CN214409123U - High-efficiency precise direct-current resistance testing system with configurable channels - Google Patents
High-efficiency precise direct-current resistance testing system with configurable channels Download PDFInfo
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- CN214409123U CN214409123U CN202022257558.1U CN202022257558U CN214409123U CN 214409123 U CN214409123 U CN 214409123U CN 202022257558 U CN202022257558 U CN 202022257558U CN 214409123 U CN214409123 U CN 214409123U
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Abstract
The utility model provides a low-cost, small, high accuracy, high efficiency and the easy configurable high efficiency precision direct current resistance test system of passageway of expanding of passageway. The utility model discloses utilize accurate direct current resistance to measure board and realize 10uA ~ 1A current output and 1M omega ~ 1M omega's resistance measurement, then dispose the channel number in a flexible way through the bridging board, can follow 64 passageways ~ 1024 passageways internal configurations, the rethread material keysets that awaits measuring is connected with the material that awaits measuring, accomplishes the measurement of opening short circuit and DCR through the control unit at last. The utility model discloses can be applied to the test field.
Description
Technical Field
The utility model relates to a measurement field especially relates to a precision direct current resistance test system of configurable high efficiency of passageway for replace standard DMM (digital multimeter)/milliohmmeter SMU (source measurement unit) among the prior art, solve these standard instrument with high costs, the test efficiency is low, bulky, integrated difficult scheduling problem, thereby be applied to open short circuit/direct current resistance test equipment in, the accurate measurement direct current resistance parameter guarantees product quality.
Background
The electronic product mainboard test equipment needs to use a large number of components such as probes, relays and switches to transfer a signal of a product to be tested to a test system, and the quality (contact resistance and stability) of the components has a large influence on the stability and reliability of the test system, so that more than 10 ten thousand times of aging and Direct Current Resistance (DCR) tests need to be performed in each batch of the components by sampling, and a multichannel parallel test system is needed to improve the efficiency and shorten the test time.
In order to save cost, components such as probes, relays, switches and the like on testing equipment are repeatedly used on the premise of ensuring quality. This requires 100% testing of these recycled components and the test current is preferably consistent with the actual use. In view of this, it is also desirable to implement programmable adjustment of the current and then select good devices based on the test results.
For another example, 100% of finished products such as various wires/PCB boards need to be subjected to open/short circuit, DCR and flying probe tests before shipment, and these applications all need a multi-channel DCR test system to be realized.
In addition, in order to examine the contact impedance and the stability of the board-to-board connector and the probe module after press-fitting, a multi-channel DCR test system is required to acquire the impedance of each path after each release-press-fitting action in real time, so as to evaluate the contact stability.
In order to solve the above technical problems, the following schemes are generally adopted in the industry to measure the multi-channel resistance.
1. The current is regulated using an E LOAD, the voltage is measured using a DMM (digital multimeter, such as Keysight 34465 a), the voltage is divided by the current to give a resistance, and a channel switching board is added to achieve multi-channel resistance measurement.
2. The direct current impedance measurement is completed by using a milliohm meter, but the current cannot be adjusted in a program control mode, and the multichannel resistance measurement is realized by adding a channel switching board card.
3. The measurement of the dc impedance is done using an SMU (source measurement unit, e.g. Keithley 2601B), plus a channel switch board to implement multi-channel resistance measurement.
4. A special flying probe tester is used to achieve multi-channel resistance measurements.
However, the above schemes 1 to 3 all use standard instruments, have high cost and low price, only provide single-channel impedance measurement, need to additionally develop a switch board to realize multi-channel measurement, and may use one set of instrument + a plurality of switch boards to expand channels in order to reduce the cost as much as possible, so that the serial test speed is slow, and the serial test is difficult to be widely applied to mass-produced equipment/platforms. In addition, a standard instrument and an external switching board are used, test software needs to coordinate time sequences between various instruments and the board card, the test efficiency is low, and at least 0.5S is needed for measuring one direct current impedance. In addition, the standard instrument used in the schemes 1-3 has large volume and low integration level, and is not suitable for being used in small-size test equipment.
Although the scheme 4 can provide multi-channel resistance measurement, the method is used for open-short circuit testing, and accurate measurement of small resistance (m-omega level) cannot be realized.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that overcome prior art not enough, provide a configurable accurate direct current resistance test system of high efficiency of passageway of low cost, small volume, high accuracy, high efficiency and the easy extension of passageway.
