Patent ID: 7893777

Claim:
A voltage controlled oscillation circuit comprising: a voltage-to-current conversion circuit, which includes a first current source and a plurality of second current sources, each being configured to output a current according to an input voltage, the voltage-to-current conversion circuit generates a current obtained by adding a current output by the first current source and currents output by the plurality of second current sources; and a current controlled oscillation circuit of which an oscillation frequency varies according to a value of an output current of the voltage-to-current conversion circuit, wherein: the first current source includes a first MOS transistor and is configured so that the input voltage is applied to a gate of the first MOS transistor, an end of a current path of the first MOS transistor is connected to a reference voltage via a first resistor and a second resistor, and thereby a current is caused to pass through the current path, and each of the plurality of second current sources includes a second MOS transistor and is configured so that a voltage at a connection node of the first resistor and the second resistor is provided to a gate of the second MOS transistor, an end of a current path of the second MOS transistor is connected to the reference voltage via at least one resistor, and thereby a current is caused to pass through the current path.