CN121679110A

CN121679110A - Calibration method for digital differential sampling power supply device and current measurement unit

Info

Publication number: CN121679110A
Application number: CN202511783453.0A
Authority: CN
Inventors: 徐友冰; 杨钊辉; 李德涛
Original assignee: Hangzhou Changchuan Technology Co Ltd
Current assignee: Hangzhou Changchuan Technology Co Ltd
Priority date: 2025-11-28
Filing date: 2025-11-28
Publication date: 2026-03-17

Abstract

The application relates to a digital differential sampling power supply device and a calibration method of a current measurement unit, wherein a driving unit is connected to a device to be tested through a high-side current wire HF, an excitation signal is output to the device to be tested, and the device to be tested is connected to an internal grounding end of the driving unit through a low-side current wire LF. The current sampling resistor is connected in series with the high-end current wire HF, the current measuring unit respectively detects the voltages to the ground at two ends of the current sampling resistor, and a first digital signal and a second digital signal are obtained through conversion and are transmitted to the control unit. The control unit analyzes the received first digital signal and the second digital signal to obtain a measured current, performs feedback adjustment according to the measured current, and outputs a control signal to the driving unit to adjust the current of the excitation signal. The current measuring units are used for respectively detecting the voltages to the ground at the two ends of the current sampling resistor, and the measured current is calculated after the voltages are converted into digital values, so that the error caused by common-mode voltage to current measurement can be effectively reduced, and the measurement accuracy is improved.

Description

Digital differential sampling power supply device and calibration method of current measurement unit

Technical Field

The application relates to the technical field of semiconductor testing, in particular to a digital differential sampling power supply device and a calibration method of a current measurement unit.

Background

In integrated circuit testing, a voltage current source (VI source) is required to perform signal stimulus and voltage current measurement on a device under test (DUT, device Under Test). In order to improve the accuracy of the output voltage and the test voltage, the VI source adopts a four-wire Kelvin (Kelvin) connection mode, which is respectively a High-side current line (HF, high Force), a High-side voltage line (HS, high Sense), a Low-side current line (LF, low Force), and a Low-side voltage line (LS, low Sense). Where the current is output (or input) from the high-side current line HF and flows back (or out) from the low-side current line LF. The voltage measurement takes the difference between a high-end voltage line HS and a low-end voltage line LS as the voltage difference on the DUT, high-impedance input ends are arranged in the HS end and the LS end, and the voltages of the near-end and the far-end of the signal are the same.

However, the VI source adopts a four-wire kelvin connection mode, and when current calibration and normal current measurement are performed on the DUT, due to the adoption of hardware differential measurement, the common mode rejection ratio of the current sampling circuit is limited, so that the common mode voltage can affect the voltage/current measurement result, and the current measurement precision is low, and especially, the measurement error caused by the common mode voltage under the scene that the VI source outputs high voltage is particularly obvious.

Disclosure of Invention

In view of the above, it is necessary to provide a digital differential sampling power supply device and a calibration method of a current measurement unit that can improve measurement accuracy.

A first aspect of the present application provides a digital differential sampling power supply device, comprising:

the driving unit is connected to a device to be tested through a high-end current wire HF, and outputs an excitation signal to the device to be tested, and the device to be tested is connected to the internal grounding end of the driving unit through a low-end current wire LF;

the current sampling resistor is connected in series with the high-side current line HF;

The current measuring unit is connected with two ends of the current sampling resistor, respectively detects the voltages to the ground at the two ends of the current sampling resistor, converts the voltages to obtain a first digital signal and a second digital signal, and transmits the first digital signal and the second digital signal to the control unit;

The control unit is connected with the driving unit and the current measuring unit, analyzes and obtains a measured current according to the received first digital signal and the received second digital signal, performs feedback adjustment according to the measured current, and outputs a control signal to the driving unit to adjust the current of the excitation signal.

In one embodiment, the control unit determines a corresponding sampling machine measurement value according to the first digital signal and the second digital signal output by the current measurement unit, and calculates the measured current according to the sampling machine measurement value and the set current calibration parameter.

In one embodiment, the power supply device further comprises a universal meter, wherein the universal meter is used for respectively detecting the measured values of the voltmeter at two ends of the current sampling resistor and detecting the current flowing through the current sampling resistor;

The control unit controls the driving unit to output a plurality of groups of different excitation voltages when in no-load, respectively determines sampling machine measurement values according to a first digital signal and a second digital signal output by the current measurement unit in real time, respectively reads the geodetic voltmeter measurement values at two ends of the current sampling resistor through the universal meter, carries out linear fitting based on the geodetic voltmeter measurement values at the first end of each group of the current sampling resistor measured in no-load and the corresponding sampling machine measurement values, and carries out linear fitting based on the geodetic voltmeter measurement values at the second end of each group of the current sampling resistor measured in no-load and the corresponding sampling machine measurement values, and determines a current machine measurement value expression;

And when the load is carried, the control unit controls the driving unit to output a plurality of groups of different excitation currents, corresponding sampling machine measured values are respectively determined in real time according to the first digital signal and the second digital signal output by the current measuring unit, the ammeter measured values flowing through the current sampling resistor are read through the universal meter, the ammeter measured values of each group are calculated based on each group of sampler measured values and the ammeter measured value expression when the load is carried, linear fitting is carried out according to the ammeter measured values of each group and the ammeter measured values of each group, and the current calibration parameters are determined.

