Low power bypass circuit for LED open circuit and reverse polarity protection

摘要

A low power bypass circuit for use with a string of series-connected LEDs includes a semiconductor diode and resistor connected in series, which semiconductor diode and resistor combination become conductive upon the failure of an LED or upon the improper, reverse polarity connection of the string of series-connected LEDs to a power supply. When the semiconductor and resistor combination becomes conductive, a three-terminal gate-controlled semiconductor switching device becomes conductive, thereby bypassing the failed LED and protecting the integrity of the string of series-connected LEDs upon the improper reverse polarity connection of the string of series-connected LEDs to a power supply.

主权项

1. A low power bypass circuit for use with a string of series-connected LEDs, the low power bypass circuit comprising:
a zener diode connected in series with a resistor which zener diode and resistor combination becomes conductive upon the failure of an LED or the connection of the string of series-connected LEDs to a reverse polarity flow of electrical energy; said zener diode and resistor combination causing a triac to become conductive upon the failure of an LED so the flow of that electrical energy no longer flows through said zener diode and resistor combination is reduced by the flow of electrical energy through said triac; said zener diode and resistor combination causing a triac to become conductive upon the connection of the string of series-connected LEDs to a reverse polarity flow of electrical energy so that electrical energy flows through said zener diode long enough to cause said triac to become conductive, thereby reducing the flow of electrical energy through said zener diode.