Oscillating apparatus

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:
• a phase controlling current supply that is connected to the capacitor, sets a predetermined phase controlling current as a discharge current, and discharges the capacitor according to the discharge current;
• and
• a charge pump current supply that, when being connected to the capacitor via the switch circuit, charges the capacitor by running a predetermined charge pump current,
• 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.