| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a battery device having a charge and discharge control circuit that can reduce a leakage current of a bidirectional conduction type field effect transistor, and operate the bidirectional conduction type field effect transistor stably, in a charge and discharge protection circuit that controls charge and discharge of a secondary battery by one bidirectional conduction type field effect transistor. <P>SOLUTION: A charge and discharge control circuit has: a switching circuit that controls a gate of a bidirectional conduction type field effect transistor by an output of a control circuit that controls charge and discharge of a secondary battery; and two MOS transistors that prevent a charging current and a discharging current from counterflowing. A drain and a back gate of the first MOS transistor are connected to each other, and a source thereof is connected to a drain of the bidirectional conduction type field effect transistor. A drain and a back gate of the second MOS transistor are connected to each other, and a source thereof is connected to a source of the bidirectional conduction type field effect transistor. <P>COPYRIGHT: (C)2012,JPO&INPIT |