The technical proposal adopted by the utility model is that the device comprises a control unit, a switching power supply, at least one path of bridging board, at least one path of direct current resistance measuring board and a material switching board to be measured,
the control unit is used for communicating with at least one path of the direct current resistance measuring plate, sending a measuring signal to the direct current resistance measuring plate and receiving a direct current resistance measuring result uploaded by the direct current resistance measuring plate;
the switching power supply is used for supplying power to the whole system;
the bridge board is used for communication connection between the control unit and the direct current resistance measuring board and providing power supply for the direct current resistance measuring board;
the direct current resistance measuring board is used for providing at least one direct current resistance measuring channel, receiving the instruction signal from the control unit, outputting driving current to the device to be measured, measuring the voltage of the device to be measured to obtain direct current resistance, and uploading the measuring result to the control unit;
the material adapter plate to be tested is used for being connected with a device to be tested and introducing a signal of the device to be tested to the direct current resistance measuring plate of the corresponding channel;
the bridging board is a multi-channel bridging board, and the direct current resistance measuring board is a multi-channel measuring board.
The bridging board is an 8-channel bridging board, and the direct current resistance measuring board is a 64-channel measuring board.
The direct current resistance measuring board comprises an input/output interface, a to-be-measured material charging and communication interface, a measuring board charging and communication interface, 4 groups of 32-to-1 switching circuits, a six-way switch, a programmable constant current source, a voltmeter and a measuring board MCU, wherein the input/output interface is connected with the 4 groups of 32-to-1 switching circuits, the 4 groups of 32-to-1 switching circuits are respectively connected with the programmable constant current source and the input end of the voltmeter through switches, the programmable constant current source is connected with the measuring board MCU through an I2C interface, the voltmeter is connected with the measuring board MCU through an SPI interface, the measuring board charging and communication interface is connected with the measuring board MCU through a UART interface, the other end of the measuring board charging and communication interface is in communication connection with the bridging board, the to-be-measured charging and communication interface provides power for to-be-measured materials connected to the to-be-measured material switching board and performs state control on the to-be-measured materials, the measurement board MCU is respectively connected with the 32-to-1 switching circuit, the program-controlled constant current source and the voltmeter through IO ports, and the input and output ports form a 32-channel four-wire resistance measurement system, or a 64-channel two-wire resistance measurement system, or a 64-channel four-wire resistance measurement system.
The input/output interface consists of a 64-channel constant current source interface and a 64-channel differential voltage measurement interface, wherein 1-32 channels of the 64-channel constant current source interface are connected with a first group of 32-to-1 switching circuits, the rest 33-64 channels are connected with a second group of 32-to-1 switching circuits, one output end of the first group of 32-to-1 switching circuits is connected with a positive input electrode of the voltmeter after passing through a first switch, the other output end of the first group of 32-to-1 switching circuits is connected with a high input electrode of the program-controlled constant current source after passing through a second switch, one output end of the second group of 32-to-1 switching circuits is connected with a negative input electrode of the voltmeter after passing through the first switch, the other output end of the second group of 32-to-1 switching circuits is connected with a low input electrode of the program-controlled constant current source after passing through the second switch, and the 1-32 channels of the 64-channel differential voltage measurement interface are connected with a third group of 32-to-1 switching circuits, the rest 33-64 channels are connected with a fourth group of 32-from-1 switching circuits, one output end of the third group of 32-from-1 switching circuits is connected with the low input electrode of the program-controlled constant current source after passing through a third switch, the other output end of the third group of 32-from-1 switching circuits is connected with the negative input electrode of the voltmeter after passing through a fourth switch, one output end of the fourth group of 32-from-1 switching circuits is connected with the high input electrode of the program-controlled constant current source after passing through the third switch, and the other output end of the fourth group of 32-from-1 switching circuits is connected with the positive input electrode of the voltmeter after passing through the fourth switch.
The program-controlled constant current source consists of a constant current source circuit and a 16-Bits DAC (digital-to-analog converter), the constant current source circuit consists of a sampling resistor, an MOS (metal oxide semiconductor) tube and an operational amplifier feedback, and the constant current output current range of the program-controlled constant current source is 10 uA-1A.
The voltmeter consists of an instrument operational amplifier and a 24bits ADC, and the voltage measurement range of the voltmeter is +/-0.1 mV to +/-5V.
The bridge board comprises 8 paths of UART connectors, a switch power connector, two USB plugs and two USB-to-UART modules, the USB plugs, the USB-to-UART modules and the UART connectors are sequentially connected, and the switch power connector supplies power to the 8 paths of UART connectors.
When the input and output interface is a 32-channel four-wire resistance measurement system, the material adapter plate to be measured comprises 32 constant-current source interfaces, 32 differential voltage measurement interfaces and a first adapter plate side material electrifying and communication interface, 32 high-low connecting poles of the 32 constant-current source interfaces are respectively and correspondingly connected with two ends of 1 path of material to be measured, the 32 path of material to be measured is K1-K32, 32 positive poles and negative poles of the 32 path of differential voltage measurement interfaces are respectively and correspondingly connected with two ends of 1 path of material to be measured, and the 32 path of material to be measured is electrified and controlled to be switched on and off through the first adapter plate side material to be measured and the communication interface.
