Patent attributes
The present invention provides a drive device and a power supply system capable of driving a power transistor with low power while reflecting variations in manufacture process and external environments. A trigger detection circuit monitors a voltage between terminals or a current between terminals in a switching period of a power transistor and detects that the voltage between terminals or the current between terminals reaches a predetermined reference value. A current switching circuit selects a register outputting a current value to a variable current driver circuit from a plurality of registers and switches the register to be selected using a detection result of the trigger detection circuit as a trigger in the switching period, thereby making the drive current of the variable current driver circuit shift.
