Evaluate Power Supply Requirements
- Understand the current, voltage, and power requirements of your embedded system. Consult the datasheets of all components.
- Consider load variations and the potential need for multiple voltage rails for different parts of the system.
Select Appropriate Testing Tools
- Use a digital multimeter (DMM) for basic voltage, current, and resistance measurements.
- Apply an oscilloscope with a differential probe to observe and analyze voltage transients, noise, and ripple.
- Employ a programmable electronic load to simulate different load conditions and verify the power supply performance.
Create a Testing Plan
- Define test cases that involve minimum, typical, and maximum load scenarios for the power supply.
- Include transient testing in your plan to observe the power supply's response to rapid load changes.
- Schedule time to measure both dynamic and static load behaviors under normal and stressed environmental conditions (temperature and humidity).
Perform Initial Power-Up Test
- Use a DMM to confirm that the input voltage matches the power supply specifications before connecting it to the system.
- Connect the power supply to the embedded system and monitor the output voltage to ensure it remains within specified limits.
Analyze Voltage Regulation
- Measure the output voltage under varying load conditions using an oscilloscope to evaluate voltage regulation.
- Assess line and load regulation by applying step changes to the input voltage and load current, respectively.
Assess Ripple and Noise
- Use an oscilloscope to measure output voltage ripple and noise across a range of load conditions.
- Compare these measurements against the acceptable limits defined in the system requirements or component specifications.
Test Transient Response
- Apply step-increases and decreases to the load current and observe the power supply's transient response using an oscilloscope.
- Examine the magnitude and duration of transient voltage deviations to ensure they do not exceed specified thresholds.
Examine Efficiency
- Utilize the programmable load to record input vs. output power across a broad range of operating conditions to calculate efficiency.
- Analyze efficiency at different load levels to verify that it matches the design expectations.
Check Over-Current and Short-Circuit Protection
- Intentionally induce over-current conditions or short circuits to validate that the power supply's protection mechanisms activate properly.
- Ensure the power supply recovers gracefully once the fault condition is removed.
Perform Thermal Testing
- Use infrared thermography to monitor the power supply temperature under sustained load conditions.
- Verify that the power supply does not exceed its thermal limits either with natural or forced cooling solutions.
Document Results and Perform Iterations
- Thoroughly document all test results, anomalies, and any deviations from expected performance.
- If necessary, perform iterations of redesign or recalibration to address any identified shortcomings.
