A scrambling device and method for a direct current power supply

Abstract

The application discloses a scrambling device and method for a direct current power supply, relates to the technical field of single-board hardware testing, and aims to provide a technical scheme for scrambling any interference frequency signal in a direct current power supply in a power supply PSRR test. The scrambling device for the direct current power supply comprises a waveform signal generator, a transformer and a to-be-tested terminal. The waveform signal generator is used for generating first alternating current scrambling signals with different frequencies according to PSRR test requirements. The primary end of the transformer is connected with the waveform signal generator, the transformer is used for obtaining the first alternating current scrambling signals from the waveform signal generator, and the amplitude value of the first alternating current scrambling signals is adjusted to obtain second alternating current scrambling signals. The secondary end of the transformer is used for passing the direct current power supply signals and scrambling the second alternating current scrambling signals onto the direct current power supply signals to form the direct current power supply signals with the alternating current scrambling signals. The direct current power supply signals with the alternating current scrambling signals are output to the to-be-tested terminal.

Description

Technical Field

[0001] This invention relates to the field of single-board hardware testing technology, and in particular to a scrambling device and method for DC power supplies. Background Technology

[0002] PSRR (Power Supply Rejection Ratio), also known as power supply rejection ratio, is an important parameter for measuring the ability of a circuit to suppress ripple from the input power supply. It is expressed as the logarithmic ratio of the output ripple to the input ripple, and its unit is decibels (dB). Its calculation formula is:

[0003] In the formula:

[0004] Peak-to-peak value of ripple in the input voltage;

[0005] Peak-to-peak value of ripple in the output voltage;

[0006] As can be seen from the formula, the larger the PSRR, the smaller the ripple at the output for the same input ripple. For RF and wireless applications with high ripple requirements, power supply chips have very high requirements for PSRR. Therefore, PSRR testing is very important for chip power supply performance.

[0007] The principle of PSRR measurement is as follows: a certain frequency is superimposed on the DC voltage input to the power supply, and the peak-to-peak value is Ripple. input AC voltage V in_AC (The peak-to-peak value of AC voltage is typically several hundred millivolts), then measure V in the LDO output voltage. out_DC AC voltage V out_AC peak-to-peak Ripple output Finally, the PSRR at that frequency is calculated using the formula above.

[0008] However, in actual PSRR measurements, it is difficult to superimpose AC interference voltage of arbitrary frequency onto a DC voltage. One existing method is to use a signal generator with bias voltage function to power the chip. However, this method is unsuitable for measuring chips with high output power because the maximum output current of the signal generator is typically only tens of milliamps. Another method is to use a DC power supply with external scrambling function, but this only supports scrambling signals up to 1kHz, and cannot achieve higher scrambling frequencies. Summary of the Invention

[0009] The purpose of this invention is to provide a scrambling device and method for DC power supplies, which provides a technical solution for scrambling arbitrary interference frequency signals in DC power supplies during PSRR testing.

[0010] In a first aspect, the present application provides a scrambling device for a direct current power supply, which is applied to a PSRR test of the direct current power supply, and comprises a waveform signal generator, a transformer and a to-be-tested end.

[0011] The waveform signal generator is configured to generate a first alternating current scrambling signal with different frequencies according to the PSRR test requirement.

[0012] The primary end of the transformer is connected with the waveform signal generator, and is configured to obtain the first alternating current scrambling signal from the waveform signal generator and adjust the amplitude value of the first alternating current scrambling signal to obtain a second alternating current scrambling signal.

[0013] The secondary end of the transformer is electrically connected with the output end of the direct current power supply, and is configured to pass through a direct current power supply signal, add the second alternating current scrambling signal to the direct current power supply signal to form a direct current power supply signal with an alternating current scrambling signal, and output the direct current power supply signal with the alternating current scrambling signal to the to-be-tested end, wherein the to-be-tested end is configured to provide the direct current power supply signal with the alternating current scrambling signal to the PSRR test.

