Patent ID: 8633723

Claim:
A semiconductor apparatus comprising: a semiconductor substrate; one or more main semiconductor devices on the semiconductor substrate, the main semiconductor devices making a main current flow; one or more main sensing semiconductor devices on the semiconductor substrate, the sensing semiconductor devices making a sensing current flow for measuring the main current; and a plurality of the main semiconductor devices exhibiting different current capacities or a plurality of the sensing semiconductor devices exhibiting different current capacities; wherein, a combination of a plurality of the main semiconductor devices and a sensing semiconductor device, a combination of a main semiconductor device and a plurality of the sensing semiconductor devices, or a combination of a plurality of the main semiconductor devices and a plurality of the sensing semiconductor devices is selected for setting a sensing ratio that is a ratio between the main current and the sensing current to be constant in a main current range used, wherein, at least one of the main semiconductor devices comprises a main MOS transistor comprising a main MOSFET; at least one of the sensing semiconductor devices comprises a sensing MOS transistor comprising a sensing MOSFET or a sensing IGBT; and a design value of the sensing ratio is determined by a ratio between a total area of a source layer or an emitter layer in the main MOS transistor and a total area of a source layer or an emitter layer in the sensing MOS transistor; the semiconductor apparatus further comprising: two pieces of the sensing MOS transistor, the current capacities thereof being different from each other; a gate electrode pad common to the main and sensing MOS transistors; a drain electrode or a collector electrode common to the main and sensing MOS transistor; a source electrode or an emitter electrode of the main MOS transistor; source electrodes or emitter electrodes of the two pieces of the sensing MOS transistor; and five terminals connected to the drain electrode or the collector electrode, the source electrodes or the emitter electrodes, and the gate electrode pad.