When the input/output interface is a 64-channel two-wire resistance measurement system, the material adapter plate to be measured comprises a second adapter plate side material power-on and communication interface, a first constant-current voltage measurement interface and a second constant-current voltage measurement interface, wherein the first constant-current voltage measurement interface and the second constant-current voltage measurement interface are used for providing 32 paths of constant-current and voltage measurement respectively, the first constant-current voltage measurement interface and the second constant-current voltage measurement interface are connected to two ends of the 32 paths of materials to be measured respectively, a constant-current source is provided for each path of materials to be measured respectively, the resistance at two ends of the materials to be measured is read, and 64 paths of materials to be measured are powered on and controlled to be switched on and off through the second adapter plate side material to be measured and the communication interface.
When the input and output interface is a 64-channel four-wire resistance measuring system, the material adapter plate to be measured comprises a first voltage measuring interface, a second voltage measuring interface and a constant current source providing interface, the first voltage measuring interface and the second voltage measuring interface respectively provide 32 voltage measuring ports, the 64 voltage measuring ports are respectively and correspondingly connected to two ends of 64 materials to be measured, the constant current source providing interface sequentially connects the 64 materials to be measured in series to form a loop, and the constant current source providing interface provides a constant current source for the 64 materials to be measured.
The switching power supply provides +24V, +12V, -12V and 5V voltage outputs.
The measuring board MCU is selected from a processor with the model number of STM32F103, and the control unit is a desktop computer or a handheld computer.
The utility model has the advantages that: the utility model discloses utilize accurate direct current resistance measuring board to realize 10uA ~ 1A current output and 1M omega ~ 1M omega's resistance measurement, then dispose the channel number through the bridging board is nimble, can follow 64 passageways ~ 1024 passageways internal configurations, and rethread material keysets to be measured is connected with the material to be measured, accomplishes the measurement of opening short circuit and DCR through the control unit at last; compared with the prior art, the utility model has the advantages of as follows:
1. high flexibility: 64-1024 DCR test channels can be configured by selecting different numbers of direct current circuit test boards;
2. high adaptability: by designing and switching aiming at different materials to be measured, various types of resistance measurement such as probes, relays, switches, wires, board-to-board connectors, PCB (printed circuit board) impedance and the like can be completed;
3. high efficiency: by taking 64 channels as the minimum unit, parallel testing of each unit is realized, the fastest DCR testing path only needs 0.1 second, and the fastest DCR testing path only needs 6.4 seconds after 1024 channels are scanned;
4. the cost is low: if the fastest speed of 6.4S of 1024 channels is required, the hardware cost of the standard instrument scheme needs more than 10 ten thousand yuan RMB, but the utility model only needs 1.2 ten thousand yuan RMB;
5. small volume: if the fastest 6.4S speed of 1024 channels is required to be achieved, a standard instrument is used for carrying out the operation, the size of the system is not less than the volume of more than L W H =400mm 1600mm, the utility model discloses only L W H =200mm 300mm 200mm, and the occupied space only has 1/16 of the instrument scheme;
therefore, the utility model discloses the test can realize the target of high flexibility, high efficiency, high accuracy, low cost, small volume, can be used to replace standard DMM milliohmmeter SMU, solves these standard instrument with high costs, the efficiency of software testing is low, bulky, integrated difficult scheduling problem to be applied to in the open short circuit DC resistance test equipment, the accurate direct current resistance parameter of measurement guarantees product quality.
Drawings
FIG. 1 is a block diagram of a simplified system of the present invention;
FIG. 2 is a simple block diagram of the DC resistance measuring plate;
FIG. 3 is a simple block diagram of the bridge plate;
fig. 4 is a block diagram of a simple structure of the adapter plate for the material to be measured when the input/output interface is a 32-channel four-wire resistance measurement system;
fig. 5 is a block diagram of a simple structure of the material adapter plate to be measured when the input/output interface is a 64-channel two-wire resistance measurement system;
fig. 6 is a block diagram of a simple structure of the material adapter plate to be measured when the input/output interface is a 64-channel four-wire resistance measurement system;
fig. 7 is a simple structural block diagram of the constant current source circuit.
Detailed Description
The utility model discloses a specifically as follows.
As shown in fig. 1, the utility model discloses a control unit 1, switching power supply 2, at least bridging board 3 all the way, at least direct current resistance measurement board 4 all the way and the material keysets 5 that awaits measuring.
The control unit 1 is configured to communicate with at least one path of the dc resistance measuring board 4, send a measurement signal to the dc resistance measuring board 4, and receive a dc resistance measurement result uploaded by the dc resistance measuring board 4; in this embodiment, the control unit is a desktop computer or a handheld computer. The control unit is connected with the direct current resistance test system through a USB line, sends a command to the test system through the USB port, and reads back a test result.
The switching power supply 2 is used for supplying power to the whole system; in the present embodiment, the switching power supply 2 provides voltage outputs of +24V, +12V, -12V, and 5V.
