Consumer Electronics and Game Console Power Supplies: Secondary Winding and the "Margin-less" Winding Window

Engineers working on consumer chargers, power adapters, or the power supply inside a game console are squeezed from two sides at once: the enclosure has to get thinner and the power higher, yet the primary–secondary isolation distance cannot give up a single millimetre. This article starts from the end application: in the isolation transformer inside your consumer or gaming power supply, how should the secondary winding be wound so you can reclaim the winding window eaten by margin tape? We first set out the topologies and the safety path (IEC 62368-1) of this class of power supply, then look at how margin tape compresses the winding window, and finally explain why approved "margin-less" triple insulated wire (TIW) is the common answer that makes miniaturisation possible, together with its honest limits. All DAH JIN product values are "per the Approval Document".

1. Consumer and Gaming Power Supplies: High Volume, an ODM Ecosystem, Topologies Landing on Flyback and LLC

AC-DC power for consumer electronics is a very large market. According to market research, the AC-DC power adapter market will be worth about USD 53.76 billion in 2026, with consumer electronics the largest end segment at about 42% of revenue in 2025; and this market relies heavily on the ODM and contract-manufacturing ecosystem in Taiwan and Asia for supply. For the wound-magnetics supply side, this means a design and cost sensitivity of "the same small isolation transformer, multiplied by enormous shipment volumes".

The topologies of these power supplies land in two bands:

• Low-to-medium-power chargers and adapters: the mainstream is flyback and its derivatives (quasi-resonant QR flyback, active clamp flyback ACF). Flyback is structurally simple, uses few parts and is low-cost, which makes it the common choice for external AC-DC power adapters, LED drivers and similar "modest power, but mandatory isolation barrier" scenarios.
• Higher-power internal console power supplies: game consoles mostly use a built-in PSU; once the power goes up, the main isolation stage usually runs an LLC resonant half-bridge (the same route as PC power supplies) in exchange for higher efficiency. This stage likewise has an isolation transformer bridging primary and secondary.

Whether flyback or LLC, between the user-touchable output side (SELV) and the mains side (100–240 VAC) there must be one compliant primary–secondary isolation. In these power supplies, TIW sits on the windings of that isolation barrier, in particular the secondary winding (or whichever winding crosses the barrier). In recent years GaN has let flyback and ACF push switching frequency upward, the transformer has shrunk accordingly and ultra-thin chargers have become the trend, so winding-window space is tighter than ever; how to wind this isolation small and compliant has become the main battleground of the design.

2. The Isolation Pressure on the Secondary Winding: IEC 62368-1 Primary–Secondary Isolation

Since 20 December 2020, safety for consumer electronics and audio/video equipment has been governed by IEC 62368-1. That day was the Date of Withdrawal of IEC 60950-1 (information and communication technology equipment) and IEC 60065 (audio/video equipment); both were replaced by IEC 62368-1, whose scope includes the external power supplies for such equipment. In other words, your charger or console power supply follows the hazard-based isolation requirements of 62368-1.

At the winding level, 62368-1 provides the path of Annex J (Insulated winding wires for use without interleaved insulation), which allows an approved insulated winding wire to serve as the safeguard of a wound component without adding interleaved insulation between layers. The standard's details are only touched on here (this article does not go through it clause by clause); what it means for the designer is that the "reinforced / double" isolation required between primary and secondary can be carried by the wire itself, rather than propped up entirely by tape and margins.

The winding you have to make carries the safety isolation of the whole power supply; fitting it into an ever-smaller winding window without giving up the isolation grade is the tug-of-war of the next section.

3. Margin Tape vs "Margin-less": The Few Millimetres Eaten Out of the Winding Window

The traditional approach uses margin tape plus layer tape to leave creepage distance at both ends of the bobbin and keep the primary and secondary windings apart. Industry design guides put it bluntly: the side effect of margin tape is that it "shortens the bobbin width, thus reducing the space available for the windings". On the small bobbins typical of consumer and gaming power supplies, those few millimetres of margin are often the make-or-break line: if the margin is wide enough, the wire will not fit, or you have to move to a larger core (size, cost and weight all go up); if the margin is not wide enough, you fail the primary–secondary creepage requirement.

The mainstream way out of this dilemma is to switch to approved triple insulated wire. Industry wound-magnetics material explains it clearly: triple insulated wire "meets the major international safety standards, enabling transformers to be manufactured to meet safety isolation standards without the need of margins and tape barriers"; and "because triple insulated wire removes the need for creepage margins, the whole bobbin can be used for winding", characteristics that "serve to downsize switching transformers, and promise high production efficiency and cost reduction". Another high-voltage safety design reference shows the same thing: when the secondary is chosen as triple insulated wire, the creepage and clearance specifications between windings are no longer applicable; this is where the term "margin-less (margin = 0)" comes from.

