Test method and test system

Abstract

This disclosure relates to test methods and test systems. One test method includes the following operations: generating a multi-frequency signal using a signal generator; transmitting the multi-frequency signal to an input terminal of a device under test (DUT) using the signal generator; measuring the input terminal and an output terminal of the DUT using a spectrum analyzer to obtain complex input ripple intensity and complex output ripple intensity at corresponding complex frequency points; and generating a complex power supply rejection ratio (PSRR) corresponding to the corresponding frequency points using a control device based on the input ripple intensity and the output ripple intensity.

Description

Technical Field

[0001] This disclosure relates to a testing technique, and more particularly to a testing method and system that enables rapid testing. Background Technology

[0002] The power supply rejection ratio (PSRR) is an important parameter used to judge the degree to which a power supply circuit suppresses input ripple.

[0003] In some related technologies, oscilloscopes are used to perform measurements in the time domain. However, oscilloscopes can only measure voltages in the millivolt range, thus limiting the range of power supply rejection ratios (PSRs) they can measure (e.g., 40 dB to 50 dB). Therefore, if the PSR of a device under test exceeds this range (e.g., 60 dB), the oscilloscope will be unable to accurately measure the PSR. Summary of the Invention

[0004] Some embodiments disclosed herein relate to a test method. The test method includes the following operations: generating a multi-frequency signal using a signal generator; transmitting the multi-frequency signal to an input terminal of a device under test (DUT) using the signal generator; measuring the input terminal and an output terminal of the DUT using a spectrum analyzer to obtain complex input ripple intensity and complex output ripple intensity at corresponding complex frequency points; and generating a complex power supply rejection ratio (PSRR) corresponding to the corresponding frequency points using a control device based on the input ripple intensity and the output ripple intensity.

[0005] Some embodiments disclosed herein relate to a test system. The test system includes a signal generator, a spectrum analyzer, and a control device. The signal generator generates a multi-frequency signal and transmits the multi-frequency signal to an input terminal of a device under test (DUT). The spectrum analyzer is coupled to the DUT and measures the input terminal and an output terminal of the DUT to obtain complex input ripple strength and complex output strength at corresponding complex frequency points. The control device is coupled to the spectrum analyzer and generates a complex power supply rejection ratio (PSRR) corresponding to the corresponding frequency points based on the input ripple strength and the output ripple strength.

[0006] In summary, this disclosure allows for the input of multi-frequency signals to the device under test (DUT), and the use of a spectrum analyzer to perform multi-frequency measurements at both the input and output terminals, thereby rapidly measuring the power supply rejection ratio (PSRR) of the DUT at different frequency points. Furthermore, since this disclosure performs measurements in the frequency domain, it improves the dynamic range of the measurement. Attached Figure Description

[0007] To make the above and other objects, features, advantages and embodiments of this disclosure more apparent and understandable, the accompanying drawings are described below:

[0008] Figure 1 This is a schematic diagram of a test system illustrated according to some embodiments of the present disclosure;

[0009] Figure 2 It is illustrated in accordance with some embodiments of this disclosure. Figure 1 A schematic diagram of the device under test;

[0010] Figure 3 This is a flowchart illustrating a test method according to some embodiments of this disclosure;

[0011] Figure 4 This is a schematic diagram illustrating an inverse Fourier transform according to some embodiments of this disclosure;

[0012] Figures 5A-5B These are schematic diagrams illustrating the input ripple intensity and output ripple intensity according to some embodiments of this disclosure;

[0013] Figure 6 This is a schematic diagram illustrating the generation of power supply rejection ratio according to some embodiments of this disclosure;

[0014] Figure 7 It is illustrated in accordance with some embodiments of this disclosure. Figure 3 A detailed flowchart of one of the operations; and

[0015] Figure 8 It is illustrated in accordance with some embodiments of this disclosure. Figure 3 A detailed flowchart of one of the operations. Detailed Implementation

[0016] The term "coupled" as used in this article can also refer to "electrical coupling," and the term "connection" can also refer to "electrical connection." "Coupled" and "connection" can also refer to two or more components cooperating or interacting with each other.

