Flash analog-to-digital conversion system and method with reduced comparators

A method for performing analog-to-digital conversion, the method comprising:

• receiving an analog signal;
• comparing said analog signal with a plurality of reference signals to form a thermometer code representative of said analog signal;
• dynamically adjusting the plurality of reference signals used in said comparing;
• decoding said thermometer code to produce a decoding of said thermometer code;
• and
• adding a reference value corresponding to dynamic adjustments of the plurality of reference signals to the decoding of said thermometer code to produce a scaled digital decode of said thermometer code, wherein said scaled digital decode corresponds to said analog signal;
• wherein said dynamically adjusting the plurality of reference signals allows for use of a reduced number of comparators, wherein the reduced number of comparators is less than a number of bits in the scaled digital decode.

An analog-to-digital converter, comprising:

• a first plurality of comparators each coupled to receive a combined analog signal, wherein the combined analog signal includes an analog input signal and an analog feedback signal, wherein each comparator is further coupled to receive a respective reference signal for comparison with the combined analog signal, wherein the plurality of comparators are each further configured to output a digital value indicative of the comparison of the combined analog signal with the respective reference signal;
• a digital summer coupled to receive the digital values output from the plurality of comparators, wherein the digital summer is configured to output a digital signal representative of the analog input signal;
• a register coupled to receive and store the digital signal from the digital summer, wherein the register is further configured to output the stored digital signal corresponding to the analog input signal;
• a digital-to-analog (D/A) converter coupled to receive the digital signal from the register, wherein the D/A converter is configured to generate the analog feedback signal in response to the digital signal;
• wherein the digital summer is further coupled to receive the digital signal from the register, wherein the digital summer is further configured to combine the digital output with the outputs of the plurality of comparators to produce the digital signal, wherein the digital signal corresponds to the analog input signal.

A method for performing analog to digital conversion, the method comprising:

• receiving an analog input signal;
• subtracting a feedback signal from the analog input signal, thereby producing a combined analog signal;
• comparing the combined analog signal with a plurality of reference signals to form a thermometer code representative of the combined analog signal;
• summing the thermometer code with a digital value to generate a digital output signal wherein the digital output signal corresponds to the analog input signal;
• wherein the analog input signal has a value within a first voltage range, wherein the method performs analog to digital conversion on the analog input signal within the first voltage range;
• wherein said comparing operates to compare the combined analog signal with the plurality of reference signals using a second voltage range that is less than the first voltage range.

An analog-to-digital converter, comprising:

• a plurality of comparators each coupled to receive an analog input signal, wherein each comparator is further coupled to receive a respective comparator reference signal for comparison with the analog input signal, wherein the plurality of comparators are each further configured to output a digital value indicative of the comparison of the analog input signal with the respective comparator reference signal;
• a decoder coupled to receive the outputs of the plurality of comparators, wherein the decoder is configured to output a digital signal representative of the analog input signal;
• and
• a dynamic reference controller coupled to the first plurality of comparators and the decoder, wherein the dynamic reference controller is configured to dynamically output one or more dynamic reference voltages to the first plurality of comparators, wherein the first plurality of comparators are operable to dynamically receive different comparator reference voltages for comparing with the analog input signal;
• wherein the one or more dynamic reference voltages are output based on the analog input signal and the digital signal representative of the analog input signal.

An analog-to-digital converter, comprising:

• a plurality of comparators each coupled to receive an analog input signal, wherein each comparator is further coupled to receive a respective comparator reference signal for comparison with the analog input signal, wherein the plurality of comparators are each further configured to output a digital value indicative of the comparison of the analog input signal with the respective comparator reference signal;
• a decoder coupled to receive the outputs of the plurality of comparators, wherein the decoder is configured to output a digital signal representative of the analog input signal;
• and
• a dynamic reference controller coupled to the first plurality of comparators and the decoder, wherein the dynamic reference controller is configured to dynamically output one or more dynamic reference voltages to the first plurality of comparators, wherein the first plurality of comparators are operable to dynamically receive different comparator reference voltages for comparing with the analog input signal;
• wherein the number of comparators is at least two less than the number of bits output by the analog-to-digital converter.

An analog-to-digital converter, comprising:

• a plurality of comparators each coupled to receive an analog input signal, wherein each comparator is further coupled to receive a respective comparator reference signal for comparison with the analog input signal, wherein the plurality of comparators are each further configured to output a digital value indicative of the comparison of the analog input signal with the respective comparator reference signal;
• a decoder coupled to receive the outputs of the plurality of comparators, wherein the decoder is configured to output a digital signal representative of the analog input signal;
• and
• a dynamic reference controller coupled to the first plurality of comparators and the decoder, wherein the dynamic reference controller is configured to dynamically output one or more dynamic reference voltages to the first plurality of comparators, wherein the first plurality of comparators are operable to dynamically receive different comparator reference voltages for comparing with the analog input signal;
• wherein the one or more dynamic reference voltages include a high reference voltage, wherein the dynamic reference controller is configured to dynamically output different high reference voltages to the first plurality of comparators;
• wherein the one or more dynamic reference voltages further include a low reference voltage, wherein the dynamic reference controller is configured to dynamically output both the different high reference voltages and different low reference voltages to the first plurality of comparators.