PLL power supply filter (with pump) having a wide voltage range and immunity to oxide overstress

A method of filtering noise on a power line supplying operating power from a power supply to a target circuit, the method comprising:

• providing an N-channel source follower circuit coupled between the power supply and the target circuit, the N-channel source follower circuit including a resistor-capacitor circuit and a transistor with a threshold voltage;
• maintaining the transistor in a saturation state through placing a charge pump in the N-channel source follower circuit, the charge pump receiving a first clock signal and a second clock signal;
• and
• allowing the voltage provided to a target circuit to exceed the voltage of the power line minus the threshold voltage while maintaining the transistor in a saturation state.

A processor comprising:

• an instruction decoder;
• a scheduler coupled to the instruction decoder;
• an execution core including a plurality of execution units;
• and
• a timing control circuit coupled to the execution core and the scheduler, the timing control circuit including a phase-locked loop circuit coupled to a power supply filter, the power supply filter including:
• a resistor-capacitor circuit coupled to a power supply line;
• a transistor coupled between the resistor-capacitor circuit and the power supply line;
• a charge pump coupled to the resistor-capacitor circuit to keep the transistor in a saturation state;
• at least one clock signal coupled to the charge pump;
• and
• at least one capacitive circuit coupled to at least one of the at least one clock signal, the at least one capacitive circuit including at least two capacitors in series with a middle node located between the at least two capacitors, the middle node coupled to a second supply line, the second supply line providing approximately half the voltage of the power supply line.