Two-dimensional analysis of surge response in thyristor lightning surge protection devices

The dynamics of surge response, which influences surge-handling capability, for thyristor lightning surge protection devices were investigated by a two-dimensional numerical device simulation. Maximum power dissipation appears in the open-base avalanche transistor operation at turn-on. The power dissipation increases by a few orders of magnitude with increase in the input surge. On the other hand, turn-on time is shorter and changes by less than one order of magnitude, caused by the field-aiding effect. As a result, the energy dissipation, which converts to self-heating and influences surge-handling capability, increases with increase in the input surge. To improve surge-handling capability by designing for low energy dissipation, fast switching time is effective for the open-base avalanche transistor which has narrow base width and uses a thin substrate with large carrier lifetime.