Patent ID: 7313380
Filing Date: 2007-12-25
Classification: H03M

Abstract:
1. A variable resolution analog-to-digital converter comprising: a sample-and-hold circuit including a plurality of sample-and-hold units connected in parallel and selectively activated corresponding to a required resolution to sample and hold an analog input signal; a plurality of first conversion stages connected in cascade to an output of the sample-and-hold circuit, each of the first conversion stages including a first sub-analog-to-digital converter unit configured to convert a first analog signal to a first digital signal and a plurality of first sub-multiplying-digital-to-analog converter units connected in parallel and selectively activated according to the required resolution to convert the first digital signal to a second analog signal, generate a first difference signal between the first analog signal and the second analog signal and multiply the first difference signal by a given value, the first analog signal being an analog signal corresponding to the analog input signal; a plurality of second conversion stages connected in cascade to an output of a last one of the first conversion stages, each of the second conversion stages including a second sub-analog-to-digital converter unit configured to convert a third analog signal into a second digital signal and a second sub-digital-to-analog converter unit to convert the second digital signal into a fourth analog signal and output a second difference signal between the third analog signal and the fourth analog signal, the third analog signal being an analog signal corresponding to the analog input signal; and a synthesis circuit to synthesize the first digital signal output from each of the first conversion stages and the second digital signal output from each of the second conversion stages, to generate a digital output signal.