USB-C PD 3.1: Understanding the 240W Revolution
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Visualizing: USB-C PD 3.1: Understanding the 240W Revolution
USB Power Delivery (PD) has long been capped at 100W (20V at 5A). This was enough for ultrabooks, but gaming laptops often required bulky proprietary bricks.
Enter EPR (Extended Power Range)
USB PD 3.1 introduces EPR, pushing the voltage ceiling from 20V to 48V. With the current limit remaining at 5A, this allows for a theoretical maximum of 240W.
Do you need a new cable?
Yes. Standard USB-C cables are rated for 60W (3A). High-end ones are rated for 100W (5A). To handle 240W, a cable must have a specific E-Marker chip that handshakes with the charger to confirm it can safely handle 48V without arcing.
If you use an old 100W cable with a 140W MacBook Pro charger, it will safely negotiate down to 100W.
Technical References
- USB-IF: USB Power Delivery Specification Revision 3.1.
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