REGULATED DRAIN DETECTION CIRCUIT AND VOLTAGE CONTROLLED OSCILLATOR USING IT

摘要

A regulated drain detection circuit and a voltage controlled oscillator using the same are provided to obtain stable yield with only a digital process by increasing stability of the voltage controlled oscillator by reflecting process variation to the voltage controlled oscillator. A long channel transistor has a long channel length. A short channel transistor has a short channel length. A feedback circuit fixes a drain voltage of the long channel transistor and a drain voltage of the short channel transistor with an equal voltage. A regulated drain detection circuit(610) detects a difference between a gate voltage of the long channel transistor and a gate voltage of the short channel transistor according to process variation.