A PMU and reference voltage source dual-function circuit based on ATE testing

Abstract

The present application relates to the technical fields of semiconductor automation testing, in particular to a PMU and reference voltage source dual-function circuit based on ATE testing, comprising an AD5522 chip, a function switching module, a multi-DUT expansion module, a precision optimization module and a control module; the whole adopts single chip function multiplexing design, solves the pain point of large PCB space occupation, achieves the effect of significant space reduction, adopts single PMU multi-DUT expansion design, solves the pain point of high DUT test cost, achieves the effect of significant test cost reduction, adopts Kelvin four-wire and feedback closed loop design, solves the problem of low reference voltage precision, adopts relay switching and programming control design, solves the problem of poor function flexibility.

Description

Technical Field

[0001] This invention relates to the field of semiconductor automated testing technology, specifically to a dual-function circuit based on ATE testing, consisting of a PMU and a reference voltage source. Background Technology

[0002] In the semiconductor design, manufacturing, and packaging processes, automated test equipment (ATE) is crucial for ensuring product yield and quality, and its core performance directly determines the accuracy of test results. Within an ATE system, the reference voltage source and the power supply unit (PMU) are the two core modules ensuring test accuracy. The former provides a stable reference voltage for testing, and current technologies mainly include high-precision bandgap reference voltage sources, parallel (Zener) reference voltage sources, series reference voltage sources, and ultra-precision reference voltage sources, requiring independent circuit design based on test voltage requirements. The latter is responsible for accurately measuring DC parameters of the DUT pins, supporting two core modes: "Drive Voltage to Current Measurement (FVMI)" and "Drive Current to Voltage Measurement (FIMV)." It typically includes a high-precision current source, voltmeter, range switching circuit, and protection circuit, requiring dedicated PCB space.

[0003] As semiconductor feature sizes shrink and testing requirements upgrade, users increasingly demand multi-channel, highly integrated, and low-cost ATE equipment, leading to significant limitations in existing technologies: On the one hand, PMUs and reference voltage sources require independent circuit design, which, if covering commonly used test voltages and multi-channel requirements, occupies a large amount of PCB space, making it difficult to meet the needs of highly integrated board designs; on the other hand, in multi-DUT testing scenarios, independent PMU resources need to be configured according to the number of DUTs, resulting in increased waste of test resources and rising costs, making it difficult to meet traditional testing needs.

[0004] In summary, the independent design mode of PMU and reference voltage source in existing ATE test boards cannot meet the test requirements of high integration, low cost and high precision. Therefore, this invention provides a dual-function circuit of PMU and reference voltage source based on ATE test. Summary of the Invention

[0005] This invention aims to provide a dual-function circuit for PMU and reference voltage source based on ATE testing. The overall design adopts a single-chip function reuse design, which solves the problem of large PCB space occupation and achieves a significant space reduction effect. The single-channel PMU multi-DUT expansion design solves the problem of high DUT testing cost and achieves a significant reduction in testing cost. The Kelvin four-wire and feedback closed-loop design solves the problem of low reference voltage accuracy. The relay switching and programmable control design solves the problem of poor functional flexibility.

[0006] The present invention solves the above-mentioned technical problems through the following technical invention: a dual-function circuit of PMU and reference voltage source based on ATE test, including AD5522 chip, function switching module, multi-DUT expansion module, accuracy optimization module and control module;

[0007] The AD5522 chip has 4 PMU output channels, 4 high-level measurement channels, and 4 DUT grounding channels;

[0008] The function switching module is a relay group RL1-RL5, where RL1-RL4 correspond to 4 PMU output channels respectively, and are used to switch the channel function to PMU output or reference voltage source output. RL5 is used to switch the connection between the high-level measurement channel and the reference voltage source output terminal.

