Integrated frequency divider
AssigneeEbauches S.A.
InventorJacob Luscher
Life of this patent
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Abstract
The frequency divider allows division of the frequency of two signals in phase opposition .phi..sub.1 (t) and .phi..sub.2 (t). A shift register 10 comprises an assembly of transistors and capacitors which form a plurality of cells connected one after the other, each cell being comprised of two identical stages which are connected in series and are supplied respectively by the periodic signals. Means for detecting particular stages of the register comprise the MOS transistors T.sub.8, T.sub.9, and T.sub.10. Means for producing a signal with a frequency which is a sub-multiple of that of the said periodic signals comprise the transistors T.sub.11 and T.sub.12, the transistor T.sub.13, the capacitor C.sub.7 and the capacitor C.sub.9. The divider is especially suitable for use in quartz oscillator watches.
Claims10
A frequency divider circuit for two periodic signals in phase opposition comprising, integrated in a semi-conductor substrate, a first shift register comprising a plurality of transistors and capacitors which form a plurality of cells connected one after the other, each cell being constituted by two identical stages which are connected in series and are supplied, in use, by the two periodic signals respectively, first detection means for detecting a particular state of the register, and first production means, responsive to the detecting of the said state to produce a first signal with a frequency which is a sub-multiple of that of the said periodic signals, and wherein each stage of the shift register comprises an MOS transistor structure which has two principal electrodes respectively forming the input and output of the stage and two control electrodes, one of which is, in operation, connected to a bias source and the other of which is connected to the output principal electrode, and a capacitor, one plate of which is connected to the said output electrode and the other plate of which receives one of the said periodic signals.
Dependencies are inferred from the claim text.