Communication circuit for 2-wire protocols between HVAC systems and smart-home devices

Abstract

A circuit for stealing power from an external system without interfering with a communication protocol may include wiring connectors configured to receive wires from the external system; a first voltage regulator to regulate a voltage on the plurality of wiring connectors at a plurality of voltage levels to encode a first multi-bit binary message according to the communication protocol to be sent to the external system; a current monitor to measure a plurality of current levels received through the plurality of wiring connectors and decode the plurality of current levels to determine a second multi-bit binary message sent from the external system according to the communication protocol; and a power converter that adjusts an amount of power stolen from the plurality of wiring connectors based at least in part on the voltage on the plurality of wiring connectors.

Dependencies are inferred from the claim text.