Case study of short-term resolution of peak current issues of AC/DC Power Adapters — Desktop & Wall-Mount through semi-customization

The power kept shutting off repeatedly at startup, and the cause was unknown… What was happening with the commercially available third-party AC/DC Power Adapters — Desktop & Wall-Mount the customer was using? This article concisely summarizes the issue and our approach to solving it from both procurement and technical perspectives, as a real case in which our company resolved a customer’s problem. It provides valuable insights for companies considering peak current countermeasures. We hope you find it worth reading.


Case Study: Solution to Power Failures Caused by Online Procured Devices

This article summarizes a real-world case where a customer's use of a generic AC adapter purchased from an online store led to overheating, cutoff, and noncompliance with standards, ultimately requiring replacement in a short time. The issue was resolved using our semi-custom power supply.

Alongside information necessary for adoption decisions (cost/delivery/compliance/mass production risk), we also briefly introduce replacement procedures and key points of compatibility evaluation.

Customer Challenges and Background

In the customer's production lot, the existing AC adapter (third-party DC 6V 2.8A model) repeatedly experienced voltage drops and recoveries due to inrush current at startup. Additionally, changes in the internal layout of third-party adapters were suspected to have caused variations in the OCP (overcurrent protection) threshold. The customer consulted us to resolve these issues.

Our Solution

Key Points in Our Approach

ItemCurrent SituationNotes/Expectations
Peak Current

4.2A instantaneous (measured value)

Needs verification against OCP threshold

OCP Setting

Third-party: Estimated at 2.8A

Configure with margin to prevent malfunction

Support Workflow

  1. Customer Requirement Review

Confirm failure symptoms, timing, and operating environment

  1. Root Cause Analysis and On-site Measurement

Measure current waveform and estimate overload protection trigger point

  1. Design and Prototyping

Set optimal configuration using UV324 series and define semi-custom specification

  1. Evaluation and Verification

Confirm operation, conduct safety testing and long-term performance testing

  1. Reflect in Mass Production

Update BOM, finalize manufacturing procedures, implement quality control framework

  1. Customer Reporting

Report on results, effects, and future supply structure

 

Key Point: Optimize overcurrent protection and utilize existing series to withstand instantaneous peaks

Upon analyzing the results, we identified that the power supply was shutting down due to the activation of overcurrent protection. We developed a semi-custom version of our UV324 series that prevents overload protection from triggering up to 4.2A MAX, achieving improvements balancing cost and development speed.

Results After Implementation

  1. The malfunction symptoms disappeared, and the issue with repeated power drops and restarts was eliminated
  2. Identifying the root cause provided confidence from both procurement and technical perspectives
  3. Optimized overload protection ensured stable operation even during peak current
  4. Semi-custom solution enabled rapid reflection in mass production
  5. Decision made to continue using the solution, establishing a stable supply system

Customer Feedback

"The malfunction disappeared and we were greatly relieved to have confirmed the root cause. We plan to continue using UNIFIVE’s products going forward."

─ Product Development Representative, Sewage Treatment Equipment Manufacturer

For Those With Similar Concerns

When matching products and adapters, devices using motors or amplifiers can draw instantaneous currents exceeding ratings, potentially causing operational failures.

If you're using adapters with such devices, please feel free to consult us. We can offer advice and optimal custom or semi-custom solutions.