[0017] refer to Figure 1 . Figure 1 This is a schematic diagram of a test system 100 illustrated according to some embodiments of the present disclosure. The test system 100 is used to test a device under test (DUT) to quickly generate the power supply rejection ratio (PSRR) of the DUT. In some embodiments, the DUT may be a power supply chip, and the test system 100 may test the power supply chip to quickly generate the PRR of the power supply chip.

[0018] by Figure 1For example, the test system 100 includes a control bus BUS, a signal generator 110, a spectrum analyzer 120, a control device 130, a DC meter 140, a filter 150, and a switching device 160.

[0019] Signal generator 110, spectrum analyzer 120, control unit 130, DC meter 140, and device under test (DUT) are all coupled to a control bus (BUS). Signal generator 110 is coupled to the input terminal IN of the DUT. The output terminal OUT of the DUT is coupled to a load Z. Control unit 130 is coupled to switching device 160. Spectrum analyzer 120 is coupled to filter 150. Filter 150 is coupled to DC meter 140. Switching device 160 is coupled to the input terminal IN of the DUT, the output terminal OUT of the DUT, filter 150, and DC meter 140.

[0020] In some embodiments, the coupling between the signal generator 110 and the device under test (DUT), and the coupling between the DUT and the load Z, can be achieved via a wire. In some embodiments, the coupling between the switching device 160 and the input terminal IN, and the coupling between the switching device 160 and the output terminal OUT, can be achieved via a cable or probe. In some embodiments, the coupling between the control device 130 and the switching device 160 can be achieved via another control bus.

[0021] The control device 130 can be a tablet computer, notebook computer, desktop computer, or other electronic device with control and data processing functions. The filter 150 can be used to filter out the DC component, allowing only the AC component to pass through for measurement by the spectrum analyzer 120. The switching device 160 can be a single-pole double-throw (SPDT) switcher.

[0022] refer to Figure 2 . Figure 2 It is illustrated in accordance with some embodiments of this disclosure. Figure 1 A schematic diagram of the device under test (DUT) in the diagram.

[0023] As mentioned above, the device under test (DUT) is, for example, a power supply chip; however, the present invention is not limited thereto. Figure 2For example, a device under test (DUT) may include a reference circuit 210, an amplifier circuit 220, and a switching circuit 230. The reference circuit 210 is coupled between its input terminal IN and ground terminal GND. The first input terminal (e.g., negative input terminal) of the amplifier circuit 220 is coupled to the reference circuit 210, and its second input terminal (e.g., positive input terminal) is coupled to its output terminal OUT. The first terminal of the switching circuit 230 is coupled to its input terminal IN, its second terminal is coupled to its output terminal OUT, and its control terminal is coupled to the output terminal of the amplifier circuit 220.

[0024] In some embodiments, the input terminal IN of the device under test (DUT) can be used to receive a DC input voltage V. IN (For example: 5 volts), and the DC input voltage V IN Perform voltage conversion (e.g., step-down) to generate a DC output voltage V. OUT (For example: 3.3 volts).

[0025] However, under normal operating conditions, except for the DC input voltage V IN In addition, the input terminal IN may contain an input ripple RP1. Since the device under test (DUT) is not a nonlinear component, the input ripple RP1 at the input terminal IN will cause an output ripple RP2 at the output terminal OUT after passing through the DUT. For example, if the input ripple RP1 has a fundamental frequency (e.g., 1 MHz), the output ripple RP2 will contain multiple harmonic sine waves (e.g., 2 MHz, 3 MHz). Furthermore, noise may exist on the path P1-P3, and this noise will also contribute to the output ripple RP2.

