NB/T 10288-2019Highly accelerated life test methods of AC-DC switching power supply (English PDF)

3.1 Highly accelerated life test

In the product development stage, different stresses are applied to the test samples to quickly expose product defects and analyze and correct them, and then determine and Programmatic type test to improve the working limit and damage limit of the product.

3.2 Temperature lower operational limit

The low temperature limit value for the normal operation of the product.

3.3 Temperature upper operational limit

The high temperature limit value for the normal operation of the product.

3.4 Vibration upper operational limit

The vibration limit value for the normal operation of the product.

3.5 Temperature lower destruct limit

The low temperature limit value of product failure, the product cannot return to normal operation after the low temperature stress is removed.

3.6 Temperature upper destruct limit

The high temperature limit value of product failure, the product cannot return to normal operation after the high temperature stress is removed.

3.7 Vibration upper destruct limit

The vibration limit value for product failure, the product cannot resume normal operation after the vibration stress is removed.

4.1 Product working stress limit test

The product working stress limit (low temperature, high temperature, vibration) determined by the highly accelerated life test should meet the requirements of Table 1.

4.2 Comprehensive environmental stress test

The comprehensive environmental stress test meets the following requirements.

--No failure of the test sample occurred during the test;

--After the test, the test sample shall be restored at room temperature for 24 hours, and the electrical performance, common mode noise and body noise shall be in compliance with the product specifications. Grid requirements.

Among them, the common mode noise test method is carried out in accordance with the specifications in Appendix A, and the body noise test method is carried out in accordance with the specifications in Appendix B.

5.1 General requirements

5.1.1 Highly accelerated life test equipment requirements

--Highly accelerated life test chamber can provide six degrees of freedom random vibration, and can generate at least 50 Grms in a wide frequency range (2 kHz~5 kHz)

Vibration intensity --The temperature change range of the highly accelerated life test chamber is at least (-60~120)°C;

--Highly accelerated life test chamber must use liquid nitrogen to cool down to achieve a sufficient temperature change rate, the temperature change rate must be greater than or equal to 45 °C /min;

--With programmable high-power AC power supply and DC electronic load;

-Equipped with data collector and thermocouple wire to monitor the internal temperature of the test sample;

-Equipped with a spectrum analyzer and accelerometer to monitor the vibration response of the test sample.

5.1.2 Requirements on the number of samples for highly accelerated life test.

--The number of samples for each test should be no less than 3 pieces (including 3 pieces).

5.2 Product working stress limit test

5.2.1 Low temperature step stress test

5.2.1.1 Test purpose

Determine the lower limit of low temperature work and the lower limit of low temperature damage of the product.

5.2.1.2 Test conditions

Initial ambient temperature. 0 °C; Each step temperature interval. 10 °C;

Hold time. 10 minutes; power off the test sample during the temperature change of the high accelerated life test chamber, and the internal temperature of the test sample (pass After the thermocouple wire is pasted in the sample to confirm) stable, stay for 10 minutes, during this period input the nominal voltage to the test sample, and the output Full load Temperature change rate. greater than or equal to 45 °C/min.

Function monitoring. During the power-on period of the test sample, monitor the function of the test sample, and determine whether the test sample is working properly according to product specifications. often.

5.2.1.3 Test procedure

S1 Input the nominal voltage to the test sample at room temperature, output the rated full load, check the function of the test sample, according to the product specifications Determine whether the test sample is working normally;

S2 If the test sample works normally, power off the test sample and set the ambient temperature as the starting ambient temperature;

S3 After the internal temperature of the test sample (determined by pasting the thermocouple wire in the sample) stabilizes, stay for 10 minutes, and give the test during this period Input the nominal voltage of the test sample, output the rated full load, monitor the function of the test sample, and determine the test sample according to the product specifications Whether it is working properly; during the period when the internal temperature of the test sample is not stable, the test sample is in a power failure in the high accelerated life test box status;

S4 If the test sample works normally, the test sample is powered off, the ambient temperature is reduced by 10 °C, and the temperature change rate during the cooling process is greater than Equal to 45 °C/min;

S5 Repeat steps S3 and S4 until the test sample fails (the output voltage is not within the product specifications) or the ambient temperature drops to -60°C;

S6 If the test sample fails, raise the ambient temperature to 25 °C; S7 Repeat step S3;

S8 If the test sample fails at 25°C, record the ambient temperature value set when the test sample fails as the lower limit of low temperature damage.