In one embodiment, the current measurement unit includes a following operational amplifier U1, a following operational amplifier U2, a differential operational amplifier U3, a differential operational amplifier U4, an analog-to-digital converter ADC1, and an analog-to-digital converter ADC2;

The non-inverting input end of the following operational amplifier U1 is connected with the first end of the current sampling resistor, the inverting input end of the following operational amplifier U1 is connected with the output end of the following operational amplifier U1, the output end of the following operational amplifier U1 is connected with the first input end of the differential operational amplifier U3, the second input end of the differential operational amplifier U3 is connected with the grounding end, the output end of the differential operational amplifier U3 is connected with the analog-to-digital converter ADC1, and the analog-to-digital converter ADC1 is connected with the control unit;

The non-inverting input end of the following operational amplifier U2 is connected with the second end of the current sampling resistor, the inverting input end of the following operational amplifier U2 is connected with the output end of the following operational amplifier U2, the output end of the following operational amplifier U2 is connected with the first input end of the differential operational amplifier U4, the second input end of the differential operational amplifier U4 is connected with the grounding end, the output end of the differential operational amplifier U4 is connected with the analog-to-digital converter ADC2, and the analog-to-digital converter ADC2 is connected with the control unit.

In one embodiment, the calculation formula for measuring the current is:

MI=kMI*[(VFB_RsH*Gain1*kRsH+bRsH)-(VFB_RsL*Gain2*kRsL+bRsL)]/Rs+bMI

Wherein MI is the measured current, kMI, bMI, kRsH, bRsH, kRsL, bRsL is the current calibration parameter, VFB_RsH and VFB_RsL are the sampling machine measurement values of the analog-to-digital converter ADC1 and the analog-to-digital converter ADC2 respectively, rs is the nominal value of the current sampling resistor, gain1 is the hardware Gain of the link where the analog-to-digital converter ADC1 is located, gain2 is the hardware Gain of the link where the analog-to-digital converter ADC2 is located, and VFB_ RsH, gain1, kRsH + bRsH and VFB_RsL, gain2, kRsL + bRsL are the ground voltage machine measurement values of the first end and the second end of the current sampling resistor respectively.

In one embodiment, the power supply device further includes:

The HS voltage measurement unit is connected to the device to be tested through a high-end voltage line HS, detects the ground voltage of the high-end voltage line HS, and converts the ground voltage into a HS digital signal to be transmitted to the control unit;

the LS voltage measuring unit is connected to the device to be measured through a low-end voltage line LS, detects the ground voltage of the low-end voltage line LS, and transmits LS digital signals obtained through conversion to the control unit;

The control unit is also connected with the HS voltage measurement unit and the LS voltage measurement unit, analyzes and obtains measurement voltage according to the received HS digital signal and LS digital signal, carries out feedback adjustment according to the measurement voltage, and outputs a control signal to the driving unit to adjust the voltage of the excitation signal.

In one embodiment, the control unit determines an HS sampling machine measurement value and an LS sampling machine measurement value according to the HS digital signals and the LS digital signals respectively output by the HS voltage measurement unit and the LS voltage measurement unit, and calculates the measured voltage according to the HS sampling machine measurement value, the LS sampling machine measurement value and the set voltage calibration parameter.

In one embodiment, the multimeter is further configured to detect a ground voltmeter measurement of the high-side voltage line HS and a ground voltmeter measurement of the low-side voltage line LS, respectively;

And when the load is carried, the control unit controls the driving unit to output a plurality of groups of different excitation currents, the HS sampling machine measured value and the LS sampling machine measured value are respectively obtained in real time, the HS geodetic voltmeter measured value and the LS geodetic voltmeter measured value are respectively read through the universal meter, linear fitting is carried out on the basis of each group of HS sampling machine measured value and the HS geodetic voltmeter measured value, linear fitting is carried out on the basis of each group of LS sampling machine measured value and the LS geodetic voltmeter measured value, and the voltage calibration parameters are determined.

In one embodiment, the HS voltage measurement unit includes a following operational amplifier U5, a differential operational amplifier U6, and an analog-to-digital converter ADC3, where a non-inverting input end of the following operational amplifier U5 is connected to a high-end voltage line HS, an inverting input end of the following operational amplifier U5 is connected to an output end of the following operational amplifier U5, an output end of the following operational amplifier U5 is connected to a first input end of the differential operational amplifier U6, a second input end of the differential operational amplifier U6 is connected to a ground end, an output end of the differential operational amplifier U6 is connected to the analog-to-digital converter ADC3, and the analog-to-digital converter ADC3 is connected to the control unit;

the LS voltage measurement unit comprises a following operational amplifier U7, a differential operational amplifier U8 and an analog-to-digital converter ADC4, wherein the in-phase input end of the following operational amplifier U7 is connected with a low-end voltage line LS, the inverting input end of the following operational amplifier U7 is connected with the output end of the following operational amplifier U7, the output end of the following operational amplifier U7 is connected with the first input end of the differential operational amplifier U8, the second input end of the differential operational amplifier U8 is connected with a grounding end, the output end of the differential operational amplifier U8 is connected with the analog-to-digital converter ADC4, and the analog-to-digital converter ADC4 is connected with the control unit.

In one embodiment, the calculation formula of the measured voltage is:

MV=(VFB_HS*Gain3*kHS+bHS)-(VFB_LS*Gain4*kLS+bLS)

Wherein MV is the measurement voltage, kHS, bHS, kLS, bLS is the voltage calibration parameter, VFB_HS is the HS sampling machine measurement value of the analog-to-digital converter ADC3, VFB_LS is the LS sampling machine measurement value of the analog-to-digital converter ADC4, gain3 is the hardware Gain of the link where the analog-to-digital converter ADC3 is located, gain4 is the hardware Gain of the link where the analog-to-digital converter ADC4 is located, and VFB_HS is kHS + bHS and VFB_LS is Gain4 is kLS +bLS are the HS voltage to ground machine measurement value and the LS voltage to ground machine measurement value respectively.

