| 摘要 |
PURPOSE:To facilitate the design of a pulse generating circuit without taking changes in constants of a lighting circuit into consideration by setting preset data set by a presettable counter in a setting switch to form a non-overlap interval setting means. CONSTITUTION:When a counter circuit 2 starts to count a clock signal CLK and all outputs Q1-Q12 of the circuit 2 become 'H', a ripple carry signal RCY is output. The signal RCY makes an enable signal ENB to become 'H', and simultaneously, an output pulse signal OUT becomes 'H'. Interval setting data DB1-DB12 are preset at the circuit 2, and the count of the signal CLK is started. Upon the output of the signal RCY, the output pulse signal becomes 'L' while another enable signal ENA becomes 'H'. This operation is repeated. Accordingly, the 'H' and 'L' intervals of the output pulse signal OUT can be arbitrarily set on the basis of the interval setting data DA1-DA12 and DB1-DB12, to set an ON or OFF duty. |