The bridging board 3 is used for communication connection between the control unit 1 and the direct current resistance measuring board 4, and provides power for the direct current resistance measuring board 4; the bridging plate 3 is a multi-channel bridging plate, and the direct current resistance measuring plate 4 is a multi-channel measuring plate. In this embodiment, the bridging plate 3 is an 8-channel bridging plate, and the dc resistance measuring plate 4 is a 64-channel measuring plate.
The direct current resistance measuring board 4 is used for providing at least one direct current resistance measuring channel, receiving an instruction signal from the control unit 1, outputting a driving current to a device to be measured, measuring the voltage of the device to be measured to obtain a direct current resistance, and uploading a measuring result to the control unit 1; the direct current resistance measuring board provides 64 direct current resistance measuring channels at most, receives a USB communication instruction, the built-in MCU controls the IO port to select a specific channel, outputs a proper driving current, measures the voltage on the material to be measured, calculates the direct current resistance, and then sends a measuring result to a computer through USB communication.
The material adapter plate 5 to be tested is used for being connected with a device to be tested and introducing a signal of the device to be tested to the direct current resistance measuring plate 4 of the corresponding channel; the material keysets that awaits measuring will be according to the material that awaits measuring and test demand customization development, and the purpose is just to place the material that awaits measuring on the material keysets that awaits measuring to through walking line with the material signal connection that awaits measuring to 64Pin board to the line connector, just so can be connected with the direct current resistance measurement board through 64Pin winding displacement.
The computer communicates with the direct current resistance measuring board through the USB, the testing software sends direct current resistance measuring instructions of different channels for 64 times in a circulating mode, and the 64-channel direct current resistance measurement can be completed by receiving the measuring result; meanwhile, the test software supports multi-thread parallel test, for example, 6 direct current resistance test boards are used in the whole test system, so that 6 threads can be tested in parallel, the test time can be effectively shortened, and the efficiency is improved. According to the above contents, the system is very flexible, a test system can be quickly built according to requirements, at most 8 direct current resistance test boards with 64 channels can be connected to 1 bridging board, that is, at most 8 direct current resistance test boards with 64=512 channels are supported, and by analogy, the number of channels of the test system can be expanded to 1024 channels by using 2 bridging boards, and the requirements of probes, relays, switches, board-to-board connectors, ICT tests and PCB board flying probe tests can be completely met.
As shown in fig. 2, the dc resistance measurement board 4 includes an input/output interface, a to-be-measured material power-on and communication interface J3, a measurement board power-on and communication interface J4, a 4-group 32-to-1 switching circuit, a six-way switch, a programmable constant current source, a voltmeter, and a measurement board MCU7, the input/output interface is connected to the 4-group 32-to-1 switching circuit, the 4-group 32-to-1 switching circuit is connected to the programmable constant current source and the input end of the voltmeter through switches, the programmable constant current source is connected to the measurement board MCU7 through an I2C interface, the voltmeter is connected to the measurement board MCU7 through an SPI interface, the measurement board power-on and communication interface J4 is connected to the measurement board MCU7 through an UART interface, the other end of the measurement board power-on and communication interface J4 is in communication connection with the bridging board 3, the to-be-measured material power-on and communication interface J3 provides a power supply for the to-be-measured material connected to-measured on the to-be-measured material adapter board 5 and performs power supply and measurement on the to-be-measured material And the MCU7 of the measuring board is respectively connected with the switching circuit for 1-out-of-32, the program-controlled constant current source and the voltmeter through an IO port, and the input and output ports form a 32-channel four-wire resistance measuring system, or a 64-channel two-wire resistance measuring system, or a 64-channel four-wire resistance measuring system. The input/output interface comprises a 64-channel constant current source interface J1 and a 64-channel differential voltage measurement interface J2, the 1-32 channels G1_ 1-G1 _32 of the 64-channel constant current source interface J1 are connected with a first group of the 32-to-1 switching circuit 6_1, the remaining 33-64 channels G2_ 1-G2 _32 are connected with a second group of the 32-to-1 switching circuit 6_2, one output end of the first group of the 32-to-1 switching circuit 6_1 is connected with a positive input electrode VOL _ P of the voltmeter after passing through a first switch S1, the other output end of the first group of the 32-to-1 switching circuit 6_1 is connected with a high input electrode CUR _ HI of the programmable constant current source after passing through a second switch S2, one output end of the second group of the 32-to-1 switching circuit 6_2 is connected with a negative input electrode VOL _ N of the voltmeter after passing through a first switch S1, and the other output end of the second group of the 32-to-1 switching circuit 6_2 of the voltmeter after passing through a second switch S2 A low input electrode CUR _ LO of the current source is connected, 1 to 32 channels G3_1 to G3_32 of the 64-channel differential voltage measurement interface J2 are connected to the 32-selected-1 switching circuit 6_3 of the third group, the remaining 33 to 64 channels G4_1 to G4_32 are connected to the 32-selected-1 switching circuit 6_4 of the fourth group, one output end of the 32-selected-1 switching circuit 6_3 of the third group is connected to the program-controlled low input electrode CUR _ LO of the constant current source through a third switch S3, the other output end of the 32-selected-1 switching circuit 6_3 of the third group is connected to the negative input electrode VOL _ N of the voltage meter through a fourth switch S4, one output end of the 32-selected-1 switching circuit 6_4 of the fourth group is connected to the high input electrode CUR _ HI of the program-controlled constant current source through a third switch S3, and the other output end of the 32-selected-1 switching circuit 6_4 of the fourth group is connected to the positive input electrode VOL _ P4 of the voltage meter.
