Semiconductor device

Abstract

First and second external terminals are connected to high-voltage and low-voltage terminals, respectively, of a direct-current voltage source circuit in which first and second direct-current voltage sources are connected in series. A third external terminal is connected to a connecting point between the first and second direct-current voltage sources. A first switching element is connected between the first and fourth external terminals. A second switching element is connected between the fourth and second external terminals. A first AC switch unit includes third and fourth switching elements connected in inverse series between the third and fourth external terminals. A second AC switch unit includes fifth and sixth switching elements connected in inverse series between the third and fourth external terminals. The first and second AC switch units are connected in parallel. The first and second switching elements and the first and second AC switch units are incorporated in one module.

What is claimed is: 
     
         1 . A semiconductor device comprising:
 first and second external terminals connected to a high-voltage terminal and a low-voltage terminal, respectively, of a direct-current voltage source circuit in which first and second direct-current voltage sources are connected in series;   a third external terminal connected to a connecting point between the first and second direct-current voltage sources;   a fourth external terminal;   a first switching element connected between the first external terminal and the fourth external terminal;   a second switching element connected between the fourth external terminal and the second external terminal;   a first AC switch unit including third and fourth switching elements connected in inverse series connection with each other between the third external terminal and the fourth external terminal; and   a second AC switch unit including fifth and sixth switching elements connected in inverse series connection with each other between the third external terminal and the fourth external terminal,   wherein the first and second AC switch units are connected in parallel with each other, and   the first and second switching elements and the first and second AC switch units are incorporated in one module.   
     
     
         2 . The semiconductor device according to  claim 1 , further comprising first to sixth diodes connected in inverse parallel connection with the first to sixth switching elements respectively.