Patent ID: 6072372
Filing Date: 2000-06-06
Classification: H03K,H03L

Abstract:
A voltage-controlled oscillator, comprising:an odd number of inverter circuits connected in series in a ring, wherein each of said inverter circuits is connected between a first power supply voltage and a second power supply voltage;a plurality of sub-frequency band selection circuits which receive a commonly input select signal and which respectively correspond to said inverter circuits, each of said plurality of sub-frequency band selection circuits connected between a corresponding one of said inverter circuits and either said first power supply voltage or said second power supply voltage, wherein said plurality of sub-frequency band selection circuits are responsive to the commonly input select signal to select a desired sub-frequency band from a plurality of sub-frequency bands, and to divide a range of frequency of output pulse signals respectively output from corresponding ones of said inverter circuits; anda plurality of output pulse signal frequency adjustment circuits which receive a commonly input bias signal and which respectively correspond to each of said inverter circuits and said plurality of sub-frequency band selection circuits, each of said plurality of output pulse signal frequency adjustment circuits connected in parallel to a corresponding one of said sub-frequency band selection circuits and between a corresponding one of said inverter circuits and either said first power supply voltage or said second power supply voltage, said plurality of output pulse signal frequency adjustment circuits responsive to the commonly input bias signal to adjust the frequency of said output pulse signals respectively output from corresponding ones of said inverter circuits within said desired sub-frequency band.