GaN is a selling point, and that makes it easy to over-claim. The audit question is not whether a factory has heard of gallium nitride, but whether the design, the thermal verification and the process records behind the quoted product are real. This framework is built to answer that in one visit.
This guide is part of our GaN Charger Technology. Read the full topic guide for the decisions that come before and after this step.
GaN Charger Factory: the audit in one line
Four checks decide the audit. Verify the platform, the thermal evidence, the process records and the certification status, in that order. Each of the four has a physical answer: the platform is a design file and a tested sample, the thermal evidence is a measurement, the process records are batch documents, and the certification status is a report that names the model.
Process chain from SMT to packing
Walk the line in production order: incoming inspection against the BOM, SMT placement and reflow, hand assembly, functional test, aging under load and packing. At each station ask what happens when a unit fails and ask to see the written instruction. A GaN design with tight thermal margins depends on process consistency, so the assembly and test stages matter as much as the power stage.
Thermal verification: what to ask for
Ask for the temperature rise at full load in the intended enclosure, at a stated ambient temperature, with the load applied through the ports that will be sold. A measurement taken at half load or in an open housing does not describe the product. If the design relies on derating above a certain ambient, the derating point should be stated and documented.
Efficiency data and how to read it
Efficiency should be reported as a curve at defined load points rather than a single figure. The conditions matter: input voltage, load percentage and whether the measurement includes the cable. A supplier who can provide the curve is describing a tested design; a supplier who provides only a headline number is describing a brochure.
| Claim | Evidence to request | Why it matters |
|---|---|---|
| Small enclosure | Temperature rise at full load in that enclosure | Size and thermal headroom trade off |
| High efficiency | Efficiency curve at 25/50/75/100% load | Load-point behaviour differs |
| Multi-port output | Power-sharing rule under simultaneous load | Total wattage is not per-port output |
| Certified platform | Report naming the model and market | Certification is model and market specific |
Quality records behind a GaN batch
Pick a carton and ask to trace it: batch, date code, component lots and test data. On a GaN line, the component lots include the controller and the power switch, which are the parts most affected by allocation and substitution. The traceability chain is what allows a defect investigation to identify whether a specific lot or a process condition caused a failure.
Certification status and the brand’s responsibility
A platform may hold reports for several markets, but the brand places the product on the market and owns the importer identification, the model designation and the packaging language. Ask which reports exist, whether they name the model being quoted, and what the factory needs from the brand to complete the technical file. Treat “certified” without a market and model as unanswered.
Ten questions that reveal the real capability
- Which platform is this quotation built on, and what is already certified on it?
- Which topology and switch family are used at this wattage?
- What is the temperature rise at full load in the shipping enclosure?
- Can you provide the efficiency curve at four load points?
- How is power shared between ports under simultaneous load?
- Which station performs the 100% functional test?
- What load and duration does the aging step use?
- How do you verify a GaN switch lot on receipt?
- Which records link a finished unit to its component lots?
- Who answers a technical question during the quotation stage?
What a remote audit can and cannot prove
A remote audit can review documents, watch a live test and inspect records on camera. It cannot verify housekeeping, equipment condition, material segregation or how the line behaves unobserved. Where a visit is not possible, ask for a live walkthrough and a real-time traceability exercise rather than an edited video.
Substitution control and change notification
On a GaN design, the controller and the power switch are the parts most exposed to allocation and substitution, and both can change the thermal and electromagnetic behaviour of the product. A credible factory holds a written policy: which components are safety-critical, who approves an alternate, what testing is required before it is used, and how the customer is notified. Ask to see the policy and test it with a scenario. If the answer is that the factory would “find something equivalent”, the certification file and the approved sample are not protected.
Documentation to collect during the audit
Collect the evidence while you are on site: the quality certificate with its scope, the test reports that name the quoted model, the process control plan, a recent batch record, a calibration certificate for the test equipment, and the warranty and spares terms. Where a document cannot be produced during the visit, note it and request it in writing afterwards. The list is short, and a factory that cannot assemble it has either an incomplete system or a product it does not manufacture.
FAQ
How is thermal performance verified in an audit?
By asking for the measurement taken in the shipping enclosure and, where possible, watching it repeated on a unit from the audit. The condition of the measurement matters as much as the figure. Ask for the measurement taken in the shipping enclosure and, where possible, watch it repeated on a unit from the audit, because the condition matters as much as the figure.
How should efficiency figures be read?
As a curve rather than a single number. Efficiency varies with load, and a figure quoted at one operating point says little about behaviour at the low loads a charger spends most of its life at. Read the curve rather than a single number, because a figure quoted at one operating point says little about the low loads a charger spends most of its life at.
What does substitution control protect?
It protects the validation. Where an approved component can be replaced without notification, the test evidence describes a product that may no longer be the one being shipped, and the brand carries the difference. Where an approved component can be replaced without notification, the test evidence describes a product that may no longer be the one being shipped, and the brand carries the difference.
What can a remote audit not prove?
It cannot confirm that the line behaves on an ordinary day in the way it behaves during the audit, and it cannot verify a measurement that is not repeated on camera. The documentation reviewed is genuine; the inference drawn from it has limits. It cannot confirm that the line behaves on an ordinary day as it does during the audit, and the inference drawn from genuine documents has limits.
Next step
Wecent Group runs GaN charger engineering, assembly, testing and packing on one site in Bao’an, Shenzhen, and supports factory visits and third-party audits. Request the document pack or arrange a walkthrough through the contact page. Related reading: our charger factory, quality control and GaN applications. External references: ISO 9001, IEC standards, USB-IF documentation, UL, TUV and EU CE marking.