Lighting apparatus with improved current overload protection circuit

Lighting apparatus comprising:

• a low voltage lighting apparatus means for providing illumination in response to a low A.C. voltage in the range of 1 to 30 volts;
• a transformer having a primary winding supplied with said primary line voltage and through which a primary current flows, and a secondary winding providing said low voltage and a secondary current drawn by said low voltage lighting apparatus;
• means responsive to flow of an activating current therethrough for permitting flow of said primary current and responsive to termination of the flow of said activating current to interrupt said primary current;
• means including at least one triac optoisolator for providing said activating current in response to initial application of power to said transformer and responsive to an output signal for shutting off said activating current, thereby interrupting the flow of said primary current;
• means for developing an A.C. current sample proportional to said secondary current;
• means for converting said current sample to a D.C. voltage;
• and
• comparator means for comparing said D.C. voltage to a reference voltage and generating said output signal in response to an instantaneous increase in said secondary current.

Power supply and circuit protection apparatus for use with a lighting apparatus comprising:

• a transformer having a primary winding supplied with said primary line voltage and through which a primary current flows and a secondary winding providing a secondary voltage and a secondary current for supply to said lighting apparatus;
• means responsive to flow of an activating current therethrough for permitting flow of said primary current and responsive to termination of the flow of said activating current to interrupt said primary current;
• means for providing said activating current in response to initial application of power to said transformer and responsive to an output signal for shutting off said activating current, thereby interrupting the flow of said primary current;
• means for developing an A.C. current sample proportional to said secondary current;
• means for converting said current sample to a D.C. voltage;
• and
• comparator means for comparing said D.C. voltage to a reference voltage and generating said output signal in response to an instantaneous increase in said secondary current.