US 11,768,558 B2
Touch sensing circuit and its method for sensing multi-frequency signals
Kyu Tae Lee, Daejeon (KR); Mun Seok Kang, Daejeon (KR); Jae Hwan Lee, Daejeon (KR); Jeong Kwon Nam, Daejeon (KR); Hyun Soo Chung, Daejeon (KR); Jin Yoon Jang, Daejeon (KR); Hee Ra Yun, Daejeon (KR); and Yeon Ju Yu, Daejeon (KR)
Assigned to LX SEMICON CO., LTD., Daejeon (KR)
Filed by LX Semicon Co., Ltd., Daejeon (KR)
Filed on Dec. 15, 2021, as Appl. No. 17/552,270.
Claims priority of application No. 10-2020-0179469 (KR), filed on Dec. 21, 2020.
Prior Publication US 2022/0197468 A1, Jun. 23, 2022
Int. Cl. G06F 3/044 (2006.01); G06F 3/041 (2006.01)
CPC G06F 3/04166 (2019.05) [G06F 3/0441 (2019.05); G06F 3/0442 (2019.05)] 13 Claims
OG exemplary drawing
 
1. A touch sensing circuit comprising:
an analog signal processing circuit configured to receive a plurality of sensing signals having different frequencies from touch electrodes in a same period, the plurality of sensing signals including a first sensing signal corresponding to a driving signal of a touch panel and a second sensing signal corresponding to a downlink signal of a stylus pen; and
a digital signal processing circuit configured to receive output data of the analog signal processing circuit and to perform a discrete Fourier transform with respect to the output data,
wherein the digital signal processing circuit separates the first signal having a frequency of the driving signal of the touch panel and the second signal having a frequency of the downlink signal of the stylus pen by the discrete Fourier transform, wherein the frequency of the first signal and the frequency of the second signal are different.