Method and apparatus for LED string short circuit detection and protection

摘要

An apparatus for LED string short circuit detection constituted of: a constant current drive circuit; a plurality of LED strings, a first end of each of the plurality of LED strings coupled to a common output of the constant current drive circuit; a first sense resistor coupled between a second end of each of the plurality of LED strings and a chassis; a second sense resistor coupled between the chassis and a return of the constant current drive circuit; and a comparing circuit arranged to compare the amount of current flow through the first sense resistor with amount of current flow through the second sense resistor, the comparing circuit arranged to assert a fault signal in the event that the amount of current flow through the second sense resistor exceeds the current flow through the first sense resistor by a predetermined minimum value.

主权项

1. An apparatus for LED string short circuit detection comprising:
a constant current drive circuit; a plurality of LED strings, a first end of each of said plurality of LED strings coupled to a common output lead of said constant current drive circuit; a first sense resistor coupled between a second end of each of said plurality of LED strings and a chassis; a second sense resistor coupled between the chassis and a return of said constant current drive circuit; and a comparing circuit arranged to compare an amount of current flowing through said first sense resistor with an amount of current flowing through said second sense resistor, said comparing circuit arranged to assert a fault signal in the event that the amount of current flowing through said second sense resistor exceeds the amount of current flowing through said first sense resistor by a predetermined minimum value.