Integrated CMOS-clock-pulse generator, uses oscillator selection circuit to control switches to select oscillator in first or second oscillator block

摘要

The clock-pulse generator has a phase detector (405) with reference signal input, a first charge pump (417), a loop capacitor (421), a second charge pump (419), a first oscillator block with a first charging current generator and a capacitor joined to the output of the first charge current generator.A first switch connects the output of the a second PLL charge pump selectively to the input of the second charge current generator in the first oscillator block, and a second switch with a first input, which is joined to the output of the voltage controlled oscillator in the first oscillator block. A third switch selectively joins an output of the first charge current generator or an output of the first charge current generator with the parallel inputs of the first and second charge pumps. An oscillator selection circuit controls the three switches so that either the voltage oscillator is selected in the first or the second oscillator block.