| 摘要 |
PURPOSE:To precisely stabilize a light source by digitally controlling the stabilization of the light source, precisely converting the status of the light source or the peak value for power supply voltage into a digital value and instantaneously determining the quantity of supply power to the light source from said digital value. CONSTITUTION:Since a photocoupler 301 does not emit light when a transistor (TR) Tr1 turns off, a TR Tr2 is also turned off and power conduct from a rectifier 302 to a halogen lamp 5 is interrupted. When the TR Tr2 is on, the photocoupler 301 emits light, a photodetector is turned on and the TR Tr2 is also turned on, so that power is supplied to the halogen lamp 5. Namely power conduct to the halogen lamp 5 is controlled in accordance with the output level of an output port 02 in a controlling part. The quantity of light emitting can be kept at a prescribed value by digitally controlling the power conduct time to the halogen lamp 5 in accordance with the variation of power voltage by an internal timer. |
