Patent ID: 7627443

Claim:
A calibration apparatus for programmable response frequency selecting elements, comprising: a basic reference source; a programmable counter, for generating different frequency signals required by different frequency selecting elements by programming said basic reference source according to said different frequency selecting elements' configured data input; a control logic unit, for generating a plurality of timing control signals according to said different frequency signals; and a frequency to time constant converter including a capacitor set having a plurality of capacitors, said frequency to time constant converter receiving said timing control signals, tuning said capacitor set according to a reference voltage and an input voltage, and determining a calibrated capacitance; wherein said frequency to time constant converter further includes: a transconductor and switching element, for receiving said input voltage, and sequentially charging and discharging said capacitor set; a comparator, for comparing the voltage of said charged capacitor set with said reference voltage; and a tuning logic unit, for determining whether each capacitor of said capacitor set is enabled after said comparison.