[0009] The multi-DUT expansion module is a 1:4 analog switch, with each analog switch corresponding to a PMU output terminal, used to expand the single-channel PMU resource to 4 DUTs;

[0010] The accuracy optimization module includes a first operational amplifier M1, a second operational amplifier F1, and a DAC1, which, together with the high-level measurement channel of the AD5522 and the DUT grounding channel, form a Kelvin four-wire connection.

[0011] The control module is used to configure the AD5522 chip parameters and to control the switching between the relay group and the analog switch through the function switching module.

[0012] Preferably, in the PMU function mode, the control module drives RL1-RL4 to switch to the PMU output position and RL5 to disconnect. The PMU output channel of the AD5522 chip is connected to the PMU output terminal through RL1-RL4. The measurement terminal of the AD5522 chip merges with the PMU output terminal to form an FVMI or FIMV test closed loop.

[0013] Preferably, in the PMU function mode, the output voltage range of the AD5522 chip is configured to -2.5V to 6.5V, the voltage measurement range is configured to ±12.5V, and the current output / measurement range is configured to ±5uA, ±20uA, ±200uA, ±2mA, or ±40mA through programming via the control module.

[0014] Preferably, in the reference voltage source function mode, the control module drives RL1-RL4 to switch to the reference voltage output position and RL5 to close. The PMU output channel of the AD5522 chip is connected to the output terminal of the reference voltage source through RL1-RL4. The high-level measurement channel is connected to the connection point between the output terminal of the reference voltage source and the DUT through RL5. The DUT grounding channel is connected to the low-level terminal of the DUT and the system ground, forming a Kelvin four-wire connection.

[0015] Preferably, in the accuracy optimization module, the first operational amplifier M1 is used to calculate the difference between the voltage acquired by the high-level measurement channel and the voltage acquired by the DUT grounding channel to obtain the true voltage across the DUT. The second operational amplifier F1 feeds back the true voltage to DAC1, and adjusts the output voltage of the AD5522 chip through DAC1 so that the voltage at the output terminal of the reference voltage source approaches the set value of DAC1.

[0016] Preferably, in the reference voltage source function mode, the output voltage configuration range of the reference voltage source output terminal is 0-6V, and the output error is ≤±300uV, through programming of the control module.

[0017] Preferably, in the DUT expansion module, each PMU output is connected to four DUTs via a single 1:4 analog switch, and the control module achieves time-sharing testing of the four DUTs using a single PMU resource by switching the analog switch.

[0018] Preferably, the relay group uses DC relays with a response time of ≤1ms, and the analog switch uses a single-ended analog switch with an on-resistance of ≤5Ω.

[0019] Preferably, the operational amplifier in the precision optimization module is a low-offset operational amplifier with an offset voltage ≤10uV, and DAC1 is a digital-to-analog converter with at least 16-bit precision.

[0020] Preferably, the control module is a microcontroller or FPGA, which communicates with the AD5522 chip and DAC1 through the SPI interface, and controls the on / off state of the relay group and analog switch through the GPIO port.

[0021] The positive and progressive effects of this invention are as follows:

[0022] 1. By integrating the PMU and reference voltage source functions through the AD5522 chip and relay switching, the two circuits do not need to be designed separately, significantly reducing the PCB space occupied. A single PMU can be expanded to 4 DUTs through a 1:4 analog switch, reducing the PMU resource requirements in multi-DUT testing scenarios and significantly reducing the cost of the test board.

[0023] 2. The core chip AD5522 of this invention, combined with peripheral relay circuits and Fanout circuits, can realize a dual-function circuit. For many designs with high PCB space requirements, this circuit can significantly reduce the PCB space required while achieving the dual functions of a PMU and a reference voltage source. Furthermore, due to the flexible switching of the circuit, the PMU resources can be greatly improved, and the accuracy of the reference voltage source can also be greatly improved through the Kelvin four-wire connection. The PMU's FV accuracy can reach within ±1mV, and the MV accuracy can reach within ±2mV. Under different current levels, the FI / MI error is within 0.02%. The reference voltage source error is ±300uV within the range of 0V to 6V. Attached Figure Description

[0024] Figure 1 The basic framework diagram of the dual-function circuit provided by the present invention.

