| 摘要 |
PROBLEM TO BE SOLVED: To arbitrarily set not only the duty ratio of a dimmer but also its frequency without influence of variation of components, in a backlight for a liquid crystal display device, or the like. SOLUTION: In this dimmer, a dimmer control circuit 2 has a count means 18 for counting a reference clock having a shorter period than a period of a drive pulse; a frequency data output means 21 outputting frequency data for controlling a frequency of the drive pulse; a duty ratio data output means 22 outputting duty ratio data for controlling the duty ratio of the drive pulse; and a control signal output means 19 outputting a control signal having the frequency corresponding to the frequency data and the duty ratio corresponding to the duty ratio data according to the count value of the count means 18, the frequency data and the duty ratio data. The frequency data of the frequency data output means 21 and the duty ratio data of the duty ratio data output means 22 can be respectively arbitrarily set from the outside. |