Record the ambient temperature value set when the sample is working normally in the previous step as the lower limit of low temperature working;

S9 If the function of the test sample returns to normal at 25°C, reduce the ambient temperature to the ambient temperature set when the test sample fails 5 °C; S10 Repeat step S3;

S11 If the test sample works normally under the failure temperature of 5 °C, record this temperature value as the lower limit of low temperature work;

If the test sample is still invalid, record the ambient temperature value set when the product is working normally in the previous step as the lower limit of low temperature work;

S12 If the test sample still works normally at an ambient temperature of -60 °C, record the ambient temperature value (-60 °C) as Low temperature working limit and low temperature damage lower limit.

5.2.1.4 Schematic diagram of low temperature step stress test

The schematic diagram of the low temperature step stress test is shown in Figure 1.

5.2.2 High temperature step stress test

5.2.2.1 Test purpose

Determine the upper limit of the product's high temperature work and high temperature damage.

5.2.2.2 Test conditions

Initial ambient temperature. 60 °C; Each step temperature interval. 10 °C;

Holding time. 10 minutes; power off the test sample during the temperature change of the high accelerated life test chamber, and the internal temperature of the test sample (pass Stick the thermocouple wire in the sample to confirm) After it is stable, stay for 10 minutes, during this period input the nominal voltage to the test sample and output the rated full load; Temperature change rate. greater than or equal to 45 °C/min;

Function monitoring. During the power-on period of the test sample, monitor the function of the test sample, and determine whether the test sample is working properly according to product specifications. often.

5.2.2.3 Test procedure

S1 Input the nominal voltage to the test sample at room temperature, output the rated full load, check the function of the test sample, according to the product specifications Determine whether the test sample is working normally;

S2 If the test sample works normally, power off the test sample and set the ambient temperature as the starting ambient temperature;

S3 After the internal temperature of the test sample (determined by pasting the thermocouple wire in the sample) stabilizes, stay for 10 minutes, and give the test during this period Input the nominal voltage of the test sample, output the rated full load, monitor the function of the test sample, and determine the test sample according to the product specifications Whether it is working properly; during the period when the internal temperature of the test sample is not stable, the test sample is in a power failure in the high accelerated life test box status;

S4 If the test sample is working normally, power off the test sample, the ambient temperature will increase by 10 °C, and the temperature change rate during the heating process will be greater than Equal to 45 °C/min;

S5 Repeat steps S3 and S4 until the test sample fails (the output voltage is not within the product specifications) or the ambient temperature rises to 120°C;

S6 If the test sample fails, reduce the ambient temperature to 25 °C; S7 Repeat step S3;

S8 If the test sample still fails at 25 °C, record the environmental temperature value set when the test sample fails as the upper limit of high temperature damage.

Record the ambient temperature value set when the sample is working normally in the previous step as the upper limit of high temperature work;

S9 If the function of the test sample returns to normal at 25 °C, increase the ambient temperature to the ambient temperature set when the test sample fails -5°C; S10 Repeat step S3;

S11 If the test sample works normally at the failure temperature of -5 °C, record this temperature value as the upper limit of high temperature work;

If the test sample is still invalid, record the ambient temperature value set when the product is working normally in the previous step as the high temperature working upper limit;

S12 If the test sample still works normally at an ambient temperature of 120 °C, record this ambient temperature value (120 °C) as High temperature working upper limit and high temperature damage upper limit.

