Sankosha Corporation

Agency of Industrial Science and Technology Ministry of International

Optotechno Co., Ltd.

Mitaka Denshi Kagaku Laboratory Inc.

Hirofumi Yoshihara

Masaaki Sato

Yutaka Hayashi

Yasuharu Yamada

Yuji Muramatsu

Hideyuki Harada

Teiji Hasegawa

Akihiro Kasai

Mitsuru Inoue

A multi-terminal surge protection device able to absorb surges of either polarity between lines and between a line and ground, in which the difference in operating time between the device elements connected to lines is reduced. A plurality of unipolar surge protection device elements are used which only operate to absorb surges of a specific polarity, and do not exhibit a reverse withstand characteristic upon application of a reverse-polarity voltage. One element is connected to a first line and another element to a second line, while a different element is connected to ground. A semiconductor substrate and second electrode are used that are common to all elements. To prevent lateral interference between elements, at least the element connected to ground is isolated from the line elements.

Multi-terminal surge protection device

A surge absorption device includes fundamentally a first semiconductor region, a second semiconductor region forming a pn junction between itself and the first region, a third region determining the effective thickness of the second region, and a fourth region provided in contact with the first region and forming an injection junction for causing first minority carriers of a kind the same as that of minority carriers in the first region to be injected into the first region. When a depletion layer formed by application of reverse bias across the pn junction reaches the third region, a punch-through region is formed in the second region. In this state, when minority carriers are injected from the fourth region into the first region, the minority carriers are absorbed by the second region to constitute the device current.

Surge absorption device

Growing community of inventors

Hamuramachi, Japan

Hirofumi Yoshihara