Power board, accuracy compensation method of power board and testing machine

Abstract

The present application relates to a power supply board and its precision compensation method and test machine. When the control module measures the current, the control module controls the channel switching module to connect to the load, so that the forward output channel module outputs a test signal to the load, and reads the current measurement value of the current measurement channel module and the voltage measurement value of the voltage measurement channel module; the measured current compensation is performed according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated current. When the control module outputs the current, the control module controls the channel switching module to connect to the load, so that the forward output channel module outputs the current to the load according to the set current value, reads the current measurement value of the current measurement channel module and the voltage measurement value of the voltage measurement channel module; the set current value is compensated according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated set current, and the forward output channel module is controlled to output the current according to the compensated set current.

Description

Technical Field

[0001] The present application relates to the field of semiconductor testing technology, and in particular to a power supply board, a precision compensation method for the power supply board, and a testing machine. Background Art

[0002] Semiconductor automated testing refers to the use of automatic test equipment (ATE) to test various parameters of the device under test (DUT) to eliminate defective products and control the factory quality of semiconductor devices. The power board is used in semiconductor test equipment to provide voltage or current excitation to the chip under test, usually with voltage output (FV), voltage measurement (MV), current output (FI) and current measurement (MI) functions and their combination.

[0003] The MI circuit of the power supply board mostly uses high-end sampling. The MI value is the differential mode voltage across the sampling resistor divided by the sampling resistor. At this time, the voltage on the unit under test DUT and the voltage generated by the line resistance will become the common mode signal across the MI sampling resistor. When using a subtractor to calculate the differential mode voltage across the sampling resistor, it will be affected by the common mode voltage, thereby affecting the accuracy of MI. In the power supply board controlled by the digital loop, the accuracy of FI is determined by the accuracy of MI. Therefore, both FI and MI will be affected by the common mode voltage. Especially under high-precision indicators, the error of FI and MI at higher voltages is unacceptable. How to improve the accuracy of FI and MI of the power supply board is an urgent problem to be solved. Summary of the invention

[0004] Based on this, it is necessary to provide a power supply board, a precision compensation method for the power supply board and a testing machine that can improve the accuracy of FI and MI in order to address the above problems.

[0005] A first aspect of the present application provides a power board, comprising a control module, a forward output channel module, a current measurement channel module, a voltage measurement channel module and a channel switching module, wherein the control module is connected to the forward output channel module, the current measurement channel module, the voltage measurement channel module and the channel switching module, the forward output channel module is connected to the current measurement channel module, and the channel switching module is connected to the current measurement channel module, the voltage measurement channel module and a load;

[0006] The control module is used to control the channel switching module to connect to the load when measuring the current, so that the forward output channel module outputs a test signal to the load, and reads the current measurement value of the current measurement channel module and the voltage measurement value of the voltage measurement channel module; and performs measurement current compensation according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated current;

[0007] The control module is also used to control the channel switching module to connect to the load when outputting current, so that the forward output channel module outputs current to the load according to the set current value, reads the current measurement value of the current measurement channel module, and the voltage measurement value of the voltage measurement channel module; and compensates the set current value according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain a compensated set current, and controls the output current of the forward output channel module according to the compensated set current;

[0008] The compensation reference data is calculated based on the measurement data of the current measurement channel module and the voltage measurement channel module when the channel switching module is connected to the calibration module or the load.

[0009] In one embodiment, the control module includes a controller and a memory, and the controller is connected to the forward output channel module, the current measurement channel module, the voltage measurement channel module, the channel switching module and the memory; when the controller controls the channel switching module to access the calibration module or the load, the measurement data of the current measurement channel module and the voltage measurement channel module are obtained and sent to the host computer, and the compensation reference data calculated by the host computer according to the measurement data is received and stored in the memory.

[0010] In one embodiment, the forward output channel module includes a digital-to-analog conversion module U5 and a gain programmable power amplifier module U6, the digital-to-analog conversion module U5 is connected to the control module and the gain programmable power amplifier module U6, and the gain programmable power amplifier module U6 is connected to the current measurement channel module.

[0011] In one embodiment, the current measurement channel module includes an analog-to-digital conversion module U2, a gain programmable operational amplifier module U3, a subtractor U4 and a gear adjustment circuit, the gear adjustment circuit is connected to the forward output channel module, the channel switching module and the control module, the subtractor U4 is connected to the gear adjustment circuit and the gain programmable operational amplifier module U3, and the analog-to-digital conversion module U2 is connected to the gain programmable operational amplifier module U3 and the control module.

[0012] In one embodiment, the voltage measurement channel module includes an analog-to-digital conversion module U7, a gain programmable operational amplifier module U8 and a subtractor U9, the subtractor U9 is connected to the channel switching module and the gain programmable operational amplifier module U8, and the analog-to-digital conversion module U7 is connected to the gain programmable operational amplifier module U8 and the control module.

[0013] In one embodiment, the channel switching module includes a switch HF, a switch LF, a switch HS, a switch LS, a switch K1, a switch K2, a switch K3, a switch K4 and a switch K5; the first end of the switch K1 is connected to the current measurement channel module and the static contact of the switch HF, the second end of the switch K1 is connected to the voltage measurement channel module and the first end of the switch K4, the first moving contact of the switch HF is connected to the first end of the calibration module, the second moving contact of the switch HF is connected to the first end of the load, the second end of the switch K4 is connected to the first end of the switch K3 and the static contact of the switch HS, and the first moving contact of the switch HS is connected to the first end of the load. The first end of the switch K2 is connected to the voltage measurement channel module and the first end of the switch K5, the second end of the switch K2 is connected to the ground terminal and the static contact of the switch LF, the first moving contact of the switch LF is connected to the second end of the calibration module, the second moving contact of the switch LF is connected to the second end of the load, the second end of the switch K5 is connected to the second end of K3 and the static contact of the switch LS, the first moving contact of the switch LS is connected to the second end of the calibration module, and the second moving contact of the switch LS is connected to the second end of the load.

