Scaled reference analog-to-digital conversion circuitry and method of operation

A method for increasing the effective resolution of an analog-to-digital (A/D) converter for converting analog voltages to digital values, the method comprising the steps of:

• (a) providing first high and low analog reference voltages to the A/D converter;
• (b) receiving the digital values from the A/D converter for an amount of time;
• (c) storing a highest digital value and a lowest digital value received during the amount of time;
• (d) replacing the first high analog reference voltage with a second high analog reference voltage that is a first predetermined number of steps above the highest digital value when the highest digital value is less than the first high analog reference voltage;
• and
• (d) replacing the first low analog reference voltage with a second low analog reference voltage that is a second predetermined number of steps below the lowest digital value when the lowest digital value is greater than the first low analog reference voltage.

Circuitry for converting analog signal voltages to digital values, the circuitry comprising:

• an analog-to-digital (A/D) converter for receiving the analog signal voltages and high and low analog reference voltages and for generating in accordance therewith the digital values;
• receiving means for receiving the digital values from the A/D converter for an amount of time;
• comparing means coupled to the receiving means for comparing a highest value of the digital values received during the amount of time to a peak threshold value stored in memory and for comparing a lowest value of the digital values received during the amount of time to a valley threshold value stored in the memory;
• first replacing means coupled to the comparing means and the A/D converter for replacing the high analog reference voltage with a voltage representative of the peak threshold value when the highest value of the digital values is less than the peak threshold value;
• and
• second replacing means coupled to the comparing means and the A/D converter for replacing the low analog reference voltage with a voltage representative of the valley threshold value when the lowest value of the digital values is greater than the valley threshold value.

Circuitry for converting analog signal voltages to digital values, the circuitry comprising:

• an analog-to-digital (A/D) converter for receiving the analog signal voltages and first high and low analog reference voltages and for generating in accordance therewith the digital values;
• receiving means for receiving the digital values from the A/D converter for an amount of time;
• storing means coupled to the receiving means for storing a highest digital value and a lowest digital value received during the amount of time;
• first replacing means coupled to the storing means and the A/D converter for replacing the first high analog reference voltage with a second high analog reference voltage that is a first predetermined number of steps above the highest digital value when the highest digital value is less than the first high analog reference voltage;
• and
• second replacing means coupled to the storing means and the A/D converter for replacing the first low analog reference voltage with a second low analog reference voltage that is a second predetermined number of steps below the lowest digital value when the lowest digital value is greater than the first low analog reference voltage.