Programmable ring oscillator
Programmable voltage controlled ring oscillator
Oscillation circuit including a ring oscillator having a changeable number of inverter circuits Patent #: 5331294
ApplicationNo. 274100 filed on 07/12/1994
US Classes:331/57, RING OSCILLATORS331/177R, WITH FREQUENCY ADJUSTING MEANS331/179Step-frequency change (e.g., band selection, frequency-shift keying)
ExaminersPrimary: Grimm, Siegfried H.
Attorney, Agent or Firm
International ClassH03K 003/354
Foreign Application Priority Data1993-08-31 JP
AbstractA ring oscillator wherein an inverter group includes five inverters (G1 to G5) connected in series, the output of the inverter (G3) is connected to the input of the first inverter (G1) through a transfer gate (TF1), and the output of the inverter (G5) is connected to the input of the inverter (G1) through a transfer gate (TF2). The ring oscillator is adapted such that, when a switching signal (S3) is "L", the CMOS transfer gates (TF1) and (TF2) are on and off, respectively, and the three inverters (G1 to G3) are connected in a loop whereas the inverters (G4, G5) function as buffers receiving the output of the inverter (G3), to provide an oscillation signal (S2) produced by the three inverters (G1 to G3) forming the loop from an output terminal (2) and such that, when the switching signal (S3) is "H", the oscillation signal (S2) produced by the five inverters (G1 to G5) forming the loop is provided, whereby the oscillation signal has a wide range of variable oscillation frequency bands.