Low current power detection circuit providing window comparator functionality

A power detection system is disclosed that includes a detector circuit and a comparator circuit. The detector circuit includes a first transistor, a second transistor that is not identical to the first transistor, and a third transistor that is substantially identical to the first transistor. Each of the transistors is commonly coupled to a current source and is coupled to a differential input voltage. The comparator circuit is for providing an output that is representative of whether the input voltage is above or below a threshold voltage responsive to a difference between the first transistor and the second transistor.