Device and method for testing ripple rejection ratio of voltage regulator

Abstract

The invention provides a device and a method for testing the ripple rejection ratio of a voltage regulator. The device comprises an alternating current signal source; a direct current signal source; the signal input module is electrically connected with the alternating current signal source through a first switch and is electrically connected with the direct current signal source through a second switch; the to-be-tested unit is used for installing a to-be-tested voltage regulator, and the to-be-tested unit is electrically connected with the direct-current signal source through a third switch and electrically connected with the signal input module through a fourth switch; the signal extraction module is electrically connected with the unit to be tested through a fifth switch and electrically connected with the signal input module through a seventh switch, and an eighth switch is connected between the input end and the output end of the signal extraction module; the electronic load is electrically connected with the signal extraction module through a sixth switch; and the signal acquisition module is electrically connected with the signal extraction module through a ninth switch. The ripple rejection ratio testing device and method for the voltage regulator are simple in structure, convenient to operate, low in cost, high in precision and high in universality.

Description

Technical Field

[0001] This application relates to the technical field of semiconductor testing, and particularly to a test device and a test method for the ripple rejection ratio of a voltage regulator. Background Art

[0002] A Low Dropout Regulator (LDO) usually undertakes the tasks of voltage conversion and voltage regulation in an electronic device, and is mainly responsible for converting the front-stage input voltage into a relatively stable output voltage for the use of the subsequent circuit. Whether the voltage regulator is stable may have a greater impact on the working state of the subsequent circuit. For example, for a microcontroller system, when the power supply fluctuates, if the output voltage of the power supply chip in the system, such as the voltage regulator, is greatly affected by the power supply fluctuation, it may cause the system to power off and restart or fail to work properly. The key parameter for measuring whether the output voltage of the voltage regulator is stable is the ripple rejection ratio. The larger the ripple rejection ratio, the smaller the impact of the output voltage of the voltage regulator on the dynamic change of the input voltage, and the more stable the chip works. This characteristic is of great significance for protecting sensitive circuits and ensuring the normal operation of electronic devices.

[0003] The Power Supply Rejection Ratio (PSRR) is used to describe the ability of a chip to suppress the change of the power supply voltage, which is the ratio of the change amount of the input AC voltage to the change amount of the output AC voltage, and the unit is expressed in dB. The voltage regulator usually has a high ripple rejection ratio in a relatively low frequency band, and the ripple rejection ratio decreases at a higher frequency. Generally, the ripple rejection ratio value at a specified frequency point is given. For scenarios with less power supply interference and less sensitivity to power supply changes, a voltage regulator with a ripple rejection ratio of about 50 dB can meet the usage requirements; while for application scenarios that are extremely sensitive to power supply changes, such as high-precision converter chips ADC, a voltage regulator with a ripple rejection ratio above 60 dB may be required. Therefore, as a key indicator for the selection of voltage regulators, the test of the ripple rejection ratio inevitably becomes an important part of the voltage regulator test.

[0004] The ripple rejection ratio is at a relatively small magnitude compared to conventional electrical parameter tests. The voltage signal to be measured is usually at the μV level. At the same time, for the test of this parameter, a periodic signal with a specified frequency and amplitude needs to be applied at the input end as a test condition, which poses certain requirements for the signal conditioning circuit at the input end. There are mainly two conventional methods for testing the ripple rejection ratio: One is to directly use precision instruments such as a power analyzer and a high-precision oscilloscope to build a system for testing. However, this method has high requirements for the instrument specifications, resulting in high costs and low test efficiency, and it cannot meet the requirements of batch testing and screening. The other is to use an automatic test equipment (ATE) to generate an input signal with a specified frequency and strong load-carrying capacity through the arbitrary waveform generation function of the power module for testing. However, limited by factors such as the arbitrary waveform generation rate of the power module and its sampling point number limit, it cannot meet the ripple rejection ratio test at frequencies above 1 kHz. Therefore, there is an urgent need for a voltage regulator ripple rejection ratio test device and test method with low cost, strong versatility, and high test accuracy. Summary of the Invention

[0005] In view of this, the purpose of this application is to propose a voltage regulator ripple rejection ratio test device and test method to solve the related problems mentioned in the background technology.

[0006] In the first aspect of this application, a voltage regulator ripple rejection ratio test device is provided, including: an AC signal source for providing an AC signal; a DC signal source for providing a DC signal; a signal input module electrically connected to the AC signal source through a first switch and to the DC signal source through a second switch, for processing the AC signal and the DC signal; a unit under test for installing the voltage regulator to be tested, the unit under test is electrically connected to the DC signal source through a third switch and to the signal input module through a fourth switch; a signal extraction module electrically connected to the unit under test through a fifth switch and to the signal input module through a seventh switch, and an eighth switch is connected between the input end and the output end of the signal extraction module, the signal extraction module is used to extract the output ripple voltage signal of the voltage regulator; an electronic load electrically connected to the signal extraction module through a sixth switch; a signal acquisition module electrically connected to the signal extraction module through a ninth switch, for calculating the ripple rejection ratio of the voltage regulator.

[0007] Further, the voltage regulator ripple rejection ratio test device further includes: a DC power supply electrically connected to the signal input module and the signal extraction module; an AC power supply electrically connected to the DC power supply, the AC signal source, the DC signal source, the signal acquisition module, and the electronic load.

[0008] Furthermore, the unit under test includes an adapter, which is electrically connected to the voltage regulator, and the unit under test and the electronic load are both grounded; the signal input module includes an AC signal input terminal, a DC signal input terminal and a signal coupling circuit; the signal extraction module includes a filtering circuit and a signal amplification circuit; the signal acquisition module includes a measuring instrument and a host computer.