The application provides a calibration method of a current measuring unit, which is applied to a control unit, wherein a digital differential sampling power supply device comprises a driving unit, a current measuring unit, a current sampling resistor and the control unit, wherein the current measuring unit is connected with two ends of the current sampling resistor, respectively detects the ground voltage at two ends of the current sampling resistor, converts the ground voltage into a first digital signal and a second digital signal and transmits the first digital signal and the second digital signal to the control unit, the driving unit is connected to a device to be tested through a high-end current wire HF, the device to be tested is connected to the internal grounding end of the driving unit through a low-end current wire LF, and the two ends of the current sampling resistor are connected in series with the high-end current wire HF, and the method comprises the following steps:

And calculating to obtain a measured current based on a sampling machine measured value and a set current calibration parameter, wherein the sampling machine measured value is respectively determined by the control unit according to a first digital signal and a second digital signal output by the current measurement unit.

In one embodiment, the universal meter is used for respectively detecting the measured value of the voltmeter at two ends of the current sampling resistor and detecting the current flowing through the current sampling resistor, and the determining the set current calibration parameters comprises:

In one embodiment, determining a current machine measurement expression based on a linear fit of the ground voltmeter measurement and the corresponding sampler measurement at a first end of each set of measured current sampling resistors at idle and a linear fit of the ground voltmeter measurement and the corresponding sampler measurement at a second end of each set of measured current sampling resistors at idle includes:

performing unitary linear fitting according to the measured value of the ground voltmeter and the measured value of the ground voltmeter at the first end of each group of measured current sampling resistors in no-load state to obtain current calibration parameters kRsH and bRsH;

performing unitary linear fitting according to the measured value of the ground voltmeter and the measured value of the ground voltmeter at the second end of each group of measured current sampling resistors in no-load state to obtain current calibration parameters kRsL and bRsL;

The current machine measurement expression is:

MI measurement= [ (vfb_ RsH x gain1 x kRsH + bRsH) - (vfb_rsl x gain2 x kRsL + bRsL) ]/Rs

Wherein, vfb_rsh and vfb_rsl are the sampling machine measurement values of the analog-to-digital converter ADC1 and the analog-to-digital converter ADC2 respectively, rs is the nominal value of the current sampling resistor, gain1 is the hardware Gain of the link where the analog-to-digital converter ADC1 is located, and Gain2 is the hardware Gain of the link where the analog-to-digital converter ADC2 is located; vfb_ RsH x gain1 x kRsH + bRsH and vfb_rsl x gain2 x kRsL + bRsL are ground voltage measurements at the first and second ends of the current sampling resistor, respectively.

In one embodiment, determining the current calibration parameters based on linear fitting of the current machine measurements of each group and the measured ammeter measurements of each group includes:

Performing unitary linear fitting on each group of calculated current machine measured values and each group of measured ammeter measured values to obtain current calibration parameters kMI and bMI;

the calculation formula of the measured current MI is:

MI=kMI*[(VFB_RsH*Gain1*kRsH+bRsH)-(VFB_RsL*Gain2*kRsL+bRsL)]/Rs+bMI。

According to the calibration method of the digital differential sampling power supply device and the current measurement unit, the driving unit is connected to the device to be tested through the high-side current wire HF, the excitation signal is output to the device to be tested, and the device to be tested is connected to the internal grounding end of the driving unit through the low-side current wire LF. The current sampling resistor is connected in series with the high-end current wire HF, the current measuring unit respectively detects the voltages to the ground at two ends of the current sampling resistor, and a first digital signal and a second digital signal are obtained through conversion and are transmitted to the control unit. The control unit analyzes the received first digital signal and the second digital signal to obtain a measured current, performs feedback adjustment according to the measured current, and outputs a control signal to the driving unit to adjust the current of the excitation signal. The current measuring units are used for respectively detecting the voltages to the ground at the two ends of the current sampling resistor, and calculating the measured current after converting the voltages into digital values, so that the error caused by common-mode voltage to current measurement can be effectively reduced, and the current measurement precision is improved.

Drawings

FIG. 1 is a block diagram of a digital differential sampling power supply device in one embodiment;

FIG. 2 is a schematic diagram of a digital differential sampling power supply device according to one embodiment;

FIG. 3 is a flow chart of calibration of the current measurement unit in one embodiment;

Fig. 4 is a flow chart of calibration of the HS voltage measurement unit and the LS voltage measurement unit in one embodiment.

Detailed Description

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. It is to be understood that in the following embodiments, "connected" is understood to mean "electrically connected", "communicatively connected", etc., if the connected circuits, modules, units, etc., have electrical or data transfer between them.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Also, the term "and/or" as used in this specification includes any and all combinations of the associated listed items.

In the prior art, high-end current sampling is adopted, current measurement is greatly influenced by common-mode voltage, and voltage measurement is relatively less influenced by the common-mode voltage. In current calibration, usually a resistive load of ohm or milliohm, HF is grounded through the load resistor and LF, and the potential of one end of the sampling resistor close to HF is close to 0, i.e. the current sampling performs current measurement calibration under the condition that the common mode voltage is close to 0. However, during normal operation, the HF voltage is raised to different degrees according to application scenes, mainly derived from voltage drop of the load resistor, and measurement errors caused by common mode voltage under a high voltage scene are particularly obvious.

