CONSTANT POWER SUPPLY FOR LED EMERGENCY LIGHTING USING SMART OUTPUT RESETTING CIRCUIT FOR NO LOAD CONDITIONS

摘要

A constant power backup power supply for LED lighting fixtures is disclosed. The power supply includes a storage battery that is charged while an AC power source is in an ON condition. When AC power transitions to an OFF condition, a capacitor bank charged by the battery supplies current to the primary side of a flyback converter operating in discontinuous conduction mode. The secondary side of the flyback converter supplies constant output power to the LED lighting fixture for an arbitrary output voltage within a predetermined range.

主权项

1. A backup power supply for driving an LED light source, the supply comprising:
a storage battery adapted to provide DC electrical current; a constant power LED driver circuit comprising a flyback converter comprising a transformer operating in discontinuous conduction mode, wherein the flyback converter has a primary inductor winding that is electrically coupled to the storage battery, and the flyback converter has a secondary inductor winding that is selectably electrically coupled to the LED light source; and further comprising one or more capacitors electrically interposed between the primary inductor winding and the storage battery, the one or more capacitors having a capacitance sufficient to supply sufficient current to the primary inductor winding to supply constant power to the LED light source over a predetermined output voltage and power range.