[0009] A second aspect of the present application provides a method for testing the ripple rejection ratio of a voltage regulator, using the voltage regulator ripple rejection ratio testing device described in the first aspect above. The method includes: closing a first switch, a second switch, a sixth switch, a seventh switch, an eighth switch, and a ninth switch, and opening the third switch, the fourth switch, and the fifth switch, to perform a self-test on a signal input module; after the self-test passes, closing the first switch, the second switch, the seventh switch, and the ninth switch, and opening the third switch, the fourth switch, the fifth switch, the sixth switch, and the eighth switch, to calibrate a signal extraction module; after the calibration passes, closing the first switch, the second switch, the fourth switch, the fifth switch, the sixth switch, and the ninth switch, and opening the third switch, the seventh switch, and the eighth switch, to test the voltage regulator and calculate the ripple rejection ratio.

[0010] Furthermore, before closing the first switch, the second switch, the sixth switch, the seventh switch, the eighth switch and the ninth switch, and opening the third switch, the fourth switch and the fifth switch, the process includes: obtaining test parameters of the voltage regulator and output parameters of the voltage regulator during normal operation, wherein the test parameters include the input DC voltage V OUT DC , test frequency f DUT AC , load current I OUT DUT , input voltage range [V IN MIN , V IN MAX ] and the characteristic value of the ripple rejection ratio PSRR DUT ; The output parameters include output voltage V OUT DUT And the corresponding output voltage range [V OUT DUTmin , V OUT DUTmax ].

[0011] Furthermore, the self-test of the signal input module includes: controlling the DC power supply to output a signal with an amplitude of V +sig With V -sig DC voltage; control the AC signal source to generate a frequency of f IN AC , the peak-to-peak value is V PP IN AC The sine wave signal controls the DC signal source to generate an amplitude of V bias The DC voltage signal controls the maximum load of the signal input module to be I LOAD MAX When VOUT DUT >0, then f IN AC =f DUT AC , and|I LOAD MAX |≥|I OUT DUT |; or, when V OUT DUT When <0, f IN AC =f DUT AC , and|I LOAD MAX |≥|I OUT DUT |, where V PP IN AC is the voltage swing; the output signal V of the signal input module is tested by the signal acquisition module coupleout real , where V coupleout real Including DC component voltage amplitude V couple real DC And the AC component voltage amplitude V couple real AC When V OUT DUT >0, if V couple real DC +V couple real AC ≤V IN MAX and V couple real DC -V couple real AC ≥V IN MIN , then the self-test passes; or, when V OUT DUT <0, if |V couple real DC |+V couple real AC ≤|V IN MIN | and |V couple real DC |-V couple real AC ≥|V IN MAX |, the self-test passes.

[0012] Furthermore, the signal extraction module is calibrated, including: controlling the DC power supply to output a signal with an amplitude of V to the signal input module. +sig With V -sig The DC voltage is output to the signal extraction module with an amplitude of V +ext With V -ext DC voltage; control the AC signal source to generate a frequency of f IN ext , the peak-to-peak value is V PP IN ext The sine wave signal satisfies f IN ext =f couple out =f IN AC , V PP IN ext =V couple AC / Av PSRR and Av ext ≥Av PSRR , where Av ext is the amplification factor of the signal extraction module, PSRR DUT =20lg(Av PSRR ), Vcouple AC is the amplitude of the output AC voltage signal of the signal input module, and f couple out is the frequency of the output AC voltage signal of the signal input module; control the AC signal source to generate a sine wave signal with an amplitude of V couple AC / Av PSRR starting from the first frequency f LF and stepping with a frequency interval of f step until the second frequency f HF to perform a frequency sweep test, and test the actual gain Av IN ext of the signal extraction module at the frequency f ext real , obtain the upper cut-off frequency f cut off1 and the lower cut-off frequency f cut off2 of the signal extraction module, where f LF < f IN ext , f HF > f IN ext ; if f cut off1 < f IN ext < f cut off2 and Av ext real ≥ Av PSRR , then the calibration passes.

[0013] Further, before closing the first switch, the second switch, the sixth switch, the seventh switch, the eighth switch and the ninth switch, and opening the third switch, the fourth switch and the fifth switch, it also includes: obtaining the test frequency accuracy; the first frequency and the second frequency satisfy f LF 4] / f IN ext << 1 - k and f HF / f IN ext >> 1 + k, where k > 0 and includes the test frequency accuracy.

[0014] Further, closing the first switch, the second switch, the fourth switch, the fifth switch, the sixth switch and the ninth switch, and opening the third switch, the seventh switch and the eighth switch includes: closing the third switch, the fifth switch, the sixth switch, the eighth switch and the ninth switch, and opening the first switch, the second switch, the fourth switch and the seventh switch; testing the output voltage V OUT real of the voltage regulator through the signal acquisition module; if V OUT real is within [V OUT DUTmin , V OUT DUTmax , then open the third switch, close the first switch, the second switch and the fourth switch; control the DC power supply to output an amplitude of V +sig to the signal input module and V -sigThe DC voltage controls the AC signal source to generate a sine wave signal with a frequency of f IN AC and a peak-to-peak value of V PP IN AC . The DC signal source is controlled to generate a DC voltage signal with an amplitude of V bias . The output voltage V of the voltage regulator is tested through the signal acquisition module OUT real2 . If V OUT real2 is within [V OUT DUTmin , V OUT DUTmax , then the eighth switch is disconnected.

[0015] Furthermore, when testing the voltage regulator and calculating the ripple rejection ratio, it includes: testing the output voltage V of the voltage regulator through the signal acquisition module OUT real3 . If V OUT real3 is within [V OUT DUTmin , V OUT DUTmax , then the output voltage frequency f OUT ext and the peak-to-peak value V PPOUT ext of the signal extraction module are tested. If f OUT ext = f IN AC , then the measured ripple rejection ratio PSRR real of the voltage regulator is calculated, where

