Patent attributes
A two-level LED security light includes a light-emitting unit comprising at least an LED load which may be turned on or turned off by a light sensing control unit. A motion sensing unit upon an intrusion detection activates the LED load to generate a high level illumination for a time length adjustable by a time setting unit. The LED load is operated in compliance with a power supply unit wherein a voltage V across each LED is confined in a range Vth<V<Vmax, with Vth a threshold voltage and Vmax a maximum voltage. The light-emitting unit may be configured with two LED lighting loads emitting lights with different color temperatures, wherein a power allocation circuitry may be installed to respectively distribute different electric powers to the two LED loads to manage a color temperature tuning scheme thru a light diffuser.
