| US 7,542,255 B2 | ||
| Input protection circuit | ||
| Shinichiro Nakata, Takahama (Japan); Hiroyuki Ban, Hazu-gun (Japan); and Satoshi Ichikawa, Gamagori (Japan) | ||
| Assigned to DENSO CORPORATION, Kariya (Japan) | ||
| Filed on Mar. 08, 2007, as Appl. No. 11/715,421. | ||
| Claims priority of application No. 2006-072545 (JP), filed on Mar. 16, 2006; and application No. 2006-074608 (JP), filed on Mar. 17, 2006. | ||
| Prior Publication US 2007/0217104 A1, Sep. 20, 2007 | ||
| Int. Cl. H02H 3/22 (2006.01) | ||
| U.S. Cl. 361—56 [361/111] | 21 Claims |
| 1. An input protection circuit comprising:
a reverse flow preventing element connected between an input terminal that receives a signal from an outside and an internal
circuit;
a series circuit connected between the input terminal and a ground and including a voltage generating element that develops
a voltage thereacross when conductive and a voltage clamp element that clamps the voltage when a surge voltage is applied
to the input terminal; and
a current path forming element that forms a current path between a first common connection point of the reverse flow preventing
element and the internal circuit and a second common connection point of the series circuit, and sets a potential at the first
common connection point to be less than a potential at the input terminal when the surge voltage is applied to the input terminal.
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