[0016] As can be seen from the above, the apparatus and method for testing the ripple rejection ratio of a voltage regulator provided by this application. The apparatus for testing the ripple rejection ratio of a voltage regulator includes: an AC signal source for providing an AC signal; a DC signal source for providing a DC signal; a signal input module electrically connected to the AC signal source through a first switch and to the DC signal source through a second switch, for processing the AC signal and the DC signal; a unit under test for installing the voltage regulator to be tested, the unit under test is electrically connected to the DC signal source through a third switch and to the signal input module through a fourth switch; a signal extraction module electrically connected to the unit under test through a fifth switch and to the signal input module through a seventh switch, an eighth switch is connected between the input terminal and the output terminal of the signal extraction module, and the signal extraction module is used to extract the output ripple voltage signal of the voltage regulator; an electronic load electrically connected to the signal extraction module through a sixth switch; a signal acquisition module electrically connected to the signal extraction module through a ninth switch, for calculating the ripple rejection ratio of the voltage regulator. By building the functional circuits of the signal input module, the signal extraction module and the signal acquisition module, replacing the current high-cost test instruments, the test cost is greatly reduced; the signal extraction module can filter and amplify the output voltage signal, and amplify the extracted ripple signal to be measured to the magnitude range that can be accurately measured by conventional test instruments; only a power supply and a load need to be equipped in addition to the device, and it can also be transferred to an automatic test equipment for use, with strong applicability and flexibility, and can be screened and tested in batches. The apparatus and method for testing the ripple rejection ratio of a voltage regulator have a simple structure, convenient operation, low test cost, high precision and strong versatility. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in this application or related technologies, the following will briefly introduce the drawings required for use in the description of the embodiments or related technologies. Obviously, the drawings in the following description are only the embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of an apparatus for testing the ripple rejection ratio of a voltage regulator;

[0019] Figure 2 It is a schematic flow diagram of a method for testing the ripple rejection ratio of a voltage regulator;

[0020] Figure 3 It is a schematic flow diagram of another method for testing the ripple rejection ratio of a voltage regulator;

[0021] Figure 4 It is a schematic circuit connection diagram for the signal input module to perform self-check;

[0022] Figure 5Schematic diagram of the self-checking process for the signal input module;

[0023] Figure 6 Schematic diagram of the circuit connection for calibrating the signal extraction module;

[0024] Figure 7 Schematic diagram of the calibration process for the signal extraction module;

[0025] Figure 8 Schematic diagram of the circuit connection for the ripple rejection ratio test;

[0026] Figure 9 Schematic diagram of the process for the ripple rejection ratio test.

[0027] Reference numerals: 1, AC signal source; 2, DC signal source; 3, signal input module; 4, unit under test; 5, signal extraction module; 6, electronic load; 7, signal acquisition module; 8, DC power supply; 9, AC power supply. Specific embodiments

[0028] To make the objectives, technical solutions, and advantages of the present application clearer and more understandable, the following further details the present application with reference to specific embodiments and the accompanying drawings.

[0029] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the ordinary meaning understood by those of ordinary skill in the field to which the present application belongs. The "first", "second", and similar terms used in the embodiments of the present application do not denote any order, quantity, or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or items appearing before this term cover the elements or items listed after this term and their equivalents, without excluding other elements or items. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0030] Hereinafter, through specific embodiments and in combination with the attached Figures 1 to 9 to detail the technical solutions of the present application.

[0031] Some embodiments of the present application provide a voltage regulator ripple rejection ratio test device, as Figure 1As shown in the figure, it includes: an AC signal source 1 for providing an AC signal; a DC signal source 2 for providing a DC signal; a signal input module 3 electrically connected to the AC signal source 1 through a first switch and to the DC signal source 2 through a second switch, for processing AC signals and DC signals; a unit under test 4 for installing a voltage regulator under test, the unit under test 4 is electrically connected to the DC signal source 2 through a third switch and to the signal input module 3 through a fourth switch; a signal extraction module 5 electrically connected to the unit under test 4 through a fifth switch and to the signal input module 3 through a seventh switch, an eighth switch is connected between the input end and the output end of the signal extraction module 5, and the signal extraction module 5 is used to extract the output ripple voltage signal of the voltage regulator; an electronic load 6 electrically connected to the signal extraction module 5 through a sixth switch; a signal acquisition module 7 electrically connected to the signal extraction module 5 through a ninth switch, for calculating the ripple rejection ratio of the voltage regulator.

[0032] The front stage of the signal input module 3 is the DC signal source 2 and the AC signal source 1. The signal input module 3 realizes the function of coupling and outputting AC and DC signals with strong load-carrying capacity through a signal coupling circuit, meeting the input condition requirements of the specified frequency (corresponding to f in the following text DUT AC ), DC bias (corresponding to V in the following text DUT DC ), and voltage swing (corresponding to V in the following text PP IN AC ) stipulated by the ripple rejection ratio test, and completes the preprocessing of the input signal.

[0033] The main function of the signal extraction module 5 is to extract the output ripple voltage signal of the voltage regulator at a specified frequency point and perform amplification processing, so that its amplitude is much higher than the noise floor and resolution of the subsequent signal acquisition module 7, realizing accurate measurement. The signal extraction module 5 can include a high-order band-pass filter, which can achieve a nearly brick-wall filtering effect and at the same time can achieve signal amplification, so as to meet the extraction of signals within the target frequency range.

[0034] The electronic load 6 is a device that consumes electrical energy by controlling the internal power or the conduction amount of transistors and relying on the power dissipation of power transistors. It can accurately detect the load voltage and precisely adjust the load current, etc.

[0035] The signal acquisition module 7 mainly realizes the direct measurement of the extracted output ripple voltage signal. The output ripple voltage signal of the voltage regulator under test can be connected through an adapter, amplified through signal extraction, and the interference signals other than the target frequency band signals are shielded, and the signal amplitude level meets the requirement that the test is not affected by the noise floor. After the peak-to-peak value of the output ripple voltage signal is obtained by the subsequent signal acquisition module 7, the ripple rejection ratio of the voltage regulator under test at the specified frequency point is calculated based on the gain of the signal extraction module 5.

[0036] Such as Figure 1As shown in the figure, the device includes a first switch K1, a second switch K2, a third switch K3, a fourth switch K4, a fifth switch K5, a sixth switch K6, a seventh switch K7, an eighth switch K8, and a ninth switch K9. By controlling the opening and closing of different switches, self-checking of the signal input module 3, calibration of the signal extraction module 5, and ripple rejection ratio test can be achieved, improving the accuracy of the test.

