Patent ID: 6057728
Filing Date: 2000-05-02
Classification: H03K

Abstract:
A semiconductor circuit comprising:a power transistor comprising a first main electrode connected to a load, a second main electrode, and a control electrode, said power transistor passing a main current between said first main electrode and said second main electrode when a control voltage applied to said control electrode is equal to or larger than a threshold voltage;an output signal line receiving and transmitting an input signal having an ON signal level and an OFF signal level which alternately and periodically vary;a driving circuit comprising an input end connected to said input signal line and an output end connected to said control electrode of said power transistor, said driving circuit outputting said control voltage equal to or larger than said threshold voltage from said output end after a delay corresponding to an ON delay time has passed after input of said input signal when the level of said input signal is at said ON signal level, and outputting said control voltage smaller than said threshold voltage from said output end after a delay corresponding to an OFF delay time has passed after input of said input signal when said level of said input signal is at said OFF signal level; anda decision circuit connected to said power transistor to receive said main current as a first input signal and connected to said control electrode of said power transistor to receive said control voltage of said power transistor as a second input signal, said decision circuit determining that said power transistor is in an overcurrent state when detecting that said control voltage is equal to or larger than said threshold voltage and said main current is equal to or larger than a certain threshold current.