[0026] and Figure 1 The test system 100 can be used to measure the input ripple RP1 at the input terminal IN and the output ripple RP2 at the output terminal OUT to quickly generate the power supply rejection ratio (PSRR) of the device under test (DUT). How to quickly generate the PSRR of the DUT will be described in detail in later paragraphs.

[0027] Please refer to the above. Figure 1 as well as Figure 3 . Figure 3 This is a flowchart illustrating a test method 300 according to some embodiments of this disclosure. In some embodiments, the test method 300 is applied to... Figure 1 The test system 100 is described herein, but this disclosure is not limited thereto. The test method 300 includes operations S310, S320, S330, and S340.

[0028] In operation of S310, a multi-frequency signal MT is generated by signal generator 110.

[0029] In some embodiments, the signal generator 110 can superimpose multiple sine waves in the time domain to generate a multi-frequency signal MT, as shown in the following formula (1):

[0030] MT=Asin(2πf1t)+Asin(2πf2t)+…Asin(2πf N t)...Formula (1)

[0031] Where A is the amplitude, f1-f N For different frequency points, t is the time point.

[0032] In some other embodiments, the signal generator 110 may also perform an inverse Fourier transform procedure in the frequency domain to generate a multi-frequency signal MT. (See reference...) Figure 4 . Figure 4 This is a schematic diagram illustrating the inverse Fourier transform according to some embodiments of this disclosure. For example, if the system sampling rate is 20 MHz and the number of frequency points is 64, it represents an output frequency resolution of 312.5 kHz. In this example, the first frequency point is 312.5 kHz, the second frequency point is 625 kHz, and so on. Figure 4 For example, if you want the time-domain output signal to have a component at the first frequency point (312.5 kHz), then you would... Figure 4 The corresponding coefficient 0 in the text should be filled with "1". If you want the time-domain output signal to not have a component at the second frequency point (625kHz), then... Figure 4 The corresponding coefficient 1 is filled with "0", and so on. After filling all the corresponding coefficients with appropriate coefficients, the signal generator 110 can perform the inverse Fourier transform program based on these corresponding coefficients to generate the multi-frequency signal MT.

[0033] Refer again Figure 3 In operation S320, the signal generator 110 transmits the multi-frequency signal MT to the input terminal IN of the device under test (DUT). In some embodiments, the signal generator 110 is further used to transmit a combination of the DC signal DS and the multi-frequency signal MT to the input terminal IN of the DUT. It should be noted that the DC signal DS can be considered as the DC input voltage V. IN The multi-frequency signal MT can be considered as the input ripple RP1. The device under test (DUT) operates based on the combination of the DC signal DS and the multi-frequency signal MT to generate a DC output signal V at the output terminal OUT. OUT Combined with output ripple RP2.

[0034] In operation 330, the spectrum analyzer 120 measures the input terminal IN and the output terminal OUT of the device under test (DUT) to obtain the complex input ripple intensity and the complex output ripple intensity. In some embodiments, the control device 130 controls the switching device 160 to couple the spectrum analyzer 120 to the input terminal IN or to the output terminal OUT.

[0035] refer to Figures 5A-5B . Figures 5A-5B These are schematic diagrams illustrating the input ripple intensity and output ripple intensity according to some embodiments of this disclosure. Figure 5A For example, when control device 130 controls switching device 160 to couple spectrum analyzer 120 to input terminal IN, spectrum analyzer 120 can measure input terminal IN of device under test (DUT) to obtain the input ripple intensity P. i1 -P iN Input ripple intensity P i1 -P iN These correspond to frequency points f1-f in the multi-frequency signal MT. N Similarly, with Figure 5B For example, when control device 130 controls switching device 160 to couple spectrum analyzer 120 to output terminal OUT, spectrum analyzer 120 can measure the output terminal OUT of device under test (DUT) to obtain the output ripple intensity P. o1 -P oN Output ripple intensity P o1 -P oN These also correspond to frequency points f1-f in the multi-frequency signal MT. N .

