Semiconductor protective control unit for controlling output transistors connected to inductive load

摘要

A protective control unit for controlling a highside-output transistor (T1) and a lowside-output transistor (T2) connected in series is provided. The highside-output transistor has a first main electrode region connected to a power supply, a second main electrode region and a first control electrode. The lowside-output transistor has a third main electrode region connected to the second main electrode region, a fourth electrode region connected to ground and a second control electrode. And an inductive load (L1) is connected to a connecting point (P) between the second and the third electrode regions. The protective control unit of the present invention has a highside-drive circuit. The highside-drive circuit pulls out charges stored in the highside-output transistor, through the first control electrode, during the periods when the highside-output transistor is in the end of reverse conducting state and reverse recovery state. The charges are pulled out by short-circuiting between the first control electrode and the second main electrode region during the periods when the highside-output transistor is in the end of reverse conducting state and reverse recovery state. Or, the charges are pulled out by a providing a potential having an opposite polarity to the charges during the periods when the highside-output transistor is in the end of reverse conducting state and reverse recovery state. <IMAGE>