Flash analog-to-digital converter

An analog-to-digital converter comprising:

• a signal input for receiving an analog input signal;
• a set of comparators, each comparator having a first input connected to the signal input, a second input connected to a reference voltage and being arranged to generate an output based on the comparison of the signals at the first input and second input, wherein the reference voltage is the same for all comparators in the set, and wherein the set of comparators has a non-identical response to the reference voltage and the input signal;
• an adder for determining a sum of the outputs of the set of comparators;
• conversion logic which is arranged to generate an output digital signal dependent on the determined sum based on a relationship between a sub-set of the total set of possible values that can be output by the adder and a corresponding digital code for each value and wherein the conversion logic is arranged to use an interpolation function to determine a digital code where the number of adders is not part of the sub-set of values stored in the look-up table.

A method of performing analog-to-digital conversion of an analog input signal comprising:

• receiving the analog input signal;
• applying the input signal to a first input of each of a set of comparators;
• applying a reference voltage to a second input of each of the set of comparators, each comparator being arranged to generate an output based on the comparison of the signals at the first input and second input and wherein the set of comparators has a non-identical response to the reference voltage and the input signal;
• determining a sum of the outputs of the set of comparators;
• generating an output digital signal dependent on the determined sum.