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Evaluation Analysis Service for Power Supply Modules
Ensuring the safety of power supply modules in various office and home electronic appliances is an important task. Including proposal of counter-measures, our company provides technical services, such as performance tests, safety inspections, failure analysis and power supply evaluation for your company's line of power supply units (*1) or units purchased for equipment installation.
- *1 Power supply units: AC adapters and on-board power sources, etc.
- Safety inspection for power supply module products
Basic characteristic tests, safety confirmation tests, various environmental and reliability tests, compliance verification tests, inspection of used components and product structure.
- Failure analysis and counter-measure proposal
Failure cause analysis and counter-measure proposal regarding power supply module function, characteristics and its applied components.
Evaluation Tests for Power Supply Modules (AC adaptors and DC-DC convertors)
For power supply evaluation we perform various environmental and reliability tests for Power Supply Modules (AC adaptors and DC-DC convertors) as follows:
Various environmental and reliability tests for Power Supply Modules (AC adaptors and DC-DC convertors)
| Test Item | Case Study |
|---|---|
| Low temperature test | Leaving 72 hours in low temperature environment as test unit, power supply module function test 2 hours after removal |
| High temperature test | Leaving 96 hours in high temperature environment as test unit, power supply module function test 2 hours after removal |
| Low temperature operation test | Operating 5 hours in low temperature environment as test unit, power supply module function test 2 hours after removal |
| High temperature operation test | Operating 5 hours in high temperature environment as test unit, power supply module function test 2 hours after removal |
| Temperature cycle test | 1 cycle: 2 hours at -20°C → 20 hours at 40°C → 20 hours at 0°C → 20 hours at 20°C Two such cycles carried out, power supply module function test 2 hours after removal |
| High humidity test | Leaving 40°C/95%RH, 48 hours, function test after 2 hours |
| AC noise tolerance test | Noise width 50/200/1000ns, output pulse 500Ω, load 1.6kV, positive and negative pulse polarity, injection phase R/S |
| Electrostatic discharge test | One point in air, 10 times 0~5kV |
| Instantaneous power interruption | Interval: 120 cycles, dip time: 2 cycles, 100% dip, 3 minutes |
| Voltage fluctuation | 100V±15% |
| Frequency fluctuation | 50/60Hz±5Hz |
| Lightning surge test | 8kV |
Power supply unit/packaging condition test
| Test Item | Unit Test Case Study |
|---|---|
| Temperature rise test | Measured at 40°C room temperature |
| Investigation of thermal emission condition | Thermal emission condition test of internal components (carried out in load state) |
| Unwanted radiation test | 3m rule |
| Packing vibration test | 5G, 5Hz, in 3 directions, 20 minutes each |
| Packing drop test | from 70cm, on 6 sides once |
Various power supply standard tests and inspections
| Test Items | Standards Test Case Study |
|---|---|
| Withstanding voltage test | AC1000V, 1 minute |
| Insulation resistance test | 500VM |
| Leak current test | Measurement within 5 seconds of power engagement |
| Current consumption | at full load, rated voltage +10% |
| Inrush current | at full load, rated voltage +10% |
| Terminal noise voltage | - |
| Secondary circuit test | short / open test |
Power supply module product failure analysis, evaluation and counter-measure proposal
Based on request, we carry out identification of power supply module failure, product failure analysis and propose countermeasures.
| Failure Origin | Failure Analysis Example | Example of Countermeasure |
|---|---|---|
| Failure by environmental, reliability test | Ex: output stops during high temperature test. To check variation, abnormal detection, and defect component by thermal emission (analysis) |
Proposal for substitute or alternative part(s). |
| Failure by product process | Ex: Declining yield rate during characteristics test. To check functional variation and to identify the cause by environmental test. |
Proposal for avoidance and countermeasure against characteristics variation and cause of dispersions. |
| Failure in market | Ex: Radiation noise generation by usage condition. To verify conformation by EMC evaluation. |
Proposal for avoidance of and countermeasure against cause of radiation noise generation. |
Performance Confirmation Tests of the Circuit Design of the Power Supply Module
Basic Characteristics Tests
We perform tests and verifications of basic characterictics (static characteristics test, rise and fall times, etc.) against data sheets (purchased units) as well as individual specifications of commercialized power supply modules.
AC input short break evaluation example
Switching noise evaluation example
Even for products with PSE mark, it is important to confirm that there is no abnormal operation regarding load condition (including ambient temperature) on both the primary (input) and secondary (output) side.
- Inrush current
No excessive load on used component from inrush current - Gradually raising and lowering input voltage
No abnormal output current and voltage
Safety Confirmation Tests
We perform safety tests (addressing insulation resistance, overcurrent protection, temperature increase on parts) which are relevant to human protection, unstable functions, abnormal thermal emission and excessive stress on components from overvoltage and overcurrent. Performing thermal characteristics evaluations (with a high resolution thermographic viewer for heat distribution measurement) in the packaged state (final product form) enables identification of high temperature elements, thus making thermal design confirmation/improvement possible.
Thermographic inspection : no defect
Thermographic inspection : defective
Visual of a power supply module board
Power supply module board: no defect
Power supply module board: defective
The thermal imaging viewer confirms thermal emission of the diode as compared with the good item.
- NOTE: In case of boards densely populated with parts consuming high currents or highly integrated devices in small electronic equipment it is advisable to evaluate thermal influence on other elements.
