Integrated circuit apparatus

An apparatus comprising:

• a first variable capacitor capable of changing capacitor;
• a second variable capacitor capable of changing capacitor;
• a filter connected to the first variable capacitor;
• a detector connected to the second variable capacitor;
• and
• a controller for controlling the first variable capacitor in accordance with a result of the detector;
• wherein the detector comprises:
• a current source circuit comprising a first current source and a second current source,
• a resistor connected between the first current source and a reference potential portion,
• a switched capacitor circuit having switches connected to terminals of the second variable capacitor, respectively, the switches repeatedly switching capable of charging a voltage to the second variable capacitor and capable of discharging a electric charge of the variable capacitor,
• an integrating circuit having an output terminal and an input terminal which is connected a portion between the second current source and the switched capacitor circuit, an integrating circuit for integrating a current from the portion and for exchanging into an output voltage of the output terminal, and
• a comparator for comparing the voltage between two end of the resistor and an output voltage of the integrating circuit.

An apparatus comprising:

• a variable capacitor capable of changing capacitor;
• a filter connected to the variable capacitor;
• a detector connected to the variable capacitor;
• and
• a controller for controlling the variable capacitor in accordance with a result of the detector;
• wherein the detector comprises:
• a current source circuit comprising a first current source and a second current source,
• a resistor connected between the first current source and a reference potential portion,
• a switched capacitor circuit having a variable capacitor and switches connected to terminals of the variable capacitor, respectively, the switches repeatedly switching capable of charging a voltage to the variable capacitor and capable of discharging a electric charge of the variable capacitor,
• an integrating circuit having an output terminal and an input terminal which is connected a portion between the second current source and the switched capacitor circuit, an integrating circuit for integrating a current from the portion and for exchanging into an output voltage of the output terminal, and
• a comparator for comparing the voltage between two end of the resistor and an output voltage of the integrating circuit.