| 摘要 |
PURPOSE:To protect the group of transistors, by controlling an IF power source circuit simultaneously by a reset signal for starting a pulse generating circuit by a micro-computer. CONSTITUTION:An inverter circuit controls the driving of a motor 4 or a load through an input power source 1, a rectifying circuit 2 and the group of power transistors 3. The control circuit unit of the inverter circuit is constituted of a control circuit power source 5, a pre-driver circuit 6, a pulse generating circuit 7 having a micro-computer in the center thereof, a power source monitoring circuit 8 and an IF power source circuit 9. The power source monitoring circuit 8 detects the fall of the power source voltage of the control circuit correctly and continues the outputting of a reset signal while the power source voltage is lower than the operation guarantee voltage of the micro-computer in order to prevent non-specified operation. The power source monitoring circuit 8 continues also the outputting of the reset signal for a given period of time after returning to a stationary condition. According to this method, the group of the power transistors 3 may be protected from the generation of the instantaneous interception or the instantaneous fall of the input power source.
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