In this embodiment, J1 and J2 can form a 32-channel four-wire resistance measurement system, and can also form a 64-channel two-wire resistance measurement system, and with the design that constant current source signals in J3 and the materials to be measured are connected in series on the adapter plate, J1 and J2 can form a 64-channel four-wire resistance measurement system, and power and IO5_ 1-4 in J3 are used for supplying power to the materials to be measured on the adapter plate or controlling the state of the materials, and J4 provides a power supply and a communication interface for the measurement plate. The 4 groups of the 32-to-1 switching circuits are completely the same, the function is to switch 32 signals to 1 signal, in order to pass 2A current, a relay is selected during switching, in order to prevent short circuit, a 5-32 decoder needs to be added, hardware mutual exclusion is realized, here, two 16-to-1 electronic switches (ADG 1406 of ADI company) are adopted, the highest power supply is 30V, the on-resistance is 9.5 omega, the current is continuously passed through 300mA, 16-path signal mutual exclusion is realized by a single chip, the output of the two 16-to-1 electronic switches is mutually exclusive by using a three-eight decoder chip (74 HC 238), in addition, IO controls all 32 signals to be completely disconnected, and then, a certain 1 signal in the 32 paths is selected through 5 IO ports of the MCU. The S1-S5 switches are controlled to select a measurement mode, and specific logics are shown in the following table 1:
| S1 | S2 | S3 | S4 | S5 | DC resistance test mode |
| 0 | 1 | 0 | 1 | 0 | 32 channel four wire resistance measurement mode, G1&Current of G2, |
| 1 | 0 | 0 | 0 | 1 | 64 channel four wire resistance measurement mode, G1&G2 go voltage, G3&G4 not used |
| 0 | 0 | 0 | 1 | 1 | 64 channel four wire resistance measurement mode, G1&G2 not used, |
| 1 | 1 | 0 | 0 | 0 | 64 channel two wire resistance measurement mode, G1&G2Current and voltage, G3&G4 not used |
| 0 | 0 | 1 | 1 | 0 | 64 channel two wire resistance measurement mode, G1&G2 not used, G3&G4 reference current and voltage |
As shown in fig. 7, the programmable constant current source is composed of a constant current source circuit M1 (the constant current source circuit M1 is composed of a sampling resistor + MOS transistor + operational amplifier feedback, wherein the sampling resistor is composed of three resistors R1, R2 and R3, as shown in fig. 7) and a 16Bits DAC (e.g., AD 5667), and can realize 10 uA-1A constant current output under the control of the MCU IO port and I2C. The voltmeter consists of an instrument operational amplifier (such as AD 8253) with programmable gain and a 24bits ADC (such as AD 7172-2), and can realize voltage measurement of +/-0.1 mV to +/-5V. The MCU controller comprises the minimum system of STM32F103, and the IO mouth is used for controlling 1~ 5 circuit, and I2C control DAC, SPI control ADC, EEPROM U6 are used for storing integrated circuit board information and calibration data, UART serial ports and bridging board communication.
As shown in fig. 3, the bridge board 3 includes 8 UART connectors J4-1 to J4-8, a switch power connector J7, two USB plugs J5, J6, and two USB to UART modules U4 and U5, the USB plug, the USB to UART module, and the UART connector are connected in sequence, and the switch power connector J7 supplies power to the 8 UART connectors J4-1 to J4-8. In the embodiment, the J5 and the U4 complete the conversion from 1 path of USB to 4 paths of UARTs 1-4, the J6 and the U5 complete the conversion from 1 path of USB to 4 paths of UARTs 5-8, and the total 8 paths of UARTs can be respectively communicated with 8 direct current resistance test boards; j7 distributes 24V/+/-12V/5V power obtained from the switch power supply to J4-1-J4-8 after passing through a filtering wave and an overcurrent protection circuit, and supplies power for 8 direct current resistance test boards respectively.
