Lowe Hauptman Ham & Berner, LLP
Lock detector and method of detecting lock status for phase lock loop
A lock detector for a PLL circuit includes a first signal counting circuit, a second signal counting circuit, a comparator, and a lock status unit. The first signal counting circuit is configured to define a plurality of observation periods according to a first oscillating signal and a predetermined cycle value. The second signal counting circuit is configured to determine a maximum counter value according to a second oscillating signal within each of the observation periods, and the second oscillating signal is generated in relation to the first oscillating signal. The comparator is configured to determine, for each of the observation periods, whether the maximum counter value equals the predetermined cycle value. The lock status unit is configured to generate a lock signal based on the maximum counter value being equal to the predetermined cycle value for a predetermined number of consecutive ones of the observation periods.
Taiwan Semiconductor Manufacturing Company, Ltd.
H
H03L
inventional
Yen-Jen Feng Wei Kyle Chewn-Pu Huan-Neng
Chen Kuo Yen Jou Chen