[0025] Figure 2 This is a schematic diagram of the circuit connection and multiple DUT expansion in the PMU functional mode provided by the present invention.

[0026] Figure 3 The detailed circuit connection diagram for the single-channel PMU function provided by this invention is shown below.

[0027] Figure 4 The detailed circuit connection diagram of the single-channel reference voltage source provided by this invention is shown below. Detailed Implementation

[0028] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments.

[0029] See Figures 1 to 4 A dual-function circuit based on ATE testing, comprising an AD5522 chip, a function switching module, a multi-DUT expansion module, a precision optimization module, and a control module;

[0030] The AD5522 chip has 4 PMU output channels, 4 high-level measurement channels, and 4 DUT grounding channels;

[0031] The function switching module is a relay group RL1-RL5, where RL1-RL4 correspond to 4 PMU output channels respectively, and are used to switch the channel function to PMU output or reference voltage source output. RL5 is used to switch the connection between the high-level measurement channel and the reference voltage source output terminal.

[0032] The multi-DUT expansion module is a 1:4 analog switch, with each analog switch corresponding to a PMU output terminal;

[0033] The precision optimization module includes a first operational amplifier M1, a second operational amplifier F1, and a DAC1;

[0034] The control module is used to configure the AD5522 chip parameters and to control the on / off switching between the relay group and the analog switch through the function switching module.

[0035] The dual-function circuit can switch between PMU function mode and reference voltage source function mode.

[0036] In the DUT expansion module, each PMU output is connected to four DUTs via a single 1:4 analog switch. The control module switches the analog switches to enable time-sharing testing of the four DUTs using a single PMU resource.

[0037] The relay group uses DC relays with a response time of ≤1ms, and the analog switch uses a single-ended analog switch with an on-resistance of ≤5Ω.

[0038] The operational amplifier in the precision optimization module is a low-offset operational amplifier with an offset voltage ≤10uV, and DAC1 is a digital-to-analog converter with at least 16-bit precision.

[0039] In the accuracy optimization module, the first operational amplifier M1 is used to calculate the difference between the voltage acquired by the high-level measurement channel and the voltage acquired by the DUT grounding channel to obtain the true voltage across the DUT. The second operational amplifier F1 feeds back the true voltage to DAC1, and adjusts the output voltage of the AD5522 chip through DAC1 so that the voltage at the output of the reference voltage source approaches the set value of DAC1.

[0040] It should be noted that in the attached diagram, RL is a relay, VREF is a reference voltage input / output, AS is a dedicated application module, which is a dedicated control element of the test system, DUT is the device under test, B is the control / data transmission channel between PMU and AS, EXTOH1 is a high current range forced output, FOH1 is a standard current range forced output, and MEASVH1 is a high potential measurement terminal.

[0041] The control module is a microcontroller or FPGA, which communicates with the AD5522 chip and DAC1 through the SPI interface, and controls the on / off state of the relay group and analog switch through the GPIO port.

[0042] In practical operation, the core chip is the AD5522 four-channel high-precision PMU chip from Analog Devices (ADI), the relay is the Panasonic TX2-5V relay, the analog switch is the ADG731 single-ended analog switch from Analog Devices (ADI), the operational amplifier is the OPA277 low offset voltage operational amplifier from TI, the DAC1 is the AD5686 high-precision DAC from Analog Devices (ADI), and the control module is the STM32F407 microcontroller.

[0043] In the PMU function mode, the control module drives RL1-RL4 to switch to the PMU output position and RL5 to disconnect. The PMU output channel of the AD5522 chip is connected to the PMU output terminal through RL1-RL4. The measurement terminal of the AD5522 chip merges with the PMU output terminal to form an FVMI or FIMV test closed loop.