[0037] The device consists of a signal input module 3, a signal extraction module 5, and a signal acquisition module 7. During the test, the device can be self-checked and calibrated first to obtain the accuracy of the coupled output of the signal input module 3 and the actual gain and passband of the signal extraction module 5. For the package and pin definition of the voltage regulator to be tested, a general adapter for this type of device can be set in the unit under test 4 to achieve the connection between the voltage regulator and the test device. The external AC input signal and DC input signal are coupled through the signal input module 3, and the coupled AC voltage signal containing the DC bias voltage is input to the voltage regulator. The voltage signal at the output end of the voltage regulator is transmitted to the signal extraction module 5 to complete the extraction of the voltage signal at the target frequency point. The peak-to-peak value of the voltage signal output by the voltage regulator is measured through the signal acquisition module 7, and finally the ratio of the peak-to-peak value of the input signal of the voltage regulator to the peak-to-peak value of the output signal is calculated to achieve the test of the ripple rejection ratio of the voltage regulator.

[0038] The functional circuit built by this device replaces expensive test instruments such as vector network analyzers and phase gain analyzers required for conventional power supply rejection ratio tests, saving test costs. The signal extraction module 5 can adopt a technical route of filtering and amplifying the output voltage signal, amplifying the measured ripple signal it extracts to a magnitude range that can be accurately measured by conventional test instruments, greatly reducing the technical difficulty and development cost of testing the power supply rejection ratio. This device is flexible and convenient. In addition to the device, only a bench power supply and a load need to be equipped, and it can also be transferred to the current mainstream automatic test equipment ATE test bench for use, with strong applicability and flexibility, and can batch-screen and test the ripple rejection ratio of voltage regulators.

[0039] In some embodiments, as Figure 1 shown, the voltage regulator ripple rejection ratio test device further includes: a DC power supply 8, electrically connected to the signal input module 3 and the signal extraction module 5; an AC power supply 9, electrically connected to the DC power supply 8, the AC signal source 1, the DC signal source 2, the signal acquisition module 7, and the electronic load 6.

[0040] The AC power supply 9 is, for example, 220V mains power, and is not specifically limited.

[0041] In some embodiments, as Figure 1As shown, the unit under test 4 includes an adapter, which is electrically connected to a voltage regulator. Both the unit under test 4 and the electronic load 6 are grounded. The signal input module 3 includes an AC signal input terminal, a DC signal input terminal, and a signal coupling circuit. The signal extraction module 5 includes a filtering circuit and a signal amplification circuit. The signal acquisition module 7 includes a measuring instrument and a host computer.

[0042] The adapter mainly defines the package pins of the voltage regulator under test, and realizes connecting the input terminal and output terminal of the voltage regulator to the corresponding ports of the test device, meeting the convenience of pluggable and replaceable DUTs. The adapter mode can perform batch screening tests for one product, and different products can be tested by replacing the adapter, with strong versatility and more flexible and convenient. Measuring instruments such as oscilloscopes, digital multimeters, etc., have low costs.

[0043] This device builds the signal input module 3, the adapter, and the signal extraction module 5, and at the same time cooperates with the measuring instrument and the host computer to realize the AC and DC signal coupling function with driving ability and the function of extracting and amplifying the AC component of the output signal.

[0044] The description of this application is given for purposes of illustration and description, and is not intended to be exhaustive or to limit the application to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are chosen and described in order to better explain the principles and practical applications of this application, and to enable those of ordinary skill in the art to understand this application and thus design various embodiments with various modifications suitable for specific purposes.

[0045] Those of ordinary skill in the art should understand that: the discussion of any embodiment above is only exemplary, and is not intended to imply that the scope of this application (including the claims) is limited to these examples; under the idea of this application, the technical features between the above embodiments or different embodiments can also be combined, and there are many other variations in different aspects of the embodiments of this application as above, which are not provided in detail for the sake of brevity.

[0046] Based on the same inventive concept, this application also provides a method for testing the ripple rejection ratio of a voltage regulator, using the voltage regulator ripple rejection ratio test device described in any of the above embodiments, as Figure 2 and Figure 3 shown, the test method includes:

[0047] S1. Close the first switch, the second switch, the sixth switch, the seventh switch, the eighth switch, and the ninth switch, and open the third switch, the fourth switch, and the fifth switch to perform self-check on the signal input module.

[0048] As Figure 4As shown, control to close the first switch K1 to connect the AC signal source to the AC signal input terminal of the signal input module; control to close the second switch K2 to connect the DC signal source to the DC signal input terminal of the signal input module; control to close the sixth switch K6 and the seventh switch K7, and connect the output terminal of the signal input module to the electronic load. If the voltage regulator to be measured is a negative voltage regulator (V OUT DUT <0), then set the electronic load to inject current into the output terminal of the signal input module; if the voltage regulator to be measured is a positive voltage regulator (V OUT DUT >0), then set the electronic load to pull current to ground; control to close the eighth switch K8 and the ninth switch K9, and connect the output terminal of the signal input module to the signal acquisition module, and the signal input module can be self-tested as shown in Figure 5 to improve the accuracy of subsequent ripple rejection ratio testing.

[0049] S2. After the self-test passes, close the first switch, the second switch, the seventh switch, and the ninth switch, and open the third switch, the fourth switch, the fifth switch, the sixth switch, and the eighth switch to calibrate the signal extraction module.

[0050] As Figure 6 shown, control to close the first switch K1 and the second switch K2 to connect the AC signal source to the AC signal input terminal of the signal input module and connect the DC signal source to the DC input terminal of the signal input module; control to close the seventh switch K7 to connect the output terminal of the signal input module to the signal extraction module; control to close the ninth switch K9 to connect the output of the signal extraction module to the signal acquisition module, and the signal extraction module can be calibrated as shown in Figure 7 to improve the accuracy of subsequent ripple rejection ratio testing.

[0051] S3. After the calibration passes, close the first switch, the second switch, the fourth switch, the fifth switch, the sixth switch, and the ninth switch, and open the third switch, the seventh switch, and the eighth switch to test the voltage regulator and calculate the ripple rejection ratio.

