| 摘要 |
PROBLEM TO BE SOLVED: To prevent an augmentation in the area of a protective substrate from being caused by using a new method instead of a conventional method, where a bidirectional Zener diode is connected with the gate-source parts of power MOSFETs for protecting gate oxide films from an electrostatic breakdown in the MOSFETs and moreover, an externally attached Zener diode is connected with the gate and the source of the MOSFETs for using the MOSFETs for a secondary cell charge and discharge battery management. SOLUTION: In a protective circuit device using MOSFETs, a diode for gate-source protection provided with the built-in MOSFETs is used as a unidirectional Zener diode, whereby the individual MOSFETs are protected from an electrostatic breakdown or the like and moreover, in the case where the MOSFETs are used for a secondary cell charge and discharge battery management, the MOSFETs can be protected by the unidirectional Zener diode even though an overvoltage is generated from a control IC between the gates and the sources of the MOSFETs and an externally attached Zener diode becomes unnecessary. As a result, a reduction in the number of parts and a space saving become possible in the protective circuit device. |