[0044] The control module communicates with the AD5522 chip to configure the working mode, range and protection limit, and outputs relay drive timing and analog switch selection control signals. The drive timing satisfies the switching order of disconnecting first and then turning on, and maintains the output node in a controlled blocking state within the switching window to suppress the impact of channel switching transients on the port of the device under test.

[0045] In the PMU function mode, RL1 to RL4 connect the PMU output channels of AD5522 to the common terminal of the multi-DUT expansion module. The output signal is sent to the target device under test port after being selected by the corresponding 1:4 analog switch. In the reference voltage source function mode, RL1 to RL4 switch at least one PMU output channel to the input terminal of the accuracy optimization module and drive the reference voltage source output node by the accuracy optimization module. RL5 connects the high-level measurement channel to the reference voltage source output node. The control module performs closed-loop adjustment on the output of DAC1 based on the sampling result of the high-level measurement channel, so that the reference voltage source output node is consistent with the target reference value. The DUT grounding channel is connected to the return terminal of the target device under test port to form a controlled return path and reduce the measurement and output errors introduced by the return impedance. This invention uses the high-level measurement channel to sample the reference output node in real time, and the control module performs closed-loop adjustment on the DAC fine-tuning path to cover the deviation caused by temperature drift and long-term drift.

[0046] In the PMU function mode, the AD5522 chip's output voltage range can be configured to -2.5V to 6.5V, the voltage measurement range to ±12.5V, and the current output / measurement range to ±5uA, ±20uA, ±200uA, ±2mA, or ±40mA through programming via the control module.

[0047] In actual operation, the control module sends configuration commands to the AD5522, setting the function mode to "PMU", the output voltage range to -2.5V to 6.5V, the current range to ±40mA, and the voltage measurement to ±12.5V. The control module drives RL1-RL4 to switch to the "PMU output" position, and RL5 is disconnected. The FOH1 channel of the AD552 outputs the set voltage / current to PMU_FORCE1. PMU_MEASURE1 and EXTFOH1 converge at point A, and the voltage / current across the DUT is measured in real time. The control module drives the ADG731 analog switch to switch to the four DUTs in sequence, realizing time-sharing testing of the four DUTs by a single PMU. The test data is uploaded to the control module through the SPI interface of the AD5522 to complete data storage and analysis.

[0048] In the reference voltage source function mode, the control module drives RL1-RL4 to switch to the reference voltage output position and RL5 to close. The PMU output channel of the AD5522 chip is connected to the output terminal of the reference voltage source through RL1-RL4. The high-level measurement channel is connected to the connection point between the output terminal of the reference voltage source and the DUT through RL5. The DUT grounding channel is connected to the low-level terminal of the DUT and the system ground, forming a Kelvin four-wire connection.

[0049] In the reference voltage source function mode, the output voltage configuration range of the reference voltage source output terminal is 0-6V, and the output error is ≤±300uV, through the control module programming.

[0050] In actual operation, the control module sends a configuration command to the AD5522, setting the function mode to "reference voltage source" with an output voltage range of 0-6V. The control module drives RL1-RL4 to switch to the "reference voltage output" position, RL5 closes, and DAC1 outputs the set voltage. The FOH1 channel of the AD5522 outputs to VREF1 through RL1. VREF1 is connected to the high-level terminal VOL1 of the DUT. OPA277 (M1) calculates VOH1-VOL1 to obtain the actual voltage across the DUT. This voltage is fed back to DAC1 through OPA277 (F1). DAC1 adjusts the output voltage according to the feedback, making VREF1 infinitely close to the set value, ultimately ensuring that the voltage error across the DUT is ≤±300uV. By repeating the above steps, high-precision output of any reference voltage within the 0-6V range can be achieved.