The present application thus provides a digital differential sampling power supply device which may be embodied as a VI source, output using the kelvin four-wire method. As shown in fig. 1, the digital differential sampling power supply device includes a driving unit 110, a current sampling resistor (not shown), a current measuring unit 120 and a control unit 130, wherein the driving unit 110 is connected to a device under test DUT through a high-side current line HF, outputs an excitation signal to the device under test DUT, applies voltage/current excitation to the device under test DUT, the device under test DUT is connected to an internal ground terminal of the driving unit 110 through a low-side current line LF, and the current sampling resistor is serially connected to the high-side current line HF. The current measuring unit 120 is connected to two ends of the current sampling resistor, and detects voltages to ground at two ends of the current sampling resistor, and converts the voltages to a first digital signal and a second digital signal, and sends the first digital signal and the second digital signal to the control unit 130. The control unit 130 is connected to the driving unit 110 and the current measuring unit 120, analyzes the received first digital signal and the received second digital signal to obtain a measured current, performs feedback adjustment according to the measured current, and outputs a control signal to the driving unit 110 to adjust the current of the excitation signal. The DUT may be a chip to be tested, or may be another device that needs to receive an excitation signal for testing. As shown in fig. 2, the current sampling resistor R _S is serially connected to the high-side current line HF. The current measuring unit 120 is used for respectively detecting the voltages to the ground at the two ends of the current sampling resistor R _S, converting the voltages to digital values and then calculating the measured current, so that the error caused by common-mode voltage existing in hardware differential measurement on current measurement can be effectively reduced, and the current measurement precision is improved.

It is understood that the voltages to ground at the two ends of the current sampling resistor R _S refer to the voltages of the first end of the current sampling resistor R _S and the ground, respectively, the voltages of the second end of the current sampling resistor R _S and the ground, respectively, and the ground voltage defaults to 0V.

In an example, the grounding terminals in the present application may be the same common ground, that is, the internal grounding terminal of the driving unit.

Referring to fig. 1 and 2, the power supply apparatus further includes an HS voltage measurement unit 140 and an LS voltage measurement unit 150, the HS voltage measurement unit 140 is connected to the device under test DUT through a high-side voltage line HS, detects a ground voltage of the high-side voltage line HS, converts the detected HS digital signal to a ground voltage, and transmits the detected HS digital signal to the control unit 130, the LS voltage measurement unit 150 is connected to the device under test DUT through a low-side voltage line LS, detects a ground voltage of the low-side voltage line LS, converts the detected LS digital signal to a ground voltage, and transmits the converted LS digital signal to the control unit 130, and the control unit 130 is further connected to the HS voltage measurement unit 140 and the LS voltage measurement unit 150, analyzes the detected HS digital signal and the LS digital signal to obtain a measured voltage, performs feedback adjustment according to the measured voltage, and outputs a control signal to the driving unit 110 to adjust a voltage of the excitation signal. HS voltage measurement unit 140 and LS voltage measurement unit 150 are used for respectively detecting HS voltage to ground and LS voltage to ground, and calculating the measured voltage after converting the HS voltage to digital quantity, so that errors caused by common mode voltage to voltage measurement are reduced, and voltage measurement accuracy is further improved.

It is understood that the ground voltage of the high-side voltage line HS and the ground voltage of the low-side voltage line LS refer to voltages with respect to the same ground terminal, and the ground terminal voltage defaults to 0V.

The driving unit 110 receives the control signal sent by the control unit 130, and outputs voltage/current excitation to the DUT. The HS voltage measurement unit 140 and the LS voltage measurement unit 150 measure the HS voltage to ground and the LS voltage to ground at two ends of the DUT, the current measurement unit 120 measures the current in the loop, the control unit 130 calculates the measured voltage/measured current according to the received corresponding digital signal, and performs feedback closed loop control according to the measured voltage/measured current to adjust the output excitation voltage/current of the driving unit 110.

In one embodiment, the current measurement unit 120 detects voltages to ground at two ends of the current sampling resistor R _S, converts the voltages to obtain a first digital signal and a second digital signal, and sends the first digital signal and the second digital signal to the control unit 130, and the control unit 130 determines a corresponding sampling machine measured value according to the first digital signal and the second digital signal output by the current measurement unit 120, and calculates a measured current according to the sampling machine measured value and a set current calibration parameter. Further, the control unit 130 determines the HS sampler measurement value and the LS sampler measurement value according to the HS digital signal and the LS digital signal output by the HS voltage measurement unit 140 and the LS voltage measurement unit 150, respectively, and calculates the measured voltage according to the HS sampler measurement value, the LS sampler measurement value and the set voltage calibration parameter.

In addition, the power supply device can further comprise universal meters for current measurement calibration and/or voltage measurement calibration, wherein the universal meters respectively detect the measured values of the voltmeters at two ends of the current sampling resistor R _S and detect the current flowing through the current sampling resistor, and/or the universal meters respectively detect the measured values of the voltmeters of the high-end voltage line HS and the measured values of the voltmeters of the low-end voltage line LS.

In one embodiment, the control unit 130 may include only a controller, and perform calibration operations on the current measurement unit 120, the HS voltage measurement unit 140, and the LS voltage measurement unit 150 according to data collected by the current measurement unit 120, the HS voltage measurement unit 140, the LS voltage measurement unit 150, and the multimeter, to determine the current calibration parameter and the voltage calibration parameter. In another embodiment, the control unit 130 may also include a controller and a terminal, where the controller is connected to the driving unit 110, the current measurement unit 120, the HS voltage measurement unit 140, the LS voltage measurement unit 150, and the terminal, uploads data collected by the current measurement unit 120, the HS voltage measurement unit 140, and the LS voltage measurement unit 150 to the terminal, and the terminal performs calibration operation on the current measurement unit 120, the HS voltage measurement unit 140, and the LS voltage measurement unit 150 in combination with data collected by the multimeter, to determine the current calibration parameter and the voltage calibration parameter. When the DUT is actually measured, the controller correspondingly analyzes and obtains the measured current and the measured current according to the digital signals output by the current measuring unit 120, the HS voltage measuring unit 140 and the LS voltage measuring unit 150, the set current calibration parameters and the set voltage calibration parameters, and feeds back and adjusts the excitation signals output by the driving unit 110. The controller may be FPGA, CPU, CPLD, MCU devices, and in this embodiment, the controller adopts an FPGA. The terminal may be, but not limited to, various personal computers, notebook computers, smartphones, tablet computers, and portable wearable devices, which may be smartwatches, smartbracelets, headsets, etc.

