TWI601963B - Detecting method of power adapter and measuring system - Google Patents

Description

Method for detecting power adapter and measuring system

The invention relates to the technical field of electromagnetic interference measurement of a notebook computer, in particular to a method and a measurement system of a power adapter.

Nowadays, notebook computers are becoming more and more popular, and they have gradually replaced the status of desktop personal computers. The electromagnetic interference problem of notebook computers has also attracted more and more attention. Among them, the conducted interference of telecom ports is one of them. The notebook computer is an information technology device. According to CISPR 22:2008 requirements for radio interference limits and measurement methods for information technology equipment, the conducted interference of the telecommunication port is measured and the measurement result is lower than the limit specified in CISPR 22:2008. . However, the interference voltage test of the existing notebook telecommunication port, because the notebook power supply and the notebook mainframe are usually not produced by the same manufacturer, the power adapter usually cannot obtain the corresponding type of notebook computer in the early stage of product development, and is often developed in the later stage. The verification phase only tests the telecom port interference caused by the notebook's power adapter, which will have a great impact on the market introduction of the product. Therefore, the manufacturer of the power adapter needs a test method to evaluate whether the DC output port will cause telecommunications. The port is over standard.

The object of the present invention is to provide a method for detecting a power adapter and a measuring system for measuring a DC output port interference voltage of a power adapter, so as to avoid the power adapter causing the telecommunications port to exceed the standard, resulting in a production cost. Increased problem.

The invention discloses a method for detecting a power adapter, which comprises collecting a radio frequency signal of a DC output port of a power adapter, wherein the radio frequency signal is used for measuring interference of the power adapter to a computer telecommunication port.

An embodiment of a method of detecting a power adapter in accordance with the present invention wherein the radio frequency signal is calibrated and compensated prior to being measured.

An embodiment of a method of detecting a power adapter in accordance with the present invention, wherein the method is performed while simulating the power adapter to be connected to a computer and operating normally.

An embodiment of a method of detecting a power adapter according to the present invention, comprising: coupling a DC output RF signal of the power adapter using a coupled decoupling network; receiving an RF coupled via the coupling decoupling network using an EMI receiver Signal; use the analog load to put the power adapter in an analog operating condition; use a manual power network to power the power adapter.

A measurement system for implementing the above method for detecting a power adapter, comprising: a coupling decoupling network, the EUT end of which is connected to a DC output end of the power adapter; and the EMI receiver, the RF input end of which is coupled to the coupling decoupling network The RF output; an analog load connected to the AE end of the coupled decoupling network; and an artificial power network connected to the AC input of the power adapter.

An embodiment of the measurement system according to the invention, wherein the AE end of the coupled decoupling network has an internal decoupling circuit to isolate the interference of the analog load.

An embodiment of a measurement system according to the invention, wherein the EMI receiver comprises a quasi-peak detector and an average detector.

An embodiment of the measurement system of the present invention, wherein the artificial power network is a V-type artificial power network.

An embodiment of the measurement system of the present invention, wherein the RF output of the coupled decoupling network is coupled to the RF input of the EMI receiver via a coaxial cable.

An embodiment of the measurement system according to the present invention, further comprising a reference grounding plate, the coupled decoupling network, the analog load, the artificial power supply network, and the power adapter being disposed on the reference ground plane.

An embodiment of the measurement system according to the present invention, wherein the coupled decoupling network, the analog load, the artificial power network, and the edge of the power adapter at the projection of the reference ground plane are greater than or equal to 0.5 m from the edge of the reference ground plane .

An embodiment of the measuring system according to the present invention, wherein the power adapter is on the insulating table and disposed at a vertical distance of 30 cm to 50 cm from the reference ground plate, and the horizontal distance of the AC end of the power adapter to the artificial power network is 70 cm. Up to 90 cm, the horizontal distance of the DC output of the power adapter to the coupled decoupling network is 70 cm to 90 cm.

