Testing machine and low-noise voltage output device thereof

Abstract

The utility model relates to a testing machine and a low-noise voltage output device thereof, and the device comprises a superposition noise reduction module which is connected with a to-be-tested device and a digital-to-analog converter, amplifies a reference voltage outputted by the to-be-tested device, and carries out the superposition noise reduction output of the amplified voltage and a DC voltage outputted by the digital-to-analog converter; and the active filter is connected with the superposition noise reduction module and is used for filtering the voltage output by the superposition noise reduction module and outputting filtered voltage. The reference voltage output by the to-be-tested device is firstly amplified and then superposed with the direct-current voltage output by the digital-to-analog converter for noise reduction, and finally the filtered voltage is output after filtering processing of the active filter, so that the noise introduced by the digital-to-analog converter and the to-be-tested device is effectively reduced, the negative influence of the noise on the test result is reduced, and the test accuracy is improved.

Description

Technical Field

[0001] The present application relates to the technical field of integrated circuit testing, and in particular to a testing machine and a low-noise voltage output device thereof. Background Art

[0002] In the manufacturing process of semiconductor devices, it is necessary to test the signal parameters generated by the device to verify whether the device can work normally. For example, for devices such as analog-to-digital converters, digital-to-analog converters, and operational amplifiers, the relevant parameters are collected to determine whether the device performance meets the standards. In the test, the differential AC signal usually needs to be superimposed with a DC common-mode voltage and sent to the device under test to reflect the true performance of the device under test. In the traditional test scheme, a DC voltage is generated by a digital-to-analog converter, and the DC voltage is added to the AC signal through an operational amplifier to test the device under test. The noise of the digital-to-analog converter is directly superimposed on the subsequent circuit, causing the performance of the test signal to degrade, affecting the test accuracy of the device under test. Utility Model Content

[0003] Based on this, it is necessary to provide a test machine and a low-noise voltage output device thereof that can improve test accuracy in order to address the above problems.

[0004] The first aspect of the present application provides a low-noise voltage output device for a test machine, comprising:

[0005] A superposition noise reduction module is connected to the device under test and the digital-to-analog converter, amplifies the reference voltage output by the device under test, and superimposes the amplified voltage and the DC voltage output by the digital-to-analog converter for noise reduction output;

[0006] The active filter is connected to the superposition noise reduction module, filters the voltage output by the superposition noise reduction module, and outputs a filtered voltage.

[0007] In one of the embodiments, the superposition noise reduction module includes a voltage amplification circuit and a voltage superposition circuit, the voltage superposition circuit is connected to the digital-to-analog converter, and is connected to the device under test through the voltage amplification circuit.

[0008] In one of the embodiments, the superposition noise reduction module further includes an impedance transformation circuit, and the voltage amplification circuit is connected to the device under test via the impedance transformation circuit.

[0009] In one embodiment, the impedance conversion circuit includes an operational amplifier U1, a resistor R1 and a resistor R2, the first end of the resistor R1 is connected to the device under test, the second end of the resistor R1 is connected to the first input end of the operational amplifier U1, the first end of the resistor R2 is connected to the second input end of the operational amplifier U1, the second end of the resistor R2 is connected to the output end of the operational amplifier U1, and the output end of the operational amplifier U1 is connected to the voltage amplifier circuit.

[0010] In one embodiment, the voltage amplification circuit includes an operational amplifier U2, a resistor R3, a resistor R4, a resistor R5 and a resistor R6, the first end of the resistor R3 is connected to the impedance conversion circuit, the second end of the resistor R3 is connected to the first end of the resistor R4 and the first input end of the operational amplifier U2, the second end of the resistor R4 is connected to the output end of the operational amplifier U2, the second input end of the operational amplifier U2 is connected to the first end of the resistor R5 and the first end of the resistor R6, the second end of the resistor R5 is grounded, the second end of the resistor R6 is connected to the output end of the operational amplifier U2, and the output end of the operational amplifier U2 is connected to the voltage superposition circuit.

[0011] In one embodiment, the voltage superposition circuit includes an operational amplifier U3, a resistor R7, a resistor R8, a resistor R9 and a resistor R10, a first end of the resistor R7 is connected to the digital-to-analog converter, a second end of the resistor R7 is connected to the first input end of the operational amplifier U3 and the first end of the resistor R8, a second end of the resistor R8 is connected to the output end of the operational amplifier U3, a first end of the resistor R9 is connected to the voltage amplification circuit, a second end of the resistor R9 is connected to the second input end of the operational amplifier U3 and the first end of the resistor R10, a second end of the resistor R10 is connected to the output end of the operational amplifier U3, and the output end of the operational amplifier U3 is connected to the active filter.

