Patent ID: 9543788
Date: 2017-01-10
CPC Classifications: F21K,F21S,F21V,F21Y,H02J,H05B,Y02B,Y04S

Claim:
1. A lighting unit comprising: a power input adapted to receive power via a power supply circuit, wherein the power supply circuit is adapted to receive a supply of power from a primary power source through a switch and includes a secondary source of power; at least one light source adapted to receive power from the secondary source of power; a sensor configured to generate an output indicative of the amount of current in an electrical signal sent onto the power supply circuit and a controller configured to: cause application of the electrical signal to the power supply circuit; determine an operational state of the switch based a comparison of one or more measurements of the amount of current in the electrical signal applied to the power supply circuit and a threshold amount of current; and cause the power from the secondary source of power to be supplied to the light source when power from the primary source is not present on the power input and the determined operational state of the switch indicates that the switch is in a closed state.