Patent ID: 8511577

Claim:
A thermostat, comprising: a plurality of HVAC (heating, ventilation, and air conditioning) wire connectors configured to receive a plurality of HVAC wires, wherein: the plurality of HVAC wires is associated with an HVAC system; and the plurality of HVAC wires comprises at least one call relay wire; a powering circuit, including a rechargeable battery, that is coupled to the plurality of HVAC wire connectors, the powering circuit being configured to provide electrical power to the thermostat by power stealing from a selected one of said at least one call relay wires, wherein: said power stealing comprises an active power stealing mode in which power is taken from said selected call relay wire while the thermostat is in a first operating mode in which the thermostat is actively calling for an HVAC function associated with said selected call relay wire, said power stealing further comprises an inactive power stealing mode in which power is taken from said selected call relay wire while the thermostat is in a second operating mode in which the thermostat is not actively calling for said HVAC function associated with said selected call relay wire, said powering circuit is configured to substantially suspend said power stealing for at least a first time period immediately following: (i) each transition of the thermostat from said first operating mode to said second operating mode, and (ii) each transition of the thermostat from said second operating mode to said first operating mode, and said powering circuit provides said electrical power to the thermostat during said times of substantially suspended power stealing at least in part by drawing power from said rechargeable battery.