[0014] A second aspect of the present application provides a method for compensating the accuracy of a power board, comprising:

[0015] When measuring current, the channel switching module is controlled to connect to the load, so that the forward output channel module outputs a test signal to the load, and the current measurement value of the current measurement channel module and the voltage measurement value of the voltage measurement channel module are read, and the measured current compensation is performed according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated current;

[0016] When outputting current, controlling the channel switching module to connect to the load, so that the forward output channel module outputs current to the load according to the set current value, reading the current measurement value of the current measurement channel module and the voltage measurement value of the voltage measurement channel module, compensating the set current value according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain a compensated set current, and controlling the output current of the forward output channel module according to the compensated set current;

[0017] The compensation reference data is calculated based on the measurement data of the current measurement channel module and the voltage measurement channel module when the channel switching module is connected to the calibration module or the load.

[0018] In one of the embodiments, the current compensation is performed according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated current, including: calculating the common mode voltage according to the current measurement value, voltage measurement value, high-end line resistance and low-end line resistance; calculating the compensated current according to the current measurement value, common mode voltage, compensation coefficient and range coefficient;

[0019] and / or

[0020] The method of compensating the set current value according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated set current includes: calculating the common mode voltage according to the current measurement value, voltage measurement value, high-end line resistance and low-end line resistance; calculating the compensated set current according to the set current value, common mode voltage, compensation coefficient and range coefficient.

[0021] In one of the embodiments, the compensation reference data includes a compensation coefficient, a range coefficient, a high-end line resistance, and a low-end line resistance.

[0022] In one embodiment, the method further comprises:

[0023] Controlling the channel switching module to access the calibration module, so that the forward output channel module outputs voltage points evenly distributed within the maximum voltage range, and reading current data at each voltage point through the current measurement channel module;

[0024] A compensation coefficient is calculated based on the voltage points and the current data read at each of the voltage points.

[0025] In one embodiment, the method further comprises:

[0026] Control the channel switching module to access the load, so that the forward output channel module outputs a set current, and obtains the measured voltage of the voltage measurement channel module;

[0027] A high-end line resistance and a low-end line resistance are calculated according to the set current and the measured voltage.

[0028] In one embodiment, the range coefficient is calculated based on the maximum value of different ranges of the current measurement channel module and the corresponding gain.

[0029] In one of the embodiments, the method further includes: controlling the channel switching module to access the calibration module to calibrate the accuracy of each current range.

[0030] A third aspect of the present application provides a testing machine, comprising a host computer and the above-mentioned power board.

[0031] The power board, the accuracy compensation method and the test machine of the power board, when measuring the current, the control module controls the channel switching module to connect to the load, so that the forward output channel module outputs the test signal to the load, and reads the current measurement value of the current measurement channel module and the voltage measurement value of the voltage measurement channel module; and the measured current compensation is performed according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated current. When the control module is also outputting current, the control module controls the channel switching module to connect to the load, so that the forward output channel module outputs the current to the load according to the set current value, reads the current measurement value of the current measurement channel module and the voltage measurement value of the voltage measurement channel module; and the set current value is compensated according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated set current, and the forward output channel module is controlled to output the current according to the compensated set current. When measuring the current and outputting the current, when the calibration module or the load is connected through the channel switching module, the compensation reference data is calculated according to the measurement data of the current measurement channel module and the voltage measurement channel module, and the current compensation is performed in combination with the compensation reference data, thereby improving the FI and MI accuracy of the power board. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a structural block diagram of a power board in one embodiment;

[0033] Figure 2 A schematic diagram of the structure of a power board in one embodiment;

[0034] Figure 3 A flowchart of a method for compensating the accuracy of a power board in one embodiment;

[0035] Figure 4 The figure is a schematic diagram of the principle of a precision compensation method for a power board in one embodiment. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0038] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0039] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0040] In one embodiment, Figure 1 As shown, a power board is provided, including a control module 110, a forward output channel module 120, a current measurement channel module 130, a voltage measurement channel module 140 and a channel switching module 150, wherein the control module 110 is connected to the forward output channel module 120, the current measurement channel module 130, the voltage measurement channel module 140 and the channel switching module 150, the forward output channel module 120 is connected to the current measurement channel module 130, and the channel switching module 150 is connected to the current measurement channel module 130, the voltage measurement channel module 140 and the load RLOAD. The control module 110 is used to control the channel switching module 150 to access the load RLOAD when measuring the current, so that the forward output channel module 120 outputs a test signal to the load RLOAD, and reads the current measurement value of the current measurement channel module 130 and the voltage measurement value of the voltage measurement channel module 140; and performs current compensation according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated current. The control module 110 is also used to control the channel switching module 150 to connect to the load RLOAD when outputting current, so that the forward output channel module 120 outputs current to the load RLOAD according to the set current value, reads the current measurement value of the current measurement channel module 130, and the voltage measurement value of the voltage measurement channel module 140; and compensates the set current value according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated set current, and controls the output current of the forward output channel module 120 according to the compensated set current.

[0041] Among them, the compensation reference data is calculated according to the measurement data of the current measurement channel module 130 and the voltage measurement channel module 140 when the channel switching module 150 is connected to the calibration module 210 or the load RLOAD. The type of compensation reference data is not unique, for example, it may include compensation coefficient, high-end line resistance, low-end line resistance, etc. The calibration module 210 contains a programmable resistor network and a high-precision voltage measurement module for calibration, which can be used to measure voltage and current. The control module 110 is connected to the relevant switches in the channel switching module 150, and the channel switching module 150 is switched and controlled, and the compensation reference data is determined in combination with the collected measurement data for storage. It should be noted that the control module 110 can calculate the compensation reference data in combination with the measurement data for storage; or the control module 110 can upload the acquired measurement data to the host computer, and the compensation reference data is calculated by the host computer and then sent to the control module 110 for storage. In practical applications, when the power board needs to measure current or output current, current compensation is performed in combination with compensation reference data to eliminate common-mode effects, thereby improving the FI and MI accuracy of the power board. There is no need to add additional common-mode error compensation hardware circuits, and the accuracy compensation cost is low.

