US Patent 10218171 Surge protection circuit

A surge protection circuit includes a DC trigger circuit that generates a trigger signal when a surge pulse occurs, and a current conducting unit, coupled to the DC trigger circuit, that generates a first clamp voltage as an output voltage of the surge protection circuit and conducts surge currents to ground in response to the trigger signal. The DC trigger circuit includes a surge detection circuit and a first amplification circuit. The surge detection circuit detects if a surge pulse occurs, and triggers the first amplification circuit to generate the trigger signal when the surge detection circuit detects a surge pulse.