[0014] Compared with the prior art, the scrambling device for the direct current power supply in the present application comprises a waveform signal generator, a transformer and a to-be-tested end; wherein the waveform signal generator can generate a first alternating current scrambling signal with different frequencies according to the PSRR test requirement, the primary end of the transformer is connected with the waveform signal generator, and is configured to obtain the first alternating current scrambling signal from the waveform signal generator and adjust the amplitude value of the first alternating current scrambling signal to obtain a second alternating current scrambling signal; and the secondary end of the transformer is electrically connected with the output end of the direct current power supply, and is configured to pass through a direct current power supply signal, add the second alternating current scrambling signal to the direct current power supply signal to form a direct current power supply signal with an alternating current scrambling signal. Based on the above description, the waveform signal generator in the present application can obtain an alternating current interference signal with different frequencies, the primary end of the transformer can adjust the amplitude value of the alternating current interference signal to obtain an alternating current interference signal (i.e. the second alternating current scrambling signal) with a required frequency and amplitude value in the PSRR test, and finally the secondary end of the transformer can add the second alternating current scrambling signal to the direct current power supply signal, and the to-be-tested end can provide the direct current power supply signal with the alternating current scrambling signal to the PSRR test. It should be understood that the second alternating current scrambling signal is a scrambling signal obtained according to the PSRR test requirement, and the frequency and amplitude value thereof can be adjusted arbitrarily according to the PSRR test requirement, so that the scrambling device for the direct current power supply in the present application can solve the problem of adding an arbitrary interference frequency signal to the direct current power supply in the power supply PSRR test.

[0015] Further, the waveform signal generator is further configured to generate the first AC interference signal with different amplitude values according to the PSRR test requirement.

[0016] Further, the primary side of the transformer is configured to adjust the amplitude value of the first AC interference signal to obtain a second AC interference signal according to the strength of the AC interference signal in the PSRR test requirement.

[0017] Further, the number of turns of the primary side of the transformer can be set differently according to the strength of the AC interference signal in the PSRR test requirement.

[0018] Further, the transformer is a high-bandwidth transformer.

[0019] Further, the interference device for the DC power supply further comprises a controller electrically connected with the waveform signal generator, configured to control the waveform signal generator to generate the first AC interference signal with different frequencies according to the PSRR test requirement.

[0020] In a second aspect, the present application further provides an interference method for a DC power supply, applied in the PSRR test of the DC power supply, comprising the following steps:

[0021] According to the PSRR test requirement, a waveform signal generator is used to generate the first AC interference signal with different frequencies;

[0022] The primary side of a transformer is used to obtain the first AC interference signal, and the amplitude value of the first AC interference signal is adjusted to obtain a second AC interference signal;

[0023] The secondary side of the transformer is used to interfere the second AC interference signal to the DC power supply signal to form a DC power supply signal with AC interference signal, and the output value of the DC power supply signal with AC interference signal is output to the to-be-tested end, wherein the to-be-tested end is configured to provide the DC power supply signal with AC interference signal to the PSRR test.

[0024] Further, before the primary side of the transformer is used to obtain the first AC interference signal, and the amplitude value of the first AC interference signal is adjusted to obtain a second AC interference signal, the interference method for the DC power supply further comprises the following steps:

[0025] According to the PSRR test requirement, the waveform signal generator is used to generate the first AC interference signal with different amplitude values.

[0026] Further, the transformer primary end is used to obtain the first AC interference signal, and the amplitude value of the first AC interference signal is adjusted to obtain a second AC interference signal.

[0027] The transformer primary end is used to obtain the first AC interference signal, and the amplitude value of the first AC interference signal is adjusted to obtain a second AC interference signal according to the strength of the AC interference signal in the PSRR test requirement.

[0028] Further, the transformer is a high-bandwidth transformer.

