Dual digital to time converter (DTC) based differential correlated double sampling DTC calibration

A method for calibrating a digital to time converter (DTC), comprising:

• generating a first DTC output signal at an output of a first DTC based on a first digital input code;
• generating a second DTC output signal at an output of a second DTC based on a second digital input code, wherein the first DTC and the second DTC are coupled to one another;
• applying a first delay to the first DTC output signal using a delay circuit, to generate a first delayed DTC output signal;
• determining a phase difference between the first delayed DTC output signal and the second DTC output signal at a phase detector circuit, thereby generating a phase detector output;
• and
• adjusting the first digital input code of the first DTC to an adjusted first code that minimizes the phase detector output using a calibration circuit, wherein the adjusted first code has a predetermined relationship with the second input digital code.

A system for calibrating a digital to time converter (DTC), comprising:

• a DTC circuit comprising:
• a first DTC and a second DTC coupled to one another and configured to alternately receive an incremented digital code at the first DTC and the second DTC, while keeping the other DTC at a constant code and generate a first output in response to the incremented digital code and generate a second output in response to a previous digital code that is not incremented;
• a phase detector circuit coupled to the first DTC via a first connection and to the second DTC via a second connection, and configured to:
• receive the first output based on the incremented digital code and the second output based on a previous digital code that has not been incremented;
• generate a first time difference of outputs of the first DTC and the second DTC corresponding to the incremented digital code;
• and
• generate a second time difference of outputs of the first DTC and the second DTC corresponding to the previous digital code;
• and
• a calibration circuit configured to:
• determine a measurement associated with a non-linearity of the first DTC and the second DTC, based on the first and the second time differences;
• and
• alternately provide the incremented digital code to the first DTC and the second DTC.

A method for calibrating a digital to time converter (DTC), comprising:

• alternately receiving an incremented digital code at a first DTC and a second DTC that are coupled to one another from a calibration circuit, while keeping the other DTC at a constant code and generating a first output in response to the incremented digital code and generating a second output in response to a previous digital code that is not incremented;
• receiving the first output based on the incremented digital code and the second output based on a previous digital code that has not been incremented at a phase detector circuit and generating a first time difference of outputs of the first DTC and the second DTC corresponding to the incremented digital code and generating a second time difference of outputs of the first DTC and the second DTC corresponding to the previous digital code;
• and
• determining a measurement associated with a non-linearity of the first DTC and the second DTC, based on the first and the second time differences at a calibration circuit.