Calibration of a charge-to-digital timer
AssigneeST-Ericsson SA
InventorsPetri Heliö, Petri Korpi, Paavo Väänänen
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Abstract
A calibration method disclosed herein calibrates at least one of a capacitive load and a charging current controlling a charge-to-digital timer (CDT). In general, the disclosed calibration method measures multiple calibration phases based on start and stop signals separated by a known time difference, and therefore having a known phase, and adjusts at least one of the capacitive load and the charging current of the CDT based on the measured calibration phases. In so doing, the disclosed calibration method reduces power dissipation and peak supply currents over the frequency range of the CDT.
Claims14
A method of calibrating at least one of a capacitive load and a charging current controlling a charge-to-digital timer, the method comprising:
- initializing the capacitive load and the charging current;
- applying first start and stop signals to the charge-to-digital timer to measure a first calibration phase during a first calibration period, said first start and stop signals separated in time by a first number of oscillator cycles;
- applying second start and stop signals to the charge-to-digital timer to measure a second calibration phase during a second calibration period, said second start and stop signals separated in time by a second number of oscillator cycles having a known relationship to the first number of oscillator cycles;
- and
- adjusting at least one of the capacitive load and the charging current based on the first and second calibration phases.
Dependencies are inferred from the claim text.