Patent ID: 7742893

Claim:
A calibration circuit for calibrating an adjustable capacitance of a circuit having a time constant depending on said adjustable capacitance, the calibration circuit being adapted to output a calibration signal having information to calibrate said adjustable capacitance, the calibration circuit comprising: a calibration loop having: a controllable capacitance unit adapted to receive a control signal and including at least one array of switched capacitors that can be activated by the control signal, the controllable capacitance unit being adapted to output a first signal representing a parameter depending on an amount of capacitance of the array activated by the control signal; a comparison unit adapted to receive said first signal to assess whether said parameter meets a preset condition and to output a comparison signal representative of a result of said assessment; a control and timing logic unit adapted to receive the comparison signal and to change the control signal based on said comparison signal, wherein said first signal is a logic signal and said parameter is a time parameter of said first signal.