POWER SUPPLY CIRCUIT, AND ILLUMINATION APPARATUS

摘要

PROBLEM TO BE SOLVED: To materialize constant current control capable of suppressing power loss and also coping with fluctuation of an input voltage with a simple circuit structure.

SOLUTION: A power supply circuit 100 supplies power to a load circuit (light source circuit LA) having constant voltage characteristics by receiving power from an ac power supply AC. A voltage detection circuit 110 detects an ac voltage input from the ac power supply AC to use it as the input voltage. An impedance circuit 120 is electrically connected in series to the load circuit (light source circuit LA), and its impedance increases as the input voltage detected by the voltage detection circuit 110 increases.

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