Flash-successive approximation analog-to-digital converter

Claim 2

A flash-successive approximation analog-to-digital converter for inputting an analog input signal and outputting n bits of digital output data which correspond to said analog input signal, comprising: an n/2 bit flash conversion circuit for sampling said analog input signal and outputting a first digital signal comprising the most significant n/2 bits of said digital output data which correspond to said analog input signal, and a first analog signal comprising an analog voltage level which corresponds to said first digital signal; and an n/2 bit successive approximation conversion circuit for subtracting said first analog signal from said analog input signal, and for outputting a second digital word comprising the least significant n/2 bits of said digital output data which corresponds to said analog input signal.

Claim 3

The flash-successive approximation analog-to-digital converter according to claim 1 wherein said n/2 bit flash conversion circuit further comprises, sample and hold means for sampling an analog input signal and for outputting a sampled voltage level; an n/2 bit flash converter for converting said analog voltage level into said first digital signal comprising the most significant n/2 bits of said digital output data which correspond to said analog input signal; latch means for latching said first digital signal; and digital-to-analog conversion means for converting said first digital signal into said first analog signal which corresponds to said first digital signal.

Claim 4

The flash-successive approximation analog-to-digital converter according to claim 1 or 2 wherein said n/2 bit successive approximation conversion circuit further comprises, subtraction means for subtracting said first analog signal from said sampled voltage level, and for outputting a second analog signal which corresponds to the least significant n/2 bits of said digital output data; a comparator for comparing said second analog signal with a third analog signal and for outputting a compared signal; successive approximation conversion means for inputting said compared signal and for outputting a second digital signal comprising the least significant n/2 bits of said digital output data which corresponds to said analog input signal; and digital-to-analog conversion means for inputting said second digital signal and for outputting said third analog signal which corresponds to the least significant n/2 bits of said digital output data.