[0036] Refer again Figure 3 In operation S340, the control device 130 determines the ripple intensity P based on the input. i1 -P iN and output ripple intensity P o1 -P oN Generate the corresponding frequency point f1-f N Complex power supply rejection ratio.

[0037] refer to Figure 6 . Figure 6 This is a schematic diagram illustrating the generation of power supply rejection ratio according to some embodiments of this disclosure.

[0038] In some embodiments, the control device 130 can control the input ripple intensity P corresponding to the frequency point f1. i1 Subtract the output ripple intensity P corresponding to frequency point f1 o1The power supply rejection ratio (PSRR) corresponding to frequency point f1 is obtained. Based on the principle of similarity, the control device 130 can subtract the output ripple intensity corresponding to other frequency points from the input ripple intensity corresponding to other frequency points to obtain the power supply rejection ratio corresponding to other frequency points.

[0039] In some related technologies, oscilloscopes are used to perform measurements in the time domain. However, oscilloscopes can only measure voltages in the millivolt range, thus limiting the range of power supply rejection ratios (PSRs) they can measure (e.g., 40 dB to 50 dB). In other words, if the PSR of a device under test exceeds this range (e.g., 60 dB), the oscilloscope will not be able to accurately measure the PSR.

[0040] Furthermore, measurements in the time domain also present issues with noise and harmonic sine waves. Specifically, the nonlinear components of the output signal generate multiple harmonic sine waves. These harmonic sine waves, whether in-phase or out-phase, will superimpose to produce different output signals. This will affect the measured output signal, and consequently, the power supply rejection ratio (PSRR).

[0041] Compared to the aforementioned related technologies, the signal generator 110 disclosed herein can generate a multi-frequency signal MT, and input the combination of the multi-frequency signal MT and the DC signal DS to the input terminal IN of the device under test (DUT). Next, the control device 130 disclosed herein can (e.g., through the control switching device 160) control the spectrum analyzer 120 to be coupled to both the input terminal IN and the output terminal OUT of the DUT, allowing the spectrum analyzer 120 to perform multi-frequency measurements on both the input terminal IN and the output terminal OUT. Since only one measurement is needed at either the input terminal IN or the output terminal OUT to quickly measure the power supply rejection ratio (PSRR) of the DUT at different frequency points, this disclosure offers the advantage of saving test time. Furthermore, since this disclosure performs measurements in the frequency domain, it can improve the dynamic range of the measurement.

[0042] In some embodiments, the control device 130 may generate a result report based on the power supply rejection ratios generated during operation S340, and display it on the display screen of the control device 130. This allows testers or circuit designers to quickly determine the frequency points f1-f1. N The power supply rejection ratio is used to adjust the circuit design or related parameters.

[0043] refer to Figure 1 as well as Figure 7 . Figure 7 It is illustrated in accordance with some embodiments of this disclosure. Figure 3The detailed flowchart of operation S330 includes operations S331A, S332A, S333A and S334A.

[0044] In operation S331A, the control device 130 controls the switching device 160 to couple the spectrum analyzer 120 to the input terminal IN. As mentioned earlier, the switching device 160 can be a single-axis dual-switch. Figure 1 As shown, the switching device 160 may include switching points T1, T2, and T3. The control device 130 may control the connection between switching point T3 and switching point T1 to couple the spectrum analyzer 120 to the input terminal IN.

[0045] In operation of S332A, the corresponding frequency points f1-f are obtained by measuring the input terminal IN of the spectrum analyzer 120. N Input ripple intensity P i1 -P iN ,like Figure 5A As shown.

[0046] In operation S333A, when the spectrum analyzer 120 measures the input ripple intensity P i1 -P iN Then, the control device 130 controls the switching device 160 to couple the spectrum analyzer 120 to the output terminal OUT. The control device 130 can control the switching point T3 to be connected to the switching point T2 to couple the spectrum analyzer 120 to the output terminal OUT.

