Self-powered comparator

摘要

Embodiments of the invention relate to an input-powered comparator. Embodiments of the invention also pertain to an active diode that includes an input-powered comparator and a switch. In a specific embodiment, the input-powered comparator only consumes power when an input source provides sufficiently high voltage. Embodiments of the active diode can be used in an energy harvesting system. The comparator can be powered by the input and the system can be configured such that the comparator only consumes power when the input is ready to provide power to the load or energy storage element. In a specific embodiment, when there is no input, or the input is too low for harvesting, the comparator does not draw any power from the energy storage element (e.g., battery or capacitor) of the system.

主权项

1. A comparator, comprising:
a first input connector; a second input connector; an input power connector; and an output connector, wherein the comparator is configured to connect to an AC voltage source via the first input connector such that an AC voltage of the AC voltage source is applied to the first input connector, wherein the comparator is configured to connect to a DC energy storage element via the second input connector such that a DC energy storage element DC voltage is applied to the second input connector, wherein the comparator is configured to connect to the AC voltage source via the input power connector such that the AC voltage of the AC voltage source is applied to the input power connector, such that the comparator is powered by the AC voltage source when the AC voltage of the AC voltage source applied to the first input connector is higher than a threshold voltage, wherein the output connector outputs a comparator output voltage, wherein the comparator only consumes power when the AC voltage of the AC voltage source is higher than the threshold voltage, wherein when the AC voltage is higher than the threshold voltage, either: (i) when the AC voltage of the AC voltage source is higher than the DC energy storage element DC voltage, the comparator output voltage is low, and when the AC voltage is lower than the DC energy storage element DC voltage, the comparator output voltage is high; or (ii) when the AC voltage of the AC voltage source is higher than the DC energy storage element DC voltage, the comparator output voltage is high, and when the AC voltage is lower than the DC energy storage element DC voltage, the comparator output voltage is low, wherein the comparator comprises a bias current source comprising a bias current source transistor, wherein a bias current source gate of the bias current source transistor is connected to the AC voltage source via the input power connector such that the AC voltage of the AC voltage source is applied to the bias current source gate of the bias current source transistor, and wherein the threshold voltage is a threshold voltage of the bias current source transistor such that when the AC voltage of the AC voltage source is higher than the threshold voltage of the bias current source transistor, the bias current source is turned on.