Patent ID: 6778114
Filing Date: 2004-08-17
Classification: G11C,H03L,H03M

Abstract:
A digital to analog converter (DAC) comprising:an escalator code generator, responsive to an externally-provided count trigger signal, to generate an escalator code; and an escalator-code-to-analog converter (ECAC) to convert said escalator code from said generator; wherein said generator is arranged to represent base 10 numbers with a mixed code having a coin code portion and a cash code portion so as to eliminate multi-bit changes in the cash code portion upon changes in count direction, said coin code corresponding to one or more of the least significant bits of said cash code but fewer than all bits of said cash code; and represent a count in a first direction as a summation of the base 10 number represented by said coin code and the base 10 number represented by said cash code; wherein said generator is operable to alter said coin code when said count changes direction while said cash code remains the same until a count capacity of said coin code is exceeded, said cash code being alterable after said count capacity of said coin code is exceeded; and wherein cycling between adjacent base 10 numbers is manifested in said coin code portion while keeping said cash code portion the same; and wherein noise introduced into an output of said ECAC due to such cycling is reduced because said cycling is manifested in said coin code portion.