It is understood that the specific structures of the driving unit 110, the current measuring unit 120, the HS voltage measuring unit 140, and the LS voltage measuring unit 150 are not unique. In one embodiment, as shown in fig. 2, the driving unit 110 specifically includes a digital-to-analog converter DAC and a power amplifier PA, where the digital-to-analog converter DAC is connected to the control unit 130 (specifically connected to the FPGA) and the power amplifier PA, the power amplifier PA is connected to the device under test DUT through a high-side current line HF, and the low-side current line LF is connected to the ground and the device under test DUT. The digital-to-analog converter DAC receives the digital signal of the FPGA, converts the digital signal into an analog signal and outputs the analog signal to the power amplifier PA, and the power amplifier PA outputs an excitation signal to the DUT through the high-end current wire HF and then flows back to the ground through the low-end current wire LF.

In one embodiment, with continued reference to fig. 2, the current measurement unit 120 includes a following operational amplifier U1, a following operational amplifier U2, a differential operational amplifier U3, a differential operational amplifier U4, an analog-to-digital converter ADC1, and an analog-to-digital converter ADC2.

Specifically, the non-inverting input terminal of the following operational amplifier U1 is connected to the first terminal of the current sampling resistor R _S, the inverting input terminal of the following operational amplifier U1 is connected to the output terminal of the following operational amplifier U1, the output terminal of the following operational amplifier U1 is connected to the first input terminal of the differential operational amplifier U3, the second input terminal of the differential operational amplifier U3 is connected to the ground terminal, the output terminal of the differential operational amplifier U3 is connected to the analog-to-digital converter ADC1, and the analog-to-digital converter ADC1 is connected to the control unit 130 (specifically connected to the FPGA). The non-inverting input end of the following operational amplifier U2 is connected with the second end of the current sampling resistor R _S, the inverting input end of the following operational amplifier U2 is connected with the output end of the following operational amplifier U2, the output end of the following operational amplifier U2 is connected with the first input end of the differential operational amplifier U4, the second input end of the differential operational amplifier U4 is connected with the grounding end, the output end of the differential operational amplifier U4 is connected with the analog-to-digital converter ADC2, and the analog-to-digital converter ADC2 is connected with the control unit 130 (specifically connected to the FPGA).

In this embodiment, one of the input ends of the differential operational amplifiers U3 and U4 is connected to two ends of the current sampling resistor R _S through the following operational amplifiers U1 and U2, respectively, and the voltages to ground at two ends of the R _S are sampled respectively, and converted to obtain a first digital signal and a second digital signal, and the first digital signal and the second digital signal are transmitted to the FPGA.

In one embodiment, as shown in fig. 2, specifically, the HS voltage measurement unit 140 includes a following operational amplifier U5, a differential operational amplifier U6, and an analog-to-digital converter ADC3, where the non-inverting input terminal of the following operational amplifier U5 is connected to the high-side voltage line HS, the inverting input terminal of the following operational amplifier U5 is connected to the output terminal of the following operational amplifier U5, the output terminal of the following operational amplifier U5 is connected to the first input terminal of the differential operational amplifier U6, the second input terminal of the differential operational amplifier U6 is connected to the ground terminal, the output terminal of the differential operational amplifier U6 is connected to the analog-to-digital converter ADC3, and the analog-to-digital converter ADC3 is connected to the control unit 130 (specifically, connected to the FPGA). The output voltage of the differential operational amplifier U6 is sampled by an analog-to-digital converter ADC3 and converted into an HS digital signal to be sent to the FPGA.

Further, the LS voltage measurement unit 150 includes a follower operational amplifier U7, a differential operational amplifier U8, and an analog-to-digital converter ADC4, where the non-inverting input terminal of the follower operational amplifier U7 is connected to the low-side voltage line LS, the inverting input terminal of the follower operational amplifier U7 is connected to the output terminal of the follower operational amplifier U7, the output terminal of the follower operational amplifier U7 is connected to the first input terminal of the differential operational amplifier U8, the second input terminal of the differential operational amplifier U8 is connected to the ground terminal, the output terminal of the differential operational amplifier U8 is connected to the analog-to-digital converter ADC4, and the analog-to-digital converter ADC4 is connected to the control unit 130 (specifically connected to the FPGA). The output voltage of the differential operational amplifier U6 is sampled by an analog-to-digital converter ADC4 and converted into an LS digital signal to be sent to the FPGA.

When the power supply device works, the digital quantity fed back by the HS voltage measuring unit 140, the LS voltage measuring unit 150 and the current measuring unit 120 is obtained by the FPGA, the digital-to-analog converter DAC in the driving unit 110 is controlled by combining the digital PID algorithm to drive the power amplifier PA to work, the voltage/current is output to the DUT through the high-end current wire HF to excite, and then the low-end current wire LF flows back to the grounding end, so that the closed loop feedback work of the digital loop VI source system is realized.

For the current measurement unit 120, the sampler measurement value of the analog-to-digital converter ADC1 is denoted as vfb_ RsH, the sampler measurement value of the analog-to-digital converter ADC2 is denoted as vfb_ VRsL, rs is the nominal value of the current sampling resistor R _S, the hardware Gain of the measurement link of the analog-to-digital converter ADC1 is denoted as Gain1, and the hardware Gain of the measurement link of the analog-to-digital converter ADC2 is denoted as Gain2. The current measurement is divided into two operation modes, namely a low-precision mode and a high-precision mode.

