Patent ID: 11954286
Assignee: SHENZHEN GOODIX TECHNOLOGY CO., LTD.
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 17:
18. A method for self-capacitor sensing in a touch panel array integrated with a display panel, the touch panel array having a plurality of channels, each having a respective channel self-capacitance that includes a respective base self-capacitance corresponding to display noise capacitively coupled onto the channel from the display panel and a respective touch capacitance that changes responsive to presence of a touch event local to the channel, the method comprising:
charging, in a first phase of a readout cycle, a voltage input (Vin) node to a charged voltage level, the Vin node being coupled with a channel of the plurality of channels, such that a voltage at the Vin node relates to a voltage across the respective self-capacitance (Ci) of the channel coupled thereto;
generating a locally noise-suppressed discharge current (Iout) by iterating sequentially through M configurations of M current sources, M being an integer greater than 1, and in each mth configuration of the M configurations, generating the Iout based on a sum of currents through M−1 of the M current sources other than an mth of the M current sources;
discharging, in a second phase of the readout cycle following the first phase, the Vin node with the Iout for a discrete discharge time, thereby discharging the Vin node to a discharge voltage level that is a first voltage level in absence of a touch event local to the channel and is a second voltage level in presence of the touch event local to the channel; and
outputting, in a third phase of the readout cycle following the second phase, a voltage output (Vout) for the channel by passively mixing at least the discharge voltage level to produce a pair of up-converted channel signals, sampling the pair of up-converted channel signals to obtain a differential voltage sample, and amplifying the differential voltage sample to generate the Vout as indicating absence or presence of the touch event local to the channel.