[0042] Specifically, Figure 2 As shown, the control module 110 includes a controller U1 and a memory U10, and the controller U1 is connected to the forward output channel module 120, the current measurement channel module 130, the voltage measurement channel module 140, the channel switching module 150 and the memory U10. When the controller U1 controls the channel switching module 150 to access the calibration module 210 or the load RLOAD, the measurement data of the current measurement channel module 130 and the voltage measurement channel module 140 are obtained and sent to the host computer 220, and the compensation reference data calculated by the host computer 220 according to the measurement data is received and stored in the memory U10. The controller U1 can be a FPGA (Field-Programmable Gate Array) or other types of control units, and the memory U10 can be a FLASH storage unit or other types of memory.

[0043] In one embodiment, Figure 2 As shown, the forward output channel module 120 includes a digital-to-analog conversion module U5 and a gain programmable power amplifier module U6 , the digital-to-analog conversion module U5 is connected to the control module 110 and the gain programmable power amplifier module U6 , and the gain programmable power amplifier module U6 is connected to the current measurement channel module 130 .

[0044] Specifically, the digital-to-analog conversion module U5 is connected to the controller U1, and the controller U1 can control the forward output channel module 120 to output voltage or current. When the forward output channel module 120 works in the voltage output mode, the controller U1 uses the difference between the voltage measurement (MV) value of the voltage measurement channel module 140 and the set voltage value as an error, and uses the PID control algorithm to adjust the forward channel output to achieve the function of stabilizing the output voltage; when the forward output channel module 120 works in the current output mode, the controller U1 uses the difference between the current measurement (MI) value of the current measurement channel module 130 and the set current value as an error, and uses the PID control algorithm to adjust the forward channel output to achieve the function of stabilizing the output current.

[0045] Continue to refer to Figure 2 The current measurement channel module 130 may include an analog-to-digital conversion module U2, a gain programmable operational amplifier module U3, a subtractor U4 and a gear adjustment circuit 132, the gear adjustment circuit 132 is connected to the forward output channel module 120, the channel switching module 150 and the control module 110, the subtractor U4 is connected to the gear adjustment circuit 132 and the gain programmable operational amplifier module U3, and the analog-to-digital conversion module U2 is connected to the gain programmable operational amplifier module U3 and the control module 110.

[0046] Specifically, the gear adjustment circuit 132 and the analog-to-digital conversion module U2 are both connected to the controller U1, and the controller U1 controls the gear adjustment circuit 132 to adjust the current range gear, and receives the current measurement value output by the analog-to-digital conversion module U2. The current measurement principle is: the voltage across the sampling resistor in the gear adjustment circuit 132 is calculated by the subtractor U4 to obtain the voltage difference, and then adjusted to the available voltage range of the analog-to-digital conversion module U2 by the gain programmable operational amplifier module U3, and then converted into a digital quantity by the analog-to-digital conversion module U2 and sent to the controller U1, and the controller U1 outputs the current measurement value and returns it to the host computer 220. Among them, when analyzing the compensation reference data, the controller U1 obtains the current measurement value according to the digital quantity output by the analog-to-digital conversion module U2, and sends the current measurement value to the host computer 220 so that the host computer 220 can calculate and determine the compensation reference data; when measuring the current in actual applications, the controller U1 obtains the current measurement value according to the digital quantity output by the analog-to-digital conversion module U2, and then measures the current compensation in combination with the voltage measurement value and the compensation reference data, and sends the compensated current value to the host computer 220 for the host computer 220 to perform data analysis.

[0047] The gear adjustment circuit 132 can support 2 or more current range gear adjustments. In this embodiment, the gear adjustment circuit 132 has three current range gears, including sampling resistors R1, sampling resistors R2 and sampling resistors R3. After the sampling resistors R1, sampling resistors R2 and sampling resistors R3 are connected in series with the corresponding control switches, the other end of each sampling resistor is connected to the input terminal - of the subtractor U4 and the gain programmable amplifier module U6, and the other end of each control switch is connected to the input terminal + of the subtractor U4 and the channel switching module 150. The control switch can be a relay or other type of controlled switch, and the resistance values ​​of the sampling resistors R1, the sampling resistors R2 and the sampling resistors R3 can be designed to be different from each other. The controller U1 connects the control ends of each control switch, switches and controls the control switches, and connects different sampling resistors to the circuit to achieve current range gear adjustment. For example, the sampling resistors R1, the sampling resistors R2 and the sampling resistors R3 correspond to the current range from small to large, respectively, and the current range can be adjusted by adjusting the connection and disconnection of the sampling resistors R1, the sampling resistors R2 and the sampling resistors R3.

