Patent ID: 6480133
Filing Date: 2002-11-12
Classification: H03M

Abstract:
An A/D converter for converting an input analog signal into a Gray code of higher m bits and lower n bits, comprising:m folding circuits for being supplied with differential analog signal pairs and differential reference voltage pairs and for outputting folded differential current pairs respectively; m first comparators for comparing said differential current pairs outputted by said folding circuits and for outputting said higher m bits of said Gray code; a plurality of sine wave generators for being supplied with said differential analog signal pairs and said differential reference voltage pairs and for outputting multi-phase sine wave pairs respectively; a current interpolation circuit for interpolating said multi-phase sine wave pairs and for outputting 2n sine wave pairs; 2n second comparators for comparing said sine wave pairs and for outputting binary data respectively; and a Gray code encoder for encoding said binary data into a Gray code of lower n bits; wherein said lower n bits of said Gray code are outputted from said Gray code encoder.