Electronic device having a high voltage breakdown protection circuit

摘要

An electronic device for use in an automobile includes first and second power transistors connected in series between two power supply terminals, a first detector producing a first detection signal when the voltage difference between the two power supply terminals is larger than a first predetermined value, and a second detector producing a second detection signal when the voltage difference between the two power supply terminals is larger than a second predetermined value which is larger than the first value, the first power transistor being driven into cut-off in response to the first detection signal and a control current to be applied to the second power transistor being bypassed to one of the power supply terminals to keep the second power transistor conductive.