Custom EEL12 EEL16 EEL22 EEL25 PCB Mount Fly Transformer For LED Driver Power System

The EEL series high frequency transformer is a low-profile switching transformer family built on EEL type ferrite cores, available in EEL12, EEL16, EEL22 and EEL25 sizes. The EEL core is a flattened version of the standard EE core: it keeps a similar effective cross-section but reduces the overall height, which makes the finished transformer noticeably thinner than an EE part of the same power class. This is why the series is widely chosen for slim adapters, LED driver boxes, wall-mount power modules and any board where vertical clearance is limited.

All four sizes share the same design logic. The transformer is wound on a horizontal or vertical bobbin with full copper enamelled wire, the primary and secondary are separated by margin tape or triple insulated wire depending on the isolation requirement, and the assembly is varnish impregnated to reduce audible noise and improve moisture resistance. Turns ratio, inductance, pin configuration, creepage distance, wire type and insulation class are all engineered to the customer's schematic rather than sold as a fixed catalogue item.

EEL12 and EEL16 are normally used for low power auxiliary and standby supplies, while EEL22 and EEL25 cover the mid power range typical of LED drivers and compact adapters. Every unit is 100% tested for inductance, turns ratio and hi-pot before packing, and production runs in our own Dongguan factory under an ISO 9001 quality system.

Note: actual output power depends on winding design, topology, switching frequency, cooling condition and ambient temperature. Final power rating is confirmed on the approval sample.

• Low-profile EEL core keeps the overall height lower than a comparable EE transformer, which suits slim adapters and boards with limited vertical clearance.
• Four sizes in one family: EEL12, EEL16, EEL22 and EEL25 let you scale power up or down while keeping the same construction, supplier and quality standard.
• Wide winding window for the core height, allowing good copper fill and reduced winding loss.
• Selectable insulation solution: margin tape construction for cost-sensitive designs, or triple insulated wire for reinforced isolation and tighter coupling.
• Controlled air gap ground to the target AL value, so the energy storage behaviour of flyback designs stays repeatable between batches.
• Optional sandwich winding to lower leakage inductance, which reduces voltage spikes, switching loss and EMI in the finished power supply.
• Full copper winding with controlled tension keeps inductance and DCR consistent across large production runs.
• Varnish impregnation suppresses winding movement, so the transformer stays quiet and resists humidity.
• Flexible pin layout: pin count, pin pitch and creepage distance are matched to your existing PCB footprint, so no board redesign is needed.
• Materials to UL94V-0 flame-retardant grade and RoHS requirements, supporting your own safety approval work.
• 100% electrical testing on every unit before packing, with test data available on request.

• LED lighting: constant-current LED drivers, downlight and panel light power modules, backlight supplies.
• Power adapters and chargers: wall-mount adapters, desktop adapters, USB and PD chargers, small charging modules.
• Industrial control: PLC power modules, sensor and relay supplies, drive control boards, automation cabinets.
• Home appliances: cooker hoods, coffee machines, air purifiers, washing machine and refrigerator control boards.
• Communication and IT: router and modem supplies, network equipment adapters, set-top boxes, auxiliary supplies in server hardware.
• Security and building systems: CCTV cameras, access control panels, alarm systems, intercom units.
• Auxiliary and standby power inside larger equipment: bias supplies for inverters, chargers and energy storage cabinets.
• Instrumentation and medical electronics requiring reinforced isolation and stable electrical performance.
• General purpose AC-DC and DC-DC switch mode power supplies in the low to mid power range.

• Established in 2000, with 26 years focused on magnetic components for industrial control and power electronics; we are a manufacturer, not a trading company.
• Self-owned 10,000 square metre factory in Dongguan with 8 complete production lines, which keeps lead times and quality consistent on repeat orders.
• A 20-person R&D team supports you from schematic review and sample building through to mass production, and a 20-person QC team controls the process.
• Complete certification framework: ISO 9001 and ISO 14001 system certification, with CE, CB, UL, cUL and RoHS product certification available.
• Annual export value of USD 42 million, shipping to North America (50%), Northern Europe (18%), South America (15%) and Southeast Asia (15%), including OEM customers such as Midea and Federal Signal.
• Flexible cooperation: MOQ from 1,000 pcs, DDP and DDU terms supported, direct factory delivery from China.

• One supplier covers the whole EEL range, so you can standardise construction, insulation system and quality criteria across several products instead of qualifying four different vendors.
• Fully customised design instead of a standard part: the transformer is matched to your controller IC, input voltage range and output requirement.
• Low-profile structure saves board height and simplifies mechanical assembly in thin adapters and embedded power modules.
• Controlled leakage inductance and balanced winding arrangement help lower voltage spikes and EMI, which shortens your EMC debugging cycle.
• Consistent gap grinding and winding process reduce inductance drift between batches, keeping loop behaviour predictable in mass production.
• Safety-oriented construction with reinforced isolation options supports your certification work in export markets.
• Free engineering support before the design is frozen: send us your schematic and target specification and we will recommend the most suitable core size in the series.