[0012] In one embodiment, the low noise voltage output device further comprises:

[0013] The output circuit is connected to the active filter, receives the filtered voltage and a preset signal, and outputs the result after superposition.

[0014] In one embodiment, the output circuit includes an operational amplifier U4, a resistor R11, a resistor R12, a resistor R13, a resistor R14 and a resistor R15, the first end of the resistor R11 is connected to a preset signal, the second end of the resistor R11 is connected to the first end of the resistor R12 and the first input end of the operational amplifier U4, the second end of the resistor R12 is connected to the output end of the operational amplifier U4, the first end of the resistor R13 is connected to the active filter, the second end of the resistor R13 is connected to the first input end of the operational amplifier U4, the second input end of the operational amplifier U4 is connected to the first end of the resistor R14 and the first end of the resistor R15, the second end of the resistor R14 is grounded, and the second end of the resistor R15 is connected to the output end of the operational amplifier U4.

[0015] A second aspect of the present application provides a testing machine, comprising a digital-to-analog converter and the above-mentioned low-noise voltage output device.

[0016] In one embodiment, the test machine also includes a first analog channel, a second analog channel, a control module and an acquisition module, the digital-to-analog converter includes a first digital-to-analog converter and a second digital-to-analog converter, the low-noise voltage output device includes a first low-noise voltage output device and a second low-noise voltage output device, the first low-noise voltage output device is connected to the first digital-to-analog converter, the first analog channel and the device under test, the second low-noise voltage output device is connected to the second digital-to-analog converter, the second analog channel, the acquisition module and the device under test, and the second analog channel is connected to the device under test; the control module is connected to the first digital-to-analog converter and the second digital-to-analog converter.

[0017] In the above-mentioned test machine and its low-noise voltage output device, the superimposed noise reduction module amplifies the reference voltage output by the device under test, and superimposes the amplified voltage and the DC voltage output by the digital-to-analog converter to output noise reduction; the active filter filters the voltage output by the superimposed noise reduction module and outputs the filtered voltage. By first amplifying the reference voltage output by the device under test, then superimposing and reducing the noise with the DC voltage output by the digital-to-analog converter, and finally outputting the filtered voltage after filtering by the active filter, the noise introduced by the digital-to-analog converter and the device under test is effectively reduced, thereby reducing the negative impact of noise on the test results and improving the test accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of a low noise voltage output device in one embodiment;

[0019] Figure 2 is a structural principle diagram of an impedance conversion circuit in one embodiment;

[0020] Figure 3is a structural principle diagram of a voltage amplifier circuit in one embodiment;

[0021] Figure 4 is a structural principle diagram of a voltage superposition circuit in one embodiment;

[0022] Figure 5 is a structural schematic diagram of an output circuit in one embodiment;

[0023] Figure 6 FIG. 4 is a schematic diagram of the structure of a testing machine in an embodiment. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0026] It is understood that the terms "first", "second", etc. used in this application can be used to describe various elements in this article, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. The "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if the connected circuits, modules, units, etc. have transmission of electrical signals or data with each other.

[0027] When used herein, the singular forms "a", "an", and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0028] In one embodiment, Figure 1As shown, a low-noise voltage output device of a test machine is provided, including a superposition noise reduction module 10 and an active filter 140, wherein the superposition noise reduction module 10 is connected to the device under test DUT and the digital-to-analog converter DAC, and the active filter 140 is connected to the superposition noise reduction module 10. The superposition noise reduction module 10 amplifies the reference voltage output by the device under test DUT, and superimposes and reduces the noise of the amplified voltage and the DC voltage output by the digital-to-analog converter DAC; the active filter 140 filters the voltage output by the superposition noise reduction module and outputs a filtered voltage. Among them, after the superposition noise reduction module 10 amplifies the reference voltage output by the device under test DUT, the amplified voltage and the DC voltage output by the digital-to-analog converter DAC may be superimposed and noise reduced at the same time, may be superimposed first and then noise reduced, or may be noise reduced first and then superimposed. The type of filtered voltage output by the active filter 140 is not unique, and may specifically include a common mode voltage or a bias voltage.

[0029] like Figure 1 As shown, the superposition noise reduction module 10 may include a voltage amplification circuit 120 and a voltage superposition circuit 130, wherein the voltage superposition circuit 130 is connected to a digital-to-analog converter DAC and is connected to a device under test DUT through the voltage amplification circuit 120. Further, the superposition noise reduction module 10 also includes an impedance transformation circuit 110, wherein the voltage amplification circuit 120 is connected to the device under test DUT through the impedance transformation circuit 110.

