USB-C charging explained: PD, PPS, GaN and how many watts you actually need
USB-C is one connector carrying several different charging standards. This guide explains the ones that matter when choosing a charger, cable or power bank, and gives practical wattage targets by device.
The standards
USB Power Delivery (USB PD)
USB PD is the universal fast-charging standard for USB-C. The charger and device negotiate a voltage and current over the cable. PD 3.0 tops out at 100 W (20 V × 5 A). PD 3.1 added Extended Power Range (EPR), which raises the ceiling to 240 W (48 V × 5 A) — mainly for large laptops. A phone, tablet or thin laptop that supports PD will charge at its own maximum speed from any PD charger that offers at least that much power; a higher-wattage charger does not harm a lower-wattage device.
PPS (Programmable Power Supply)
PPS is an optional part of PD 3.0 that lets the device request fine-grained voltage steps (20 mV) in real time, which keeps heat down and speeds up the middle of the charge curve. It matters most for Samsung Galaxy phones: "Super Fast Charging" (25 W) and "Super Fast Charging 2.0" (45 W) require PPS, not just PD. Google Pixel phones also benefit. If a charger listing does not say PPS, assume a Galaxy will fall back to slower 15–18 W charging.
Proprietary protocols
Qualcomm Quick Charge (QC 3.0/4+/5), OnePlus/Oppo SuperVOOC, Xiaomi HyperCharge and others exist alongside PD. Most modern Android phones accept PD at a reduced rate even when their fastest speed needs the proprietary protocol. Apple devices use PD only.
GaN
Gallium nitride (GaN) is a transistor material, not a charging protocol. GaN chargers run at higher switching frequencies and lower heat, so they can be roughly 30–50% smaller than silicon chargers of the same wattage. Charging speed is set by PD/PPS support and the wattage split across ports, not by GaN itself.
How many watts do you need?
| Device | Peak charging draw | Sensible charger |
|---|---|---|
| iPhone (recent models) | ~20–30 W | 20–30 W PD |
| Samsung Galaxy S/Ultra | 25–45 W (PPS required) | 45 W PD with PPS |
| iPad / Android tablet | 20–45 W | 30–45 W PD |
| MacBook Air (13"/15") | 30–70 W | 65–70 W PD |
| MacBook Pro 14" | 67–96 W | 96–100 W PD |
| MacBook Pro 16" | up to 140 W | 140 W PD 3.1 (EPR) with a 240 W-rated cable |
| Windows ultrabook | 45–65 W | 65 W PD |
| Steam Deck / ROG Ally | 45–65 W | 65 W PD |
| Nintendo Switch | ~18 W (39 W docked) | Any 30 W+ PD charger |
Figures are approximate peaks; devices draw less once past ~80% charge. When in doubt, buy the next size up — it costs a few dollars more and future-proofs the purchase.
Multi-port chargers: read the split, not the headline
A "100 W" three-port charger rarely delivers 100 W to any port while others are in use. Manufacturers publish a power-distribution table showing what each port gets when two or three devices are connected (for example 65 W + 30 W + 5 W). Before buying a multi-port charger for a laptop plus phone, check that the laptop port still gets enough with the phone connected. Dealectric records these distribution tables as structured data for this reason.
Cables are rated too
- Every USB-C to USB-C cable supports at least 60 W (3 A at 20 V).
- A cable rated for 100 W / 5 A contains an electronic marker chip (e-marker). A 100 W charger with a 60 W cable will charge at 60 W.
- 240 W cables are needed for PD 3.1 EPR charging above 100 W.
- Charging rating and data rating are independent: a 240 W cable may carry only USB 2.0 data (480 Mbps), and a Thunderbolt 4 / USB4 cable (40 Gbps) is often limited to 100 W. Check both numbers.
- USB-A to USB-C cables cannot carry PD and generally top out at 12–18 W (or QC speeds).
Power banks
Capacity is sold in mAh at the cell's nominal 3.7 V; the useful figure is watt-hours: Wh = mAh × 3.7 ÷ 1000. A 10,000 mAh bank is 37 Wh and will typically deliver 60–70% of that to a phone after conversion losses, i.e. roughly two full charges of a modern phone. Output wattage decides whether a bank can charge a laptop: look for 45 W+ for ultrabooks, 65 W+ for a MacBook Pro 14".
Airline rules: the FAA (and most carriers worldwide) allow power banks up to 100 Wh (~27,000 mAh) in carry-on without approval, 101–160 Wh with airline approval (usually two units), and nothing above 160 Wh. Power banks are never allowed in checked baggage. Several Asian carriers introduced additional in-cabin usage restrictions in 2025; check the airline before flying.
Wireless and magnetic charging
Qi2 is the current cross-platform magnetic standard (based on Apple's MagSafe geometry) and delivers 15 W to supported iPhones and Android phones; Qi2.2 raises that to 25 W for compatible devices. Apple-certified MagSafe chargers can deliver 25 W to iPhone 16 and later when paired with a 30 W+ PD adapter. Original Qi (non-magnetic) is usually 7.5 W on iPhone and 10–15 W on Android.
Quick checklist
- Match or exceed the device's peak wattage; add PPS if you own a Samsung.
- For multi-port, check the distribution table, not the headline number.
- Use a 100 W (5 A) e-marked cable for anything over 60 W; 240 W for EPR laptops.
- Keep power banks at or under 100 Wh if you fly.
- Prefer chargers with safety certification (UL/ETL listing in the US, CE in the EU) and a stated warranty — most reputable brands offer 18–24 months.
Last reviewed October 8, 2026. Specifications quoted are from manufacturer documentation and the USB-IF specifications; corrections welcome at hello@dealectric.com.