Ratiometric A/D converter with non-rationometric error offset

A ratiometric converter with non-ratiometric offset correction, comprising:

• an analog-to-digital converter for receiving an input sense signal having non-ratiometric offsets associated therewith and an input reference voltage having non-ratiometric offsets associated therewith to perform a ratiometric operation thereon and provide a digital output signal proportional to said input sense signal and inversely proportional to said input reference signal;
• a storage device for storing data and non-ratiometric offset values corresponding to the non-ratiometric offsets associated with the input sense signal and input reference voltage;
• a non-ratiometric offset device for determining the non-ratiometric offset values for storage in said storage device;
• and
• a subtraction circuit for performing a subtraction operation to subtract said stored non-ratiometric offset values during the operation of said analog-to-digital converter prior to the ratiometric operation in said analog-to-digital converter such that offsets resulting from processing of the input sense signal, the input reference voltage and the associated input non-ratiometric offsets are corrected for;
• and
• said non-ratiometric offset device operable to determine the non-ratiometric offset for each input sense signal processed by said analog-to-digital converter such that said subtraction circuit subtracts the non-ratiometric offset value determined for each input sense signal from the digital domain value thereof.

A method for providing non-ratiometric offset correction in a ratiometric converter, comprising the steps of:

• providing an analog-to-converter;
• receiving on the input of the analog-to-digital converter an input sense signal and an input reference signal, the input sense signal having associated therewith input non-ratiometric offsets, and performing a ratiometric operation thereon;
• providing an output signal from the analog-to-digital converter that is proportional to the input sense signal and inversely proportional to the input reference signal in the digital domain;
• providing a storage device;
• storing in the storage device non-ratiometric offset values corresponding to the input non-ratiometric offsets associated with the input sense signal;
• and
• subtracting the stored non-ratiometric offset values during the operation of the analog-to-digital converter and prior to the ratiometric operation in the analog-to-digital converter such that offsets resulting from processing of the input sense signal with the associated non-ratiometric offsets are corrected for.