USB-C Power Delivery Guide: Fixed PDOs, PPS & 240W EPR
Unlike legacy barrel jacks that output a single fixed voltage, USB Type-C utilizes bidirectional digital handshakes to negotiate power up to 240 Watts. Learn how Power Delivery protects your devices and unlocks maximum charging speed.
How the USB-PD Handshake Protects Devices
vSafe5V Connection
When plugged in, the charger only supplies 5 Volts (vSafe5V). High voltages are physically disconnected inside the charger until digital communication is established.
Power Data Objects (PDOs)
The charger advertises its supported voltage/current profiles across the CC (Configuration Channel) pin. The device evaluates what its internal battery charger can safely take.
Power Contract Lock
The device requests a specific PDO (e.g. 9V/3A or 20V/5A). The charger transitions its internal converter to that voltage and locks in the power contract.
Standard USB-PD Voltage Profiles & Power Tiers
| Voltage Profile | Max Current (Standard) | Max Wattage | Typical Device Category |
|---|---|---|---|
| 5V | 3.0 A | 15 W | Smartphones, Headphones, Smartwatches, E-Readers |
| 9V | 3.0 A | 27 W | iPhone Fast Charging (15/16 Pro), Wireless Charging Pads |
| 15V | 3.0 A | 45 W | iPad Pro, Nintendo Switch, Ultrabooks |
| 20V (Standard Power Range) | 3.0 A – 5.0 A | 60W – 100 W | MacBook Pro 13"/14", Dell XPS, ThinkPad Laptops |
| 28V – 48V (Extended Power Range) | 5.0 A | 140W – 240 W | MacBook Pro 16", High-End Gaming Laptops, Workstations |
The 60W (3A) vs 100W/240W (5A) E-Marker Cable Trap
Standard USB-C cables are passive and capped at 3 Amperes (60W max at 20V). If you plug a 100W or 140W charger into a laptop using a standard 3A cable, charging is automatically throttled to 60W. To deliver 100W or 240W, the cable must contain an internal E-Marker (Electronic Marker) chip that certifies 5A safety to both charger and laptop.
Test your USB-C phone and laptop charging match
Verify wattage, PPS support, and EPR compatibility with our interactive USB-PD checker.
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