Patent ID: 7605621
Filing Date: 2009-10-20
Classification: H03L

Abstract:
1. An oscillating apparatus comprising: a filter circuit that includes a capacitor and outputs a control signal based on an amount of charge accumulated in the capacitor; an oscillator that outputs an oscillation signal of a frequency that is based on the control signal; a phase comparator that compares the oscillation signal with a reference signal of a predetermined frequency, to detect a phase difference between the oscillation signal and the reference signal; a switch circuit that controls whether to charge the capacitor according to a predetermined charge current or to discharge the capacitor according to a predetermined discharge current, based on the phase difference; and a current stabilizing circuit that defines each of the charge current and the discharge current based on a predetermined reference current or a reference voltage, the current stabilizing circuit including: wherein current values respectively of the phase controlling current and of the charge pump current are set to be substantially proportional to the reference current or the reference voltage.