[0051] The results of testing the PMU and reference voltage source functions in the circuit of this embodiment are as follows:

[0052] Table 1 Test Results

[0053]

[0054] Example 1:

[0055] When this invention functions as a PMU, taking one channel as an example, the output channel of the AD5522, FOH1, can be switched via an RL1 relay. PMU_FPRCE1 serves as the PMU's output channel. PMU_MEASURE1 and EXTFOH1 both converge with PMU_FORCE1 at point A, and are then connected to the DUT via an analog switch. This allows the invention to implement FV, FI, MV, and MV functions at the DUT. Furthermore, by programming the AD5522, the output voltage range of FOH can be configured to -2.5V to 6.5V, and the voltage measurement range to ±12.5V. The current output range can also be configured to ±5uA, ±20uA, ±200uA, ±2mA, and ±40mA, and the current measurement range is configured similarly. To accommodate multi-DUT testing, FOH1 is connected to point B and then into a 4-channel analog switch, allowing one PMU to be connected to four DUTs simultaneously, thus expanding testing resources.

[0056] Example 2:

[0057] When this invention functions as a reference voltage source, taking one channel as an example, the output channel FOH1 of the AD5522 can be switched via relay RL1. VREF1, as the output channel of the reference voltage source, is connected to point C at one end of the DUT. The MEASVH1 of the AD5522 is switched to a high-level measurement pin (VOH1) via RL5 and connected to point C where VREF1 connects to the DUT, allowing for real-time voltage detection at one end of the DUT. Meanwhile, the DUTGND1 pin of the AD5522 serves as the low-level measurement pin (VOL1) of the DUT and is connected to the other end of the DUT. The DUTGND pin is connected together with the DUT's GND as GND. This connection method forms a Kelvin four-wire connection, where VREF1 is the voltage output terminal, VOH1 is the target high-level measurement terminal, VOL is the low-level measurement terminal, and GND is the common ground. The voltage applied to the DUT is measured via V0H1 and compared with the voltage across VOL1. This is then calculated using op-amp M1 to obtain a true voltage applied to the DUT, excluding voltage drops across the conductors. This voltage is then fed back to DAC1 via op-amp F1, ensuring that the voltage applied to point C consistently approximates the DAC1 output voltage. This process significantly improves the accuracy of the reference voltage source applied to the DUT. Furthermore, by programming the AD5522, the output voltage range of the reference voltage source can be set from 0V to 6V, thus covering most reference voltage ranges.

[0058] Furthermore, to improve testing accuracy, the first stage of this invention focuses on the output channel, covering both output voltage and output current modes. The control computer sends setpoints to the programmable measurement unit via a control interface, causing the output to generate corresponding analog quantities. The output is then directly connected to an external high-precision standard meter for independent measurement. To ensure data representativeness, the control computer selects several calibration points within a preset range. The range coverage of these calibration points is determined using a proportional distribution method, encompassing three regions: low, middle, and high. Typical proportional points are 10%, 50%, and 90%, with additional points added to each region to form a point series of 5 to 10 points. The proportional points are determined because the output channel is more prone to exposing offset and gain errors at the two ends of the range, while the middle section is used to constrain linear consistency, thereby obtaining stable fitting results with a limited number of points. During each calibration point execution, the control computer first sends the setpoints and initiates the stability criterion, then triggers the standard meter to collect the actual output value and transmit it back.

[0059] The stability criterion is jointly defined by three types of parameters: output convergence threshold, number of consecutive stable readings, and maximum waiting time limit. The output convergence threshold is set to three times the minimum resolution unit of the standard meter in the selected range to suppress misjudgments caused by minor jitter. The number of consecutive stable readings is set to 10, requiring adjacent reading changes to continuously meet the threshold to exclude transients. The maximum waiting time limit is set to 2 seconds; if the time limit is exceeded, it is determined that the point has not entered a steady state and the process is repeated for that point. The determination of the above thresholds follows the same principle: the threshold should not be lower than the repeatable reading level of the standard meter's resolution capability, and at the same time, it should not be higher than the upper limit of the allowable error for the target accuracy, avoiding efficiency reduction due to excessive stringency or offsetting of compensation parameters due to excessive leniency.