[0048] In one embodiment, the voltage measurement channel module 140 includes an analog-to-digital conversion module U7, a gain programmable operational amplifier module U8 and a subtractor U9, wherein the subtractor U9 is connected to the channel switching module 150 and the gain programmable operational amplifier module U8, and the analog-to-digital conversion module U7 is connected to the gain programmable operational amplifier module U8 and the control module 110. The analog-to-digital conversion module U7 is specifically connected to the controller U1, and the voltage measurement principle is as follows: the voltage between the input terminal + and the input terminal - of the subtractor U9 is conditioned to the usable range of the analog-to-digital conversion module U7 by the gain programmable operational amplifier module U8 after the voltage difference is determined by the subtractor U9, and then converted into a digital quantity by the analog-to-digital conversion module U7 and sent to the controller U1, and the controller U1 returns the voltage measurement value to the host computer 220. Among them, when analyzing the compensation reference data, the controller U1 obtains the voltage measurement value according to the digital quantity output by the analog-to-digital conversion module U7, and sends the voltage measurement value to the host computer 220, so that the host computer 220 can calculate and determine the compensation reference data; when measuring voltage in actual applications, the controller U1 can also obtain the voltage measurement value according to the digital quantity output by the analog-to-digital conversion module U7 and then perform voltage compensation, and send the compensated voltage value to the host computer 220, so that the host computer 220 can perform data analysis.

[0049] In addition, the channel switching module 150 may specifically include switch HF, switch LF, switch HS, switch LS, switch K1, switch K2, switch K3, switch K4 and switch K5; the first end of switch K1 is connected to the current measurement channel module 130 and the static contact of switch HF, specifically connected to each control switch in the current measurement channel module 130 and the input end + of the subtractor U4, the second end of switch K1 is connected to the voltage measurement channel module 140 and the first end of switch K4, specifically connected to the input end + of the subtractor U9 in the voltage measurement channel module 140. The first moving contact of switch HF is connected to the first end of the calibration module 210, the second moving contact of switch HF is connected to the first end of the load RLOAD, the second end of switch K4 is connected to the first end of switch K3 and the static contact of switch HS, the first moving contact of switch HS is connected to the first end of the calibration module 210, and the second moving contact of switch HS is connected to the first end of the load RLOAD; the first end of switch K2 is connected to the voltage measurement channel module 140 and the first end of switch K5, specifically connected to the input end - of the subtractor U9 in the voltage measurement channel module 140, the second end of switch K2 is connected to the ground end and the static contact of switch LF, the first moving contact of switch LF is connected to the second end of the calibration module 210, the second moving contact of switch LF is connected to the second end of the load RLOAD, the second end of switch K5 is connected to the second end of K3 and the static contact of switch LS, the first moving contact of switch LS is connected to the second end of the calibration module 210, and the second moving contact of switch LS is connected to the second end of the load RLOAD. Among them, switch HF, switch LF, switch HS, switch LS, switch K1, switch K2, switch K3, switch K4 and switch K5 can all be controlled switches using relays or other types of controlled switches. The controller U1 is connected to the control ends of each switch to control the on and off of each switch for Kelvin detection.

[0050] Furthermore, the control module 110 is also used to control the channel switching module 150 to access the calibration module 210 to calibrate the accuracy of each current range. Vcal ) range, calibrate the accuracy of each current range of the current measurement channel module 130, obtain the calibration parameters of each current range and save them, and the full-scale values ​​of voltage and current are respectively Vcal and Ical. The calibration parameters may specifically include gain and offset. In actual use, the control module 110 performs current output and current measurement according to the saved calibration parameters to ensure the accuracy of current output and current measurement. For example, when calculating compensation reference data (such as compensation coefficient, etc.), the accuracy of current measurement can be improved by collecting the required current measurement data through the current measurement channel module 130 after range accuracy calibration at low voltage, thereby ensuring accurate compensation reference data. In addition, when the power board is operating in the current measurement or output current mode, it can also ensure that the current measurement channel module 130 collects accurate current measurement values, and then performs corresponding compensation processing in combination with the compensation reference data.

[0051] Among them, the accuracy of each current range is calibrated by controlling the channel switching module 150 to be connected to the calibration module 210, so that the forward output channel module 120 outputs voltage points evenly distributed within the low voltage range, and reads the current data at each voltage point through the current measurement channel module 130; based on the current data and the corresponding expected current value, the calibration parameters of each current range are calculated.

[0052] like Figure 2 As shown, the host computer 220 can send instructions to the controller U1, and the controller U1 directly controls the switches K1, K2, and K3 to be disconnected, and the switches K4 and K5 to be closed, and the switches HF, LF, HS, and LS are controlled to be switched to the calibration module 210, and the sampling resistor R1 is closed, and a suitable load resistor is selected in the calibration module 210. , set the channel working mode to FVMI, and output ± Vcal N uniformly distributed voltage points (V1, V2, ..., V N ), read M current data at each voltage point through the MI function, use the golbus algorithm to check the M current data, remove the points with large deviation, take the average of the remaining data as the current measurement value, and collect the measurement values ​​of N voltage points in sequence (Imeas1, Imeas2, ..., Imeas N The calibration module 210 uses the same method as MI, using the high-precision voltage measurement module inside the calibration module 210 to measure the actual current value of the calibration programmable resistor network, and measures the corresponding N actual currents (Iact1, Iact2, ..., Iact N ) is used as the expected current value, and the upper computer 220 uses the least squares method to calculate the calibration parameters such as formula (1-1) and formula (1-2).

[0053] (1-1)

[0054] (1-2)

[0055] Repeat the accuracy calibration of the current ranges corresponding to all sampling resistors in turn, and obtain the calibration parameters of the corresponding range MI and FI as follows: , . In addition, the same method can be used to calibrate the calibration parameters of the corresponding ranges FV and MV. The above calibration parameters include gain and offset. The upper computer 220 sends the calculated gain and offset parameters of each range to the controller U1 and saves them in the memory U10. Furthermore, the upper computer 220 can also encode the gain and offset, and send the encoded data and CRC checksum to the controller U1, and save them in the memory U10.