[0052] As Figure 8 shown, control to close the first switch K1, the second switch K2, the fourth switch K4, the fifth switch K5, the sixth switch K6, and the ninth switch to test the voltage regulator, obtain the peak-to-peak value of the output voltage signal, and thus calculate the ripple rejection ratio.

[0053] The method first performs self - inspection and calibration on the device to obtain the accuracy of the coupled output of the signal input module and the actual gain and passband of the signal extraction module; the external AC input signal and DC input signal are coupled through the signal input module, and the coupled AC voltage signal containing the DC bias voltage is input to the voltage regulator to be measured; the voltage signal at the output end of the voltage regulator to be measured is transmitted into the signal extraction module to complete the extraction of the voltage signal at the target frequency point; the peak - to - peak value of the output voltage signal of the voltage regulator to be measured is measured through the signal acquisition module, and finally the ratio of the peak - to - peak value of the input signal to the peak - to - peak value of the output signal of the voltage regulator to be measured is calculated to achieve the test of the ripple rejection ratio of the voltage regulator.

[0054] In some embodiments, before step S1, it includes:

[0055] S0. Obtain the test parameters of the voltage regulator and the output parameters during normal operation, where the test parameters include the input DC voltage V DUT DC , the test frequency f DUT AC , the load current I OUT DUT , the input voltage range [V IN MIN , V IN MAX and the characteristic value PSRR of the ripple rejection ratio DUT ; the output parameters include the output voltage V OUT DUT and the corresponding output voltage range [V OUT DUTmin , V OUT DUTmax .

[0056] The input DC voltage V DUT DC , the test frequency point corresponding frequency f DUT AC , the load current I OUT DUT , the input voltage range [V IN MIN , V IN MAX , the characteristic value PSRR of the ripple rejection ratio DUT , the output voltage V OUT DUT , the corresponding output voltage range [V OUT DUTmin , V OUT DUTmax can be obtained according to the data sheet of the voltage regulator to be measured for setting the input conditions of subsequent tests and comparing the output results. Among them, the characteristic value of the ripple rejection ratio can be the minimum value or some typical values, etc., and is not specifically limited.

[0057] In some embodiments, self - inspection is performed on the signal input module, as Figure 5 shown, including:

[0058] S101. Control the DC power supply to output DC voltages with amplitudes of V +sig and V -sig to the signal input module.

[0059] Confirm that the AC signal source, DC signal source, and DC power supply are powered on; the AC signal source is set to the sine signal output mode, and the DC signal source and DC power supply are set to the DC voltage output mode. Control the DC power supply output amplitude to V +sig With V -sig The DC voltage, V +sig With V -sig Meet the power supply requirements of the core circuit in the signal input module.

[0060] S102, control the AC signal source to generate a frequency of f IN AC , the peak-to-peak value is V PP IN AC The sine wave signal controls the DC signal source to generate an amplitude of V bias The DC voltage signal controls the maximum load of the signal input module to be I LOAD MAX When V OUT DUT >0, then f IN AC =f DUT AC , and|I LOAD MAX |≥|I OUT DUT |; or, when V OUT DUT <0, then f IN AC =f DUT AC , and|I LOAD MAX |≥|I OUT DUT |, where V PP IN AC is the voltage swing.

[0061] S1021--Control the AC signal source to generate a frequency of f IN AC , the peak-to-peak value is V PP IN AC The sine wave signal controls the DC signal source to generate an amplitude of V bias The maximum load of the signal input module is I LOAD MAX .

[0062] If the voltage regulator to be tested is a positive output voltage regulator (V OUT DUT >0), then f IN AC , V bias Need to satisfy f IN AC =f DUT AC and V bias =V DUT DC To ensure that the voltage regulator under test is in normal working condition, that is, the output voltage is within the range specified in the data sheet, it is necessary to meet as well as We can further deduce that V bias 、V PP IN AC Needs to be satisfied and |I LOAD MAX|≥|I OUT DUT |。

[0063] Similarly, if the voltage regulator to be measured is a negative output voltage regulator (V OUT DUT < 0), then f IN AC , V PP IN AC , V bias respectively need to satisfy f IN AC = f DUT AC , and |I LOAD MAX |≥|I OUT DUT |。

[0064] S1022--The output signal voltage amplitude generated after the input signals of the AC signal source and the DC signal source are coupled and processed by the signal input module is V couple out , the DC component voltage amplitude included in the output signal is V couple DC , the AC component voltage amplitude is V couple AC , and the output signal frequency is f couple out . Among them, the amplification factor of the signal input module for the AC signal is A AC , and the amplification factor for the DC signal is A DC . In this embodiment, the core circuit of the signal input module is selected as a follower for the generality of the test, that is, the magnitudes of A AC and A DC are 1. Therefore, V couple DC , V couple AC and f couple out should satisfy f couple out = f IN AC , V couple DC = V bias ×A DC = V bias and

[0065] S1023--It can be obtained from steps S1021 and S1022 that if the voltage regulator to be measured is a positive output voltage regulator (V OUT DUT > 0), then V couple AC and V couple DC need to satisfy V couple DC + V couple AC ≤ V IN MAX and V couple DC - V couple AC ≥ V IN MIN .

[0066] If the voltage regulator to be measured is a negative output voltage regulator (V OUT DUT < 0), then V couple AC and V couple DC need to satisfy |V couple DC|+V couple AC ≤|V IN MIN |and|V couple DC |-V couple AC ≥|V IN MAX |.

[0067] S103. Test the output signal V of the signal input module through the signal acquisition module coupleout real , where V coupleout real includes the DC component voltage amplitude V couple real DC and the AC component voltage amplitude V couple real AC ; when V OUT DUT > 0, if it satisfies V coutple real DC +V couple real AC ≤V IN MAX and V couple real DC -V couple real AC ≥V IN MIN , the self - test passes; or, when V OUT DUT < 0, if it satisfies |V couple real DC |+V couple real AC ≤|V IN MIN |and|V couple real DC |-V couple real AC ≥|V IN MAX |, the self - test passes.