• Margin tape + layer tape — Winding window (usable bobbin width)：Margins at both ends eat into the usable width；Effect on miniaturisation：Wire hard to fit; often forced to a larger core
• Approved triple insulated wire (margin-less) — Winding window (usable bobbin width)：The whole bobbin is available for winding；Effect on miniaturisation：Frees the winding window; helps shrink the magnetics and cut cost

For high-volume consumer and gaming power supplies, "the whole winding window can be wound" means every transformer saves space and material; multiplied by shipment volume, that is a substantial size and cost benefit.

4. How Triple Insulated Wire Frees the Winding Window, and Its Honest Limits

Winding the secondary (or the winding that crosses the barrier) with approved triple insulated wire lets you drop the creepage distance and interlayer insulation that tape would otherwise have to prop up between primary and secondary, which frees the winding window. But one boundary has to be stated first, so the claim is not overstated:

What is waived is "winding to winding", not "all distances". Triple insulated wire can bring winding-to-winding creepage and clearance down to near zero, but it does not waive the distance from terminals to the core: the core is treated as a conductive part, and the bobbin pins and connectors must still keep the minimum creepage and clearance to the core. In other words, TIW solves the isolation inside the winding window; the safety distance between board-level pins and the core still has to be designed to the safety standard.

End-product compliance still requires overall evaluation. Switching the secondary to approved TIW is a common and effective way to achieve primary–secondary isolation; but whether the whole power supply meets the isolation requirements of IEC 62368-1 still depends on the conditions of applicability in that wire's Approval Document (working voltage, test frequency, wire diameter range and so on) and on the end-product evaluation. A compliant wire does not automatically make a compliant design.

As for DAH JIN's product line on the IEC 62368-1 path for consumer and gaming power supplies, all four triple insulated wire types (TLW-B, TLW-BB, TLW-B7S, TLW-F) are listed in the scope of evaluation under Annex J (IEC 62368-1) of VDE 40008834 Anlage 200, and can be selected to suit the design; the specific working voltage, peak and test frequency are always per the Approval Document and are not repeated here. For the boundary between wire thermal class and insulation-system thermal class, see Wire Thermal Class vs Insulation System Thermal Class; for the correspondence between Annex J and 61558 Annex K, see IEC 62368-1 Annex J and 61558 Annex K. This article makes no claim that DAH JIN products have been designed into any specific game console or consumer power supply product.

5. Selection and First-hand Conditions: Settle Temperature and Structure First, Then Talk Part Numbers

For which type to choose for a consumer or gaming power supply, the order is "settle your winding conditions first, then check them against the Approval Document":

1. Temperature environment: a typical desktop charger can run on the 130(B) class; inside a console, close to the power stage with a higher ambient temperature, consider TLW-F (Class F, 155 °C). It is evaluated as Reinforced under Annex J (IEC 62368-1) and UL 2353, but is not on the DJ-130 component list; when adopting it, make sure the part number is the one bound to the Approval Document. For the first fork (B 130 °C vs F 155 °C), see the Triple Insulated Wire Selection Guide.
2. Winding structure: where a stranded conductor is needed to reduce high-frequency copper loss, choose TLW-B7S (7-strand, single strand 0.10–0.30 mm); for the ordinary solid-conductor path, TLW-B / TLW-BB, wire diameter 0.10–1.00 mm.
3. Whether an insulation system on record is used: if the design is to be defined by an electrical insulation system (EIS) on record, the components of DJ-130 (UL E318181) are only TLW-BB and TLW-B7S, and adopting that system requires an Authorization Letter.

• Applicable safety path — Content：IEC 62368-1 (ITE / AV; evaluated under Annex J of VDE 40008834 Anlage 200)
• Selectable types — Content：TLW-B, TLW-BB, TLW-B7S, TLW-F (all four listed in the Annex J scope of evaluation)
• High-temperature option — Content：TLW-F (Class F, 155 °C; Annex J + UL 2353 Reinforced; not on the DJ-130 list)
• Stranded-conductor need — Content：TLW-B7S (7-strand, single strand 0.10–0.30 mm)
• General wire diameter range — Content：0.10–1.00 mm
• Working voltage / peak / test frequency — Content：Per the Approval Document
• Insulation system (if on record) — Content：DJ-130 (UL E318181), components only TLW-BB / TLW-B7S, Authorization Letter required
• Manufacturing — Content：Own plant in Guiren, Tainan, Taiwan; wire manufacturer (not a trading company)

When adopting, define the part number and wire diameter range by the Approval Document. For case-specific selection, contact our sales team.