5.2.2.4 Schematic diagram of high temperature step stress test

The schematic diagram of the high temperature step stress test is shown in Figure 2.

5.2.3 Random vibration step stress test

5.2.3.1 Test purpose

Determine the upper limit of product vibration work and the upper limit of vibration damage.

5.2.3.2 Test conditions

Ambient temperature. 25 °C; Initial vibration intensity. 10 Grms; Vibration intensity interval for each step. 10 Grms;

Holding time. 10 min; after the vibration of the test sample is stable (determined by the response value of the accelerometer pasted in the sample), stay for 10 min, During this period, input the nominal voltage to the test sample and output the rated full load.

Function monitoring. During the power-on period of the test sample, monitor the function of the test sample, and determine whether the test sample is working properly according to product specifications. often.

5.2.3.3 Test procedure

S1 sets the ambient temperature to 25 °C; S2 Set the vibration intensity as the initial vibration intensity;

S3 After the vibration of the test sample is stable (determined by the response value of the accelerometer pasted in the sample), continue to vibrate for 10 minutes.

Input the nominal voltage to the test sample, output the rated full load, monitor the function of the test sample, and determine the test according to the product specifications. Check whether the sample is working properly;

S4 If the test sample works normally, increase the vibration intensity by 10 Grms;

S5 Repeat steps S3 and S4 until the test sample fails (the output voltage is not within the product specifications) or the vibration intensity increases to 50 Grms;

S6 If the test sample fails, reduce the vibration intensity to 0 Grms; S7 Repeat step S3;

S8 If the test sample fails at 0 Grms, record the vibration intensity value set when the test sample fails as the upper limit of vibration damage.

Record the vibration intensity value set when the sample is working normally in the previous step as the upper limit of vibration work;

S9 If the function of the test sample returns to normal at 0 Grms, increase the vibration intensity to -5 Grms when the test sample fails; S10 Repeat step S3;

S11 If the test sample works normally under the condition of failure vibration intensity -5 Grms, record this vibration intensity value as the vibration work Limit; if the test sample still fails, record the vibration intensity value of the previous step when the sample is working normally as the upper limit of vibration work.

S12 If the test sample still works normally when the vibration intensity is increased to 50 Grms, record the vibration intensity value (50 Grms)

It is the upper limit of vibration work and the upper limit of vibration damage.

5.2.3.4 Schematic diagram of random vibration step stress test

The schematic diagram of random vibration step stress test is shown in Figure 3.

5.3 Comprehensive environmental stress test

5.3.1 High and low temperature cycling conditions for comprehensive environmental stress test Low temperature working point of high and low temperature cycle. The lower limit of low temperature working recorded in low temperature step stress test is 10 °C.

High and low temperature cycle high temperature working point. the high temperature working upper limit recorded in the high temperature step stress test -10 °C. Temperature change rate. greater than or equal to 45 °C/min.

High temperature and low temperature residence time. After the internal temperature of the test sample (determined by the thermocouple wire attached to the sample) stabilizes, it stays for 10 minutes each. High and low temperature cycle. 5 comprehensive cycles.

5.3.2 Random vibration conditions for comprehensive environmental stress test Vibration intensity during temperature change. the upper limit of vibration damage recorded in the vibration step stress test × 25%.

Vibration intensity during temperature stabilization. the upper limit of vibration damage recorded in the vibration step stress test × 50%.

5.3.3 Electrical stress in comprehensive environmental stress test

Test sample input voltage. nominal voltage. Test sample output load. rated full load.

5.3.4 Schematic diagram of comprehensive environmental stress test

The schematic diagram of the comprehensive environmental stress test is shown in Figure 4.

A.1 Test purpose

The common mode noise test is mainly to measure the common mode noise level produced by a switching power supply with AC terminals during normal operation. The noise level will It directly affects the control sensitivity of the touch screen device during charging.

