{
  "patent_number": "US 9874914",
  "country": "US",
  "title": "How Devices Negotiate Power Sharing When Connected Together",
  "original_title": "Power management contracts for accessory devices",
  "summary": "A system for host devices like laptops to automatically set and update power-sharing rules with connected accessories based on identity and real-time power needs.",
  "what_it_does": "This patent describes a method for a host device to manage how it shares electricity with an accessory, such as a docking station. When an accessory is plugged in, the host checks its identity against a list of authorized devices. Once verified, the host applies a 'power management contract' that dictates the direction of power flow (who charges whom) and current limits. If conditions change—like the accessory suddenly needing more power for other connected peripherals—the host and accessory can renegotiate these rules in real-time to prevent system crashes or hardware damage.",
  "what_it_does_not_cover": [
    "Does not cover generic power delivery protocols like standard USB-PD that lack the specific identity-based contract structure described.",
    "Does not cover devices that lack a mechanism to identify themselves via credentials or specific resistor values.",
    "Does not cover passive power cables that do not participate in a two-way communication or negotiation process."
  ],
  "filed": "2014-05-19",
  "granted": "2018-01-23",
  "expires": null,
  "status": "active",
  "holder": "Microsoft Technology Licensing LLC",
  "holder_url": "https://patentbrief.org/company/microsoft-technology-licensing-llc",
  "inventors": [
    {
      "name": "Heng Huang",
      "url": "https://patentbrief.org/inventor/heng-huang"
    },
    {
      "name": "Gene Robert Obie",
      "url": "https://patentbrief.org/inventor/gene-robert-obie"
    },
    {
      "name": "Duane Martin Evans",
      "url": "https://patentbrief.org/inventor/duane-martin-evans"
    },
    {
      "name": "Yi He",
      "url": "https://patentbrief.org/inventor/yi-he"
    }
  ],
  "times_cited": 6,
  "tags": [
    "consumer_electronics",
    "mechanical",
    "semiconductors"
  ],
  "abstract": "Power management contracts for accessory devices are described. In one or more implementations, a power management contract is established for a system including a host computing device and an accessory device based at least in part upon power exchange conditions observed for the system. The power management contracts define operating constraints for power exchange between components of the system, including at least a power exchange direction and current limits. The host computing device and accessory devices are each configured to renegotiate the power management contract to dynamically change operating constraints in “real-time.” Additionally, different power management contracts may be associated with identifying data corresponding to different types of accessory devices.",
  "url": "https://patentbrief.org/patent/us/9874914/hololens-mixed-reality-display",
  "markdown_url": "https://patentbrief.org/patent/us/9874914/hololens-mixed-reality-display/md",
  "google_patents_url": "https://patents.google.com/patent/US9874914",
  "relatedPatents": []
}