Semiconductor device, power supply device, and information processing device

Abstract

A semiconductor device (100) includes a MOS transistor (10) having a back gate region ''a'', a first region ''b'' serving as one of a source region and a drain region, and a second region ''c'' serving as the other of the source region and the drain region. The semiconductor device further includes an input terminal (20) connected to the first region ''b'' and to which an input voltage is applied from outside the semiconductor device (100), an output terminal (30) connected to the second region ''c'' and outputting an output voltage outside the semiconductor device (100), and a back gate control circuit (40) for applying the input voltage or the output voltage to the back gate region ''a''. With this configuration of the semiconductor device having the output MOS transistor, even when a reverse bias is applied between the input and the output terminal, the terminals are insulated from each other and lowering of the drain current by the substrate bias effect can be suppressed.

Description

technical field [0001] The present invention relates to a semiconductor device using a MOS transistor as an output device. Background technique [0002] As shown in FIG. 9 , a conventional power supply device outputs a desired output voltage via an output terminal 30 by turning on and off the gate of an output MOS transistor 900 . Here, between the source region and the drain region of the output MOS transistor 900, there generally exists a body diode BD as a parasitic device. Thus, if for some reason a reverse bias is applied between the input terminal 20 and the output terminal 30, the current will flow between the source and the drain through the body diode BD and this makes it impossible to Insulation between the region and the drain region. [0003] In Patent Document 1 listed below, a method of overcoming the above-mentioned problems due to the presence of the body diode BD is disclosed. However, this approach requires multiple switches. Therefore, a large circuit ...

AI Technical Summary

Problems solved by technology

However, this approach requires multiple switch

Therefore, a large circuit area is required

Also, this method uses series-connected MOS transistors, so there is a high on-state resistance across the MOS transistors in the steady output state, resulting in inefficiency

[0004] Another approach shown in Figure 10 is to connect the back gate of the MOS transistor 910 to the reference potential so that the body diode BD cannot be formed

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