[0029] Compared with the prior art, the method for the DC power supply provided by the present application has the same beneficial effects as the device for the DC power supply, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0030] The accompanying drawings, which are included to provide a further understanding of the present application, constitute a part of the present application and illustrate the preferred embodiments of the present application and specific examples thereof, and are used to explain the present application, and do not limit the present application in any way. In the drawings:

[0031] Figure 1 It is a schematic diagram of the PSRR measurement principle;

[0032] Figure 2 It is a schematic diagram of a device for the DC power supply provided by the present application;

[0033] Figure 3 It is a schematic diagram of the structure principle of the transformer provided by the present application;

[0034] Figure 4 It is a step flow chart of a method for the DC power supply provided by the present application. DETAILED DESCRIPTION

[0035] In order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, the same items or similar items with basically the same functions and effects are distinguished by using "first", "second", etc. For example, the first threshold and the second threshold are only used to distinguish different thresholds, and do not limit the order. Those skilled in the art can understand that "first", "second", etc. do not limit the number and execution order, and "first", "second", etc. also do not limit the difference.

[0036] It should be noted that in the present application, the words "exemplary" or "for example" are used to mean "an example of" or "an example, only. Any embodiment or design described as "exemplary" or "for example" in the present application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the exemplary or for example embodiments are presented in order to best explain certain concepts.

[0037] In the present application, "at least one" means one or more, and "multiple" means two or more. The "and / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the cases of A alone, A and B together, B alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b or c can represent a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b and c can be single or multiple.

[0038] PSRR (Power supply rejection ratio) is also called power supply rejection ratio, which is an important parameter for measuring the size of the input power supply ripple rejection of a circuit, expressed as the logarithmic ratio of the output ripple and the input ripple, with the unit of decibel (dB), and its calculation formula is:

[0039] In the formula:

[0040] : the peak-to-peak value of the input voltage ripple;

[0041] : the peak-to-peak value of the output voltage ripple;

[0042] As can be seen from the formula, the larger the PSRR, the smaller the output ripple of the same input ripple. In the radio frequency and wireless applications with high requirements for ripple, the power supply chip has high requirements for PSRR, so the PSSR test is very important for the power supply performance of the chip.

[0043] The PSRR measurement principle is shown in Figure 1 : a certain frequency and peak-to-peak value of the ac voltage V in_DC (AC voltage peak-to-peak value is generally hundreds of millivolts) is superimposed on the DC voltage V input of the power supply input, and then the ac voltage V in_AC of V out_DC in the LDO output voltage is measured.out_AC Peak-to-peak Ripple output Finally, the PSRR at that frequency is calculated using the above formula.

[0044] However, in actual PSRR measurements, it is difficult to superimpose AC interference voltage of arbitrary frequency onto a DC voltage. One existing method is to use a signal generator with bias voltage function to power the chip. However, this method is unsuitable for chips with high output power because the maximum output current of the signal generator is typically only tens of milliamps. Another method is to use a DC power supply with external scrambling functionality, such as the ARB function of the N6705C. However, this only supports scrambling signals up to 1kHz, and cannot achieve higher signal scrambling frequencies.

[0045] Based on this, in a first aspect, embodiments of the present invention provide a device for solving the problem that arbitrary interference frequency signals cannot be added to a DC power supply during power supply PSRR testing. (Refer to...) Figure 2 The scrambling device for DC power supply provided in this embodiment of the invention includes a waveform signal generator, a transformer, and a test terminal; the waveform signal generator is used to generate a first AC scrambling signal of different frequencies according to the PSRR test requirements;

[0046] The primary end of the transformer is connected to the waveform signal generator to obtain the first AC scrambling signal from the waveform signal generator and adjust the amplitude value of the first AC scrambling signal to obtain the second AC scrambling signal.

[0047] The secondary end of the transformer is electrically connected to the output end of the DC power supply. It is used to pass the DC power supply signal and scramble the second AC scrambling signal onto the DC power supply signal to form a DC power supply signal with AC scrambling signal. The DC power supply signal with AC scrambling signal is then output to the test terminal. The test terminal is used to provide the DC power supply signal with AC scrambling signal to the PSRR test.

