, making it suitable for micro-nano metal sintering molds of different specifications. It also facilitates system upgrades and expansions in the future, improving the system's adaptability and scalability.

[0030] like Figure 5As shown, the power group control circuit includes multiple MOSFETs, each corresponding to a pressure sensor group. The source and drain of the MOSFET are connected to the power supply bus and the corresponding pressure sensor group, respectively, and the gate is connected to a parallel output pin of the corresponding shift register.

[0031] Sixteen pressure sensors can be grouped together to form a pressure sensor group, for a total of 16 groups. The power grouping control circuit is used to ensure that only one pressure sensor group is powered at any given time. This reduces the load current, which not only reduces the voltage drop across the wires but also lowers the power supply capacity requirements.

[0032] The pressure sensor signal gating control circuit is used for gating control of multiple pressure sensors, so that only one pressure sensor signal is output to the signal processing unit at any given time. Figures 3 to 5 In this configuration, U3, U4, U5, and U6 are all 8-to-2 multiplexed switches, J1~J16 are 16 pressure sensors from one of the pressure sensor groups, and HC1~HC16 are 16 shift registers, which can be model 74HC595. The data shift output HC1Q7S of HC1 is connected to the data input of HC2, and the subsequent connections follow the same method. Using cascaded shift registers can reduce the number of output control lines of the controller and alleviate wiring burden.

[0033] The steps for selecting pressure sensor J1 in the first pressure sensor group are as follows: When the Q4 pin (VCTL1) of HC1 is set to low level and the Q4 pin (VCTL2~VCTL16) of HC2~HC16 is set to high level, only the MOS transistor Q1 corresponding to the first pressure sensor group is turned on, and A5V supplies power to the first pressure sensor group. When the Q0 pin (HC1Q0) of HC1 is set to a high level, and the Q1~Q3 pins (HC1Q1~HC1Q3) are set to a low level, only the multiplexer U3 is enabled. At the same time, the Q5 and Q6 pins (CHA', CHB') of HC1 are both set to a low level to select the pressure sensor J1 (i.e., G1P1+, G1P1-), and output to the signals XCOM+ and YCOM-.

[0034] The total current of the m-th pressure sensor group is approximately: ; This refers to the power supply voltage (power supply bus voltage). This represents the input impedance of a single pressure sensor. In actual operation... Approximately 5V, If the current is approximately 600~800Ω, then Im is approximately 100~133mA.

[0035] If all 256 pressure sensors are powered simultaneously, the total current will reach 1.6~2.1A, which places higher demands on the power supply circuit and on the diameter and resistance of the connecting wires.

[0036] Specifically, this embodiment implements grouped power supply control for the pressure sensor group, reducing the power supply current and the requirements for connecting wires, thereby improving the system's reliability and stability. Furthermore, grouped power supply control reduces system power consumption, and shielded wire connections enhance the system's anti-interference capability, enabling the system to operate stably in complex industrial environments.

[0037] In some examples, such as Figure 2 As shown, the group control unit also includes: The first signal conditioning circuit includes a resistor R10 connected in series between the signal output terminal HC1DS ​​of the controller and the data input terminal HC1DS ​​of the first shift register, and a capacitor C13 with one end connected to the data input terminal HC1DS ​​of the first shift register and the other end connected to ground VSS. The second signal conditioning circuit includes a resistor R12 connected in series between the clock output terminal STCP of the controller and the latch clock terminal STCP of all shift registers, and a capacitor C16 with one end connected to the latch clock terminal STCP of all shift registers and the other end connected to ground VSS. The third signal conditioning circuit includes a resistor R13 connected in series between the clock output terminal SHCP of the controller and the shift clock terminal SHCP of all shift registers, and a capacitor C18 with one end connected to the shift clock terminal SHCP of all shift registers and the other end connected to ground VSS.

[0038] Specifically, the controller's signal output terminal HC1DS, clock output terminal STCP, and SHCP are used to implement pressure sensor enable control and power supply group control. These are all high-speed signals. Since the communication distance may be long, R10 and C13, R12 and C16, and R13 and C18 respectively implement signal rising edge control to suppress signal ringing and prevent data transmission errors.

[0039] In some examples, such as Figure 2 As shown, the group control unit also includes: The transient suppression circuit includes transient suppression diodes D2, D3, and D4, which are respectively connected between the output terminals of the first signal conditioning circuit, the second signal conditioning circuit, and the third signal conditioning circuit and ground VSS.

[0040] D2, D3, and D4 in the transient suppression circuit are used to suppress transient overvoltage signals that may be generated during the plugging and unplugging of the connection cable interfaces between the motherboard and the signal board.

[0041] In some examples, such as Figure 1 and Figure 6 As shown, the multi-channel micro / nano metal sintering pressure head pressure detection system also includes a signal processing unit connected between all pressure sensors and the controller, used to filter and amplify the output signals of the pressure sensors.

