Circuit and method for pulse width measurement

摘要

A circuit for pulse width measurement comprises a charging circuit, a comparator and a determining circuit. The charging circuit is configured to charge a capacitive device in response to a periodic signal. The comparator is configured to compare a voltage across the capacitor with a reference voltage level. The determining circuit is configured to determine the number of pulses of the periodic signal in response to a signal from the comparator indicating that the voltage across the capacitor reaches the reference voltage level.

主权项

1. A circuit, comprising:
a charging circuit configured to charge a capacitive device with a charging current in response to a periodic signal; a comparator configured to compare a voltage across the capacitive device with a reference voltage having a predetermined reference voltage level; a counter configured to count a number of pulses of the periodic signal; and a determining circuit electrically coupled to the counter and configured to determine the number of pulses of the periodic signal in response to a signal from the comparator indicating that the voltage across the capacitive device reaches the predetermined reference voltage level, wherein
a pulse width of the periodic signal is obtained based on a relationship:
t1=tref*COUNTref/COUNT1where t1 represents the pulse width of the periodic signal, tref represents a predetermined pulse width of a reference signal, COUNTref represents a predetermined number of pulses of the reference signal sufficient to cause the capacitive device to be charged to the predetermined reference voltage level with the charging current, and COUNT1 represents the number of pulses of the periodic signal.