[0056] In one embodiment, the compensation reference data includes a compensation coefficient Km The control module 110 can control the channel switching module 150 to connect to the calibration module 210, so that the forward output channel module 120 outputs voltage points evenly distributed within the maximum voltage range, and reads the current data at each voltage point through the current measurement channel module 130. Then, the host computer 220 calculates the compensation coefficient based on the voltage point and the current data read at each voltage point. Km Specifically, use FVMI to measure and calculate the compensation coefficient within the maximum voltage range. Km The process is as follows:

[0057] like Figure 2 As shown, the host computer 220 sends a command to the controller U1, and the controller U1 directly controls the switch K1 and the switch K2 to be closed, the switch K3 to be opened, the switch K4 and the switch K5 to be closed, and the switch HF, the switch LF, the switch HS, and the switch LS to be switched to the calibration module 210, and the maximum current range gear is selected (the sampling resistor R3 is connected), the calibration module 210 circuit is unloaded and not connected to the load, and the channel working mode is set to the FVMI mode, and the FV output is used to output N uniformly distributed voltage points (V1, V2, ..., V N ), read M current data at each voltage point through the MI function, use the golbus algorithm to check the M current data, remove the points with large deviation, take the average value of the remaining current data as the current measurement value, and get the current values ​​of N voltage points in turn (Imeas1, Imeas2, ..., Imeas N ), the host computer 220 uses the least squares method to calculate the compensation coefficient Km As shown in formula (1-3).

[0058] (1-3)

[0059] The host computer 220 sets the compensation coefficient Km The compensation coefficient is sent to the controller U1 and saved in the memory U10. Km Encoding is performed, and the encoded data and CRC checksum are sent to the controller U1 and saved in the memory U10.

[0060] In one embodiment, the compensation reference data includes a range factor Ktap , range coefficient Ktap It can be calculated based on the maximum values ​​of different ranges of the current measurement channel module 130 and the corresponding gains.

[0061] like Figure 2 As shown, the range coefficient can be calculated based on the MI range and signal conditioning ratio. Ktap , the gain between the sampling resistor R (R1 / R2 / R3) and the analog-to-digital converter U2 is G (G1 / G2 / G3), and the maximum value of the range is Imax (Imax1 / Imax2 / Imax3), then the range coefficient Ktap As shown in formula (1-4), i corresponds to different current ranges.

[0062] (1-4)

[0063] The host computer 220 sets the range coefficient Ktap The upper computer 220 can also send the range coefficient to the controller U1 and save it in the memory U10. Ktap Encoding is performed, and the encoded data and CRC checksum are sent to the controller U1 and saved in the memory U10.

[0064] In one embodiment, the compensation reference data includes the high-side line resistance R H and low-side line resistance R L The control module 110 can control the channel switching module 150 to connect to the load RLOAD, so that the forward output channel module 120 outputs the set current and obtains the measured voltage of the voltage measurement channel module 140. Then, the host computer 220 calculates the high-end line resistance according to the set current and the measured voltage. R H and low-side line resistance R L .

[0065] Specifically, low voltages (± Vcal ) range, use FIMV to measure and calculate the high-side line resistance R H and low-side line resistance RL The measured voltage may include a first measured voltage Vl and a second measured voltage Vh, which are used to calculate the corresponding low-end line resistance. R L And high-side line resistance R H .like Figure 2 As shown, the host computer 220 sends instructions to the controller U1, and the controller U1 directly controls switches K1, K2, K3, and K5 to close, and switches K4 to open, and controls switches HF and HS to switch to the load RLOAD, selects the mA current range, sets the working mode to FIMV, sets the FI output current I to 1mA, uses the MV function test to obtain the second measurement voltage Vh, and calculates the high-end line resistance R H =Vh / I; control switches K1, K2, K3, and K4 to be closed, switch K5 to be opened, and switches LS and LF to be switched to load RLOAD (switches HF and HS can be switched to load RLOAD or kept open. In this embodiment, switches HF and HS are kept open as an example for explanation). Use MV function test to obtain the first measured voltage Vl, and calculate the low-end line resistance R L =V1 / I. The host computer 220 sets the high-end line resistance R H and low-side line resistance R L The data is sent to the controller U1 and stored in the memory U10. R H and low-side line resistance R L Encoding is performed, and the encoded data and CRC checksum are sent to the controller U1 and saved in the memory U10.

[0066] After the control module 110 saves the compensation reference data, when the current needs to be measured or the output current is needed in actual use, the method of combining the compensation reference data to perform current compensation is not unique. In one embodiment, when measuring the current, the control module 110 calculates the common mode voltage according to the current measurement value, the voltage measurement value, the high-end line resistance and the low-end line resistance; and calculates the compensated current according to the current measurement value, the common mode voltage, the compensation coefficient and the range coefficient.

[0067] Specifically, when measuring current, the control module 110 measures voltage and current simultaneously, and calculates the compensated current by combining the high-end line resistance and the low-end line resistance, the range coefficient and the compensation coefficient, thereby improving the MI accuracy. Figure 2As shown, the host computer 220 sends instructions to the controller U1, and the controller U1 directly controls the switches K1, K2, and K3 to be disconnected, and the switches K4 and K5 to be closed, and controls the switches HF, LF, HS, and LS to be switched to the load RLOAD, and the sampling resistor Ri to be closed (switched to the current range of actual application), and the full-scale values ​​of the voltage and current are respectively Vcal and Ical , set the channel working mode to FXMI mode, control FI or FV to output within the range, and read the voltage measurement value by the controller U1 or the host computer 220 Vdut , current measurement value Ioriginal , then the common mode voltage Vcm The calculation is shown in formula (1-5).

[0068] (1-5)

[0069] Compensated current Imeas As shown in formula (1-6).

[0070] (1-6)

[0071] Furthermore, when outputting current, the control module 110 calculates the common mode voltage according to the current measurement value, the voltage measurement value, the high-end line resistance and the low-end line resistance; and calculates the compensated set current according to the set current value, the common mode voltage, the compensation coefficient and the range coefficient. After obtaining the compensated set current, the control module 110 controls the output current of the forward output channel module according to the compensated set current, for example, using the compensated set current as a new set value, and using the difference between the current measurement value and the new set value as an error, and using the PID control algorithm to adjust the forward channel output, thereby improving the FI accuracy.

