Invention Grant
- Patent Title: Method and device for reducing radio frequency interference of proximity and touch detection in mobile devices
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Application No.: US14530156Application Date: 2014-10-31
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Publication No.: US09864464B2Publication Date: 2018-01-09
- Inventor: Chaouki Rouaissia , Eric Vandel
- Applicant: Semtech Corporation
- Applicant Address: US CA Camarillo
- Assignee: Semtech Corporation
- Current Assignee: Semtech Corporation
- Current Assignee Address: US CA Camarillo
- Agency: Patent Law Group: Atkins and Associates, P.C.
- Agent Brian M. Kaufman; Robert D. Atkins
- Main IPC: G09G5/00
- IPC: G09G5/00 ; G06F3/041 ; G06F3/044 ; H01Q1/24 ; H01Q1/44 ; H03K17/955

Abstract:
A proximity sensor has a sensing node. A radio frequency signal is received at the sensing node. The radio frequency signal is coupled to an intermediate node through a first capacitor. The radio frequency signal is coupled from the intermediate node to a ground node through a second capacitor. An RF amplifier is coupled to the sensing node. The radio frequency signal is generated using the RF amplifier. A third capacitor is coupled between the RF amplifier and the sensing node. An antenna is coupled to the sensing node. The radio frequency signal is transmitted using the antenna. A capacitance of the antenna is measured using the proximity sensor. The capacitance of the antenna is compared to a threshold to determine proximity of a conductive object. An inductor is coupled between the sensing node and the antenna. A shielding area is coupled to the intermediate node.
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