A switch-mode power converter for converting an input voltage from an input source to an output voltage for supply to a load coupled to converter load terminals, the power converter comprising: a power isolation transformer (T 3; T 10; T 12) further comprising a magnetic core having a center leg and outer legs, one or more primary windings (N P2; N 10), and one or more secondary windings (N S1, N S2; N 11) of the power isolation transformer wound on the center leg; a primary converter circuit comprising one or more primary controllable power switches (Q 1, Q 2; Q 10, Q 11) effective to supply the input voltage to one or more of the primary windings (N P2; N 10) of the power isolation transformer (T 3; T 10; T 12); a secondary converter circuit fully isolated from the primary converter circuit and comprising one or more secondary switches (S 1, S 2; Q 20, Q 21) being individually switchable and further coupled between the one or more secondary windings (N S1, N S2; N 11) and the load terminals; a primary switch control circuit effective to control conduction of the one or more primary controllable power switches (Q 1, Q 2; Q 10, Q 11); a secondary switch control circuit effective to control conduction of the one or more secondary switches (S 1, S 2; Q 20, Q 21); and a control circuit effective to control operation of the primary switch control circuit and of the secondary switch control circuit based at least in part on a feedback signal, characterised by a drive transformer (T 3; T 10; T 12) comprising two or more drive transformer windings (N 1, N 2, N 3; N 12, N 13; 100, 101) wound entirely on one outer leg of the magnetic core, the two or more drive transformer windings configured to provide power for controlling the primary controllable power switches (Q 1, Q 2; Q 10, Q 11), the drive transformer windings further configured to provide isolation between the primary and secondary switch control circuits (31, 32), wherein the windings (N 1, N 2, N 3; N 12, N 13; 100, 101) of the drive transformer are tightly coupled with each other on said one outer leg, and further loosely coupled with the windings (N P2, N S1, N S2; N 10, N 11) of the power transformer, and wherein the control circuit is arranged to generate voltage waveforms in the secondary windings (N 3; N 12; 101) of the drive transformer for a short period of time sufficient to initiate turn-on or turn-off of the primary controllable power switches coupled to the power isolation transformer. a power isolation transformer (T 3; T 10; T 12) further comprising a magnetic core having a center leg and outer legs, one or more primary windings (N P2; N 10), and one or more secondary windings (N S1, N S2; N 11) of the power isolation transformer wound on the center leg; a primary converter circuit comprising one or more primary controllable power switches (Q 1, Q 2; Q 10, Q 11) effective to supply the input voltage to one or more of the primary windings (N P2; N 10) of the power isolation transformer (T 3; T 10; T 12); a secondary converter circuit fully isolated from the primary converter circuit and comprising one or more secondary switches (S 1, S 2; Q 20, Q 21) being individually switchable and further coupled between the one or more secondary windings (N S1, N S2; N 11) and the load terminals; a primary switch control circuit effective to control conduction of the one or more primary controllable power switches (Q 1, Q 2; Q 10, Q 11); a secondary switch control circuit effective to control conduction of the one or more secondary switches (S 1, S 2; Q 20, Q 21); and a control circuit effective to control operation of the primary switch control circuit and of the secondary switch control circuit based at least in part on a feedback signal, characterised by a drive transformer (T 3; T 10; T 12) comprising two or more drive transformer windings (N 1, N 2, N 3; N 12, N 13; 100, 101) wound entirely on one outer leg of the magnetic core, the two or more drive transformer windings configured to provide power for controlling the primary controllable power switches (Q 1, Q 2; Q 10, Q 11), the drive transformer windings further configured to provide isolation between the primary and secondary switch control circuits (31, 32), wherein the windings (N 1, N 2, N 3; N 12, N 13; 100, 101) of the drive transformer are tightly coupled with each other on said one outer leg, and further loosely coupled with the windings (N P2, N S1, N S2; N 10, N 11) of the power transformer, and wherein the control circuit is arranged to generate voltage waveforms in the secondary windings (N 3; N 12; 101) of the drive transformer for a short period of time sufficient to initiate turn-on or turn-off of the primary controllable power switches coupled to the power isolation transformer.