[0072] Specifically, when outputting current, the control module 110 measures the voltage and current simultaneously, and calculates the compensated set value by combining the high-end line resistance and the low-end line resistance, the range coefficient and the compensation coefficient. Figure 2 As shown, the host computer 220 sends a command to the controller U1, and the controller U1 directly controls the switches K1, K2, and K3 to be disconnected, and the switches K4 and K5 to be closed, and the switches HF, LF, HS, and LS are controlled to be switched to the load RLOAD, and the sampling resistor Ri is closed (switched to the current range of actual application), and the channel working mode is set to FIMX mode, and the FI is controlled to output the set current value Iset within the range, and the controller U1 cyclically reads the voltage measurement value. Vdut , current measurement value Ioriginal , then the common mode voltage Vcm The calculation is shown in formula (1-7).

[0073] (1-7)

[0074] Compensated set current I As shown in formula (1-8).

[0075] (1-8)

[0076] In one embodiment, Figure 3 As shown, a method for compensating the accuracy of a power board is also provided, including:

[0077] Step S110: When measuring current, control the channel switching module to connect to the load, so that the forward output channel module outputs a test signal to the load, and reads the current measurement value of the current measurement channel module and the voltage measurement value of the voltage measurement channel module, and performs current compensation based on the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated current.

[0078] Step S120: When outputting current, control the channel switching module to connect to the load, so that the forward output channel module outputs current to the load according to the set current value, read the current measurement value of the current measurement channel module, and the voltage measurement value of the voltage measurement channel module, and compensate the set current value according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated set current, and control the output current of the forward output channel module according to the compensated set current.

[0079] The compensation reference data is calculated based on the measurement data of the current measurement channel module and the voltage measurement channel module when the channel switching module is connected to the calibration module or the load. The compensation reference data may specifically include the compensation coefficient, the range coefficient, the high-end line resistance and the low-end line resistance. The range coefficient is calculated based on the maximum value of different ranges of the current measurement channel module and the corresponding gain.

[0080] In one embodiment, in step S110, current compensation is performed based on the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated current, including: calculating the common mode voltage based on the current measurement value, voltage measurement value, high-end line resistance and low-end line resistance; calculating the compensated current based on the current measurement value, common mode voltage, compensation coefficient and range coefficient.

[0081] In one embodiment, in step S120, the set current value is compensated according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated set current, including: calculating the common mode voltage according to the current measurement value, voltage measurement value, high-end line resistance and low-end line resistance; calculating the compensated set current according to the set current value, common mode voltage, compensation coefficient and range coefficient.

[0082] In one embodiment, the method also includes: controlling the channel switching module to access the calibration module so that the forward output channel module outputs voltage points evenly distributed within the maximum voltage range, and reading current data at each voltage point through the current measurement channel module; and calculating the compensation coefficient based on the voltage point and the current data read at each voltage point.

[0083] In one embodiment, the method further includes: controlling the channel switching module to access the load so that the forward output channel module outputs a set current and obtains a measured voltage of the voltage measurement channel module; and calculating the high-end line resistance and the low-end line resistance based on the set current and the measured voltage.

[0084] In one embodiment, the method further includes: when the control channel switching module is connected to the calibration module, the accuracy of each current range is calibrated.

[0085] It can be understood that the specific embodiment of the accuracy compensation method of the above-mentioned power board card has been explained in detail in the above-mentioned power board card, and will not be repeated here.

[0086] In one embodiment, a testing machine is provided, including a host computer and the above-mentioned power board.

[0087] like Figure 4 As shown, the accuracy compensation method of the power board provided by the present application firstly Vcal ) condition, the current measurement value is calibrated, and the corresponding calibrated voltage and current full-scale values ​​are Vcal and Ical Then the compensation factor is measured and calculated under no-load conditions by the FVMI function. Km , calculate the range coefficient based on the current range and signal conditioning ratio on the hardware Ktap Each time the tester connection line changes, the board's own FIMV function measures and calculates the high-end line resistance under the same voltage and current conditions as the calibration. R H and low-side line resistance R L Finally, when measuring current, both voltage and current are measured simultaneously. Ioriginal , combined with high-side line resistance R H and low-side line resistance R L , calibrate the full scale value Vcal and Ical Calculate the common mode voltage Vcm , then the measured current value after compensation ; When outputting current, the control loop continuously compensates the set value according to the measured voltage . After compensation, the current output and measurement accuracy can be kept consistent with the calibration accuracy within a larger voltage range. This solution only calculates the compensation coefficient in the largest current range. Through the range coefficient, other current ranges can be used to improve efficiency. The line resistance is taken into account when performing compensation calculations to improve compensation accuracy. In the process of calculating calibration parameters and compensation coefficients, each data point uses a test function to filter out data with large deviations, and then takes the average value of the remaining data, which improves the stability of the calibration parameters and compensation coefficients.

[0088] The accuracy compensation method of the power board has the following advantages:

[0089] 1. After compensation, the current output and current measurement have high accuracy in the full voltage range.

[0090] 2. The compensation coefficient only needs to be measured and calculated in the maximum current range. Other current ranges can be used by using the range coefficient.

[0091] 3. The influence of line resistance during actual testing is taken into account, especially when the current is large, and the compensation accuracy is also high.

[0092] 4. The compensation coefficient is valid for both current output and current measurement.

[0093] 5. The compensation process can be based on the hardware function modules of the power board itself, without adding new common-mode error compensation hardware circuits.