[0047] In operation of S334A, the corresponding frequency points f1-f are obtained by measuring the output terminal OUT of the spectrum analyzer 120. N Output ripple intensity P o1 -P oN ,like Figure 5B As shown.

[0048] In other words, in Figure 7 In the example, the spectrum analyzer 120 first measures the input ripple intensity P at the input terminal IN. i1 -P iN Next, measure the output ripple intensity P at the output terminal OUT. o1 -P oN .

[0049] refer to Figure 8 . Figure 8 It is illustrated in accordance with some embodiments of this disclosure. Figure 3 The detailed flowchart of operation S330 includes operations S331B, S332B, S333B and S334B.

[0050] In operation S331B, the control device 130 controls the switching device 160 to first couple the spectrum analyzer 120 to the output terminal OUT. The control device 130 can control the connection between switching point T3 and switching point T2 to first couple the spectrum analyzer 120 to the output terminal OUT.

[0051] In operation of S332B, the corresponding frequency points f1-f are obtained by measuring the output terminal OUT of the spectrum analyzer 120. N Output ripple intensity P o1 -P oN ,like Figure 5B As shown.

[0052] In operation of S333B, when the spectrum analyzer 120 measures the output ripple intensity P o1 -P oN Then, the control device 130 controls the switching device 160 to couple the spectrum analyzer 120 to the input terminal IN. The control device 130 can control the switching point T3 to be connected to the switching point T1 to couple the spectrum analyzer 120 to the input terminal IN.

[0053] In operation of S334B, the corresponding frequency points f1-f are obtained by measuring the input terminal IN of the spectrum analyzer 120. N Input ripple intensity P i1 -P iN ,like Figure 5A As shown.

[0054] In other words, in Figure 8 In the example, the spectrum analyzer 120 first measures the output ripple intensity P at the output terminal OUT. o1 -P oN Next, the input ripple intensity P at the input terminal IN is measured. i1 -P iN .

[0055] In some embodiments, when the control device 130 controls the switching point T3 to connect with the switching point T1, the DC meter 140 can thereby connect to measure the input DC component signal at the input terminal IN, so that the control device 130 or other analysis device can perform DC characteristic analysis. When the control device 130 controls the switching point T3 to connect with the switching point T2, the DC meter 140 can thereby connect to measure the output DC component signal at the output terminal OUT, so that the control device 130 or other analysis device can perform DC characteristic analysis.

[0056] In summary, this disclosure allows for the input of multi-frequency signals to the device under test (DUT), and the use of a spectrum analyzer to perform multi-frequency measurements at both the input and output terminals, thereby rapidly measuring the power supply rejection ratio (PSRR) of the DUT at different frequency points. Furthermore, since this disclosure performs measurements in the frequency domain, it improves the dynamic range of the measurement.

[0057] Although this disclosure has been described above with reference to embodiments, it is not intended to limit this disclosure. Any person with ordinary knowledge in the art may make various modifications and alterations without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the appended claims.

[0058] [Symbol Explanation]

[0059] 100: Test System

[0060] 110: Signal Generator

[0061] 120: Spectrum Analyzer

[0062] 130: Control device

[0063] 140: DC flow meter

[0064] 150: Filter

[0065] 160: Switching device

[0066] 210: Reference Circuit

[0067] 220: Amplifier Circuit

[0068] 230: Switching circuit

[0069] 300: Test Methods

[0070] DUT: Device Under Test

[0071] BUS: Control Bus

[0072] IN: Input terminal

[0073] OUT: Output terminal

[0074] Z: Load

[0075] GND: ground terminal

[0076] V IN DC input voltage

[0077] RP1: Input ripple

[0078] V OUT DC output voltage

[0079] RP2: Output ripple

[0080] DS: DC signal

[0081] MT: Multi-frequency signal

[0082] T1, T2, T3: Switching points

[0083] P1, P2, P3: Paths

[0084] f1-f N Frequency point

[0085] P i1 -P iN Input ripple intensity

[0086] P o1 -P oN Output ripple intensity

[0087] S310, S320, S330, S340, S331A, S332A, S333A, S334A, S331B, S332B, S333B, S334B: Operation

