Measuring dissipated electrical power on a power rail

A method of measuring an amount of power provided to a smart-home device through a main power rail, the method comprising:

• providing power to one or more components of the smart-home device through a main power rail;
• storing energy on an energy-storage device using an integrator that is coupled to the main power rail, wherein the energy stored on the energy-storage device is representative of an amount of power provided to the smart-home device through the main power rail during an integration cycle of the integrator, and wherein:
• each integration cycle of the integrator begins when the energy stored on the energy-storage device is reset;
• and
• each integration cycle of the integrator ends when an electrical measurement of the energy-storage device meets or exceeds a threshold;
• counting a number of integration cycles performed by the integrator during a time interval;
• and
• calculating a total amount of power provided to the smart-home device through the main power rail during the time interval using:
• a product of a number of integration cycles performed by the integrator during the time interval and a known total amount of energy provided to the main power rail during a single integration cycle divided by a length of the time interval;
• and
• the energy stored on the energy-storage device.

A power-measurement circuit comprising:

• an integrator coupled to a main power rail, wherein the integrator stores energy on an energy-storage device, and the energy stored on the energy-storage device is representative of an amount of power provided through the main power rail during an integration cycle of the integrator, and wherein:
• each integration cycle of the integrator begins when the energy stored on the energy-storage device is reset;
• and
• each integration cycle of the integrator ends when an electrical measurement of the energy-storage device meets or exceeds a threshold;
• and
• a counter that stores a number of integration cycles performed by the integrator during a time interval, wherein a total amount of power provided through the main power rail during the time interval is represented by:
• a product of a number of integration cycles performed by the integrator during the time interval and a known total amount of energy provided to the main power rail during a single integration cycle divided by a length of the time interval;
• and
• the energy stored on the energy-storage device.