When the input and output interface is a 32-channel four-wire resistance measurement system, the material adapter plate 5 to be measured comprises 32 constant-current source interfaces J8, 32 differential voltage measurement interfaces J9 and a first adapter plate side material electrifying and communication interface J10, 32 high-low connecting poles of the 32 constant-current source interfaces J8 are respectively and correspondingly connected with two ends of 1 path of material to be measured, the 32 path of material to be measured is K1-K32, 32 positive poles and negative poles of the 32 differential voltage measurement interfaces J9 are respectively and correspondingly connected with two ends of 1 path of material to be measured, and the 32 path of material to be measured is electrified and controlled to be switched on and off through the first adapter plate side material electrifying and communication interface J10. As shown in fig. 4, K1-K32 represent materials to be measured, and may be probes, relays, switches, wires, traces, board-to-board connector modules, etc., J8 is a 32-way constant current source interface, and after connection, current flows through the materials to be measured, J9 is a 32-way differential voltage measurement interface, and after connection, the voltage at two ends of the materials to be measured is measured, and then a power supply and a control signal on J10 are used to control the channel or turn-off of the materials to be measured, which is a typical four-wire method for measuring resistance, and is generally used for precise measurement of small resistance (several m Ω to several Ω).
When the input/output interface is a 64-channel two-wire resistance measurement system, the material adapter plate 5 to be measured comprises a second adapter plate side material to be measured electrifying and communication interface J13, a first constant-current voltage measurement interface J11 and a second constant-current voltage measurement interface J12 which respectively provide 32 paths of constant current and voltage measurement, the first constant-current voltage measurement interface J11 and the second constant-current voltage measurement interface J12 are respectively connected to two ends of the 32 paths of materials to be measured, respectively provide a constant current source for each path of materials to be measured and read the resistance at two ends of the materials to be measured, and 64 paths of materials to be measured are electrified and controlled to be switched on and off through the second adapter plate side material to be measured electrifying and communication interface J13. As shown in fig. 5, K1-K64 represent materials to be tested, and different from fig. 4, the scheme measures voltage by a two-wire method, each pair of differential lines of J11 and J12 provides a constant current source and reads voltage, and since the constant current source and the voltage measurement share a transmission line, and the measurement result includes the resistance of the transmission line (in the order of several Ω), the scheme can only measure the resistance of more than tens of Ω, and is suitable for open-short circuit tests, such as open-short circuit tests in ICT tests/wire tests/flying probe tests.
When the input/output interface is a 64-channel four-wire resistance measurement system, the material adapter plate 5 to be measured comprises a first voltage measurement interface J14, a second voltage measurement interface J150 and a constant current source providing interface J16, the first voltage measurement interface J14 and the second voltage measurement interface J150 respectively provide 32 voltage measurement ports, the 64 voltage measurement ports are respectively and correspondingly connected to two ends of 64 materials to be measured, the constant current source providing interface J16 sequentially connects the 64 materials to be measured in series to form a loop, and the constant current source providing interface J16 provides a constant current source for the 64 materials to be measured. As shown in fig. 6, K1-K64 represent the materials to be measured, and the resistance is measured by a four-wire method as in fig. 4, which is used for precise measurement of small resistance (several m Ω -several Ω), except that the method uses J16 to provide a constant current source, and connects all 64 paths of the materials to be measured in series, so that the current can flow through 64 materials to be measured at one time, J14 and J15 are both used as voltage measurement ports, the number of channels is twice as large as that of the scheme of fig. 4, and the switching of the constant current source is reduced, only voltage needs to be read in sequence, the speed is more than twice as large as that of the scheme of fig. 3, only the materials to be measured need to be connected in series when the adapter board is designed, and the probe, the relay, and the board-to-board connector are very suitable for measurement by the method.
In specific application, such as a probe test & aging DCR tester, when DCR of 100 probes is required to be measured each time and the target impedance is 120m Ω, 2 direct current resistance test boards are used to build a system, that is, 128 channels can be supported at most to realize DCR measurement. For another example, if the board-to-board connector contact impedance analysis platform requires to measure DCR of 400Pin board-to-board connectors and the target impedance is 100m Ω, 7 dc resistance test boards are used to build the system, i.e. at most 512 channels DCR measurement can be supported. For another example, the Type-C wire open short circuit & DCR tester requires to measure the open short circuit and DCR between 24Pin networks, the target impedance is 20m Ω -200 m Ω, and 1 dc resistance test board is used to build a system, i.e. at most 64-channel DCR measurement can be supported.
The utility model discloses a one set possesses that the passageway can dispose, easily expand, high efficiency, high accuracy, low cost, small volume's direct current resistance test system for replace standard DMM milliohmmeter SMU, it is with high costs to solve these standard instruments, and efficiency of software testing is low, and is bulky, integrated difficult scheduling problem, thereby the wide application is in opening short circuit/direct current resistance test equipment, and accurate measurement direct current resistance parameter guarantees product quality. The device can be used in aging test equipment of devices such as a probe/button/relay/temperature control switch and the like, and the DCR value after each release-action is recorded in real time, so that the contact performance and the service life of the probe/button/relay/temperature control switch are evaluated; the device can be used in wire open-short circuit test equipment to measure the on-off and DCR of the wire, thereby evaluating whether the wire diameter and the welding effect of the wire reach the standard or not; the device can be used in a board-to-board connector contact performance evaluation device to measure the on-off and DCR of each pin of the board-to-board connector, thereby evaluating the performance and the service life of the board-to-board connector; the method can be used in ICT/FCT/flying probe test equipment to measure open/short circuit and DCR of a line/network, thereby evaluating the product quality.
