A power transmission device for inductive energy transfer, wherein the power transmission device comprises: a first stage adapted to be connected to a supply input voltage and adapted to convert the supply input voltage to an operating voltage; a second stage including a resonant circuit connected to the first stage and adapted to generate an oscillating voltage from the operating voltage so as to generate a magnetic field for inductive transfer of energy from the power transmission device to a target device; a control circuit connected to the second stage, the control circuit being adapted to detect a parameter value of the second stage, the detected parameter indicating whether the target device is being recharged or not, and adapted to start or stop amplification of the resonant circuit based on the detected parameter value; characterised in that the resonant circuit is composed by the parallel connection of a capacitor with a winding of a transfer coil L1 and a magnetically coupled sensing coil L2, both coils L1, L2 being wound around a core and serving as primary coils for inductively transferring energy to a target device including a secondary coil, and the control circuit is adapted to detect the parameter of the sensing coil L2; in that the second stage further includes a switching element connected to the resonant circuit, the switching element being adapted to amplify the oscillations of the resonant circuit so as to start or stop amplification of the resonant circuit; and in that the control circuit is adapted to detect an oscillation voltage value of the sensing coil L2 of the resonant circuit and to switch the switching element in-phase with the oscillations of the resonant circuit so as to amplify the oscillation of the resonant circuit, the switching of the switching element being performed as zero-voltage switching amplification of the resonant circuit. a first stage adapted to be connected to a supply input voltage and adapted to convert the supply input voltage to an operating voltage; a second stage including a resonant circuit connected to the first stage and adapted to generate an oscillating voltage from the operating voltage so as to generate a magnetic field for inductive transfer of energy from the power transmission device to a target device; a control circuit connected to the second stage, the control circuit being adapted to detect a parameter value of the second stage, the detected parameter indicating whether the target device is being recharged or not, and adapted to start or stop amplification of the resonant circuit based on the detected parameter value; characterised in that the resonant circuit is composed by the parallel connection of a capacitor with a winding of a transfer coil L1 and a magnetically coupled sensing coil L2, both coils L1, L2 being wound around a core and serving as primary coils for inductively transferring energy to a target device including a secondary coil, and the control circuit is adapted to detect the parameter of the sensing coil L2; in that the second stage further includes a switching element connected to the resonant circuit, the switching element being adapted to amplify the oscillations of the resonant circuit so as to start or stop amplification of the resonant circuit; and in that the control circuit is adapted to detect an oscillation voltage value of the sensing coil L2 of the resonant circuit and to switch the switching element in-phase with the oscillations of the resonant circuit so as to amplify the oscillation of the resonant circuit, the switching of the switching element being performed as zero-voltage switching amplification of the resonant circuit.