According to an embodiment of the measuring system of the present invention, the vertical distance of the power adapter from the reference ground plate is 40 cm, and the horizontal distance of the AC end of the power adapter to the artificial power network is 80 cm, and the DC output of the power adapter The horizontal distance to the coupled decoupling network is 80 cm.

In summary, the present invention can accurately predict the test result of the telecom port of the notebook computer power adapter product when the notebook is connected with the notebook computer by accurately measuring the interference voltage of the notebook type power adapter, so that during the development of the power adapter product It is possible to predict whether the telecommunication port measurement value meets the standard requirements according to the DC output port interference voltage measurement value without a notebook computer. If the standard requirements are not met, the improvement can be achieved by applying an improvement measure to enable the telecommunication port to be measured later. It can successfully reach the standard.

1‧‧‧ artificial power network

2‧‧‧Power adapter

3‧‧‧EMI receiver

4‧‧‧Coupling decoupling network

5‧‧‧simulated load

6‧‧‧Reference grounding plate

7‧‧‧ Non-conductive table

10‧‧‧Coaxial cable

A‧‧‧Telecom port measurement results curve

B‧‧‧Measurement curve of DC output port

Figure 1 shows the structure of the measurement system for detecting the power adapter.

Figure 2 to Figure 4 are the measurement curves of the telecommunication port conduction disturbance of the three notebook computers and the DC output port of the power adapter.

The inventor of the present application found that the conducted interference of the telecommunication port has a great relationship with the AC/DC power adapter of the notebook computer when actually measuring the conducted interference of the telecommunication port of the notebook computer, and the test results with different power adapters sometimes differ. Very big. Through the analysis of the principle of conducted interference on the notebook telecom port, it is found that the electromagnetic interference signal of the power adapter can be transmitted to the telecom port of the notebook through the DC output port of the adapter, which becomes an important factor for the unqualified test of the telecom port. Therefore, the present application specifically developed a power adapter DC output port conducted interference voltage measurement system and method.

According to the method for detecting the power adapter of the present invention, the RF signal of the DC output port of the power adapter is collected, and the RF signal is used to measure the interference of the power adapter to the computer telecom port. Furthermore, in order to more accurately collect and analyze the RF signal of the DC output port of the power adapter, it is necessary to calibrate and compensate the RF signal before it is measured.

FIG. 1 is a structural diagram of a measurement system for detecting a power adapter. The measurement system for further detecting a method of detecting a power adapter is shown in FIG. 1. The power adapter DC output port conduction interference voltage measurement system includes: a coupling decoupling network 4 (Coupling Decoupling Network), analog load 5, Line Impedance Stabilization Network, and EMI receiver 3.

Referring to FIG. 1, the connection structure of the measurement system and the power adapter 2 includes an artificial power supply network 1 connected to an AC input terminal of the power adapter 2 to supply power to the power adapter 2. The DC output of the power adapter 2 is connected to the EUT end of the coupling decoupling network 4, the RF output of the coupling decoupling network 4 is connected to the RF input of the EMI receiver 3, and the AE end of the coupling decoupling network 4 is connected to the analog load 5. The coupled decoupling network 4 couples the DC output RF signals of the power adapter 2.

The working principle of the DC output port conduction interference voltage measuring system of the power adapter is briefly described below with reference to FIG. 1. The artificial power network 1 provides AC power to the power adapter 2, and the analog load 5 is used as a load for the analog notebook computer, which is generally an analog notebook computer. The load of power consumption. The DC output of the power adapter 2 is connected to the EUT end of the coupling decoupling network 4, and the AE end of the coupling decoupling network 4 is connected to the analog load 5. The RF output of the coupled decoupling network 4 is coupled to the RF input of the EMI receiver 3. The EMI receiver 3 measures the level of the interfering signal coupled out by the coupled decoupling network 4. In general, the EMI receiver 3 should include a quasi-peak detector and an average detector to measure the quasi-peak and average of the interfering signal, respectively. Further, the AE terminal of the coupled decoupling network 4 has an internal decoupling circuit to isolate the interference generated by the analog load 5. The impedance of the coupled decoupling network 4 is 150 Ω, which is the same as the impedance of the common mode interference signal of the impedance stabilization network used by the telecommunication port measured by the manual power network measurement notebook. The RF output port of the artificial power network 1 is terminated with a 50 Ω impedance.

