Patent ID: 8120487
Filing Date: 2012-02-21
Classification: G06F,H04B,H04W,Y02D

Abstract:
1. A wireless input device, comprising: an antenna; a radio frequency identification (RFID) transponder, for receiving an AC signal via the antenna; a first power supply unit, coupled to the RFID transponder; a sensing unit, powered by the first power supply unit only, for generating an input signal to the RFID transponder; wherein, the RFID transponder, which is powered only by the AC signal in a first mode and powered by the AC signal and the first power supply unit in a second mode, demodulates the AC signal to generate a request signal, and performs load modulation according to the input signal to generate a reply signal in response to the request signal, followed by transmitting the reply signal via the antenna, and a second power supply unit, coupled to the RFID transponder and the sensing unit, receiving no power from the AC signal in the first mode and the second mode, wherein the RFID transponder and the sensing unit are powered by the AC signal, the first power supply unit and the second power unit in a third mode, wherein energy of the first power supply is consumed before energy of the second power supply in the third mode.