US 12,407,348 B2
Touch detection circuit and operation device
Fu-Chiang Chuang, Hsinchu (TW); and Chieh-Sheng Tu, Hsinchu Science Park (TW)
Assigned to NUVOTON TECHNOLOGY CORPORATION, Hsinchu Science Park (TW)
Filed by Nuvoton Technology Corporation, Hsinchu Science Park (TW)
Filed on May 22, 2023, as Appl. No. 18/321,184.
Claims priority of application No. 111136663 (TW), filed on Sep. 28, 2022.
Prior Publication US 2024/0106433 A1, Mar. 28, 2024
Int. Cl. H03K 17/00 (2006.01); G06F 3/023 (2006.01); G06F 3/044 (2006.01); H03K 17/96 (2006.01)
CPC H03K 17/962 (2013.01) [G06F 3/023 (2013.01); G06F 3/044 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A touch detection circuit for detecting whether a key is being touched, comprising:
a comparator comprising an inverting input, a non-inverting input, and an output terminal;
a compensation capacitor coupled to the inverting input;
a first processing circuit adjusting the capacitance of the compensation capacitor according to a voltage level of the output terminal; and
a voltage control circuit providing an output voltage to the non-inverting input,
wherein in a calibration mode, the voltage control circuit adjusts the output voltage according to the voltage level of the output terminal.