[0042] like Figure 6 As shown, the signal processing unit includes a precision differential operational amplifier U1. The pressure signals XCOM+ and YCOM- output from the multiple pressure sensors after gating control are connected as follows: XCOM+ is connected to ground VSS via resistor R3 and capacitor C1, and YCOM- is connected to ground VSS via resistor R7 and capacitor C11. A capacitor C8 is connected in series between the common terminal AIN0-S1 of capacitor C1 and resistor R3 and the common terminal AIN1-S1 of resistor R7 and capacitor C11. Resistors R3 and R7, and capacitors C1, C8, and C11 form a filter circuit.

[0043] AIN0-S1 is connected to the -IN pin of U1 and is also connected to ground VSS through resistor R4. AIN1-S1 is connected to the +IN pin of U1 and is also connected to VREF through resistor R6. R4 and R6 are pull-down and pull-up resistors, respectively, used for sensor disconnection detection.

[0044] The signal output from U1, after passing through resistor R5, becomes signal ADCIN0. Signal ADCIN0 is connected to ground VSS via parallel capacitors C9 and C10, and also to the anode of diode D1. The cathode of diode D1 is connected to A3V3. U1 and its peripheral circuitry form an adder amplifier circuit, while resistor R5 and capacitors C9 and C10 form a low-pass filter circuit. Signal ADCIN0 is connected to the controller, and diode D1 is used for signal clamping to prevent excessively high ADCIN0 levels from damaging the controller.

[0045] In some examples, such as Figure 7 As shown, the voltage acquisition unit includes a resistor divider circuit, a voltage follower circuit, and two filter circuits; among which, The two input terminals of the resistor voltage divider circuit are connected to the power supply bus and VSS ground respectively, and the output terminal is connected to the input terminal of the voltage follower circuit. A filter circuit is configured at both the input and output terminals of the voltage follower circuit.

[0046] like Figure 7 As shown, the signal board and the main board are connected by a wire RLINE, and the distance between them is not fixed. Therefore, a certain voltage drop will occur when current flows through them. Furthermore, replacing the connecting wire, oxidation at the wire port, etc., will change the impedance RLINE of the wire, thus affecting the sensor's power supply voltage and ultimately the sensor's signal output amplitude. Therefore, it is necessary to collect the power supply bus voltage to compensate for the pressure sensor's output signal.

[0047] Resistors R14 and R15 form a resistor divider circuit located on the signal board. The divided voltage signal A5VFB output from the resistor divider circuit is connected to one end of capacitor C15 on the main board via a connecting wire. The other end of capacitor C15 is connected to ground VSS. Capacitor C15 is used for signal filtering. U2A is a voltage follower circuit. Its input is connected to the divided voltage signal A5VFB, and its output, after passing through resistor R11, becomes signal ADCIN1. Signal ADCIN1 is connected to ground VSS via capacitor C17. Resistor R11 and capacitor C17 form a low-pass filter circuit. Signal ADCIN1 is connected to the controller.

[0048] In some examples, the temperature sensor can be a general-purpose digital temperature sensor, such as the DS18B20, which acquires temperature information through digital communication. The advantage of digital communication is that it is not strict about the length of the connecting cable.

[0049] like Figure 8 As shown, the channel micro / nano metal sintering pressure detection method involved in the above embodiments includes: The output signals of all pressure sensors were collected sequentially. ; The voltage of the power supply bus acquired by the voltage acquisition unit And the ambient temperature of the pressure sensor detected by the temperature sensor. ; use Calculate the pressure value of each pressure head ;in, k mn V represents the pressure calibration coefficient of the nth pressure sensor in the mth pressure sensor group. J X(T) is the power supply bus voltage recorded during pressure calibration, and X(T) is the sensor pressure offset coefficient corresponding to ambient temperature T.

[0050] like Figure 9 As shown, the output signals of all pressure sensors are collected sequentially. Specifically, it includes: Step a, initialize m=1, n=1; Step b: Enable the power supply of the m-th pressure sensor group through the group control unit; Step c: Enable the signal output of the nth pressure sensor in the mth pressure sensor group through the group control unit, and after the signal stabilizes, acquire the output signal of that pressure sensor. ; Step d: Let n = n + 1, return to step c, until n is greater than the total number N of pressure sensors in the m-th pressure sensor group; Step e: Let m = m + 1, return to step b, until m is greater than the total number M of the pressure sensor groups.

[0051] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A multi-channel micro / nano metal sintering pressure head pressure detection system, characterized in that, include: Multiple pressure sensor groups, each pressure sensor group having multiple pressure sensors, each pressure sensor being used to detect the pressure of a pressure head of a micro / nano metal sintering mold; Temperature sensor is used to detect the ambient temperature of the pressure sensor. The voltage acquisition unit is used to acquire the power supply bus voltage of the pressure sensor; wherein, the power supply outside the environment where the pressure sensor is located is connected to the power supply bus located inside the environment where the pressure sensor is located through the wire, and the power supply bus is connected to each pressure sensor. The controller is connected to the pressure sensor group, temperature sensor and voltage acquisition unit respectively. It is used to compensate the signal output by the pressure sensor based on the ambient temperature and the power supply bus voltage to obtain the pressure value of the pressure head.

