Self-calibrating digital to analog converter

A self-calibrating DAC system comprising:

• a segmented non-binary DAC having a thermometric weighted segment having a first plurality of switches and resistive elements controllable by a most significant plurality of bits of a digital input signal and a sub-binary weighted segment having a second plurality of switches and resistive elements controllable by a least significant plurality of bits of the digital input signal;
• an ADC configured to selectively receive an output from the DAC;
• a memory module;
• an input code conversion module configured to apply a scaling factor stored in the memory module to a digital input during normal operation of the DAC system;
• and
• a calibration controller configured to:
• provide a first cumulative series of calibration input digital signals to the thermometric weighted segment and measure a corresponding first series of outputs of the DAC with the ADC;
• provide a second non-cumulative series of calibration input digital signals to the thermometric weighted segment and measure a second series of outputs of the DAC with the ADC;
• calculate a first scaling factor for the first plurality of switches and resistive elements by dividing each of the second series of outputs of the DAC by a difference between adjacent ones of the first series of outputs of the DAC;
• calculate a second scaling factor for the second plurality of switches from a sum of the first series of outputs of the DAC divided by a measured output range of the DAC;
• and
• store the first and second scaling factors in the memory module.

A computer program comprising instructions to cause a computer processor to perform a method of calibrating non-linearity of a segmented non-binary DAC in a self-calibrating DAC system, the segmented non-binary DAC having a thermometric weighted segment having a first plurality of switches and resistive elements controllable by a most significant plurality of bits of a digital input signal and a sub-binary weighted segment having a second plurality of switches and resistive elements controllable by a least significant plurality of bits of the digital input signal, the method comprising:

• providing a first cumulative series of calibration input digital signals to the thermometric weighted segment and measuring a corresponding first series of outputs of the DAC with an ADC;
• providing a second non-cumulative series of calibration input digital signals to the thermometric weighted segment and measuring a second series of outputs of the DAC with the ADC;
• calculating a first scaling factor for the first plurality of switches and resistive elements by dividing each of the second series of outputs of the DAC by a difference between adjacent ones of the first series of outputs of the DAC;
• calculating a second scaling factor for the second plurality of switches from a sum of the first series of outputs of the DAC divided by a measured output range of the DAC;
• and
• storing the first and second scaling factors in a memory module of the self-calibrating DAC system for applying to a digital input during normal operation of the DAC system.