In the low-precision mode, based on the logic of the hardware circuit, the precision and the nonlinear error of the hardware device are not considered:

VRsH=VFB_RsH*Gain1

VRsL=VFB_RsL*Gain2

MI=(VRsH-VRsL)/Rs

the specific implementation mode is that the sampling machine measured values VFB_RsH and VFB_RsL of the analog-digital converter ADC1 and the analog-digital converter ADC2 are obtained in real time, then

MI=(VFB_RsH*Gain1-VFB_RsL*Gain2)/Rs

In the high precision mode, calibration is required for the measurement link in which the analog-to-digital converter ADC1 and the analog-to-digital converter ADC2 are located.

In one embodiment, a multimeter is used to detect the voltage-to-ground measurements across current sampling resistor R _S and to detect the current flowing through current sampling resistor R _S, respectively.

The control unit 130 controls the driving unit 110 to output a plurality of groups of different excitation voltages when in idle load, determines a sampler test value according to the first digital signal and the second digital signal output by the current measurement unit 120 in real time, reads the voltmeter test values at two ends of the current sampling resistor R _S respectively through a universal meter, performs linear fitting based on the voltmeter test value at the first end of each group of measured current sampling resistor R _S when in idle load and the corresponding sampler test value, and determines a current machine test value expression based on the linear fitting based on the voltmeter test value at the second end of each group of measured current sampling resistor when in idle load and the corresponding sampler test value.

The VI source is unloaded, either unloaded or with a high load resistance (megaohm level) connected, with the high side current line HF and the high side voltage line HS connected, and the low side voltage line LS and the low side current line LF connected. And the VI source is connected with the DUT, outputs current through the high-end current wire HF, and flows back to the low-end current wire LF through the DUT.

As shown in FIG. 3, step Sa is to output n groups of different excitation voltages when the VI sources are empty, respectively read the sampling machine measurement values of the analog-to-digital converter ADC1 and the analog-to-digital converter ADC2 in real time, and the multimeter reads the ground voltmeter measurement values at the two ends of the current sampling resistor R _S to obtain arrays VFB_ RsH [ n ], VRsH [ n ], VFB_RsL [ n ], VRsL [ n ].

Step Sb, performing a unitary linear fit on the voltmeter measured value VRsH [ n ] at the first end of the current sampling resistor R _S under no load and the corresponding sampler measured value vfb_ RsH [ n ], and performing a unitary linear fit on the voltmeter measured value VRsL [ n ] at the second end of the current sampling resistor R _S under no load and the corresponding sampler measured value vfb_rsl [ n ], and calculating the value of kRsH, bRsH, kRsL, bRsL in VRsH =vfb_ RsH +gain1× kRsH +brsh, vrsl=vfb_rsl×gain2× kRsL + bRsL to obtain the current machine measured value expression:

The vfb_rsh and vfb_rsl are the sampled machine measurement values of the analog-to-digital converter ADC1 and the analog-to-digital converter ADC2, rs is the nominal value of the current sampling resistor, gain1 is the hardware Gain of the link where the analog-to-digital converter ADC1 is located, gain2 is the hardware Gain of the link where the analog-to-digital converter ADC2 is located, and vfb_ RsH ×gain1× kRsH + bRsH and vfb_rsl×gain2× kRsL + bRsL are the ground voltage machine measurement values of the first end and the second end of the current sampling resistor R _S, that is, the ground voltage of the first end of the current sampling resistor R _S and the ground voltage of the second end of the current sampling resistor R _S.

Further, during loading, the control unit 130 controls the driving unit 110 to output a plurality of groups of different exciting currents, determines corresponding sampled machine measurement values according to the first digital signal and the second digital signal output by the current measurement unit 120 in real time, reads the ammeter measurement values flowing through the current sampling resistor R _S through the multimeter, calculates the ammeter measurement values of each group based on the sampler measurement values and the ammeter measurement expression during loading, performs linear fitting according to the ammeter measurement values of each group and the ammeter measurement values of each group, and determines the current calibration parameters.

With continued reference to FIG. 3, step Sc is that the VI source carries out m groups of different current excitation, the sampling machine measurement values of the analog-to-digital converter ADC1 and the analog-to-digital converter ADC2 are respectively read in real time, and the multimeter reads the ammeter measurement value flowing through the current sampling resistor R _S to obtain arrays VFB_ RsH [ m ], VFB_RsL [ m ] and IMRs [ m ].

And Sd, substituting VFB_ RsH [ m ] and VFB_RsL [ m ] into the current machine measurement expression to calculate and obtain an array MI machine measurement [ m ].

Step Se, the MI machine measured values [ m ] and IMRs [ m ] are subjected to unitary linear fitting (Rs is inaccurate and the MI machine measured values are required to be corrected), and the values of kMI and bMI in the IMRs =MI machine measured values kMI + bMI are calculated, so that the calculation formula of the measured current is as follows:

MI=kMI*[(VFB_RsH*Gain1*kRsH+bRsH)-(VFB_RsL*Gain2*kRsL+bRsL)]/Rs+bMI

Wherein MI is the measured current, kMI, bMI, kRsH, bRsH, kRsL, bRsL is the current calibration parameter, VFB_RsH and VFB_RsL are the sampling machine measurement values of the analog-digital converter ADC1 and the analog-digital converter ADC2 respectively, rs is the nominal value of the current sampling resistor, gain1 is the hardware Gain of the link where the analog-digital converter ADC1 is located, and Gain2 is the hardware Gain of the link where the analog-digital converter ADC2 is located. Vfb_ RsH x gain1 x kRsH + bRsH and vfb_rsl x gain2 x kRsL + bRsL are ground voltage measurements at the first and second ends of the current sampling resistor, respectively. And setting kMI, kRsH, kRsL to 1, and setting bMI, bRsH and bRsL to 0 to obtain the low-precision mode.

