Patent ID: 8803617
Filing Date: 2014-08-12
Classification: H03K

Abstract:
1. Oscillator circuitry comprising a switching inverting amplifier arranged in a ring oscillator configuration of at least two stages; a bias generator for supplying the amplifiers of neigbouring stages, said bias generator being responsive to an enable signal to supply the amplifiers when the enable signal is asserted and not to supply the amplifiers when the enable signal is deasserted, the enable signal being first passed through a threshold circuit before being used to enable bias generators and releasing initial conditions to ensure that the ring oscillator will start smoothly; a first pair of transistors, one of said pair coupled to an input of one of the amplifiers and the other of said pair coupled to an output of said amplifier, said pair of transistors being driven in common by said enable signal such that when the enable signal is deasserted the transistors of the pair are turned on to impose conflicting levels at said input and said output such that said amplifier is forced to switch; a second pair of transistors, one of said pair coupled to an input of the other of the amplifiers and the other of said pair coupled to an output of said other amplifier, said second pair of transistors being driven in common by said enable signal such that when the enable signal is deasserted the transistors of the pair are turned on to impose conflicting levels at said other amplifier input and said other amplifier output such that said other amplifier is forced to switch; the neighbouring amplifiers providing said switching events to trigger ring oscillator oscillation thereafter.