Phase synchronizing circuit with feedback to control charge pump

A phase synchronizing circuit comprising:

• phase comparison means for effecting a comparison between the phase of a first input signal, and the phase of a second input signal so as to output a phase difference detection signal representative of the difference in phase between the first and second input signals;
• means supplying a first power supply potential and a second power supply potential, the difference between the potentials being a power supply voltage;
• charge means connected to receive the power supply voltage for passing, in accordance with said phase difference detection signal, a drive current;
• loop filter means connected to be selectively charged or discharged by said drive current so as to produce an output voltage;
• voltage-electric current converting means comprising a converted electric current value setting resistor and operative for generating a converted electric current which is in response to the output voltage of said loop filter means;
• and
• electric current-frequency converting means for producing an oscillator output signal at a frequency which is in response to the value of said converted electric current, as a source of the second input signal, wherein
• said charge means has an electric current source for said drive current which passes an electric current which is substantially proportional to said converted electric current, and
• said loop filter means comprise:
• an output terminal for supplying the output voltage;
• first capacitor means connected between said output terminal and a point at the first power supply potential;
• second capacitor means connected between said output terminal and a point at the second power supply potential;
• and capacitance ratio varying control means for changing the capacitance ratio between said first and second capacitor means in response to the generation of said phase difference detection signal while maintaining the total capacitance of said first and second capacitor means.