[0030] Specifically, the impedance transformation circuit 110 is connected to the ground terminal DUT_GND of the device under test DUT, and is connected to the reference voltage for impedance transformation and then output to the voltage amplifier circuit 120. The voltage amplifier circuit 120 amplifies the input voltage by N times and sends the amplified voltage to the voltage superposition circuit 130. The specific value of N is not unique and can be set according to actual needs. The voltage superposition circuit 130 accesses the amplified voltage and the DC voltage output by the digital-to-analog converter DAC for superposition and noise reduction processing, which can be superposition and noise reduction at the same time, can be superposition first and then noise reduction, or can be noise reduction first and then superposition. For example, the voltage superposition circuit 130 can first access the amplified voltage and the DC voltage output by the digital-to-analog converter DAC for superposition, and then reduce the superimposed voltage and noise by N times to complete noise reduction, and output the voltage to the active filter 140. The active filter 140 has an extremely low cut-off frequency and a fast step response curve, and filters the input voltage to reduce noise.

[0031] The above-mentioned low-noise voltage output device first amplifies the reference voltage output by the device under test DUT, then superimposes it with the DC voltage output by the digital-to-analog converter DAC to reduce noise, and finally outputs the filtered voltage after filtering by the active filter 140. A multi-stage circuit is used to amplify, superimpose noise reduction and filter the voltage signal noise to achieve the purpose of reducing noise, effectively reduce the noise introduced by the digital-to-analog converter DAC and the device under test DUT, thereby reducing the negative impact of noise on the test results and improving the test accuracy.

[0032] The specific structure of the impedance conversion circuit 110 is not unique. In one embodiment, Figure 2 As shown, the impedance conversion circuit 110 includes an operational amplifier U1, a resistor R1 and a resistor R2, wherein a first end of the resistor R1 is connected to the device under test DUT, a second end of the resistor R1 is connected to a first input end of the operational amplifier U1, a first end of the resistor R2 is connected to a second input end of the operational amplifier U1, a second end of the resistor R2 is connected to an output end of the operational amplifier U1, and the output end of the operational amplifier U1 is connected to a voltage amplifier circuit 120.

[0033] Furthermore, if Figure 3 As shown, the voltage amplifier circuit 120 includes an operational amplifier U2, a resistor R3, a resistor R4, a resistor R5, and a resistor R6, the first end of the resistor R3 is connected to the impedance conversion circuit 110, the second end of the resistor R3 is connected to the first end of the resistor R4 and the first input end of the operational amplifier U2, the second end of the resistor R4 is connected to the output end of the operational amplifier U2, the second input end of the operational amplifier U2 is connected to the first end of the resistor R5 and the first end of the resistor R6, the second end of the resistor R5 is grounded, the second end of the resistor R6 is connected to the output end of the operational amplifier U2, and the output end of the operational amplifier U2 is connected to the voltage superposition circuit 130. Among them, the first end of the resistor R3 is specifically connected to the output end of the operational amplifier U1 in the impedance conversion circuit 110.

[0034] In one embodiment, Figure 4As shown, the voltage superposition circuit 130 includes an operational amplifier U3, a resistor R7, a resistor R8, a resistor R9 and a resistor R10, the first end of the resistor R7 is connected to the digital-to-analog converter DAC, the second end of the resistor R7 is connected to the first input end of the operational amplifier U3 and the first end of the resistor R8, the second end of the resistor R8 is connected to the output end of the operational amplifier U3, the first end of the resistor R9 is connected to the voltage amplifier circuit 120, the second end of the resistor R9 is connected to the second input end of the operational amplifier U3 and the first end of the resistor R10, the second end of the resistor R10 is connected to the output end of the operational amplifier U3, and the output end of the operational amplifier U3 is connected to the active filter 140. Among them, the first end of the resistor R9 is specifically connected to the output end of the operational amplifier U2 in the voltage amplifier circuit 120. The specific form of the voltage superposition circuit 130 can achieve simultaneous voltage superposition and voltage noise reduction.

[0035] Further, continue to refer to Figure 1 The low-noise voltage output device also includes an output circuit 150, which is connected to the active filter 140, receives the filtered voltage and the preset signal, and outputs them after superposition. Depending on the type of the filtered voltage, the type of the preset signal will also be different. When the filtered voltage is a common-mode voltage, the preset signal can be an AC differential signal; when the filtered voltage is a bias voltage, the preset signal can be a single-ended signal. The output circuit 150 can output the AC differential signal in combination with the common-mode voltage, or it can output the single-ended signal in combination with the bias voltage.

