Patent ID: 6404295
Filing Date: 2002-06-11
Classification: H03K,H03L

Abstract:
A voltage controlled oscillator comprising:a first converter outputting a first current in response to an input voltage, a rate of increase of said first current is continuously decreased as said input voltage is increased above a first threshold voltage of a MOS transistor and below an upper voltage; a second converter outputting a second current in response to said input voltage, a rate of increase of said second current is continuously increased as said input voltage is increased above the first threshold voltage and below the upper voltage; an oscillator outputting an oscillation signal in response to a summation of said first current and said second current; and wherein said first converter includes: a first P-channel MOS transistor and a first N-channel MOS transistor which are connected in series between a power supply voltage and a ground; a second P-channel MOS transistor connected with said power supply voltage and outputting said first current to said oscillator, and wherein said input voltage is supplied to a gate of said first N-channel MOS transistor, and a drain and gate of said first P-channel MOS transistor and a gate of said second P-channel MOS transistor are connected with each other.