Claims (12)
1. A high-efficiency precise direct-current resistance testing system with configurable channels is characterized in that: it comprises a control unit (1), a switching power supply (2), at least one path of bridging board (3), at least one path of direct current resistance measuring board (4) and a material switching board (5) to be measured,
the control unit (1) is used for communicating with at least one path of direct current resistance measuring plate (4), sending a measuring signal to the direct current resistance measuring plate (4), and receiving a direct current resistance measuring result uploaded by the direct current resistance measuring plate (4);
the switching power supply (2) is used for supplying power to the whole system;
the bridging board (3) is used for communication connection between the control unit (1) and the direct current resistance measuring board (4), and provides power for the direct current resistance measuring board (4);
the direct current resistance measuring board (4) is used for providing at least one direct current resistance measuring channel, receiving the instruction signal from the control unit (1), outputting a driving current to a device to be measured, measuring the voltage of the device to be measured to obtain a direct current resistance, and uploading the measuring result to the control unit (1);
the material adapter plate (5) to be tested is used for being connected with a device to be tested and introducing a signal of the device to be tested to the direct current resistance measuring plate (4) of the corresponding channel;
the bridge plate (3) is a multi-channel bridge plate, and the direct current resistance measuring plate (4) is a multi-channel measuring plate.
2. The system of claim 1, wherein the channel-configurable, high-efficiency, precision dc resistance testing system comprises: the bridge plate (3) is an 8-channel bridge plate, and the direct current resistance measuring plate (4) is a 64-channel measuring plate.
3. The system of claim 2, wherein the channel-configurable high-efficiency precision direct current resistance test system comprises: the direct current resistance measuring board (4) comprises an input/output interface, a material charging and communication interface (J3) to be measured, a measuring board charging and communication interface (J4), 4 groups of 32-to-1 switching circuits, a six-way switch, a program-controlled constant current source, a voltmeter and a measuring board MCU (7), wherein the input/output interface is connected with the 4 groups of 32-to-1 switching circuits, the 4 groups of 32-to-1 switching circuits are respectively connected with the program-controlled constant current source and the input end of the voltmeter through switches, the program-controlled constant current source is connected with the measuring board MCU (7) through an I2C interface, the voltmeter is connected with the measuring board MCU (7) through an SPI interface, the measuring board charging and communication interface (J4) is connected with the measuring board MCU (7) through a UART interface, and the other end of the measuring board charging and communication interface (J4) is in communication connection with the bridging board (3), the power-on and communication interface (J3) of the material to be measured provides power for the material to be measured connected to the material transfer board (5) to be measured and controls the state of the material to be measured, the measurement board MCU (7) is respectively connected with the 32-to-1 switching circuit, the program-controlled constant current source and the voltmeter through IO ports, and the input and output interface forms a 32-channel four-wire resistance measurement system, or a 64-channel two-wire resistance measurement system, or a 64-channel four-wire resistance measurement system.
4. The system of claim 3, wherein the channel-configurable high-efficiency precision direct current resistance test system comprises: the input/output interface consists of a 64-channel constant current source interface (J1) and a 64-channel differential voltage measurement interface (J2), 1-32 channels (G1 _ 1-G1 _ 32) of the 64-channel constant current source interface (J1) are connected with a first group of 32-to-1 switching circuits (6 _ 1), the rest 33-64 channels (G2 _ 1-G2 _ 32) are connected with a second group of 32-to-1 switching circuits (6 _ 2), one output end of the first group of 32-to-1 switching circuits (6 _ 1) is connected with a positive input electrode (VOL _ P) of the voltmeter after passing through a first switch (S1), the other output end of the first group of 32-to-1 switching circuits (6 _ 1) is connected with a high input electrode (CUR _ HI) of the programmable constant current source after passing through a second switch (S2), one output end of the second group of the 32-to-1 switching circuits (6 _ 2) is connected with a negative input electrode (VOL _ N) of the voltmeter after passing through a first switch (1), the other output end of the second group of the 32-to-1 switching circuit (6 _ 2) is connected with the low input electrode (CUR _ LO) of the programmable constant current source after passing through a second switch (S2), the 1-32 channels (G3 _ 1-G3 _ 32) of the 64-channel differential voltage measurement interface (J2) are connected with the 32-to-1 switching circuit (6 _ 3) of the third group, the remaining 33-64 channels (G4 _ 1-G4 _ 32) are connected with the 32-to-1 switching circuit (6 _ 4) of the fourth group, one output end of the 32-to-1 switching circuit (6 _ 3) of the third group is connected with the low input electrode (CUR _ LO) of the programmable constant current source after passing through a third switch (S3), the other output end of the 32-to-1 switching circuit (6 _ 3) of the third group is connected with the negative input electrode (VOL _ N) of the voltage meter after passing through a fourth switch (S4), and the other output end of the 32-to-1 switching circuit (6 _ 4) of the third group after passing through a third switch (S3) of the fourth switch (S4) And the high input electrode (CUR _ HI) of the program-controlled constant current source is connected, and the other output end of the fourth group of the 32-to-1 switching circuits (6 _ 4) is connected with the positive input electrode (VOL _ P) of the voltmeter after passing through a fourth switch (S4).
