Adjustable phase-locked loop with independent frequency outputs

Phase-locked loops (PLLs) are used to synchronize the frequency of an oscillator with a reference. This work explains the architecture of a new multi-purpose PLL that can deliver different types of output signals which can be set independently to different frequencies ranging from 61 Hz up to 4 MHz. Possible outputs are square wave signals, sinusoidal signals and single voltage pulses with adjustable width. If no external oscillator is available, this PLL can also operate autonomously without reference. To reduce power consumption, the complete circuit can be sent to standby mode. Additionally, the whole structure is fully integrable in ICs and does not require external parts.