Patent ID: 8884673

Claim:
A clock trimming apparatus receiving a reference signal, the clock trimming apparatus comprising: an oscillator having an input terminal receiving a bias signal and an output terminal generating a clock signal, wherein during a specified time duration of the reference signal, a frequency of the clock signal generated by the oscillator is correlated with an amplitude of the bias signal; a judging unit receiving the clock signal and the reference signal, wherein after a frequency division is performed on the clock signal, the judging unit generates a frequency-divided signal, wherein if the frequency-divided signal matches the reference signal, a pass signal generated by the judging unit is activated; a latching unit for generating a trimming completion signal, wherein after the pass signal is activated, the trimming completion signal is activated; and a tracking unit for receiving the reference signal, counting a pulse number of the reference signal, generating a trimming code, and providing the bias signal to the oscillator according to the trimming code, wherein after the trimming completion signal is activated, the trimming code is stopped being adjusted.