Case of resolving the peak current issue of the AC/DC Power Adapters — Desktop & Wall-Mount in a short time with semi-customization

The power repeatedly shut down during startup, and the cause was unknown... What exactly happened with the commercially available third-party AC/DC Power Adapters — Desktop & Wall-Mount the customer was using? This article concisely summarizes the approach we took to resolve the customer's issue, addressing both procurement and technical challenges. It provides valuable insights for companies considering peak current countermeasures. We hope you find it helpful.


Case Study: Resolving Power Supply Issues Caused by Online Procurement

This article summarizes a case where a third-party off-the-shelf AC adapter, sourced via an online shop, triggered problems such as overheating, shutdowns, and standard noncompliance. The issues, which resulted in unavoidable replacement in a short period, were resolved by using our semi-custom power supply.

In addition to essential information required for adoption decisions (cost, delivery time, compliance, and mass production risks), we also concisely introduce the replacement procedure and compatibility evaluation points.

Customer Challenges and Background

In the customer’s production lot, inrush current at startup caused repeated voltage drops and recoveries in an existing AC adapter (third-party DC 6V 2.8A product). It was also suspected that internal layout changes in the third-party adapter altered the OCP threshold. The customer consulted us to address these issues.

Our Solution

Key Points of Our Response

ItemCurrent SituationNotes/Assumptions
Peak Current

4.2A Instantaneous (Measured Value)

Need to confirm compatibility with OCP threshold

OCP Setting

Third-Party Product: Estimated 2.8A

Prevent malfunctions with generous threshold settings

Response Process

  1. Customer Requirements Hearing

Confirmed failure symptoms, occurrence timing, and usage environment

  1. Root Cause Analysis & On-Site Measurement

Measured current waveform and estimated overload protection trigger point

  1. Design Review & Prototyping

Optimized setting with UV324 series; determined semi-custom specification

  1. Evaluation & Verification

Operation check, safety testing, long-term operation testing

  1. Mass Production Implementation

BOM update, manufacturing procedure finalization, quality management system development

  1. Customer Report

Explanation of response results, effectiveness, and future supply system

Key Point: Optimized Overcurrent Protection to Withstand Instantaneous Peak Using Existing Series

Based on the hearing, we determined that the overcurrent protection function was being triggered, causing shutdowns. Using our UV324 series, we developed a semi-custom model that does not activate overload protection up to 4.2A MAX. This enabled us to propose improvements that balanced both cost and development speed.

Results after Implementation

  1. Malfunctions were eliminated, and power drop/restart issues no longer occurred
  2. Identifying the root cause provided reassurance in both procurement and technical aspects
  3. Optimized overcurrent protection enabled stable operation even during peak current
  4. Semi-custom model allowed rapid transition to mass production
  5. Secured continued usage policy and stable supply structure

Customer Feedback

"Malfunctions disappeared, and we were greatly reassured by clearly identifying the cause. We intend to continue using Unifive’s products moving forward."

─ Developer from a Wastewater Treatment Equipment Manufacturer

For Those with Similar Issues

When matching products with adapters, devices that use motors or amps can draw an instantaneous overcurrent, potentially causing malfunctions.

If you're using adapters with such equipment, please feel free to consult us. We will provide advice and proposals for the optimal custom or semi-custom solution.