A galvanically isolated dc-dc converter circuit comprising a galvanic isolation barrier comprising an isolation transformer configured to transmit a power signal, said dc-dc converter circuit comprising a power oscillator with resonant load connected to a first winding of said isolation transformer and configured to output an always present alternate voltage (V i) which amplitude is regulated by a control voltage (V CTRL) to said isolation transformer, and n≥1 data communication channels (DT; OUT) on which a stream of data (P, D1...Dn) is to be conveyed through said galvanic isolation barrier by modulating the power signal, comprising a transmitter configured to perform an amplitude modulation of said power signal at a secondary winding of said isolation transformer by causing a mismatch of said resonant load, a rectifier connected to the secondary winding of the isolation transformer configured to obtain an output DC voltage (V o) by rectifying the received power AC signal on said second winding characterized in that said galvanically isolated dc-dc converter circuit further includes a comparator configured to receive as input said output DC voltage (V o) and a reference voltage value (REF; V REF) and to produce a voltage error signal (ε), an analog to digital converter configured to convert said error signal (ε) in a digital power control value and a multiplexer configured to multiplex together said digital power control value with said n-channel data obtaining a multiplexed bitstream, a transmitter configured to perform the amplitude modulation of said power signal driven by said multiplexed bitstream, a receiver connected to the first winding configured to demodulate the amplitude modulated signal at such first winding, a demultiplexer configured to demultiplex said n-data channels (D1...Dn) and digital power control value, a digital to analog converter configured to convert the digital power control value in an analog control signal and to supply said analog control signal as said control voltage (V CTRL) of the power oscillator for power regulation. a transmitter configured to perform an amplitude modulation of said power signal at a secondary winding of said isolation transformer by causing a mismatch of said resonant load, a rectifier connected to the secondary winding of the isolation transformer configured to obtain an output DC voltage (V o) by rectifying the received power AC signal on said second winding characterized in that said galvanically isolated dc-dc converter circuit further includes a comparator configured to receive as input said output DC voltage (V o) and a reference voltage value (REF; V REF) and to produce a voltage error signal (ε), an analog to digital converter configured to convert said error signal (ε) in a digital power control value and a multiplexer configured to multiplex together said digital power control value with said n-channel data obtaining a multiplexed bitstream, a transmitter configured to perform the amplitude modulation of said power signal driven by said multiplexed bitstream, a receiver connected to the first winding configured to demodulate the amplitude modulated signal at such first winding, a demultiplexer configured to demultiplex said n-data channels (D1...Dn) and digital power control value, a digital to analog converter configured to convert the digital power control value in an analog control signal and to supply said analog control signal as said control voltage (V CTRL) of the power oscillator for power regulation.