[0060] At each calibration point, the control computer subtracts the actual output value measured by the standard meter from the issued setpoint to obtain the original output error at that point. Then, using the setpoint sequence as the input axis and the actual value sequence of the standard meter as the output axis, a linear error model of the output channel is established. Linear regression is then used to obtain two core parameters: the output gain parameter, used to characterize the scaling deviation of the setpoint; and the output offset parameter, used to characterize zero-point drift and static offset. The determination of the output gain parameter involves slope fitting: the control computer calculates the scaling factor that best matches the overall trend using all data points, minimizing the sum of squared residuals. The determination of the output offset parameter involves intercept fitting: after determining the scaling factor, a constant offset that minimizes the overall error mean is obtained. To avoid outlier contamination of the fitting, an outlier judgment threshold and a re-acquisition mechanism are set: when the absolute value of the error at a point exceeds five times the upper limit of the target accuracy for the same range, it is judged as an outlier and re-acquired at that point; if the same point triggers an outlier twice consecutively, it is judged as a connection or load status anomaly, and the current calibration round is terminated. After fitting is complete, the control computer converts the output gain parameter and output offset parameter into a setpoint compensation parameter pair. This compensation parameter pair is used to linearly correct the setpoint in subsequent outputs: before issuing any target voltage or target current, the control computer first calculates the compensated value based on the compensation parameter pair, and then sends the compensated value to the programmable measurement unit, thereby aligning the actual value at the output with the target value. The compensation parameter pair is stored in the output calibration parameter table, which at least distinguishes between the output voltage channel and the output current channel and binds them to the range settings to prevent systematic deviations caused by misuse of cross-range settings.

[0061] The second stage of this invention focuses on the measurement channel, covering both voltage and current measurement modes. The hardware connection utilizes a DC calibration board to form a self-calibration loop: the output terminals of the programmable measurement unit are connected to their respective measurement input terminals according to channel type, with the output voltage terminal connected to the voltage measurement input terminal and the output current terminal connected to the current measurement input terminal. The DC calibration board provides controlled connection paths, isolation, and range switching to ensure that the measurement input terminals are under electrical boundary conditions consistent with actual applications. During each measurement calibration point, the control computer first calls the output compensation logic of the first stage to compensate and distribute the target output value, resulting in a highly consistent excitation signal at the output terminal. This excitation signal simultaneously enters two acquisition links: the first link enters an external high-precision standard meter to form a reference value, and the second link enters the measurement channel of the programmable measurement unit to form the original measurement reading. The reference value is defined based on the standard meter reading because the standard meter plays the role of the final arbitration standard in this invention; the compensated set value is used to improve excitation consistency but not to replace the arbitration reference. The stability criteria for the measurement channel adopts a three-threshold structure with specific settings: the input convergence threshold is set to 3 times the minimum resolution unit of the measurement channel in the selected range, the number of consecutive stable measurements is set to 10, and the maximum waiting time is set to 2 seconds, ensuring that the reference value and the original reading are collected within the same steady-state window, thereby reducing the system error caused by asynchronous sampling.

[0062] In the data processing stage, the control computer subtracts the original readings of the measurement channel from the corresponding reference values ​​to obtain the original measurement error at each point. Then, using the reference value sequence as the input axis and the original reading sequence as the output axis, a linear error model of the measurement channel is established. Linear regression is used to determine two core parameters: the measurement gain parameter, which characterizes the proportional response deviation of the measurement channel; and the measurement offset parameter, which characterizes the equivalent offset between the measurement channel's zero point and the input. The solution process for the measurement gain and measurement offset parameters is consistent with the output stage, the difference being that the calibration target is to correct the measurement readings rather than correcting the issued setpoints. Therefore, in subsequent actual measurements, the measurement channel first outputs the original readings, and then performs a linear back-calculation correction on the original readings based on the measurement gain and measurement offset parameters, outputting the final measurement result to align with the reference value. The measurement gain and measurement offset parameters are stored in the measurement calibration parameter table, which at least distinguishes between the measurement voltage channel and the measurement current channel and is bound to the measurement range.

