Patent ID: 6597179
Filing Date: 2003-07-22
Classification: B61L,G01R,H05B

Abstract:
A fuse blow-out circuit for establishing a short circuit between first and second voltage and current supply lines to blow out a protection fuse through which a current supplied to a light-emitting load by the first and second lines flows, said fuse blow-out circuit comprising:a) a resistor and a capacitor connected in series between the first and second lines, said resistor having a given resistance value, and said capacitor having a given capacitance value and a capacitor charge period dependent on said given resistance value and said given capacitance value; b) a trigger circuit connected in parallel with the capacitor, and comprising a first controllable switch member closed in response to the current supplied to the light-emitting load to discharge said capacitor; and c) a second controllable switch member defining a current path between said first and second lines and closed in response to a given voltage amplitude across the capacitor; whereby, in the absence of current supplied to the light-emitting load for a duration equivalent to said capacitor charge period, said given voltage amplitude across said capacitor is reached to thereby close said second switch member, establish said current path and provide the short circuit between the first and second lines that will blow out the protection fuse and emulate an open circuit of a defective incandescent lamp.