[0048] According to the above description, the waveform signal generator provided in the embodiment of the present application can generate first AC interference signals of different frequencies according to PSRR test requirements, the primary end of the transformer is connected with the waveform signal generator, for obtaining the first AC interference signals from the waveform signal generator and adjusting the amplitude value of the first AC interference signals to obtain second AC interference signals; the secondary end of the transformer is electrically connected with the output end of the DC power supply, for passing the DC power supply signal and adding the second AC interference signals to the DC power supply signal to form a DC power supply signal with AC interference signals. Therefore, the embodiment of the present application can obtain AC interference signals of different frequencies through the waveform signal generator, then adjust the amplitude value of the AC interference signals through the primary end of the transformer to obtain AC interference signals (i.e. the second AC interference signals) of the required frequency and amplitude value in the PSRR test, finally, add the second AC interference signals to the DC power supply signal through the secondary end of the transformer, and provide the DC power supply signal with AC interference signals to the PSRR test through the to-be-tested end. It should be understood that the above-mentioned second AC interference signals are interference signals obtained according to the PSRR test requirements, and the frequency and amplitude value thereof can be adjusted arbitrarily according to the PSRR test requirements, so that the interference device of the DC power supply in the present application can solve the problem of adding arbitrary interference frequency signals to the DC power supply in the power supply PSRR test.

[0049] In the above, the primary end of the transformer is used to adjust the amplitude value of the first AC interference signals according to the intensity of the AC interference signals in the PSRR test requirements, to obtain the second AC interference signals.

[0050] Further, in practice, the waveform signal generator can also be used to generate first AC interference signals with different amplitude values according to the PSRR test requirements. Based on this, the waveform signal generator can not only generate first AC interference signals of different frequencies, but also generate first AC interference signals of different amplitude values, and then the primary end of the transformer can adjust the amplitude value of the first AC interference signals according to the amplitude value of the first AC interference signals and the PSRR test requirements, to obtain the second AC interference signals meeting the PSRR test requirements.

[0051] When generating first scrambled signals of varying amplitudes using a waveform generator, a transformer primary with a fixed number of turns can be used. It should be understood that when the number of turns at the transformer primary cannot meet the signal strength requirements for PSRR testing, the first scenario is as follows: If adjusting the amplitude of the first AC scrambled signal using the transformer primary results in a second AC scrambled signal whose strength is still less than the PSRR test requirement, the waveform generator can be controlled to generate a first scrambled signal with a larger amplitude without changing the number of turns at the transformer primary. This ensures that the second AC scrambled signal obtained after passing through the transformer primary meets the PSRR test requirements. The second scenario is as follows: If adjusting the amplitude of the first AC scrambled signal using the transformer primary results in a second AC scrambled signal whose strength is still greater than the PSRR test requirement, the waveform generator can be controlled to generate a first scrambled signal with a smaller amplitude without changing the number of turns at the transformer primary. This ensures that the second AC scrambled signal obtained after passing through the transformer primary meets the PSRR test requirements.

[0052] As one possible implementation, the number of turns on the primary side of the transformer can be set differently depending on the strength of the AC scrambling signal in the PSRR test requirements.

[0053] Specifically, when the amplitude of the first AC scrambling signal after passing through the waveform generator deviates significantly from the strength required for the PSRR test, the primary winding of the transformer can be set to have a larger number of turns. Conversely, when the amplitude of the first AC scrambling signal after passing through the waveform generator deviates slightly from the strength required for the PSRR test, the primary winding of the transformer can be set to have a smaller number of turns.

[0054] The aforementioned transformer can be a high-bandwidth transformer. In this embodiment of the invention, the amplitude and frequency limitation of the scrambling signal are related to the selection of the transformer. A suitable turns ratio is selected according to the required scrambling amplitude, and a high-bandwidth transformer can be selected according to the required scrambling frequency.

