| 摘要 |
PURPOSE: To provide a constant light color output over an enlarged dimming range by providing a light return controller so as to monitor a light emitting output, and adjusting luminance by a variable frequency DC pulse current. CONSTITUTION: A pulse control current source 800 supplies a direct current, the current level, pulse width and wave-height of which are determined by a shunt current controller 700 concerned in frequency and a pulse width and an inductor 802. The current source 800 has a self current level adjusting function in high frequency and outputs a variable frequency DC pulse current, which is converted into an AC current by a current transformer 500, thereby adjusting luminance of a lamp 300. The current transformer 500 is driven by a current transformer driver 600. The driver 600 executes a dividing function by using 2 as a divisor, so that each of AC paths in the current transformer 500 can be activated only for 50% of a time period. Furthermore, a light return controller 900 directly monitors a light emitting output from the lamp 300 to maintain a predetermined luminance. Consequently, a luminance apparatus 200 can exhibit the ability to provide a constant light color output over an enlarged luminance range with a relatively simple design. |
