Calibration of a delay circuit

A method of calibrating a delay generation circuit, the circuit comprising:

• a capacitive element of integration of a first current supplied by a first current source, wherein the first current source comprises a first digital-to-analog converter controlled by a first digital control code;
• a circuit of initialization of the capacitive element on order of an initialization signal;
• a comparator of a first charge voltage of said capacitive element with respect to a second voltage, said second voltage being generated from a second digital-to-analog converter controlled by a second digital control code, the comparator having a comparison output delivering an output signal having a desired delay with respect to the initialization signal;
• and
• wherein, during a phase of use of the delay generation circuit, only one code, called selection code, among the first and second digital control codes is used to select the desired delay, the other control code, called adjustment code, remaining at a predefined value;
• and
• wherein, during a phase of calibration of the delay generation circuit, the first and second digital control codes are used to defined said predefined value and the comparison output is coupled to an input of a phase comparator;
• and
• wherein the calibration method comprises the steps of:
• in a first test phase:
• a1) applying a first set of first and second digital control codes and applying an initialization signal;
• b1) delivering, on another input of the phase comparator, a calibration signal having a first reference delay with respect to the initialization signal;
• c1) analyzing the output signal of the phase comparator;
• and
• in a second test phase:
• a2) applying a second set of first and second digital control codes and applying an initialization signal;
• b2) delivering, on said other input of the comparator, a calibration signal having a delay equal to the sum of the first reference delay and of a second reference delay;
• c2) analyzing the output signal of the phase comparator.