The new warp-speed Thunderbolt interface is pushing the limits on serial data rates — and USB’s response (so far) is pushing the limits of power delivery. While Thunderbolt is four times faster than the 5Gbps USB 3.0, the new USB Power Delivery (USB-PD) specification is set deliver up to 10 times the power!
I recently attended the USB-PD Developers Conference in Washington DC and have been talking with many customers globally. Here’s my take: USB-PD could be a major game changer. But there’s a lot more work to be done before product certifications begin in early 2013.
New USB-PD silicon needs to become generally available. New chipsets will include the logic that will be able to:
- Detect when USB-PD-compliant cables are plugged in.
- Communicate with other USB-PD devices over VBUS to request, approve or deny power capability and availability.
- Expose the power delivery status to the operating system.
Also, new connectors and cables need to be generally available. New connectors and cables will be required to:
- Support higher power levels – up to 20 volts @ 5 amps. (Higher current requires bigger wires in the cable and more robust contacts in the connector.)
- Differentiate between legacy lower power USB cables and new USB-PD cables. (You don’t want to put 100Wonto a legacy cable and cause safety issues. The same thing applies to connectors.)
- New Standard-A plugs have an extended shell, while Standard-A receptacles add insertion detect and PD-detect capability. Micro-B/AB plugs include passive components inside the connector or over-mold that are used to signal the USB-PD devices of their power capability.
Lastly, new circuit protection components are needed to protect the higher-power interface for safety reasons. This will require that:
- The allowable power must stay under 100W (per the USB-PD specification).
- Protection devices must meet necessary specifications such as UL60950. It is unlikely that USB-PD power management ICs (PMICs) will include constant current features due to cost and complexity. External overcurrent safety protection device(s) are the economical and robust choice.
I’ll keep you updated as USB-PD gets off the ground. In the meantime, let me know:
Do you think USB-PD will spell the end to proprietary power connectors including barrel jacks in laptops and ultra-thin computers?