For an embodiment, the artificial power network may use a V-type artificial power network.

To ensure the accuracy of the test, the measurement system should simulate the power adapter to connect to the computer and test it under normal operating conditions. The specific arrangement includes: with further reference to FIG. 1, the entire measurement system is disposed on a reference ground plane 6, and the projection edge of each device in the entire measurement system should be at least 0.5 m from the edge of the reference ground plane 6. In order to ensure that the DC output port conducted interference measurement result of the power adapter 2 is as close as possible to the interference level of the DC output port when the notebook computer is actually used, the common mode environment introduced by the DC output port measurement arrangement of the power adapter 2 needs to be as Similar to the common mode environment in the measurement arrangement of the telecom port, so Referring to the layout method of the telecommunication port in the CISPR 22:2008 standard, the DC output port test arrangement is designed. As shown in FIG. 1, the power adapter 2 is placed on a non-conductive table 7 of 40 cm height, and the artificial power network 1 is fixed on the reference ground plate 6. Keep well grounded. The horizontal distance from the AC input end of the power adapter 2 to the artificial power supply network 1 is 80 cm, and if the power supply line of the power adapter 2 exceeds 80 cm in length, the excess portion can be bundled into a figure-eight wire harness. The DC output of the power adapter 2 is connected to the EUT port of the coupled decoupling network 4; the RF output of the coupled decoupling network 4 can be connected to the RF input of the EMI receiver 3 via a 50 Ω coaxial cable 10; the coupled decoupling network 4 The AE is terminated with an analog load 5; the coupled decoupling network 4 is fixed to the reference ground plane 6 and is well grounded. The horizontal distance from the DC output port of the power adapter 2 to the coupled decoupling network 4 is 80 cm, and if the length of the DC output line of the power adapter 2 exceeds 80 cm, it is bundled into a figure-eight wire harness.

Of course, the above distance values are only preferred examples and are not fixed. In fact, those skilled in the art can also slightly adjust the above distance value to maintain a certain range, for example, the vertical distance between the power adapter 2 and the reference grounding plate 6 is between 30 cm and 50 cm, and the power adapter 2 The horizontal distance from the AC input to the artificial power network 1 is between 70 cm and 90 cm, and the horizontal distance from the DC output of the power adapter 2 to the coupled decoupling network 4 is between 70 cm and 90 cm.

In order to verify the effectiveness of the prediction of the method of detecting the power adapter on the conducted disturbance of the telecommunication port, three power adapters can be taken as samples, and the notebook type measurement method is first used to match the respective notebook computer and the detection power adapter. The method does not measure the common mode disturbance voltage of the power adapter 150kHz to 30MHz separately with the notebook computer, and the measurement curves of the telecommunication port conduction disturbance of the three notebook computers and the DC output port of the power adapter are respectively shown in FIG. 2 to FIG. 2 to A in Figure 4 represent the measurement result curve of the telecommunication port, and B represents the measurement result curve of the DC output port. From the comparison of Fig. 2 to Fig. 4, the following results can be obtained: (1) in the range of 150 kHz to 5 MHz, measurement The obtained common-mode disturbance voltage of the DC output port is greater than the common mode disturbance voltage of the telecommunication port, and the trend and shape of the measurement curves of the two methods are very consistent; (2) some of the results measured on the telecommunication port are Narrowband harassment signals, whose amplitude is higher than the measured value of the DC output port. These narrowband signals are generated by the notebook itself and have nothing to do with the power adapter.