For the HS voltage measurement unit 140 and the LS voltage measurement unit 150, the HS sampler measurement value of the analog-to-digital converter ADC3 is denoted as vfb_hs, the LS sampler measurement value of the analog-to-digital converter ADC4 is denoted as vfb_ls, the hardware Gain of the analog-to-digital converter ADC3 measurement link is denoted as Gain3, and the hardware Gain of the analog-to-digital converter ADC4 measurement link is denoted as Gain4. Voltage measurement is also divided into two modes of operation, a low precision mode and a high precision mode.

VHS=VFB_HS*Gain3

VLS=VFB_LS*Gain4

MV=VHS-VLS

the specific implementation mode is that the HS sampling machine measured values VFB_HS and LS sampling machine measured values VFB_LS of the analog-digital converter ADC3 and the analog-digital converter ADC4 are

MV=VFB_HS*Gain3-VFB_LS*Gain4

In the high precision mode, calibration is required for the measurement link in which the analog-to-digital converter ADC3 and the analog-to-digital converter ADC4 are located.

In one embodiment, the multimeter is further configured to detect the voltmeter measurement of the high-side voltage line HS and the voltmeter measurement of the low-side voltage line LS, respectively.

The control unit 130 controls the driving unit 110 to output a plurality of groups of different exciting currents when in load, respectively acquires the HS sampling machine measurement value and the LS sampling machine measurement value in real time, respectively reads the HS geodetic voltmeter measurement value and the LS geodetic voltmeter measurement value through a universal meter, performs linear fitting based on each group of HS sampling machine measurement value and HS geodetic voltmeter measurement value, and determines the voltage calibration parameters based on each group of LS sampling machine measurement value and LS geodetic voltmeter measurement value.

As shown in FIG. 4, in step Sf, VI source load outputs n groups of different current excitation, the HS sampling machine measurement value of the analog-to-digital converter ADC3 and the LS sampling machine measurement value of the analog-to-digital converter ADC4 are respectively read in real time, and the universal meter reads the HS voltmeter measurement value and the LS voltmeter measurement value to obtain arrays VFB_HS [ n ], VHS [ n ], VFB_LS [ n ] and VLS [ n ].

Step Sg, performing unitary linear fitting on the measured values of the HS sampling machine vfB_HS [ n ] and the measured value of the HS to ground voltmeter VHS [ n ], and performing unitary linear fitting on the measured values of the LS sampling machine vfB_LS [ n ] and the measured values of the LS to ground voltmeter VLS [ n ], and calculating the values of kHS, bHS, kLS, bLS in the measured values of VHS=VFB_HS, gain3, kHS +bHS, VLS=VFB_LS, gain4, kLS +bLS, wherein the calculation formula of the measured voltage is as follows:

MV=(VFB_HS*Gain3*kHS+bHS)-(VFB_LS*Gain4*kLS+bLS)

Wherein MV is the measured voltage, kHS, bHS, kLS, bLS is the voltage calibration parameter, VFB_HS is the HS sampler measurement value of the analog-to-digital converter ADC3, VFB_LS is the LS sampler measurement value of the analog-to-digital converter ADC4, gain3 is the hardware Gain of the link where the analog-to-digital converter ADC3 is located, and Gain4 is the hardware Gain of the link where the analog-to-digital converter ADC4 is located. Vfb_hs Gain3+ kHS +. BHS and vfb_ls Gain4 × kLS +bLS are respectively measured by HS voltage to ground machine LS is a ground voltage measurement. And setting kHS and kLS to 1, and bHS and bLS to 0, namely the low-precision mode.

According to the digital differential sampling power supply device, the ground voltages of the four points of the two ends, HS and LS of the current sampling resistor Rs are sampled through the multipath ADC, the single-ended ground voltage of the signal is measured firstly, the differential voltage is calculated in the FPGA after the signal is converted into the digital quantity, and then the digital quantity is converted into the corresponding measured voltage MV and the corresponding measured current MI.

In one embodiment, the method is also provided for calibrating a current measuring unit, and is applied to a control unit, wherein the digital differential sampling power supply device comprises a driving unit, a current measuring unit, a current sampling resistor and a control unit, the current measuring unit is connected with two ends of the current sampling resistor, respectively detects the voltages to the ground at the two ends of the current sampling resistor, converts the voltages to obtain a first digital signal and a second digital signal, and transmits the first digital signal and the second digital signal to the control unit, the driving unit is connected to a device to be tested through a high-end current wire HF, the device to be tested is connected to the internal grounding end of the driving unit through a low-end current wire LF, and the two ends of the current sampling resistor are serially connected to the high-end current wire HF, and the method comprises the following steps:

and step S1, calculating to obtain a measured current based on a sampling machine measured value and a set current calibration parameter, wherein the sampling machine measured value is respectively determined by a control unit according to a first digital signal and a second digital signal output by a current measurement unit.

Step S11, the control unit controls the driving unit to output a plurality of groups of different excitation voltages when no-load, respectively determines sampling machine measured values according to a first digital signal and a second digital signal output by the current measuring unit in real time, respectively reads the geodetic voltmeter measured values at two ends of the current sampling resistor through the universal meter, carries out linear fitting based on the geodetic voltmeter measured values at the first end of each group of the current sampling resistor measured when no-load and the corresponding sampling machine measured values, and carries out linear fitting based on the geodetic voltmeter measured values at the second end of each group of the current sampling resistor measured when no-load and the corresponding sampling machine measured values, and determines a current machine measured value expression;

And step S12, when the load is carried, the control unit controls the driving unit to output a plurality of groups of different exciting currents, corresponding sampling machine measured values are respectively determined in real time according to the first digital signal and the second digital signal output by the current measuring unit, the ammeter measured values flowing through the current sampling resistor are read through the universal meter, the ammeter measured values of each group are obtained through calculation based on each group of sampler measured values and the ammeter measured value expression during the load, linear fitting is carried out according to the ammeter measured values of each group and each group of measured ammeter measured values, and the current calibration parameters are determined.