Claims

1. A testing method, comprising: A multi-frequency signal is generated by a signal generator; The multi-frequency signal is transmitted to an input terminal of a device under test by the signal generator. A spectrum analyzer is used to perform multi-frequency measurements on the input and output of the device under test (DUT) to obtain the complex input ripple intensity and complex output ripple intensity at corresponding complex frequency points; and A control device generates a complex power supply rejection ratio (PSR) corresponding to certain frequency points based on the input ripple intensity and the output ripple intensity. in, The testing method also includes performing one of the following operations: The control device controls a switching device to couple the spectrum analyzer to the input terminal, and the spectrum analyzer measures the input terminal to obtain the input ripple intensity corresponding to the corresponding frequency points. After the spectrum analyzer measures the input ripple intensity, the control device further controls the switching device to couple the spectrum analyzer to the output terminal, and the spectrum analyzer measures the output terminal to obtain the output ripple intensity corresponding to the corresponding frequency points. The control device controls the switching device to couple the spectrum analyzer to the output terminal, and the spectrum analyzer measures the output terminal to obtain the output ripple intensity corresponding to the frequency points. After the spectrum analyzer measures the output ripple intensity, the control device further controls the switching device to couple the spectrum analyzer to the input terminal, and the spectrum analyzer measures the input terminal to obtain the input ripple intensity corresponding to the frequency points.

2. A testing system, comprising: A signal generator for generating a multi-frequency signal and transmitting the multi-frequency signal to an input terminal of a device under test; A spectrum analyzer is coupled to the device under test and is used to perform multi-frequency point measurements on the input terminal and an output terminal of the device under test to obtain the complex input ripple intensity and complex output ripple intensity at the corresponding complex frequency points. A control device, coupled to the spectrum analyzer, is used to generate a complex power supply rejection ratio corresponding to the frequency points based on the input ripple intensity and the output ripple intensity. as well as A switching device, wherein the test system satisfies one of the following: The control device controls the switching device to couple the spectrum analyzer to the input terminal, and the spectrum analyzer measures the input terminal to obtain the input ripple intensity corresponding to the corresponding frequency points. After the spectrum analyzer measures the input ripple intensity, the control device further controls the switching device to couple the spectrum analyzer to the output terminal, and the spectrum analyzer measures the output terminal to obtain the output ripple intensity corresponding to the corresponding frequency points. The control device is used to control the switching device to couple the spectrum analyzer to the output terminal, and the spectrum analyzer measures the output terminal to obtain the output ripple intensity corresponding to the frequency points. After the spectrum analyzer measures the output ripple intensity, the control device is further used to control the switching device to couple the spectrum analyzer to the input terminal, and the spectrum analyzer measures the input terminal to obtain the input ripple intensity corresponding to the frequency points.

3. The test system according to claim 2, wherein the device under test is a power chip.

4. The test system according to claim 2, wherein the control device is further configured to subtract a corresponding output ripple intensity of a corresponding frequency point from a corresponding input ripple intensity of a corresponding frequency point to generate a corresponding power supply rejection ratio among the power supply rejection ratios.

5. The test system according to claim 2, wherein the signal generator is further configured to superimpose a complex number of sine waves to generate the multi-frequency signal, wherein the sine waves correspond to the respective frequency points.

6. The test system of claim 2, wherein the signal generator is further configured to perform an inverse Fourier transform procedure to generate the multi-frequency signal.

7. The test system of claim 2, wherein the signal generator is further configured to transmit a combination of the multi-frequency signal and the DC signal to the input terminal of the device under test.

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