Patent ID: 6968249

Claim:
A current measuring circuit measuring a current driven to a load by an applied voltage from a voltage apply terminal, comprising: an operational amplifier having a second input terminal connected to said voltage apply terminal for applying a voltage equal to a voltage supplied to a first input terminal to said load; a PNP type first transistor electrically coupled between an output terminal of said operational amplifier and said voltage apply terminal; and a PNP type second transistor electrically coupled between the output terminal of said operational amplifier and a current measuring terminal and constituting a current mirror with said PNP type first transistor; said PNP type first and second transistors having their bases connected to said second input terminal of said operational amplifier and to said voltage apply terminal and, when activated in response to said applied voltage, said PNP type first transistor driving a current to said load via said voltage apply terminal, and said PNP type second transistor driving a mirror current of the drive current of said PNP type first transistor to said current measuring terminal.