Low Power Current Starved Sub-Harmonic Injection Locked Ring Oscillator

This paper proposes a new current starved ring oscillator based on current mode injection locked frequency multiplier (ILFM). This low power oscillator is the main building block of low power transceivers. These transceivers are mainly used in biomedical sensor nodes, where the consuming power is crucial. The operation frequency of the oscillator was chosen to be 500MHz. One 50MHz accurate low phase noise reference signal is used to improve the phase noise of the oscillator. Deliberately, bias current of the oscillator can change and subsequently pulls the frequency of free running oscillator to the harmonics of the reference signal. Total power consumption of the oscillator at 500MHz, is 25 mu W, the oscillator locks to the 10th harmonic of the reference signal. The order of the multiplication can be increased or reduced by increase and reduction in the bias current of the oscillator. The proposed circuit has been simulated under Advanced Design System simulator using TSMC RF CMOS 0.18um technology.