One example discloses an inductive power supply device, comprises: an inductive coupler including a resonant circuit having a first resonant state in response to an object at a first distance from the inductive power supply, and a second resonant state in response to the object at a second distance from the inductive power supply; a driver circuit coupled to send a first power-level to the inductive coupler when in a charge-object state and to send a second power-level to the inductive coupler when in a detect-object state, wherein the second power-level is less than the first power-level; and an object detector coupled to detect the first and second resonant states and place the driver circuit in the charge-object state in response to the first resonant state, and place the driver circuit in the detect-object state in response to the second resonant state.