[0068] The signal acquisition module tests the output signal V of the signal input module coupleout real , and confirms whether V coupleout real meets the conditions derived in step S1023. If it meets the conditions, it means that the accuracy of the output signal of the signal input module meets the test condition requirements of the voltage regulator to be tested; if it does not meet the conditions, it means that the accuracy of the output signal of the signal input module does not meet the test condition requirements of the voltage regulator to be tested, and the adjustment device needs to be checked and the self - test steps need to be repeated until the conditions are met.

[0069] In some embodiments, calibrate the signal extraction module, as Figure 7 shown, including:

[0070] S201. Control the DC power supply to output DC voltages with amplitudes of V +sig and V -sig to the signal input module, and output DC voltages with amplitudes of V +ext and V -ext to the signal extraction module.

[0071] Confirm that the AC signal source is powered on, the DC signal source is powered on, and the DC power supply is powered on; the AC signal source is adjusted to the sine signal output mode, and the DC power supply is adjusted to the output mode. Control the DC power supply to output DC voltages with amplitudes of V +sig and V -sig to the signal input module, where V+sig With V -sig Meet the power supply requirements of the core circuit in the signal input module; control the DC power supply to output the amplitude of V to the signal extraction module +ext With V -ext The DC voltage, V +ext With V -ext Meet the power supply requirements of the core circuits in the signal extraction module.

[0072] S202, control the AC signal source to generate a frequency of f IN ext , the peak-to-peak value is V PP IN ext The sine wave signal satisfies f IN ext =f couple out =f IN AC , V PP IN ext =V couple AC / Av PSRR and Av ext ≥Av PSRR , where Av ext is the amplification factor of the signal extraction module, PSRR DUT =20lg(Av PSRR ), V couple AC is the amplitude of the output AC voltage signal of the signal input module, f couple out The frequency of the output AC voltage signal of the signal input module.

[0073] Control the AC signal source to generate a frequency of f IN ext , the peak-to-peak value is V PP IN ext The sine wave signal can be obtained from the above steps S0, S101 and S102. The ripple rejection ratio of the voltage regulator to be tested is PSRR DUT The output AC voltage signal amplitude of the signal input module is V couple AC , frequency f couple out , and the signal extraction module needs to extract the AC signal passing through the voltage regulator to be tested. Therefore, the calibration input AC signal frequency f of the signal extraction module is IN ext and V PP IN ext And the magnification Av ext Need to meet f IN ext =f couple out =f IN AC , V PP IN ext =V couple AC / Av PSRR and Av ext ≥Av PSRR Among them, Av PSRR It is the general ripple rejection ratio, which is converted to PSRR DUT =20lg(Av PSRR ).

[0074] S203. Control the AC signal source to generate a sine wave signal with an amplitude of V couple AC / Av PSRR starting from the first frequency f LF and stepping in frequency intervals of f step until the second frequency f HF for a sweep frequency test. The test signal extraction module measures the actual gain Av IN ext at the frequency f ext real to obtain the upper cut-off frequency f cut off1 and the lower cut-off frequency f cut off2 of the signal extraction module, where f LF < fIN ext and f HF >f IN ext .

[0075] Control the AC signal source to output a sine wave with an amplitude of V couple AC / Av PSRR starting from the first frequency f LF and stepping in frequency intervals of f step until the second frequency f HF for the sine wave signal. The test signal extraction module measures the actual gain Av IN ext at the sine wave frequency f ext real and performs a sweep frequency test until the upper cut-off frequency f cut off1 and the lower cut-off frequency f cut off2 of the signal extraction module are obtained.

[0076] Specifically, the aforementioned step S0 further includes obtaining the test frequency accuracy. In step S203, the first frequency and the second frequency satisfy f LF / f IN ext <<1 - k and f HF / f IN ext >>1 + k, where k>0 and includes the test frequency accuracy. The measurement of much greater than or much less than in the formula can differ by an order of magnitude, and no specific limitation is made.

[0077] S204. If f cut off1 <f IN ext <f cut off2 and Av ext real ≥Av PSRR , then the calibration passes.

[0078] If the above conditions are not met, the parameters of the filter circuit and the amplifier circuit in the signal extraction module need to be readjusted until the calibration passes.

[0079] In some embodiments, closing the first switch, the second switch, the fourth switch, the fifth switch, the sixth switch, and the ninth switch, and opening the third switch, the seventh switch, and the eighth switch includes:

[0080] S301. Close the third switch, the fifth switch, the sixth switch, the eighth switch, and the ninth switch, and open the first switch, the second switch, the fourth switch, and the seventh switch.

[0081] Control to close the third switch K3 to connect the DC signal source to the input end of the adapter. Close the fifth switch K5 and the sixth switch K6 to connect the electronic load to the output end of the adapter to apply a current load to the voltage regulator under test. If the voltage regulator under test is a negative voltage regulator (V OUT DUT <0), the electronic load injects current into the voltage regulator under test; if the voltage regulator under test is a positive voltage regulator (V OUT DUT >0), the electronic load pulls current to the ground. Close the eighth switch K8 and the ninth switch K9 to connect the output end of the adapter to the signal acquisition module.

[0082] Confirm that the DC signal source is powered on, that is, the DC signal source is adjusted to the output mode. If the voltage regulator under test is a negative voltage regulator (V OUT DUT <0), the electronic load injects current I OUT DUT into the voltage regulator under test; if the voltage regulator under test is a positive voltage regulator (V OUT DUT >0), the electronic load pulls current I OUT DUT to the ground.

[0083] S302. Test the output voltage V OUT real of the voltage regulator through the signal acquisition module.

[0084] S303. If V OUT real is within [V OUT DUTmin , V OUT DUTmax , then open the third switch and close the first switch, the second switch, and the fourth switch.

[0085] After the output voltage of the voltage regulator is stable, the signal acquisition module tests the output voltage V OUT real of the voltage regulator. If V OUT real is not within the range [V OUT DUTmin , V OUT DUTmax specified in the data sheet, then the voltage regulator and the adapter need to be checked until the adapter and the voltage regulator can work properly.

