Electric power tool

An electric power tool, comprising:

• a power supply including
• a battery that is configured to supply electricity, and
• a first switch circuit that is electrically connected to said battery, and that is configured to receive the electricity supplied by said battery and to operate in one of a conducting state and a non-conducting state;
• a driving unit including
• a second switch circuit that is electrically connected to said first switch circuit, and that is configured to operate in one of a conducting state and a non-conducting state,
• a motor that is electrically connected to said second switch circuit, and
• a switch-control circuit that is electrically connected to said second switch circuit, and that is configured to control said second switch circuit to drive said motor;
• a sensing unit configured to detect conditions of said power supply and said driving unit, and to output a detection result related to the conditions thus detected;
• and
• a control unit including
• a primary controller that is electrically connected to said power supply, said driving unit and said sensing unit, and that is configured to receive the detection result from said sensing unit, and
• a secondary controller that is electrically connected to said power supply and said sensing unit, and that is configured to receive the detection result from said sensing unit,
• wherein when said first switch circuit operates in the conducting state, said second switch circuit receives the electricity supplied by said battery from said first switch circuit, and provides, under control of said switch-control circuit, the electricity to said motor for driving said motor to operate,
• wherein said primary controller is configured to disable said driving unit when it is determined by said primary controller that there is a malfunction based on the detection result, and
• wherein said secondary controller is configured to control said first switch circuit to operate in the non-conducting state to cut off the electricity supplied from said battery to said second switch circuit when it is determined by said secondary controller that there is a malfunction based on the detection result.