english
Español
日本語
Mainstream Transformer Types for PD Fast Chargers (Adapted for GaN Fast Charging)
2026/05/23
Mainstream Transformer Types for PD Fast Chargers (Adapted for GaN Fast Charging)
PD fast charger transformers are primarily divided by topology (which determines operating principles and power limits) and core structure (which determines size, frequency, thermal performance – the key to GaN miniaturization). These are fully compatible with 30W, 65W, 100W+ GaN PD fast chargers, representing mainstream mass‑production solutions that fit the dominant QR Flyback, LLC, and other architectures.
I. Classification by Topology (Core Selection Basis)
Different topologies suit different PD power levels – this is the foundation of solution design. When paired with GaN devices, they can significantly increase frequency, reduce size, and lower losses.
1. QR Flyback Transformer (Mainstream for 30–65W PD, Standard for PD30)
The most critical and widely used transformer type for 30W GaN PD chargers (PD30). It works with mainstream co‑packaged GaN solutions like DK025G and U8722BAS, and is the benchmark for consumer fast chargers.
Operating principle: Uses QR valley‑switching technology; the transformer stores energy and transforms voltage – no additional inductor needed, extremely simple circuit. Valley locking and frequency reduction modes optimize efficiency across the whole load range.
Key parameters: Operating frequency 120–220kHz (far exceeding traditional silicon thanks to GaN), full‑load efficiency 92–94%, standby power <30mW.
Power range: 5W–65W, perfectly covering single‑port 30W PD, 45W, and 65W medium‑power fast charging.
Advantages: Low BOM count, low cost, strong compatibility, mature protection logic, suited for 100–240V wide input voltage.
Applications: All PD30 GaN chargers, single‑port phone/tablet fast chargers, entry‑level UFCS fusion chargers.
2. Active Clamp Flyback Transformer (ACF, for High‑End 65W PD)
An upgrade to QR Flyback, optimized for medium‑to‑high‑power GaN fast chargers. Solves the high‑loss issue of traditional flyback under high voltage, often used in premium 65W multi‑port PD chargers.
Key features: Adds an active clamp circuit to absorb leakage spike energy, reduces high‑frequency switching losses, supports higher frequencies (200kHz+).
Performance advantages: 15–20% higher power density than standard QR Flyback, lower heat generation, flatter efficiency across all loads.
Applications: 65W 2C1A multi‑port GaN PD chargers, ultra‑thin card‑style chargers.
3. LLC Resonant Transformer (for 100W+ Flagship PD)
The core choice for high‑power PD fast charging, used in 100W, 120W, 160W high‑end multi‑port GaN chargers, typically with a PFC pre‑stage.
Operating principle: Resonant soft‑switching; the transformer only transforms voltage (does not store energy), resulting in very low losses.
Key parameters: Operating frequency 150–300kHz, full‑load efficiency >95%, supports sustained full‑load output.
Power range: 65W–300W, targeting notebook/gaming laptop high‑power PD charging.
Advantages: Much better stability under high‑power conditions compared to flyback, smooth multi‑port current sharing, no excessive heat even under sustained loads.
Applications: Anker 160W, Ugreen 100W multi‑port GaN fast chargers, desktop flagship PD chargers.
4. Forward Transformer (Niche, Higher Power PD)
Characteristics: Requires a reset winding; good efficiency at medium power, but higher circuit complexity and cost.
Applications: 50W+ industrial PD power supplies, niche high‑power adapters – rarely used in consumer fast charging.
II. Classification by Core Structure (Key to GaN Miniaturization)
GaN’s high‑frequency capability has driven a complete evolution of traditional transformer cores. Below are the mainstream mass‑production core types for PD fast chargers – they directly determine charger size and weight.
1. EE‑Core Transformer (Mainstream, 30W PD30 Standard)
Common models: EE1610, EE1910 (dedicated for PD30 GaN chargers)
Key advantages: Mature structure, very low cost, works with 200kHz high frequency, fits compact stacked‑PCB thermal designs.
Matching solutions: Mainstream 30W co‑packaged GaN solutions like DK025G, U8722BAS.
Size characteristics: Fits 30×30×40mm compact enclosures – the backbone of PD30 extreme miniaturization.
2. PQ, ATQ‑Core Transformer (Mainstream for 65W–100W High‑End PD)
Common models: PQ20, PQ26, PQ35, ATQ23.7, ATQ2516, ATQ2716....
Key advantages: High core utilization, low leakage flux, low high‑frequency losses, uniform heat dissipation – ideal for multi‑port high‑power output.
Applications: 65W multi‑port, 100W flagship GaN PD chargers; the preferred core for TI and Infineon reference designs.
3. POT‑Core Ultra‑Thin Transformer (For Card‑Style Ultra‑Thin PD)
Key features: Ultra‑thin, flat structure, designed for 200kHz+ GaN switching frequencies, very low core loss.
Advantages: Minimized thickness, fits 10mm‑class ultra‑thin enclosures – the core component of Huawei, CukTech, and other card‑style fast chargers.
Applications: 65W ultra‑thin card‑style GaN PD chargers, portable highly compact chargers.
4. Planar Transformer (Top‑Tier Miniaturization)
Key features: Uses PCB planar windings instead of traditional copper wire windings – extremely thin profile, excellent consistency, uniform heat dissipation.
Applications: High‑end ultra‑thin GaN PD chargers, high‑density high‑power adapters; can achieve power density >1.3W/cm³.
III. Quick Selection Table for PD Fast Charger Transformers (Mass‑Production Standard)
Power Level Optimal Topology Mainstream Core Models Frequency Range Typical Efficiency Target Products
30W (PD30) QR Flyback EE1610, EE1910, ATQ18, etc. 180–220kHz 92%+ Single‑port 30W GaN PD fast charger
45–65W QR / ACF Flyback PQ20, PQ26, ATQ23.7, ATQ2516. 150–200kHz 93%+ Multi‑port 65W PD fast charger
100W+ PFC + LLC Resonant PQ35,ATQ2716 200–300kHz 95%+ Flagship multi‑port high‑power PD charger
Ultra‑thin 65W High‑frequency QR Flyback POT / Planar 220kHz+ 93%+ Card‑style portable GaN fast charger
IV. Key Design Points for GaN Fast Charger Transformers
High‑frequency adaptation: Leverage GaN’s high switching frequency – abandon traditional 65kHz low‑frequency transformers and use 150kHz+ high‑frequency models, reducing transformer volume by >50%.
Low‑loss core: Use high‑frequency low‑loss ferrite cores that match GaN’s high‑frequency characteristics, prevent excessive temperature rise, and keep charger surface temperature ≤40°C.
Minimal turns ratio: Wide‑voltage (100–240V) universal turns ratio design, compatible with global mains, and supports PD multiple voltage outputs (5V/9V/15V/20V).
Thermal management matching: Work with the stacked‑PCB “sandwich” structure – optimize transformer placement for uniform heat dissipation in compact enclosures.
