公开(公告)号：US20220214765A1

公开(公告)日：2022-07-07

申请号：US17141483

申请日：2021-01-05

Applicant: Synaptics Incorporated

Inventor： Chunbo LIU ,  Selim GUNCER ,  Osman Emir EROL ,  Jonathan KU

IPC: G06F3/044 ,  H03F3/45 ,  G01D5/241

Abstract: A method and apparatus of global coarse baseline correction (GCBC) for capacitive scanning. An input device may include a number (N) of sensor electrodes, a GCBC circuit, and detection circuitry. Each sensor electrode is associated with a respective channel. The GCBC circuit produces sensing signals in each of the N channels and the detection circuitry may detect changes in the capacitances of one or more sensor electrodes based on the sensing signals. In some implementations, the GCBC circuit may include a current source which outputs a first current, a transimpedance amplifier (TIA) which converts the first current to a sensing voltage, and a number (N) of resistors that can be coupled between the output of the TIA and the N sensor electrodes, respectively. The coupling of each resistor between the TIA and a respective sensor electrode produces a sensing signal in the channel associated with the sensor electrode.