| 摘要 |
PURPOSE:To make it possible to change and stabilize a current flowing through a fluorescent lamp by performing a control based on an output signal from a microcomputer in which an automatic stabilization and manual adjustment of luminous energy are mixed. CONSTITUTION:The control is performed so that, as a detected voltage becomes higher than a potential of a reference voltage side terminal, an output is reduced and, as becomes lower, the output is increased. As a result, a lamp current flowing through a current transformer T2 is usually controlled to be a constant value determined by an outside signal A. Accordingly, in response to a potential of dead time control terminal, a minimum OFF time of a NPN transistor is determined independent of a signal from an error amplifier. A feedback is performed from a feedback terminal to a reference voltage terminal 2 through a capacitor C3, to perform a phase correction of the error amplifier. |
