CIRCUIT FOR CONTROLLING LUMINANCE

摘要

PURPOSE: A brightness control circuit is provided to change the voltage which is applied to a power supply unit through the dimmer, thereby facilitating the change of brightness. CONSTITUTION: An input voltage detection unit (630) detects the input voltage. The input voltage is generated from a power supply unit (600). The error voltage is based on the detected voltage and the output voltage of the power supply unit. A control unit (640) increases the output power when the error voltage increases. The control unit decreases the output power when the error voltage decreases. [Reference numerals] (631) Voltage distribution unit; (632) Voltage transferring unit; (633) Current converting unit; (640) Control unit; (AA) Input voltage; (BB) Output voltage