Patent ID: 8451023

Claim:
A semiconductor device comprising: a semiconductor substrate having a first conductivity type, having a first principal surface and a second principal surface, and including a main region and a sensing region, wherein an area of the sensing region on the first principal surface is smaller than the main region; a diode-built-in insulated-gate bipolar transistor having an insulated-gate bipolar transistor and a free wheel diode, which are disposed in the main region of the substrate, wherein the insulated-gate bipolar transistor has a gate electrode, and is driven with a driving signal input into the gate electrode; and a diode current sensing element disposed in the sensing region of the substrate, wherein the free wheel diode includes a FWD anode having a second conductive type and a FWD cathode having the first conductive type, wherein the FWD anode is provided by a first surface portion of the main region in the substrate on the first principal surface, and provides a base of the insulated-gate bipolar transistor, wherein the FWD cathode is disposed in a second surface portion of the main region in the substrate on the second principal surface, wherein the insulated-gate bipolar transistor includes a collector disposed in a third surface portion of the main region in the substrate on the second principal surface, which is different from the second surface portion, wherein the diode current sensing element includes a sensing element anode having the second conductive type, wherein the sensing element anode is disposed in a fourth surface portion of the sensing region in the substrate on the first principal surface, and wherein the diode current sensing element passes current in proportion to current flowing through the free wheel diode.