Abstract: A power supply arrangement comprises a primary side and a secondary side. There is a power transformer between the primary side and the secondary side. On the primary side certain switching means are arranged to repeatedly switch, at a certain frequency, an electric current coupled into the power transformer for cyclically transferring energy from the primary side to the secondary side at said certain frequency. A wireless feedback link exists between the primary side and the secondary side. On the secondary side there are feedback pulse generating means for generating feedback pulses at a certain frequency to be transferred from the secondary side to the primary side over the wireless feedback link. On the primary side there are means for utilizing the feedback pulses in controlling the rate at which energy is transferred from the primary side to the secondary side.

Abstract: The invention concerns a charger (CU) for batteries (A) in an electrical mobile device (MU), wherein a power oscillator (OSZ) produces an alternating magnetic field with the primary part (W.sub.PRI) of an inductive coupler, for the inductive transmission of charging power. By alternatingly receiving power for charging the batteries (A), the mobile device (MU) which is coupled to the charger (CU), charges the entire inductive coupler via its secondary coupler part (W.sub.SEC). The charger (CU) contains detection means (SEL, AMP, RE and FE-DEM) which generate at least one control signal (S.sub.C 1, S.sub.C 2) when the inductive load of the coupler is periodically changed in order to switch the power level, which is inductively transmitted by the charger (CU) to the mobile device (MU), from a low average value in the stand-by mode to a higher average value for the charging operation.

Abstract: A device for charging batteries is comprised of a mobile electrical device MD and a charging unit CU and inductively transmits electrical power by means of a alternating magnetic field from at least one primary winding W1, W2 to at least one secondary winding W3, W4 in the mobile device MD. According to the invention, the alternating magnetic field is generated by a self-oscillating push-pull oscillator which contains switches Q1, Q2 that are reciprocally connected with positive feedback and in each push-pull branch, contains a resonance circuit with the effective inductance of at least one primary winding W1 or W2 and with a circuit capacitance C1, C3 or C2, C4, wherein the primary windings W1 and W2 in the charging unit CU are disposed spatially separate from each other so that each generates a magnetic alternating field in a different spatial region and the secondary windings W3, W4 in the mobile device are disposed so that each spatial region is equally loaded.

Abstract: The invention relates to a method and a circuit to control the output voltage and current of a switched-mode power supply. In order to restrict the output current, a voltage value proportional to the primary current of a switched-mode power supply is measured and compared to a variable reference voltage U.sub.ext the value of which is determined by the total effect of the constant charging current of a capacitor C.sub.ext and a discharge circuit operating in step with the secondary diode of the power supply. If the voltage value proportional to the primary current is bigger than said reference voltage, the switching pulses of the primary current switch are shortened. In order to restrict the output voltage, an image voltage is generated for the secondary voltage of the power supply transformer which is filtered and rectified and combined with the aforementioned reference voltage in order to produce pulse-width-modulated switching pulses of the primary current switch.

Abstract: Thus far a substantial amount of energy was required for the two coils for the dynamic line frequency convergence in a device for radial, static and dynamic convergence. So as to improve this situation, a magnetic bridge is arranged between the two legs of a U-shaped electromagnet forming part of the convergence device, the magnetic resistance of this bridge being comparatively small in the magnetic circuit of the coils for the dynamic line frequency convergence and comparatively large in the magnetic circuit of the coils for the static and field frequency convergence.