[0055] It should be understood that, with reference to Figure 3 A transformer is a static electrical appliance that uses electromagnetic induction between coils to convert alternating current (AC) energy of one voltage level into AC energy of another voltage level at the same frequency.

[0056] The main components of a transformer are the iron core and the two windings wound around it. The two windings are only magnetically coupled and not electrically connected. When an alternating voltage is applied to the primary winding, an alternating magnetic flux is generated that links the primary and secondary windings, inducing electromotive forces in both windings.

[0057] When the primary winding is connected to an AC power supply, an AC current flows through the winding, and an alternating magnetic flux is generated in the core, which has the same frequency as the applied voltage. This alternating magnetic flux is interlinked with both the primary winding and the secondary winding. The induction of the primary winding and the secondary winding is respectively represented as:

[0058] ;

[0059] Then:

[0060] ;

[0061] The transformation ratio k represents the turns ratio of the primary winding and the secondary winding, and is equal to the ratio of the induced voltage of the primary winding to the induced voltage of the secondary winding. By changing the transformation ratio of the transformer, the output voltage can be changed.

[0062] The transformer has only magnetic coupling between the two sides, and there is no electrical connection, so the two sides are isolated. The AC interference signal added to the DC power supply will not be affected. By adjusting the specifications of the transformer, the turns ratio and the bandwidth, the required interference frequency and amplitude can be obtained for the PSRR test.

[0063] In some examples, the above-mentioned interference device for a DC power supply further comprises a controller electrically connected with the waveform signal generator, for controlling the waveform signal generator to generate first AC interference signals of different frequencies according to the PSRR test requirements.

[0064] Based on this, the embodiment of the present application can automatically control the waveform signal generator to generate first AC interference signals of different frequencies according to the PSRR test requirements, which can improve the accuracy and timeliness of control to a certain extent.

[0065] In a second aspect, referring to Figure 4 The embodiment of the present application further provides an interference method for a DC power supply, which is applied to the PSRR test of a DC power supply, and comprises the following steps:

[0066] S100, generating first AC interference signals of different frequencies by using a waveform signal generator according to the PSRR test requirements;

[0067] S200, obtaining the first AC interference signals by using the primary side of a transformer, and adjusting the amplitude value of the first AC interference signals to obtain second AC interference signals;

[0068] S300, scrambling the second AC interference signal onto the DC power signal by using the secondary end of the transformer to form a DC power signal with AC interference signal, and outputting the DC power signal with AC interference signal to the to-be-tested end, wherein the to-be-tested end is configured to provide the DC power signal with AC interference signal to the PSRR test.

[0069] Further, before obtaining the first AC interference signal by using the primary end of the transformer and adjusting the amplitude value of the first AC interference signal to obtain the second AC interference signal, the scrambling method for the DC power supply further comprises the following steps:

[0070] According to the PSRR test requirement, the waveform signal generator is used to generate the first AC interference signal with different amplitude values.

[0071] Further, the obtaining the first AC interference signal by using the primary end of the transformer and adjusting the amplitude value of the first AC interference signal to obtain the second AC interference signal comprises:

[0072] The first AC interference signal is obtained by using the primary end of the transformer, and the amplitude value of the first AC interference signal is adjusted according to the strength of the AC interference signal in the PSRR test requirement to obtain the second AC interference signal.

[0073] Further, the transformer is a high-bandwidth transformer.

[0074] Based on the above description, the waveform signal generator can be used to obtain AC interference signals with different frequencies, and the amplitude value of the AC interference signal is adjusted by using the primary end of the transformer to obtain an AC interference signal (i.e. the second AC interference signal) with a required frequency and amplitude value in the PSRR test. Finally, the second AC interference signal is scrambled onto the DC power signal by using the secondary end of the transformer, and the to-be-tested end is used to provide the DC power signal with AC interference signal to the PSRR test. It should be understood that the above-mentioned second AC interference signal is a scrambling signal obtained according to the PSRR test requirement, and the frequency and amplitude value thereof can be adjusted arbitrarily according to the PSRR test requirement. Therefore, the scrambling device for the DC power supply in the present application can solve the problem of scrambling any interference frequency signal in the power supply PSRR test.

