Charging unit for charging energy storage device of e.g. mobile radio telephone, has evaluation circuit to provide degree of detuning in frequency or phase detuning representing signal for processing from which object is determined

摘要

The charging unit has a sensor coil arrangement (SSA) attached with a sensor coil (LS) that is fixed close to a field-generating coil (LP) of a controllable resonance circuit (Cp). An evaluation circuit (AS) is adapted to detect frequency or phase imbalance of the sensor coil arrangement and to provide degree of detuning the frequency or phase detuning to represent a signal for processing from which the presence and/or location of frequency or phase upset-inducing object is determined.