| 摘要 |
A duty cycle tuner measures high and low periods of a signal, calculates an actual duty cycle, generates duty control signals based on the actual duty cycle and a desired duty cycle, and adjusts the duty cycle responsive to the duty control signals. The high and low periods are measured using high-speed counters to provide a high count for the high period and a low count for the low period. The actual duty cycle value is then computed from the high and low counts, and compared to the desired duty cycle value to generate increment and decrement signals which may be positive or zero, to increase, decrease or maintain the actual duty cycle. In this manner, even if the high and low counts are subject to variations due to process, temperature or power supply voltage, their ratio is independent of such variations, so the tuner is immune to those effects. |
