Semiconductor device

Abstract

In a semiconductor device with an overcurrent protection function for a horizontal type insulated gate bipolar transistor, current bias is reduced by overcurrent protection. A horizontal type insulated gate bipolar transistor (1) of a main switch element controlled by gate voltage and a horizontal type insulated gate bipolar transistor (10) for current detection are connected in parallel. A base area (109) of the horizontal type insulated gate bipolar transistor (10) and an emitter region (106) of the horizontal type insulated gate bipolar transistor (1) are connected electrically. An emitter region (108) of the horizontal type insulated gate bipolar transistor (10) and the emitter region (106) of the horizontal type insulated gate bipolar transistor (1) are connected electrically by an induction resistor (4) of a current sensing circuit (7).

Description

technical field [0001] The present invention relates to a configuration of a protection circuit for a semiconductor device, and more particularly to an overcurrent protection circuit for protecting a switching element from overcurrent in a semiconductor device having an insulated gate type switching element. Background technique [0002] Fig. 7 shows a general cross-sectional structure of a horizontal insulated gate bipolar transistor (IGBT = Insulated Gate Bipolar Transistor). In the horizontal insulated gate bipolar transistor 51 shown in FIG. 7, the N - type semiconductor substrate 201 is formed on the surface portion of the P - Type base area 205. On the surface portion of the base region 205, a N + type emitter region 206 . Further, a gate insulating film 203 is formed to extend from the emitter region 206 over the base region 205 to the semiconductor substrate 201, and the gate electrode 204 is formed on this gate insulating film 203. In addition, the surface port...

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Problems solved by technology

However, if the size of the horizontal insulated gate bipolar transistor 52 for current detection is reduced, the variation in the value of the current 59 flowing through the sense resistor 54 becomes large, and as a result, the current value (the value of the current 58 ) at which the overcurrent protection function works value) the deviation becomes larger

[0014] As mentioned above, in the semiconductor device 50 having the conventional overcurrent protection function, the inductance ratio cannot be sufficiently increased, so the inductance resistor 54 has to be designed The resistance value or the size of the horizontal insulated gate bipolar transistor 52 for current detection is small, and as a result, the deviation of the current value at which the overcurrent protection function functions becomes large, which becomes a problem.

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