Amplifier gain calibration system and method

A gain calibration system for an amplifier comprising:

• an amplifier having inputs and outputs;
• an analog to digital converter having inputs and an output;
• a voltage supply for providing a plurality of output voltages;
• a first switching circuit for coupling at least one of said output voltages to the inputs of the amplifier in a first phase;
• a second switching circuit for coupling the outputs of the amplifier to the inputs of the analog to digital converter in the first phase and coupling the sum of all of the at least one output voltages to the inputs of the analog to digital converter in a second phase, wherein said analog to digital converter in the first phase averages the amplifier outputs responsive to each of the at least one output voltages coupled to the amplifier;
• and
• a processor responsive to the outputs of said analog to digital converter in said first and second phases to calculate a calibration factor to accommodate for amplifier gain error.

A gain calibration system for an amplifier comprising:

• an amplifier having inputs and outputs;
• an analog to digital converter having inputs and an output;
• a voltage supply for providing a plurality of output voltages;
• a first switching circuit for coupling at least one of said output voltages to the inputs of the amplifier in a first phase;
• a second switching circuit for coupling the outputs of the amplifier to the inputs of the analog to digital converter in the first phase and coupling the sum of all of the at least one output voltages to the inputs of the analog to digital converter in a second phase;
• and
• a processor responsive to the outputs of said analog to digital converter in said first and second phases to calculate a calibration factor to accommodate for amplifier gain error, wherein the processor in the first phase averages each of the analog to digital converter outputs produced in response to the amplifier outputs responsive to each of the at least one output voltages coupled to the amplifier.

A gain calibration system for an amplifier comprising:

• an amplifier having inputs and outputs;
• an analog to digital converter having inputs and an output;
• a voltage supply for providing a plurality of output voltages;
• a first switching circuit for coupling at least one of said output voltages to the inputs of the amplifier in a first phase;
• a second switching circuit for coupling the sum of some of the at least one output voltages to the inputs of the analog to digital converter in a part of a second phase and coupling the sum of the remainder of the at least one output voltages in at least one additional part of said second phase;
• and
• a processor responsive to the outputs of said analog to digital converter in said first and second phases to calculate a calibration factor to accommodate for amplifier gain error.

A method of calibrating the gain of an amplifier with an analog to digital converter comprising:

• in a first phase applying at least one voltage to the input of an amplifier whose gain is to be calibrated and whose output is coupled to the input of an analog to digital converter;
• in a second phase applying the sum of all of the at least one voltages to the input of the analog to digital converter;
• and
• calculating a calibration factor from the outputs of said analog to digital converter in said first and second phases to accommodate for amplifier gain error.

A gain calibration system for an amplifier comprising:

• an amplifier having inputs and outputs;
• an analog to digital converter having inputs, an output, and terminals for receiving a reference voltage;
• a voltage divider including a plurality of impedances coupled between said reference voltage;
• a first switching circuit for coupling the voltages across impedances selected from said plurality of impedances to the inputs of the amplifier in a first phase;
• a second switching circuit for coupling the outputs of the amplifier to the inputs of the analog to digital converter in the first phase and coupling the voltage across all of the plurality of impedances to the inputs of said analog to digital converter in a second phase;
• and
• a processor responsive to the outputs of said analog to digital converter in said first and second phases to calculate a calibration factor to accommodate amplifier gain error.