[0094] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A power board, characterized in that: It includes a control module, a forward output channel module, a current measurement channel module, a voltage measurement channel module and a channel switching module, wherein the control module is connected to the forward output channel module, the current measurement channel module, the voltage measurement channel module and the channel switching module, the forward output channel module is connected to the current measurement channel module, and the channel switching module is connected to the current measurement channel module, the voltage measurement channel module and a load; The control module is used to control the channel switching module to connect to the load when measuring current, so that the forward output channel module outputs a test signal to the load, and reads the current measurement value of the current measurement channel module and the voltage measurement value of the voltage measurement channel module; and performing measurement current compensation according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain compensated current; The control module is also used to control the channel switching module to connect to the load when outputting current, so that the forward output channel module outputs current to the load according to the set current value, and reads the current measurement value of the current measurement channel module and the voltage measurement value of the voltage measurement channel module; and compensating the set current value according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain a compensated set current, and controlling the output current of the forward output channel module according to the difference between the compensated set current and the current measurement value; Wherein, the compensation reference data is calculated based on the measurement data of the current measurement channel module and the voltage measurement channel module when the channel switching module is connected to the calibration module or the load; The channel switching module includes a switch HF, a switch LF, a switch HS, a switch LS, a switch K1, a switch K2, a switch K3, a switch K4 and a switch K5; the first end of the switch K1 is connected to the current measurement channel module and the static contact of the switch HF, the second end of the switch K1 is connected to the voltage measurement channel module and the first end of the switch K4, the first moving contact of the switch HF is connected to the first end of the calibration module, the second moving contact of the switch HF is connected to the first end of the load, the second end of the switch K4 is connected to the first end of the switch K3 and the static contact of the switch HS, and the first moving contact of the switch HS is connected The first end of the calibration module and the second moving contact of the switch HS are connected to the first end of the load; the first end of the switch K2 is connected to the voltage measurement channel module and the first end of the switch K5, the second end of the switch K2 is connected to the ground end and the static contact of the switch LF, the first moving contact of the switch LF is connected to the second end of the calibration module, the second moving contact of the switch LF is connected to the second end of the load, the second end of the switch K5 is connected to the second end of K3 and the static contact of the switch LS, the first moving contact of the switch LS is connected to the second end of the calibration module, and the second moving contact of the switch LS is connected to the second end of the load; The compensation reference data includes a compensation coefficient, a range coefficient, a high-end line resistance and a low-end line resistance; the range coefficient is calculated according to the maximum value of different ranges of the current measurement channel module and the corresponding gain; The control module controls the switch K1 and the switch K2 in the channel switching module to be closed, the switch K3 to be opened, the switch K4 and the switch K5 to be closed, and the switches HF, LF, HS, and LS to be switched to the calibration module, so that the forward output channel module outputs voltage points evenly distributed within the maximum voltage range, and reads the current data at each voltage point through the current measurement channel module; and calculates the compensation coefficient according to the voltage point and the current data read at each voltage point; The control module controls switches K1, K2, K3, and K4 in the channel switching module to be closed, switch K5 to be disconnected, switches LS and LF to be switched to the load, so that the forward output channel module outputs a set current, and obtains a first measured voltage of the voltage measurement channel module; controls switches K1, K2, K3, and K5 in the channel switching module to be closed, switch K4 to be disconnected, switches HF and HS to be switched to the load, so that the forward output channel module outputs a set current, and obtains a second measured voltage of the voltage measurement channel module; and calculates a high-end line resistance and a low-end line resistance according to the set current and the first measured voltage and the second measured voltage.

2. The power board according to claim 1, characterized in that: The control module includes a controller and a memory, and the controller is connected to the forward output channel module, the current measurement channel module, the voltage measurement channel module, the channel switching module and the memory; when the controller controls the channel switching module to access the calibration module or the load, the measurement data of the current measurement channel module and the voltage measurement channel module are obtained and sent to the host computer, and the compensation reference data calculated by the host computer according to the measurement data is received and stored in the memory.

3. The power board according to claim 1, characterized in that: The forward output channel module includes a digital-to-analog conversion module U5 and a gain programmable power amplifier module U6. The digital-to-analog conversion module U5 is connected to the control module and the gain programmable power amplifier module U6. The gain programmable power amplifier module U6 is connected to the current measurement channel module.

4. The power board according to claim 1, characterized in that: The current measurement channel module includes an analog-to-digital conversion module U2, a gain programmable operational amplifier module U3, a subtractor U4 and a gear adjustment circuit, the gear adjustment circuit is connected to the forward output channel module, the channel switching module and the control module, the subtractor U4 is connected to the gear adjustment circuit and the gain programmable operational amplifier module U3, and the analog-to-digital conversion module U2 is connected to the gain programmable operational amplifier module U3 and the control module.

5. The power board according to claim 1, characterized in that: The voltage measurement channel module includes an analog-to-digital conversion module U7, a gain programmable operational amplifier module U8 and a subtractor U9, the subtractor U9 is connected to the channel switching module and the gain programmable operational amplifier module U8, and the analog-to-digital conversion module U7 is connected to the gain programmable operational amplifier module U8 and the control module.

6. The power board according to claim 1, characterized in that: The control module calculates the common mode voltage according to the current measurement value, the voltage measurement value, the high-end line resistance and the low-end line resistance; The compensated current is calculated according to the current measurement value, the common mode voltage, the compensation coefficient and the range coefficient; and / or The control module calculates the common mode voltage according to the current measurement value, the voltage measurement value, the high-end line resistance and the low-end line resistance; and calculates the compensated set current according to the set current value, the common mode voltage, the compensation coefficient and the range coefficient.