[0086] If V OUT real is within [V OUT DUTmin , V OUT DUTmaxIf they are within the range, both the adapter and the voltage regulator under test can work properly. Turn off the output mode of the electronic load and the output mode of the DC signal source. At this time, disconnect the third switch K3, close the first switch K1 and the second switch K2, switch the AC signal source to the AC signal input terminal of the signal input module, and switch the DC signal source to the DC signal input terminal of the signal input module; close the fourth switch K4, and connect the output terminal of the signal input module to the input terminal of the adapter.

[0087] S304. Control the DC power supply to output a DC voltage with an amplitude of V +sig and V -sig to the signal input module, control the AC signal source to generate a sine wave signal with a frequency of f IN AC , a peak-to-peak value of V PP IN AC , and control the DC signal source to generate a DC voltage signal with an amplitude of V bias .

[0088] Confirm that the AC signal source is powered on, the DC signal source is powered on, and the DC power supply is powered on; adjust the AC signal source to the sine signal output mode, and adjust the DC signal source and the DC power supply to the output mode. Control the DC power supply to output a DC voltage with an amplitude of V +sig and V -sig to the signal input module, where V +sig and V -sig meet the power supply requirements of the core circuit in the signal input module. Control the AC signal source to generate a sine wave signal with a frequency of f IN AC , a peak-to-peak value of V PP IN AC , and control the DC signal source to generate a DC voltage signal with an amplitude of V bias , where f IN AC、 V PP IN AC , V bias meet the conditions in reference step S102. Adjust the electronic load to the output mode. If the voltage regulator under test is a negative voltage regulator (V OUT DUT <0), the electronic load injects a current I OUT DUT into the voltage regulator under test; if the voltage regulator under test is a positive voltage regulator (V OUT DUT >0), the electronic load pulls a current I OUT DUT to the ground.

[0089] S305. Test the output voltage V OUT real2 of the voltage regulator through the signal acquisition module.

[0090] S306. If V OUT real2 is within [V OUT DUTmin , V OUT DUTmax , disconnect the eighth switch.

[0091] After the output voltage of the voltage regulator stabilizes, the signal acquisition module tests the output voltage V of the voltage regulator under test OUT real2 , if V OUT real2 is within [V OUT DUTmin , V OUT DUTmax , then the signal input module can not only output with a separate load, but also drive the voltage regulator under test to work properly. At this time, turn off the output mode of the electronic load, and turn off the output modes of the DC signal source and the DC power supply. Disconnect the eighth switch K8, connect the output terminal of the adapter to the input terminal of the signal extraction module, and switch the output terminal of the signal extraction module to the signal acquisition module for the final ripple rejection ratio test.

[0092] In some embodiments, the voltage regulator is tested to calculate the ripple rejection ratio, as Figure 9 shown, including:

[0093] S311. Test the output voltage V of the voltage regulator through the signal acquisition module OUT real3 .

[0094] S312. If V OUT real3 is within [V OUT DUTmin , V OUT DUTmax , then test the output voltage frequency f OUT ext and the peak-to-peak value V PPOUT ext of the signal extraction module.

[0095] Repeat step S304. After the output voltage of the voltage regulator stabilizes, the signal acquisition module tests the output voltage V of the voltage regulator under test OUT real3 , if V OUT real3 is within [V OUT DUTmin , V OUT DUTmax , then obtain the frequency f OUT ext and the peak-to-peak value V PPOUT ext of the output voltage of the signal extraction module measured by the host computer control measuring instrument.

[0096] S313. If f OUT ext = f IN AC , then calculate the measured ripple rejection ratio PSRR real of the voltage regulator, where

[0097] This method is simple and convenient, and can obtain a higher accuracy ripple rejection ratio.

[0098] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present application (including the claims) is limited to these examples; within the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the embodiments of the present application as above, which are not provided in detail for the sake of brevity.

[0099] In addition, in the case where details are set forth to describe exemplary embodiments of the present application, it will be apparent to those skilled in the art that the present application embodiments can be implemented without these details or with variations of these details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0100] Although the present application has been described in conjunction with the embodiments of the present application, many alternatives, modifications, and variations of these embodiments will be apparent to those of ordinary skill in the art based on the foregoing description.

[0101] The embodiments of the present application are intended to cover all such alternatives, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application shall be included within the protection scope of the present application.

Claims

1. A voltage regulator ripple rejection ratio test device, characterized in that Comprising: An AC signal source for providing an AC signal; A DC signal source for providing a DC signal; A signal input module electrically connected to the AC signal source through a first switch and to the DC signal source through a second switch, for processing the AC signal and the DC signal; A unit under test for installing a voltage regulator to be tested, the unit under test being electrically connected to the DC signal source through a third switch and to the signal input module through a fourth switch; A signal extraction module electrically connected to the unit under test through a fifth switch and to the signal input module through a seventh switch, with an eighth switch connected between the input terminal and the output terminal of the signal extraction module, the signal extraction module being used to extract the output ripple voltage signal of the voltage regulator; An electronic load electrically connected to the signal extraction module through a sixth switch; A signal acquisition module electrically connected to the signal extraction module through a ninth switch, for calculating the ripple rejection ratio of the voltage regulator.

2. The ripple suppression ratio test device for a voltage regulator according to claim 1, wherein Further comprising: A DC power supply electrically connected to the signal input module and the signal extraction module; An AC power supply electrically connected to the DC power supply, the AC signal source, the DC signal source, the signal acquisition module, and the electronic load.

3. The voltage regulator ripple rejection ratio test device according to claim 2, characterized in that The unit under test includes an adapter, the adapter being electrically connected to the voltage regulator, and both the unit under test and the electronic load are grounded; The signal input module includes an AC signal input terminal, a DC signal input terminal, and a signal coupling circuit; The signal extraction module includes a filter circuit and a signal amplification circuit; the signal acquisition module includes a measuring instrument and a host computer.

