| 摘要 |
PROBLEM TO BE SOLVED: To flexibly cope with a brightness segment of an emergency light, thereby enhance part sharing rate, and make possible miniaturizing by properly changing a pressure rise ratio of a piezoelectric transformer by means of VCO method. SOLUTION: An emergency lighting device controls a stepup of a piezoelectric transformer CT1 by means of a VCO method and lights an emergency light L1 at a high frequency. In setting of brightness of the lighting device, a current flowing the emergency light is detected, and this is amplified by an operation amplifier IC4 and is determined by a voltage value to be inputted to a differential amplifier IC1 as a feedback signal. Since brightness can be adjusted by changing a gain of the operation amplifier IC4 by means of a slide switch SSW1 of a dimming switch circuit, plural brightness settings is made possible by a single stepup transformer CT1. |