7. A method for compensating the accuracy of a power board, characterized in that: include: When measuring current, the channel switching module is controlled to connect to the load, so that the forward output channel module outputs a test signal to the load, and the current measurement value of the current measurement channel module and the voltage measurement value of the voltage measurement channel module are read, and the measured current compensation is performed according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated current; When outputting current, controlling the channel switching module to connect to the load, so that the forward output channel module outputs current to the load according to the set current value, reading the current measurement value of the current measurement channel module and the voltage measurement value of the voltage measurement channel module, compensating the set current value according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain a compensated set current, and controlling the forward output channel module to output current according to the difference between the compensated set current and the current measurement value; Wherein, the compensation reference data is calculated based on the measurement data of the current measurement channel module and the voltage measurement channel module when the channel switching module is connected to the calibration module or the load; The channel switching module includes a switch HF, a switch LF, a switch HS, a switch LS, a switch K1, a switch K2, a switch K3, a switch K4 and a switch K5; the first end of the switch K1 is connected to the current measurement channel module and the static contact of the switch HF, the second end of the switch K1 is connected to the voltage measurement channel module and the first end of the switch K4, the first moving contact of the switch HF is connected to the first end of the calibration module, the second moving contact of the switch HF is connected to the first end of the load, the second end of the switch K4 is connected to the first end of the switch K3 and the static contact of the switch HS, and the first moving contact of the switch HS is connected The first end of the calibration module and the second moving contact of the switch HS are connected to the first end of the load; the first end of the switch K2 is connected to the voltage measurement channel module and the first end of the switch K5, the second end of the switch K2 is connected to the ground end and the static contact of the switch LF, the first moving contact of the switch LF is connected to the second end of the calibration module, the second moving contact of the switch LF is connected to the second end of the load, the second end of the switch K5 is connected to the second end of K3 and the static contact of the switch LS, the first moving contact of the switch LS is connected to the second end of the calibration module, and the second moving contact of the switch LS is connected to the second end of the load; The compensation reference data includes a compensation coefficient, a range coefficient, a high-end line resistance and a low-end line resistance; the range coefficient is calculated according to the maximum value of different ranges of the current measurement channel module and the corresponding gain; the method also includes: Control switches K1 and K2 in the channel switching module to close, switch K3 to open, switch K4 and K5 to close, and switches HF, LF, HS, and LS to switch to the calibration module, so that the forward output channel module outputs voltage points evenly distributed within the maximum voltage range, and reads current data at each voltage point through the current measurement channel module; calculate the compensation coefficient according to the voltage point and the current data read at each voltage point; Control switches K1, K2, K3, and K4 in the channel switching module to be closed, switch K5 to be disconnected, switches LS and LF to be switched to the load, so that the forward output channel module outputs a set current, and obtains a first measurement voltage of the voltage measurement channel module; control switches K1, K2, K3, and K5 in the channel switching module to be closed, switch K4 to be disconnected, switches HF and HS to be switched to the load, so that the forward output channel module outputs a set current, and obtains a second measurement voltage of the voltage measurement channel module; and calculates a high-end line resistance and a low-end line resistance according to the set current and the first measurement voltage and the second measurement voltage.

8. The method according to claim 7, characterized in that The method of performing current compensation according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated current includes: calculating the common mode voltage according to the current measurement value, voltage measurement value, high-end line resistance and low-end line resistance; calculating the compensated current according to the current measurement value, common mode voltage, compensation coefficient and range coefficient; wherein the common mode voltage Vcm is: ， Compensated current Imeas for: ， in, Vcal、Ical is the full-scale value of voltage and current, R H is the high-side line resistance, R L is the low-end line resistance; Km is the compensation coefficient, Ktap i is the range coefficient of current range i; and / or The method of compensating the set current value according to the read current measurement value, voltage measurement value and preset compensation reference data to obtain the compensated set current includes: calculating the common mode voltage according to the current measurement value, voltage measurement value, high-end line resistance and low-end line resistance; calculating the compensated set current according to the set current value, common mode voltage, compensation coefficient and range coefficient; wherein the common mode voltage Vcm is: ， Compensated set current I for: ， in, Vcal、Ical is the full-scale value of voltage and current, R H is the high-side line resistance, R L is the low-end line resistance; Km is the compensation coefficient, Ktap i is the range coefficient of the current range i, Iset To set the current value.

9. The method according to claim 7, characterized in that: The calculation formula of the range coefficient is: ， in, Ktap i is the range coefficient of the current range i; G1 / G2 / G3 is the gain between the sampling resistor R1 / R2 / R3 and the analog-to-digital converter, the sampling resistor R1, the sampling resistor R2, and the sampling resistor R3 correspond to the current ranges from small to large, respectively, and Imax1 / Imax2 / Imax3 is the maximum value of the corresponding current range.

10. The method according to claim 9, characterized in that The step of calculating the compensation coefficient according to the voltage points and the current data read at each of the voltage points includes: ， in, Km is the compensation coefficient, V1, V2, ..., V N are N uniformly distributed voltage points Imeas1, Imeas2, ..., Imeas N are the current values ​​of N voltage points obtained sequentially.

11. The method according to claim 9, characterized in that The calculating the high-end line resistance and the low-end line resistance according to the set current and the first measured voltage and the second measured voltage includes: R H =Vh / I, R L =Vl / I in, R H is the high-side line resistance, R L is the low-end line resistance, Vl is the first measurement voltage, Vh is the second measurement voltage, and I is the set current.

12. The method according to claim 7, characterized in that Also includes: When the channel switching module is controlled to be connected to the calibration module, the accuracy of each current range is calibrated, specifically including: after the channel switching module is controlled to be connected to the calibration module, the forward output channel module outputs voltage points evenly distributed within the low voltage range, and reads the current data at each voltage point through the current measurement channel module; The calibration parameters of each current range are calculated based on the current data and the corresponding current expected value.

13. A testing machine, characterized in that: It comprises a host computer and a power board card as described in any one of claims 1 to 6.

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