Abstract:
An electronic thermostat and associated methods are disclosed for power stealing from an HVAC triggering circuit. The methods include making voltage measurements while controlling the amount of current drawn by the power stealing circuitry so as to determine a relationship that can be used to select how much current to draw during power stealing. Through the use of the described methods, the likelihood of inadvertent switching of the HVAC function (on or off) can be significantly reduced.
Abstract:
In a multi-sensing, wirelessly communicating learning thermostat that uses power-harvesting to charge an internal battery, methods are disclosed for ensuring that the battery does not become depleted or damaged while at the same time ensuring selected levels of thermostat functionality. Battery charge status is monitored to determine whether the present rate of power usage needs to be stemmed. If the present rate of power usage needs to be stemmed, then a progression of performance levels and/or functionalities are scaled back according to a predetermined progressive power conservation algorithm. In a less preferred embodiment, there is a simple progressive shutdown of functionalities turned off in sequence until the desired amount of discharge stemming is reached. Battery charge preservation measures are also described for cases when an interruption of external supply power used to recharge the battery is detected.
Abstract:
In a multi-sensing, wirelessly communicating learning thermostat that uses power-harvesting to charge an internal battery, methods are disclosed for ensuring that the battery does not become depleted or damaged while at the same time ensuring selected levels of thermostat functionality. Battery charge status is monitored to determine whether the present rate of power usage needs to be stemmed. If the present rate of power usage needs to be stemmed, then a progression of performance levels and/or functionalities are scaled back according to a predetermined progressive power conservation algorithm. In a less preferred embodiment, there is a simple progressive shutdown of functionalities turned off in sequence until the desired amount of discharge stemming is reached. Battery charge preservation measures are also described for cases when an interruption of external supply power used to recharge the battery is detected.