4. A method for testing the ripple rejection ratio of a voltage regulator, characterized in that, Using the voltage regulator ripple rejection ratio test device according to any one of claims 1-3, the voltage regulator ripple rejection ratio test method includes: Closing the first switch, the second switch, the sixth switch, the seventh switch, the eighth switch, and the ninth switch, and opening the third switch, the fourth switch, and the fifth switch to perform self-check on the signal input module; After the self-check passes, closing the first switch, the second switch, the seventh switch, and the ninth switch, and opening the third switch, the fourth switch, the fifth switch, the sixth switch, and the eighth switch to calibrate the signal extraction module; After the calibration passes, closing the first switch, the second switch, the fourth switch, the fifth switch, the sixth switch, and the ninth switch, and opening the third switch, the seventh switch, and the eighth switch to test the voltage regulator and calculate the ripple rejection ratio.

5. The method for testing the ripple rejection ratio of a voltage regulator according to claim 4, characterized in that Before closing the first switch, the second switch, the sixth switch, the seventh switch, the eighth switch, and the ninth switch, and opening the third switch, the fourth switch, and the fifth switch, includes: Obtain the test parameters of the voltage regulator and the output parameters during normal operation, where the test parameters include the input DC voltage V DUTDC , the test frequency f DUTAC , the load current I OUTDUT , the input voltage range [V INMIN , V INMAX , and the characteristic value PSRR of the ripple rejection ratio DUT ; the output parameters include the output voltage V OUTDUT and the corresponding output voltage range [V OUTDUTmin , V OUTDUTmax .

6. The method for testing the ripple rejection ratio of a voltage regulator according to claim 5, wherein Performing self-check on the signal input module, includes: Control the DC power supply to output a DC voltage with an amplitude of V to the signal input module +sig and V -sig ; Control the AC signal source to generate a sine wave signal with a frequency of f INAC , a peak-to-peak value of V PPINAC . Control the DC signal source to generate a DC voltage signal with an amplitude of V bias . Control the maximum load of the signal input module to be I LCADMAX ; when V OUTDUT > 0, then f INAC = f DUTAC , and |I LOADMAX | ≥ |I OUTDUT |; or, when V OUTDUT < 0, then f INAC = f DUTAC , and |I LOADMAX | ≥ |I OUTDUT |, where V PPINAC is the voltage swing; Testing the output signal V of the signal input module through the signal acquisition module coupleoutreal , where V coupleoutreal includes the DC component voltage amplitude V couplerealDC and the AC component voltage amplitude V couplerealAC ; When V OUTDUT > 0, if V couplerealDC + V cou p l e realAC ≤ V INMAX and V couplerealDC - V couplerealAC ≥ V INMIN , the self - test passes; or, when V OUTDUT < 0, if |V couplerealDC |+ V couplerealAC ≤ |V INMIN | and |V couplerealDC |- V couplerealAC ≥ |V INMAX |, the self - test passes.

7. The method for testing the ripple rejection ratio of a voltage regulator according to claim 6, wherein Calibrating the signal extraction module, includes: Control the DC power supply to output a DC voltage with an amplitude of V to the signal input module +sig and V -sig to output a DC voltage with an amplitude of V to the signal extraction module +ext and V -ext of the DC voltage; Control the AC signal source to generate a sine wave signal with a frequency of f IN ext， and a peak-to-peak value of V PPINext , satisfying f INext = f coupleout = f INAC , V PPINext = V coupleAC / Av PSRR and Av ext ≥ Av PSRR , where Av ext is the amplification factor of the signal extraction module, PSRR DUT = 20lg(Av PSRR ), V coupleAC is the amplitude of the output AC voltage signal of the signal input module, f coupleout is the frequency of the output AC voltage signal of the signal input module; Control the AC signal source to generate a sine wave signal with an amplitude of V coupleAC / Av PSRR starting from the first frequency f LF and stepping with a frequency interval of f step until the second frequency f HF to perform a frequency sweep test, and test the actual gain Av IN ext of the signal extraction module at the frequency of f extreal to obtain the upper cut-off frequency f cutoff1 and the lower cut-off frequency f cutofff2 of the signal extraction module, where f LF < f INext and f HF > f INext ; If f is satisfied cutofff1 <f INext <f cutoff2 and Av extreal ≥Av PSRR , the calibration is passed.

8. The method for testing the ripple rejection ratio of a voltage regulator according to claim 7, characterized in that, Before closing the first switch, the second switch, the sixth switch, the seventh switch, the eighth switch, and the ninth switch, and opening the third switch, the fourth switch, and the fifth switch, further includes: obtaining the test frequency accuracy; The first frequency and the second frequency satisfy f LF / f INext <<1 - k and f HF / f INext >>1 + k, where k > 0 and includes the test frequency accuracy.

9. The method for testing the ripple rejection ratio of a voltage regulator according to claim 8, wherein Closing the first switch, the second switch, the fourth switch, the fifth switch, the sixth switch, and the ninth switch, and opening the third switch, the seventh switch, and the eighth switch, includes: Closing the third switch, the fifth switch, the sixth switch, the eighth switch, and the ninth switch, and opening the first switch, the second switch, the fourth switch, and the seventh switch; Test the output voltage V of the voltage regulator through the signal acquisition module OUTreal ; If V OUT real is within [V OUTDUTmin , V OUTDUTmax , then disconnect the third switch and close the first switch, the second switch, and the fourth switch; Control the DC power supply to output a DC voltage with an amplitude of V to the signal input module +sig and V -sig ; control the AC signal source to generate a sine wave signal with a frequency of f INAC and a peak-to-peak value of V PPINAC ; control the DC signal source to generate a DC voltage signal with an amplitude of V bias ; Test the output voltage V of the voltage regulator through the signal acquisition module OUTreal2 ; If V OUTreal2 is within [V OUTDUTmin , V OUTDUTmax , then disconnect the eighth switch.

10. The method for testing the ripple rejection ratio of a voltage regulator according to claim 9, wherein Testing the voltage regulator and calculating the ripple rejection ratio includes: Test the output voltage V of the voltage regulator through the signal acquisition module OUTreal ; If V OUTrealn is within [V OUTDUTmin , V OUTDUTmax , then test the output voltage frequency f OUText and the peak-to-peak value V PPOUText ; If f OUText = f IN AC , the measured ripple rejection ratio PSRR of the voltage regulator is calculated real , where

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