[0036] It can be understood that the specific structure of the output circuit 150 is not unique. Figure 5 As shown, the output circuit 150 may include an operational amplifier U4, a resistor R11, a resistor R12, a resistor R13, a resistor R14, and a resistor R15. The first end of the resistor R11 is connected to a preset signal, which may be an AC differential signal AC or a single-ended signal. The second end of the resistor R11 is connected to the first end of the resistor R12 and the first input end of the operational amplifier U4, the second end of the resistor R12 is connected to the output end of the operational amplifier U4, the first end of the resistor R13 is connected to the active filter 140, the second end of the resistor R13 is connected to the first input end of the operational amplifier U4, the second input end of the operational amplifier U4 is connected to the first end of the resistor R14 and the first end of the resistor R15, the second end of the resistor R14 is grounded, and the second end of the resistor R15 is connected to the output end of the operational amplifier U4.

[0037] In one embodiment, a test machine is provided, comprising a digital-to-analog converter and the above-mentioned low-noise voltage output device. Figure 6As shown, the digital-to-analog converter includes a first digital-to-analog converter DAC1 and a second digital-to-analog converter DAC2, the low-noise voltage output device includes a first low-noise voltage output device 100 and a second low-noise voltage output device 200, the test machine also includes a first analog channel 300, a second analog channel 400 and an acquisition module 500, the first low-noise voltage output device 100 is connected to the first digital-to-analog converter DAC1, the first analog channel 300 and the device under test DUT, the second low-noise voltage output device 200 is connected to the second digital-to-analog converter DAC2, the second analog channel 400, the acquisition module 500 and the device under test DUT, and the second analog channel 400 is connected to the device under test DUT.

[0038] Among them, the first analog channel 300 can use an AWG (Arbitrary Waveform Generator) analog channel. In the first low-noise voltage output device 100, the impedance conversion circuit 110 is connected to the ground terminal DUT_GND of the device under test DUT and connected to the reference voltage, and the voltage superposition circuit 130 is connected to the first digital-to-analog converter DAC1, connected to the DC voltage output by the first digital-to-analog converter DAC1, and superimposed with the amplified voltage output by the voltage amplifier circuit 120 to reduce noise, and then output to the active filter 140. The output circuit 150 is connected to the filtered voltage (such as common mode voltage) output by the active filter 140, and the preset signal (such as AC differential signal AC) output by the first analog channel 300, and is superimposed and output to the device under test DUT. When the device under test DUT is tested by AWG, the noise introduced by the first digital-to-analog converter DAC1 and the noise introduced by the ground terminal DUT_GND of the device under test DUT can be effectively reduced, and the signal-to-noise ratio can be improved.

[0039] The second analog channel 400 may adopt a DIG (Digitizer) analog channel, and the acquisition module 500 corresponds to a DIG acquisition module. In the second low-noise voltage output device 200, the impedance conversion circuit 110 is connected to the ground terminal DUT_GND of the device under test DUT and connected to the reference voltage, the voltage superposition circuit 130 is connected to the second digital-to-analog converter DAC2, connected to the DC voltage output by the second digital-to-analog converter DAC2, and superimposed with the amplified voltage output by the voltage amplifier circuit 120 to reduce noise, and then output to the active filter 140. The second analog channel 400 outputs a preset signal according to the feedback signal of the device under test DUT, and the output circuit 150 is connected to the filtered voltage (such as a common mode voltage) output by the active filter 140 and the preset signal (such as an AC differential signal AC) output by the second analog channel 400, and superimposed and output to the acquisition module 500 for data acquisition. When testing the device under test (DUT) through DIG, providing a low-noise DC voltage to the output circuit 150 in the second low-noise voltage output device 200 can effectively reduce the influence of DC voltage noise and improve test accuracy.

[0040] In addition, the test machine may further include a control module 600, the control module 600 is connected to the first digital-to-analog converter DAC1 and the second digital-to-analog converter DAC2, and controls the first digital-to-analog converter DAC1 and the second digital-to-analog converter DAC2 to output a DC voltage. The control module 600 may be a single controller or a dual controller. In the present embodiment, the control module 600 includes a controller 1 and a controller 2, the controller 1 is connected to the first digital-to-analog converter DAC1, and the controller 2 is connected to the second digital-to-analog converter DAC2. The specific types of the controller 1 and the controller 2 are not unique, and may be devices such as FPGA (Field-Programmable Gate Array), MCU (Micro Control Unit), and CPU (Central Processing Unit).

[0041] The above-mentioned test machine amplifies the reference voltage output by the device under test first, then superimposes it with the DC voltage output by the digital-to-analog converter to reduce noise, and finally outputs the filtered voltage after filtering by an active filter, thereby effectively reducing the noise introduced by the digital-to-analog converter and the device under test, thereby reducing the negative impact of noise on the test results and improving the test accuracy.