A.2 Test principle and system layout

The principle and layout of common mode noise test are shown in Figure A.1. Figure A.1 Common mode noise test principle and layout diagram

A.3 Common mode noise limit

Common mode noise limits are shown in Table A.1.

A.4 General measurement conditions

A.4.1 Environmental level

The test site should be able to distinguish the harassment and environmental noise from the object under test, which can be determined by the environmental noise level (the object under test is not working).

It should be ensured that the noise level is 6dB lower than the limit specified in Table A.1.

When the combined result of environmental noise and source disturbance does not exceed the specified limit, it is not necessary to require the environmental noise level to be higher than the specified limit 6 dB lower. In this case, it can be considered that the source emission meets the specified limit requirements; when the sum of the environmental noise and the source disturbance If it exceeds the specified limit, it cannot be determined that the object under test does not meet the limit requirements, unless it can be the same at each frequency point corresponding to the limit. When meeting the following two conditions.

--The environmental noise level is at least 6 dB lower than the source disturbance plus the environmental noise level;

--The ambient noise level is at least 4.8 dB lower than the specified limit.

A.4.2 General requirements for the layout of the object to be tested

The test is carried out in a shielded room. In order to simulate the equivalent capacitive load of the mobile terminal, a specification of (100 Conductive metal box of ±1)mm×(60±1) mm×(12±1) mm. The DUT and its cable, load and simulated capacitive load should be Place it on an insulating support 30 cm high and at least 30 cm away from surrounding metal structures. The output line of the object to be tested should be placed without inductance.

The maximum projection distance from the object to the load is 1.2 m. For the DUT with rewirable wires, the output wire number is 22AWG and the length should be 1.2 m. To be The output of the test object is connected to a full load test.

The reference ground plane shall be at least 0.5 m beyond the projection of the test arrangement.

The shortest possible conductor should be used to connect the reference ground point of the impedance matching network to the ground plane. Examples of test arrangements for reference (See example). The provisions of the test layout are mainly written. Example: […]

A.5 Measurement method

A.5.1 Measuring detector

The peak detector receiver described in A.5.2 should be used for measurement.

A.5.2 Receiver

The peak measurement receiver should meet the requirements of Chapter 5 of GB/T 6113.101-2016, and have the 6 dB bandwidth required by 5.2.1 in this chapter.

A.5.3 Isolating transformer

The test uses a 1.1 isolation transformer and a built-in broadband attenuator. The frequency domain characteristics of the attenuator are shown in Figure A.2. Figure A.2 Frequency domain characteristics of attenuator

A.5.4 5 dB amplifier In order to facilitate the measurement, the signal needs to be amplified by 5 dB.

A.5.5 Impedance matching network

In order to provide a stable impedance matching the test system at the measurement end, while isolating the circuit under test from the background noise on the power grid, Need to use impedance matching network.

A.6 Measurement record

Among the disturbance levels exceeding (L-10 dB) (L is the limit level expressed in logarithmic units), at least three of the largest Disturbance level and its corresponding frequency.

In addition, the test report should also include the measurement uncertainty of the measuring instrument used for the test and related connections.

B.1 Product Classification

Class I. Products used in a quieter environment. Class II. Products used in daily ordinary environments.

Class III. Products used in environments with low noise requirements, such as Internet cafes.

B.2 Product noise requirements

B.2.1 PC power supply (ATX, PS3)

The noise of products without temperature control circuit must meet the full load requirement. The noise requirements of PC power supply (ATX, PS3) are shown in Table B.1 and Table B.2.

Note 1. The sound pressure level corresponds to the reference sound pressure of 20 µPa, and the sound power level corresponds to the reference sound power of 1 pW.

Note 2. The sound pressure level test distance is 0.5 meters and 1 meter; the sound power level test radius is 1 meter.

B.2.2 PC power supply (TFX, LFX, CFX)

B.3.2 Sound pressure level test