2. The multi-channel micro / nano metal sintering pressure head pressure detection system according to claim 1, characterized in that, It also includes a group control unit, through which the controller connects to the pressure sensors, so as to control the sequential power supply of each pressure sensor group and the enable control of each pressure sensor channel.

3. The multi-channel micro / nano metal sintering pressure head pressure detection system according to claim 2, characterized in that, The group control unit includes a power group control circuit and a pressure sensor signal gating control circuit; wherein, The power supply group control circuit is connected between the power supply bus and each pressure sensor group, and is configured to enable the power supply bus to supply power to each pressure sensor group sequentially under the control of the controller. The pressure sensor signal gating control circuit is connected to the output of each pressure sensor to ensure that at most one pressure sensor signal is output at any given time.

4. The multi-channel micro / nano metal sintering pressure head pressure detection system according to claim 3, characterized in that, The pressure sensor signal gating control circuit includes several multiplexed switches and multiple cascaded serial-to-parallel output shift registers; among them, The signal output terminal of each pressure sensor is connected to the signal input terminal of the corresponding multiplexer; Each shift register corresponds to a pressure sensor group, and all multiplexers connected to that pressure sensor group are used to ensure that all multiplexers select only one pressure sensor signal for output at any given time.

5. The multi-channel micro / nano metal sintering pressure head pressure detection system according to claim 4, characterized in that, The power group control circuit includes multiple MOSFETs, each corresponding to a pressure sensor group. The source and drain of the MOSFET are connected to the power supply bus and the corresponding pressure sensor group, respectively, and the gate is connected to a parallel output pin of the corresponding shift register.

6. The multi-channel micro / nano metal sintering pressure head pressure detection system according to claim 4, characterized in that, The group control unit also includes: The first signal conditioning circuit includes a resistor R10 connected in series between the signal output terminal HC1DS ​​of the controller and the data input terminal HC1DS ​​of the first shift register, and a capacitor C13 with one end connected to the data input terminal HC1DS ​​of the first shift register and the other end connected to ground VSS. The second signal conditioning circuit includes a resistor R12 connected in series between the clock output terminal STCP of the controller and the latch clock terminal STCP of all shift registers, and a capacitor C16 with one end connected to the latch clock terminal STCP of all shift registers and the other end connected to ground VSS. The third signal conditioning circuit includes a resistor R13 connected in series between the clock output terminal SHCP of the controller and the shift clock terminal SHCP of all shift registers, and a capacitor C18 with one end connected to the shift clock terminal SHCP of all shift registers and the other end connected to ground VSS.

7. The multi-channel micro / nano metal sintering pressure head detection system according to claim 6, characterized in that, The group control unit also includes: The transient suppression circuit includes transient suppression diodes D2, D3, and D4, which are respectively connected between the output terminals of the first signal conditioning circuit, the second signal conditioning circuit, and the third signal conditioning circuit and ground VSS.

8. The multi-channel micro / nano metal sintering pressure head pressure detection system according to claim 1, characterized in that, The voltage acquisition unit includes a resistor divider circuit, a voltage follower circuit, and two filter circuits; among them, The two input terminals of the resistor voltage divider circuit are connected to the power supply bus and VSS ground respectively, and the output terminal is connected to the input terminal of the voltage follower circuit. A filter circuit is configured at both the input and output terminals of the voltage follower circuit.

9. A method for detecting pressure in a multi-channel micro / nano metal sintering pressure head, characterized in that, It is based on the multi-channel micro / nano metal sintering pressure head pressure detection system described in claim 1, and the method includes: The output signals of all pressure sensors were collected sequentially. ; The voltage of the power supply bus acquired by the voltage acquisition unit And the ambient temperature of the pressure sensor detected by the temperature sensor. ; use Calculate the pressure value of each pressure head ;in, k mn V is the pressure calibration coefficient for the nth pressure sensor in the mth pressure sensor group. J X(T) is the power supply bus voltage recorded during pressure calibration, and X(T) is the sensor pressure offset coefficient corresponding to ambient temperature T.

10. The method for detecting pressure in a multi-channel micro / nano metal sintering pressure head according to claim 9, characterized in that, It is based on the multi-channel micro / nano metal sintering pressure head pressure detection system according to any one of claims 2-7; the output signals of all pressure sensors are collected sequentially. Specifically, it includes: Step a, initialize m=1, n=1; Step b: Enable the power supply of the m-th pressure sensor group through the group control unit; Step c: Enable the signal output of the nth pressure sensor in the mth pressure sensor group through the group control unit, wait for the signal to stabilize, and then acquire the output signal of that pressure sensor. ; Step d: Let n = n + 1, return to step c, until n is greater than the total number N of pressure sensors in the m-th pressure sensor group; Step e: Let m = m + 1, return to step b, until m is greater than the total number M of the pressure sensor groups.

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