[0075] Although the application has been described in connection with various embodiments thereof, it will be understood that the application is capable of further modifications and that this application is intended to cover any and all such variations, using the scope of the claims. The word "comprising" does not exclude other components or steps not mentioned. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. A single processor or other unit can fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0076] Although the application has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications and this application is intended to cover any and all such variations, using the scope of the claims. The description and drawings merely schematically illustrate the non-limiting exemplary embodiments of the application. It is therefore evident that the application can be altered and modified and all such alterations and modifications are intended to be within the scope of the application. Accordingly, the application is intended to include all such alterations and modifications without departing from the scope, spirit and principles of the application.

Claims

1. A scrambling device for a direct current power supply, characterized by The scrambling device for the DC power supply comprises a waveform signal generator, a transformer and a to-be-tested end. The waveform signal generator is configured to generate a first AC scrambling signal with a frequency greater than 1 kHz according to the PSRR test requirement. The primary end of the transformer is connected to the waveform signal generator and configured to obtain the first AC scrambling signal from the waveform signal generator and adjust the amplitude value of the first AC scrambling signal to obtain a second AC scrambling signal; the transformer is a high-bandwidth transformer. The secondary end of the transformer is connected in series to the output end of the DC power supply and configured to pass through the DC power supply signal and scramble the second AC scrambling signal onto the DC power supply signal to form a DC power supply signal with an AC scrambling signal and output the DC power supply signal with the AC scrambling signal to the to-be-tested end, wherein the to-be-tested end is configured to provide the DC power supply signal with the AC scrambling signal to a chip to be tested in the PSRR test.

2. The scrambling device for a direct current power supply according to claim 1, characterized by, The number of turns of the primary end of the transformer can be set differently according to the strength of the AC scrambling signal in the PSRR test requirement.

3. The scrambling device for a direct current power supply according to any one of claims 1-2, characterized in that, The scrambling device for the DC power supply further comprises a controller electrically connected to the waveform signal generator and configured to control the waveform signal generator to generate first AC scrambling signals with different frequencies according to the PSRR test requirement.

4. A scrambling method for a direct current power supply, characterized by, The scrambling method for the DC power supply comprises the following steps in the PSRR test: A waveform signal generator is used to generate a first AC scrambling signal with a frequency greater than 1 kHz according to the PSRR test requirement. A primary end of a transformer is used to obtain the first AC scrambling signal and adjust the amplitude value of the first AC scrambling signal to obtain a second AC scrambling signal; the transformer is a high-bandwidth transformer. A secondary end of the transformer is used to scramble the second AC scrambling signal onto a DC power supply signal to form a DC power supply signal with an AC scrambling signal and output the DC power supply signal with the AC scrambling signal to a to-be-tested end, wherein the to-be-tested end is configured to provide the DC power supply signal with the AC scrambling signal to a chip to be tested in the PSRR test; the secondary end of the transformer is connected in series to the output end of the DC power supply.

5. The scrambling method for a direct current power source according to claim 4, wherein, Before the primary end of the transformer is used to obtain the first AC scrambling signal and adjust the amplitude value of the first AC scrambling signal to obtain the second AC scrambling signal, the scrambling method for the DC power supply further comprises the following steps: The waveform signal generator is used to generate first AC scrambling signals with different amplitude values according to the PSRR test requirement.

6. The scrambling method for a direct current power supply according to claim 5, wherein, The primary end of the transformer is used to obtain the first AC scrambling signal and adjust the amplitude value of the first AC scrambling signal to obtain the second AC scrambling signal. The first AC interference signal is obtained by using a primary end of a transformer, and the amplitude value of the first AC interference signal is adjusted according to the strength of the AC interference signal in the PSRR test requirement, so as to obtain a second AC interference signal.

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