It can be seen from the above observations that the method of detecting the power adapter can be used to predict the compliance of the common mode disturbance of the telecommunication port. The measured value of the DC output port obtained by the method of detecting the power adapter is less than the limit value of the conducted disturbance of the telecommunication port, and the same can satisfy the measurement limit of the telecommunication port when the late power adapter is matched with the notebook computer for telecommunication port measurement. Claim. Conversely, if the conducted disturbance of the DC output port exceeds the conducted disturbance limit of the telecom port, the power adapter with the notebook may cause the telecommunication port conduction disturbance test to fail. The method of detecting the power adapter has been effectively predicted and practical for the manufacturer of the power adapter.

In summary, the present invention can accurately predict the test result of the telecom port of the notebook computer power adapter product when the notebook is connected with the notebook computer by accurately measuring the interference voltage of the notebook type power adapter, so that during the development of the power adapter product It is possible to predict whether the telecommunication port measurement value meets the standard requirements according to the DC output port interference voltage measurement value without a notebook computer. If the standard requirements are not met, the improvement can be achieved by applying an improvement measure to enable the telecommunication port to be measured later. It can successfully reach the standard.

The technical solution of the present invention has been disclosed above by the preferred embodiments. It will be appreciated by those skilled in the art that modifications and modifications may be made without departing from the scope and spirit of the invention as disclosed in the appended claims.

1‧‧‧ artificial power network

2‧‧‧Power adapter

3‧‧‧EMI receiver

4‧‧‧Coupling decoupling network

5‧‧‧simulated load

6‧‧‧Reference grounding plate

7‧‧‧ Non-conductive table

10‧‧‧Coaxial cable

Claims (12)

A method for detecting a power adapter, comprising: collecting a radio frequency signal of a DC output port of a power adapter, wherein the power adapter is used to supply power to the power adapter; using an analog load to make the power adapter in an analog working condition; using coupling The coupling network couples the DC output RF signal of the power adapter; and receives the RF signal coupled via the coupled decoupling network using an EMI receiver; and the RF signal is used to measure the interference of the power adapter to the computer telecom port. As described in the scope of claim 1, the RF signal is calibrated and compensated prior to measurement. The method of claim 1 or 2, wherein the method is performed by simulating the connection of the power adapter to the computer and operating normally. A measuring system for implementing the method according to any one of claims 1 to 3, characterized in that it comprises: a coupling decoupling network, the EUT end of which is connected to the DC output of the power adapter; the EMI receiver The RF input is connected to the RF output of the coupled decoupling network; the analog load is connected to the AE end of the coupled decoupling network; and the artificial power network is connected to the AC input of the power adapter. The measurement system of claim 4, wherein the AE end of the coupled decoupling network has an internal decoupling circuit to isolate the interference of the analog load. The measurement system of claim 4, wherein the EMI receiver comprises a quasi-peak detector and an average detector. For example, in the measurement system described in claim 4, the artificial power network is a V-type artificial power network. The measurement system of claim 4, wherein the RF output of the coupled decoupling network is coupled to the RF input of the EMI receiver via a coaxial cable. The measurement system of claim 4, further comprising a reference grounding plate, the coupled decoupling network, the analog load, the artificial power network, and the power adapter being disposed on the reference ground plane. The measurement system of claim 9, wherein the coupled decoupling network, the artificial load network, and the edge of the power adapter at a projection of the reference ground plate are greater than or equal to an edge of the reference ground plate by 0.5. m. The measuring system of claim 9, wherein the power adapter is on the insulating platform and is disposed at a vertical distance of 30 cm to 50 cm from the reference grounding plate, and the horizontal distance of the AC end of the power adapter to the artificial power network is 70cm to 90cm, the horizontal distance of the DC output of the power adapter to the coupled decoupling network is 70cm to 90cm. The measuring system of claim 11, wherein the power adapter has a vertical distance of 40 cm from the reference grounding plate, and the horizontal distance of the AC adapter of the power adapter to the artificial power network is 80 cm, and the DC output of the power adapter The horizontal distance from the end to the coupled decoupling network is 80 cm.