A pulse width modulated switch mode DC-DC boost converter comprising at least one first electronic circuit on an input side and a second electronic circuit on an output side, the input side and the output side being coupled via at least two power transformers (T1, T2), each power transformer (T1, T2) comprising a first winding (T1a, T2a) arranged in an input side converter stage (3, 4) on the input side and a second winding (T1 b, T2b) arranged in an output side converter stage on the output side, each of the windings (T1a, Tib, T2a, T2b) having a first end and a second end, wherein the first electronic circuit comprising: - terminals (A0, A1) for connecting a source or a load, at least one energy storage inductor (L1, L2) coupled in series with at least one of the first windings (T1 a, T2a) of the power transformers (T1, T2), - for each power transformer (T1, T2), an arrangement of switches (S1, S2, S3, S4), (S5, S6, S7, S8) being adapted to switch the current through the first winding (T1a, T2a) between a first ON-state, a first OFF-state, a second ON-state with a polarity opposite to the first ON-state, and a second OFF-state, and wherein the at least one energy storage inductor (L1, L2)) is arranged so as to be charged, when all switches of the switching arrangements (S1, S2, S3, S4), (S5, S6, S7, S8) are conducting, and the second electronic circuit comprising: - terminals (BO, B1) for connecting a load or a source, - a single arrangement of switches (D1, D2, D3, D4) being adapted to switch the current through the second windings (T1b, T2b) of the power transformers (T1, T2) between a first ON- state, a first OFF-state, a second ON-state with a polarity opposite to the first ON-state, and a second OFF-state, and/or being adapted to provide rectified current to the terminals (BO, B1), and wherein the second windings (T1b, T2b) of the power transformers (T1, T2) are connected in series and coupled via the single arrangement of switches (D1, D2, D3, D4) of the second circuit to the terminals (BO, B1) of the output side. - terminals (A0, A1) for connecting a source or a load, at least one energy storage inductor (L1, L2) coupled in series with at least one of the first windings (T1 a, T2a) of the power transformers (T1, T2), - for each power transformer (T1, T2), an arrangement of switches (S1, S2, S3, S4), (S5, S6, S7, S8) being adapted to switch the current through the first winding (T1a, T2a) between a first ON-state, a first OFF-state, a second ON-state with a polarity opposite to the first ON-state, and a second OFF-state, and wherein the at least one energy storage inductor (L1, L2)) is arranged so as to be charged, when all switches of the switching arrangements (S1, S2, S3, S4), (S5, S6, S7, S8) are conducting, - terminals (BO, B1) for connecting a load or a source, - a single arrangement of switches (D1, D2, D3, D4) being adapted to switch the current through the second windings (T1b, T2b) of the power transformers (T1, T2) between a first ON- state, a first OFF-state, a second ON-state with a polarity opposite to the first ON-state, and a second OFF-state, and/or being adapted to provide rectified current to the terminals (BO, B1), and wherein