[0063] To ensure long-term consistency, the measurement calibration parameter table and the output calibration parameter table use the same version management identifier. When either table is updated, a compatibility check of the other table is triggered. The check method is to perform a back-read sampling inspection: a closed-loop acquisition is performed at three points: 10%, 50%, and 90% of the measurement range. If the absolute value of the closed-loop error does not exceed the target accuracy limit, the parameters of the two tables are considered to meet the requirements. If any point exceeds the limit, the parameter coupling is considered to be mismatched and the second stage of fitting is restarted.

[0064] This invention offers an additional advantage in reference voltage source mode: when the system switches to reference voltage source operation, the control logic switches the programmable measurement unit to an output voltage and measurement voltage linkage mode, and retrieves the calibration parameter tables of the output voltage channel and measurement voltage channel to participate in the same compensation link. Specifically, the control computer generates a target setting based on the reference voltage source target value, first performs linear compensation on the target setting according to the output calibration parameter table and sends it out, resulting in a compensated reference output. Then, the measurement voltage channel samples this reference output and performs linear correction according to the measurement calibration parameter table, outputting the corrected measurement result. The control computer performs a consistency check between the corrected measurement result and the reference voltage source target value. When the deviation falls within a preset consistency threshold range, the reference voltage source enters the state of providing reference output. The consistency threshold is set to 1 times the upper limit of the system's reference output target accuracy, used to ensure that the reference mode does not introduce additional slack. If the deviation exceeds the threshold, the control computer determines that the drift caused by the current environment or load conditions is not covered by existing parameters and enters the compensation and reorganization process, re-executing the output and measurement closed-loop sampling point series related to this range to restore the accuracy consistency in the reference mode. Therefore, the reference voltage source mode does not require the introduction of a separate external reference source calibration link. It directly reuses both output and measurement calibration parameters to complete the closed-loop constraint of the reference output accuracy within the same device.

[0065] In summary, this invention establishes an arbitration benchmark using an external high-precision standard table, forms two data chains for output compensation and measurement correction through phased linear modeling, and uses three types of parameters—stability threshold, outlier threshold, and consistency threshold—to constrain the acquisition and fitting quality. Furthermore, it achieves a traceable calibration application path by binding parameter tables by channel and range, thereby realizing unified accuracy control and engineering reproducibility in four operating modes: output voltage, output current, measured voltage, and measured current.

[0066] This invention is not limited to the embodiments described above. Any changes in shape or structure shall fall within the protection scope of this invention. The protection scope of this invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of this invention, but all such changes and modifications shall fall within the protection scope of this invention.

Claims

1. A dual-function circuit based on ATE testing, comprising a PMU and a reference voltage source, characterized in that, It includes the AD5522 chip, a function switching module, a multi-DUT expansion module, a precision optimization module, and a control module; The AD5522 chip has 4 PMU output channels, 4 high-level measurement channels, and 4 DUT grounding channels; The function switching module is a relay group RL1-RL5, where RL1-RL4 correspond to 4 PMU output channels respectively, and are used to switch the channel function to PMU output or reference voltage source output. RL5 is used to switch the connection between the high-level measurement channel and the reference voltage source output terminal. The multi-DUT expansion module is a 1:4 analog switch, with each analog switch corresponding to a PMU output terminal; The precision optimization module includes a first operational amplifier M1, a second operational amplifier F1, and a DAC1; The control module is used to configure the AD5522 chip parameters and to control the on / off switching between the relay group and the analog switch through the function switching module. The dual-function circuit can switch between PMU function mode and reference voltage source function mode. In the reference voltage source function mode, the control module drives RL1-RL4 to switch to the reference voltage output position and RL5 to close. The PMU output channel of the AD5522 chip is connected to the reference voltage source output terminal through RL1-RL4. The high-level measurement channel is connected to the connection point between the reference voltage source output terminal and the DUT through RL5. The DUT grounding channel is connected to the low-level terminal of the DUT and the system ground, forming a Kelvin four-wire connection. In the accuracy optimization module, the first operational amplifier M1 is used to calculate the difference between the voltage acquired by the high-level measurement channel and the voltage acquired by the DUT grounding channel to obtain the true voltage across the DUT. The second operational amplifier F1 feeds the true voltage back to DAC1, and adjusts the output voltage of the AD5522 chip through DAC1 so that the voltage at the output of the reference voltage source approaches the set value of DAC1.

