Low-Power Current-Starved Digitally-Controlled Oscillator for Phase-Locked Loop in Battery- Powered Devices

The demand for IoT SoCs with low power and high precision internal oscillators is greatly increasing. This paper presents a design of digitally controlled oscillator which has low power consumption suitable for use in phase-locked loop inside battery-powered devices. The design incorporates current-starved logic buffers in ring configuration to produce oscillating logic signal as clock source. The circuit has been implemented and fabricated in 180-nm CMOS technology. The measured fabricated chip achieves frequency range from 1.1 MHz to 200 MHz. The power consumption is very low that only consumes 872 µW at maximum frequency and 59.4 µW at minimum frequency.