A charger with all three protections listed on its specification returned from a customer with a swollen battery case. The over-voltage threshold had been set above the level the device would accept, so the protection existed, engaged late, and did …

Four items decide whether surge protection is real or nominal: the level the product has to withstand, the paths the energy can take, how the protection coordinates with the fuse, and what happens after the protection has done its job …

A safety design is not a list of protection features on a datasheet. It is a set of behaviours that have to work at the boundaries: the current limit that holds during a fault, the temperature threshold that derates before …

A customer connected a laptop and a phone and found that the laptop charged at half its usual rate. Nothing was faulty: the sharing rule had reduced the primary port to keep the total inside the budget, and the rule …

Two multi-port chargers with the same total output reached the market in the same season. One carried a sharing rule that the packaging explained in a sentence; the other left customers to discover it, and the returns were concentrated in …

The densest charger in a range is rarely the one that sells best. Density buys a smaller product and costs thermal margin, electromagnetic work and money, and the trade is worth making only where size is part of the retail …

Four paths carry heat out of a charger: conduction into the housing, convection from the surfaces, radiation from the warmest parts, and the connectors and cable. A design that only counts the first two usually discovers the third and fourth …

A programme adopted a GaN platform, kept the original enclosure and discovered at the first thermal test that the design derated above two thirds of its rated output. The switching stage had been chosen; the design around it had not …

Two high-power adapters were compared on the same bench. The one using a resonant stage ran cooler at full load and produced a lower electromagnetic signature; the other met the same limits at a lower cost with a simpler control. …

An efficiency figure that beats the competition on the first page and disappears at half load is not a design advantage. Efficiency is a curve, and the useful specification states the points on that curve, the input voltage they were …

Two 65 W chargers were compared side by side: one GaN, one silicon, both meeting the same specification. The GaN unit was smaller and slightly more efficient at high line and full load; the silicon unit was cheaper by a …

Five items decide whether an extended range claim survives first contact with a customer: the voltage class of the construction, the marked cable in the box, the connector rating, the thermal result at the top of the range, and the …