In one embodiment, determining a current machine measurement expression based on a linear fit of the ground voltmeter measurement and the corresponding sampler measurement at a first end of each set of measured current sampling resistors at idle and based on a linear fit of the ground voltmeter measurement and the corresponding sampler measurement at a second end of each set of measured current sampling resistors at idle comprises:

Step S111, performing unitary linear fitting on the measured value of the voltage to ground machine and the measured value of the voltage to ground meter at the first end of each group of current sampling resistors measured during no-load to obtain current calibration parameters kRsH and bRsH;

step S112, performing unitary linear fitting on the measured value of the voltmeter to the ground according to the measured value of the second end of each group of measured current sampling resistors in no-load state to obtain current calibration parameters kRsL and bRsL;

The current machine measurement expression is:

In one embodiment, determining the current calibration parameters based on linear fitting of the current machine measurements of each group and the current meter measurements of each group comprises:

And S113, performing unitary linear fitting on each group of calculated current machine measured values and each group of measured ammeter measured values to obtain current calibration parameters kMI and bMI. The calculation formula of the measured current MI is:

MI=kMI*[(VFB_RsH*Gain1*kRsH+bRsH)-(VFB_RsL*Gain2*kRsL+bRsL)]/Rs+bMI。

It can be appreciated that the calibration method of the current measurement unit, the specific embodiments of which are explained in detail in the above digital differential sampling power device, are not described herein.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims

1. A digital differential sampling power supply device, comprising:

2. The power supply device according to claim 1, wherein the control unit determines a corresponding sampling machine measurement value according to the first digital signal and the second digital signal output by the current measurement unit, and calculates a measurement current according to the sampling machine measurement value and a set current calibration parameter.

3. The power supply device of claim 2, further comprising a multimeter for detecting a voltage-to-ground measurement across the current sampling resistor and detecting a current flowing through the current sampling resistor, respectively;

4. The power supply device according to claim 1, wherein the current measurement unit includes a following operational amplifier U1, a following operational amplifier U2, a differential operational amplifier U3, a differential operational amplifier U4, an analog-to-digital converter ADC1, and an analog-to-digital converter ADC2;

5. The power supply device according to claim 4, wherein the calculation formula of the measured current is:

MI=kMI*[(VFB_RsH*Gain1*kRsH+bRsH)-(VFB_RsL*Gain2*kRsL+bRsL)]/Rs+bMI

6. The power supply apparatus according to any one of claims 1 to 5, characterized by further comprising:

7. The power supply device according to claim 6, wherein the control unit determines an HS sampler measurement value and an LS sampler measurement value from the HS digital signal and the LS digital signal output from the HS voltage measurement unit and the LS voltage measurement unit, respectively, and calculates the measured voltage from the HS sampler measurement value, the LS sampler measurement value, and the set voltage calibration parameter.

8. The power supply device of claim 7, wherein the multimeter is further configured to detect a ground voltmeter measurement of the high-side voltage line HS and a ground voltmeter measurement of the low-side voltage line LS, respectively;

9. The power supply device according to claim 6, wherein,

The HS voltage measurement unit comprises a following operational amplifier U5, a differential operational amplifier U6 and an analog-to-digital converter ADC3, wherein the non-inverting input end of the following operational amplifier U5 is connected with a high-end voltage line HS, the inverting input end of the following operational amplifier U5 is connected with the output end of the following operational amplifier U5, the output end of the following operational amplifier U5 is connected with the first input end of the differential operational amplifier U6, the second input end of the differential operational amplifier U6 is connected with a grounding end, the output end of the differential operational amplifier U6 is connected with the analog-to-digital converter ADC3, and the analog-to-digital converter ADC3 is connected with the control unit;

10. The power supply device according to claim 9, wherein the calculation formula of the measured voltage is:

MV=(VFB_HS*Gain3*kHS+bHS)-(VFB_LS*Gain4*kLS+bLS)

11. The calibration method of the current measuring unit is characterized by being applied to a control unit, wherein a digital differential sampling power supply device comprises a driving unit, a current measuring unit, a current sampling resistor and a control unit, the current measuring unit is connected with two ends of the current sampling resistor, ground voltages at two ends of the current sampling resistor are detected respectively, a first digital signal and a second digital signal are obtained through conversion and are transmitted to the control unit, the driving unit is connected to a device to be measured through a high-end current wire HF, the device to be measured is connected to the internal grounding end of the driving unit through a low-end current wire LF, two ends of the current sampling resistor are connected in series to the high-end current wire HF, and the method comprises the following steps:

12. The method of claim 11, wherein the multimeter is configured to detect a voltage-to-ground measurement across the current sampling resistor and to detect a current flowing through the current sampling resistor, respectively, and wherein determining the set current calibration parameter comprises:

13. The method of claim 12, wherein determining the current machine measurement expression based on the linear fit of the ground voltmeter measurement at the first end of each set of measured current sampling resistors and the corresponding sampler measurement at the no-load and the linear fit of the ground voltmeter measurement at the second end of each set of measured current sampling resistors and the corresponding sampler measurement at the no-load comprises:

The current machine measurement expression is:

14. The method of claim 13, wherein determining the current calibration parameters based on linear fitting of the current machine measurements of each group and the current meter measurements of each group comprises:

the calculation formula of the measured current MI is:

MI=kMI*[(VFB_RsH*Gain1*kRsH+bRsH)-(VFB_RsL*Gain2*kRsL+bRsL)]/Rs+bMI。