The invention relates to a
converter circuit comprising at least one phase module (100) having an upper and a lower converter valve (T1, ..., T6), wherein each converter valve (Tl, ..., T6) has at least one two-pole subsystem. According to the invention, each two-pole subsystem (14) has four
semiconductor switches (21, 23, 25, 27), which can be switched off and are connected electrically in series, four diodes (22, 24, 26, 28), which are each connected electrically back-to-back in parallel with one
semiconductor switch (21, 23, 25, 27) which can be switched off, two unipolar storage capacitors (29, 30), which are connected electrically in series and in parallel with the series circuit comprising the
semiconductor switches (21, 23, 25, 27), and an electronic
system (32), whose reference potential connection (M) is electrically conductively connected to a common potential (P0).; This results in a subsystem (14), at whose connection terminals (X2, Xl) it is possible to generate a
terminal voltage (UX21) having four potential stages, which requires only one electronic
system (32), whose
energy supply takes place symmetrically, and which does not require any increased complexity in terms of potential isolation.