| 摘要 |
PURPOSE:To prevent a drive transistor from damaging by providing a bias circuit of a diode and a resistor in a protection fuse, and applying a reverse bias to the transistor. CONSTITUTION:A drive circuit (for one phase) of a transistor inverter INV disconnects or applies a drive signal through a current amplifier of transistors (Tr) Tr1-Tr3 to a drive transistor Tr4. In this case, a series circuit of a diode D0 and a resistor R0 is connected in parallel with a fuse F as means for protecting the drive Tr4 at fuse melting time. Thus, the series circuit of the diode D0 applies a reverse bias to between the base and the emitter of the Tr4, a current is flowed in a path of (c) in the drawing at fuse melting time to prevent the current due to the floating capacity of the Tr3 from flowing to the base of the Tr4 to prevent it from damaging. |
