Patent ID: 7471188
Filing Date: 2008-12-30
Classification: G06K

Abstract:
1. A semiconductor device comprising: an antenna circuit; a converter circuit which converts an AC voltage to a DC voltage through rectification; a first comparator circuit; a second comparator circuit a first reference voltage source; a second reference voltage source; a first switch element electrically connected to the first comparator circuit and the ground; a second switch element electrically connected to the second comparator circuit and the ground; a first capacitor electrically connected to the antenna circuit and the first switch element; and a second capacitor electrically connected to the antenna circuit and the second switch element, wherein the antenna circuit is electrically connected to the converter circuit, wherein the first comparator circuit compares an output voltage of the first reference voltage source with an output voltage of the converter circuit, and wherein the second comparator circuit compares an output voltage of the second reference voltage source with the output voltage of the converter circuit.