[0042] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A low-noise voltage output device for a test machine, characterized in that: include: A superposition noise reduction module is connected to the device under test and the digital-to-analog converter, amplifies the reference voltage output by the device under test, and superimposes the amplified voltage and the DC voltage output by the digital-to-analog converter for noise reduction output; The active filter is connected to the superposition noise reduction module, filters the voltage output by the superposition noise reduction module, and outputs a filtered voltage.

2. The device according to claim 1, characterized in that The superposition noise reduction module includes a voltage amplification circuit and a voltage superposition circuit. The voltage superposition circuit is connected to the digital-to-analog converter and is connected to the device under test through the voltage amplification circuit.

3. The device according to claim 2, characterized in that The superposition noise reduction module further includes an impedance conversion circuit, and the voltage amplification circuit is connected to the device under test via the impedance conversion circuit.

4. The device according to claim 3, characterized in that The impedance conversion circuit includes an operational amplifier U1, a resistor R1 and a resistor R2, wherein the first end of the resistor R1 is connected to the device under test, the second end of the resistor R1 is connected to the first input end of the operational amplifier U1, the first end of the resistor R2 is connected to the second input end of the operational amplifier U1, the second end of the resistor R2 is connected to the output end of the operational amplifier U1, and the output end of the operational amplifier U1 is connected to the voltage amplifier circuit.

5. The device according to claim 3, characterized in that The voltage amplification circuit includes an operational amplifier U2, a resistor R3, a resistor R4, a resistor R5 and a resistor R6, the first end of the resistor R3 is connected to the impedance conversion circuit, the second end of the resistor R3 is connected to the first end of the resistor R4 and the first input end of the operational amplifier U2, the second end of the resistor R4 is connected to the output end of the operational amplifier U2, the second input end of the operational amplifier U2 is connected to the first end of the resistor R5 and the first end of the resistor R6, the second end of the resistor R5 is grounded, the second end of the resistor R6 is connected to the output end of the operational amplifier U2, and the output end of the operational amplifier U2 is connected to the voltage superposition circuit.

6. The device according to claim 2, characterized in that The voltage superposition circuit includes an operational amplifier U3, a resistor R7, a resistor R8, a resistor R9 and a resistor R10, a first end of the resistor R7 is connected to the digital-to-analog converter, a second end of the resistor R7 is connected to the first input end of the operational amplifier U3 and the first end of the resistor R8, a second end of the resistor R8 is connected to the output end of the operational amplifier U3, a first end of the resistor R9 is connected to the voltage amplification circuit, a second end of the resistor R9 is connected to the second input end of the operational amplifier U3 and the first end of the resistor R10, a second end of the resistor R10 is connected to the output end of the operational amplifier U3, and the output end of the operational amplifier U3 is connected to the active filter.

7. The device according to any one of claims 1 to 6, characterized in that: Also includes: The output circuit is connected to the active filter, receives the filtered voltage and a preset signal, and outputs the result after superposition.

8. The device according to claim 7, characterized in that The output circuit includes an operational amplifier U4, a resistor R11, a resistor R12, a resistor R13, a resistor R14 and a resistor R15. The first end of the resistor R11 is connected to a preset signal, the second end of the resistor R11 is connected to the first end of the resistor R12 and the first input end of the operational amplifier U4, the second end of the resistor R12 is connected to the output end of the operational amplifier U4, the first end of the resistor R13 is connected to the active filter, the second end of the resistor R13 is connected to the first input end of the operational amplifier U4, the second input end of the operational amplifier U4 is connected to the first end of the resistor R14 and the first end of the resistor R15, the second end of the resistor R14 is grounded, and the second end of the resistor R15 is connected to the output end of the operational amplifier U4.

9. A testing machine, characterized in that: It comprises a digital-to-analog converter and the low-noise voltage output device according to any one of claims 1 to 8.

10. The testing machine according to claim 9, characterized in that: It also includes a first analog channel, a second analog channel, a control module and an acquisition module, the digital-to-analog converter includes a first digital-to-analog converter and a second digital-to-analog converter, the low-noise voltage output device includes a first low-noise voltage output device and a second low-noise voltage output device, the first low-noise voltage output device is connected to the first digital-to-analog converter, the first analog channel and the device under test, the second low-noise voltage output device is connected to the second digital-to-analog converter, the second analog channel, the acquisition module and the device under test, and the second analog channel is connected to the device under test; The control module is connected to the first digital-to-analog converter and the second digital-to-analog converter.

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