US Patent 11290117 Low-frequency arithmetic multiplying PLL for HDL devices

A high-density logic circuit device low-frequency phase-locked loop system includes a digital logic input-output module; an internal clock; an instant-lock module; an instant-adjust error module; a high-speed count comparator; a multiplication factor-is-zero-state detect module with a reset function; a pulse generator; and a high-speed pulse generator. The high-speed count comparator includes a high-speed counter and a high-speed comparator. The input-output module receives an input frequency and transmits an output frequency. The instant lock module locks the output frequency in phase to a leading edge the input frequency within two internal propagation delays. The instant-adjust error module emits a pulse request until a last pulse is identified. The high-speed count comparator receives the pulse request and emits the output frequency. The pulse generators receive the input frequency and internal clock pulses and output a frequency-in pulse. The HDL device has a digital low-frequency PLL function without the use of external components.