Patent ID: 7391295

Claim:
A high voltage over-current protection device, comprising: a positive temperature coefficient (PTC) electrically conductive heat-dissipation layer, comprising: at least one polymer; an electrically conductive filler substantially uniformly distributed in the polymer; and a heat conductive filler uniformly substantially distributed in the polymer; and two metal electrodes disposed on upper and lower surfaces of the PTC electrically conductive heat-dissipation layer, respectively, so as to form an electrically conductive path; wherein the withstand voltage of the high voltage over-current protection device is larger than 250 volts and the PTC electrically conductive heat-dissipation layer has the following characteristic when tripped: Δ T B (5)/Δ T A (50)>60% wherein ΔT B (5) stands for a temperature difference between a tripped-state surface layer temperature of the PTC electrically conductive heat-dissipation layer being tripped for 5 seconds and the room temperature, and ΔT A (50) stands for a temperature difference between a tripped-state centric hot line layer temperature of the PTC electrically conductive heat-dissipation layer being tripped for 50 seconds and the room temperature.