5. The system of claim 4, wherein the channel-configurable high-efficiency precision direct current resistance test system comprises: the program-controlled constant current source consists of a constant current source circuit (M1) and a DAC (U1) of 16Bits, the constant current source circuit (M1) consists of a sampling resistor, an MOS (metal oxide semiconductor) tube and an operational amplifier feedback, and the constant current output current range of the program-controlled constant current source is 10 uA-1A.
6. The system of claim 4, wherein the channel-configurable high-efficiency precision direct current resistance test system comprises: the voltmeter consists of an instrument operational amplifier (U2) and a 24bits ADC (U3), and the voltage measurement range of the voltmeter is +/-0.1 mV to +/-5V.
7. The system of claim 4, wherein the channel-configurable high-efficiency precision direct current resistance test system comprises: the bridge board (3) comprises 8 paths of UART connectors (J4-1-J4-8), a switch power supply connector (J7), two USB plugs (J5, J6) and two USB-to-UART modules (U4, U5), wherein the USB plugs, the USB-to-UART modules and the UART connectors are sequentially connected, and the switch power supply connector (J7) supplies power to the 8 paths of UART connectors (J4-1-J4-8).
8. The system of claim 3, wherein the channel-configurable high-efficiency precision direct current resistance test system comprises: when the input and output interface is a 32-channel four-wire resistance measurement system, the material adapter plate (5) to be measured comprises 32 paths of constant current source interfaces (J8), 32 paths of differential voltage measurement interfaces (J9) and a power-on and communication interface (J10) of the material to be measured on the side of the first adapter plate, 32 paths of high-low connecting poles of the 32 paths of constant current source interfaces (J8) are respectively and correspondingly connected with two ends of 1 path of material to be measured, the 32 paths of material to be measured are K1-K32, 32 paths of positive and negative poles of the 32 paths of differential voltage measurement interfaces (J9) are respectively and correspondingly connected with two ends of 1 path of material to be measured, and the 32 paths of material to be measured are switched on and controlled to be switched on and off through the power-on and communication interface (J10) of the material to be measured on the side of the first adapter plate.
9. The system of claim 3, wherein the channel-configurable high-efficiency precision direct current resistance test system comprises: when the input and output interface is a 64-channel two-wire resistance measurement system, the material adapter plate (5) to be measured comprises a second adapter plate side material power-on and communication interface (J13) for the material to be measured, a first constant-current voltage measurement interface (J11) and a second constant-current voltage measurement interface (J12) for providing 32 paths of constant current and voltage measurement respectively, the first constant-current voltage measurement interface (J11) and the second constant-current voltage measurement interface (J12) are connected to two ends of the 32 paths of material to be measured respectively, a constant current source is provided for each path of material to be measured respectively, the resistance of two ends of the material to be measured is read, and the 64 paths of material to be measured are powered on and controlled to be switched on and off through the second adapter plate side material power-on and communication interface (J13) for the material to be measured.
10. The system of claim 3, wherein the channel-configurable high-efficiency precision direct current resistance test system comprises: when the input and output interface is a 64-channel four-wire resistance measurement system, the material adapter plate (5) to be measured comprises a first voltage measurement interface (J14), a second voltage measurement interface (J150) and a constant current source providing interface (J16), the first voltage measurement interface (J14) and the second voltage measurement interface (J150) respectively provide 32 voltage measurement ports, the 64 voltage measurement ports are respectively and correspondingly connected to two ends of 64 materials to be measured, the constant current source providing interface (J16) sequentially connects the 64 materials to be measured in series to form a loop, and the constant current source providing interface (J16) provides a constant current source for the 64 materials to be measured.
11. The system of claim 1, wherein the channel-configurable, high-efficiency, precision dc resistance testing system comprises: the switching power supply (2) provides +24V, +12V, -12V and 5V voltage outputs.
12. The system of claim 1, wherein the channel-configurable, high-efficiency, precision dc resistance testing system comprises: the measuring board MCU (7) is selected from a processor with the model number of STM32F103, and the control unit (1) is a desktop computer or a handheld computer.
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