Patent ID: 7132966

Claim:
A method to convert a digital floating point number directly into an analog signal is comprising: provide a linear current digital-to-analog converter cascaded with an exponential current digital-to-analog converter; split a floating-point number into its mantissa and exponent; convert said exponent to a current representing an analog signal of the exponent using said exponential current digital-to-analog converter wherein the output current of said exponential current digital-to-analog converter corresponds to the equation: I 1 = I 0 × ∏ j = min max ⁢ 2 2 j ⁢ e j , wherein I 1 is the output current of the exponential digital-to-exponential converter, I 0 is a biasing current, e i ∈ {0, 1} represent the significant bit positions of the exponent wherein i is ranging from the MSB bit, signified by “max” to the LSB bit, signified by “min”; and convert said digital floating point number into an analog current by converting said mantissa by said linear current digital-to-analog converter using the output current of the previous step as biasing reference current.