2. The dual-function circuit of PMU and reference voltage source based on ATE testing as described in claim 1, characterized in that: In the PMU function mode, the control module drives RL1-RL4 to switch to the PMU output position and RL5 to disconnect. The PMU output channel of the AD5522 chip is connected to the PMU output terminal through RL1-RL4. The measurement terminal of the AD5522 chip merges with the PMU output terminal to form an FVMI or FIMV test closed loop.

3. The dual-function circuit of PMU and reference voltage source based on ATE testing as described in claim 2, characterized in that: In the PMU function mode, the AD5522 chip's output voltage range can be configured to -2.5V to 6.5V, the voltage measurement range to ±12.5V, and the current output / measurement range to ±5uA, ±20uA, ±200uA, ±2mA, or ±40mA through programming via the control module.

4. The dual-function circuit of PMU and reference voltage source based on ATE testing as described in claim 1, characterized in that: In the reference voltage source function mode, the control module drives RL1-RL4 to switch to the reference voltage output position and RL5 to close. The PMU output channel of the AD5522 chip is connected to the output terminal of the reference voltage source through RL1-RL4. The high-level measurement channel is connected to the connection point between the output terminal of the reference voltage source and the DUT through RL5. The DUT grounding channel is connected to the low-level terminal of the DUT and the system ground, forming a Kelvin four-wire connection.

5. The dual-function circuit of PMU and reference voltage source based on ATE testing as described in claim 4, characterized in that: In the accuracy optimization module, the first operational amplifier M1 is used to calculate the difference between the voltage acquired by the high-level measurement channel and the voltage acquired by the DUT grounding channel to obtain the true voltage across the DUT. The second operational amplifier F1 feeds back the true voltage to DAC1, and adjusts the output voltage of the AD5522 chip through DAC1 so that the voltage at the output of the reference voltage source approaches the set value of DAC1.

6. The dual-function circuit of PMU and reference voltage source based on ATE testing as described in claim 4, characterized in that: In the reference voltage source function mode, the output voltage configuration range of the reference voltage source output terminal is 0-6V, and the output error is ≤±300uV, through the control module programming.

7. The dual-function circuit of PMU and reference voltage source based on ATE testing as described in claim 1, characterized in that: In the DUT expansion module, each PMU output is connected to four DUTs via a single 1:4 analog switch. The control module switches the analog switches to enable time-sharing testing of the four DUTs using a single PMU resource.

8. The dual-function circuit of PMU and reference voltage source based on ATE testing as described in claim 1, characterized in that: The relay group uses DC relays with a response time of ≤1ms, and the analog switch uses a single-ended analog switch with an on-resistance of ≤5Ω.

9. A dual-function circuit for PMU and reference voltage source based on ATE testing as described in claim 1, characterized in that: The operational amplifier in the precision optimization module is a low-offset operational amplifier with an offset voltage ≤10uV, and DAC1 is a digital-to-analog converter with at least 16-bit precision.

10. A dual-function circuit for PMU and reference voltage source based on ATE testing as described in claim 1, characterized in that: The control module is a microcontroller or FPGA, which communicates with the AD5522 chip and DAC1 through the SPI interface, and controls the on / off state of the relay group and analog switch through the GPIO port.

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