US 12,340,053 B2
Touch sensing system
Hua Liu, Shanghai (CN); Dingfei Zhu, Shanghai (CN); and Jianjun Wang, Shanghai (CN)
Assigned to SHANGHAI HYNITRON TECHNOLOGY CO., LTD., Shanghai (CN)
Appl. No. 18/696,930
Filed by Shanghai Hynitron Technology Co., Ltd., Shanghai (CN)
PCT Filed Aug. 14, 2023, PCT No. PCT/CN2023/112835
§ 371(c)(1), (2) Date Mar. 28, 2024,
PCT Pub. No. WO2024/192958, PCT Pub. Date Sep. 26, 2024.
Claims priority of application No. 202310265136.4 (CN), filed on Mar. 20, 2023.
Prior Publication US 2025/0130672 A1, Apr. 24, 2025
Int. Cl. G06F 3/044 (2006.01); G01D 5/24 (2006.01); G06F 3/041 (2006.01); H03K 17/96 (2006.01)
CPC G06F 3/044 (2013.01) [G01D 5/24 (2013.01); G06F 3/0416 (2013.01); H03K 17/962 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A touch sensing system, comprising a detected capacitor Cm, a transmitting electrode and a receiving electrode of a sensor being arranged at two ends of the detected capacitor Cm, one end of the detected capacitor Cm corresponding to the receiving electrode being connected to a modulation module via a GM module, an excitation signal being input from the transmitting electrode, the GM module converting a charge transferred to the receiving electrode into a current and outputting same to the modulation module, and the modulation module performing integration and modulation according to the current to obtain an output parameter characterizing the detected capacitor Cm;
the modulation module comprising: an integrating capacitor C1, a current source IMS_SNK, a current source IMS_SRC, a comparator CMP and a current source ICOM, the output of the GM module being connected to one end of the integrating capacitor C1, the other end of the integrating capacitor C1 being grounded, the current source IMS_SNK being connected to one end of the integrating capacitor C1 through a switch SW1, and the current source IMS_SRC being connected to one end of the integrating capacitor C1 through a switch SW3, one end of the integrating capacitor C1 being also connected to a positive input terminal of the comparator CMP, a negative input terminal of the comparator CMP being connected to a reference voltage Vref, and an output signal of the comparator CMP being used for controlling the turning off or disconnecting of the switch SW1 and the switch SW3;
a current value of the current source IMS_SNK being equal to that of the current source IMS_SRC, being equal to a current value IMS;
the current source ICOM being connected to one end of the integrating capacitor C1 through a switch SW0, at the beginning of each cycle of the excitation signal of the transmitting electrode, the current source ICOM at to being turned on to compensate; an amplitude of the excitation signal of the transmitting electrode being VTX, a voltage at the positive input terminal of the comparator CMP being Vcap; when Vcap is greater than Vref by a threshold, the current source IMS_SNK releasing the charge transferred to the integrating capacitor C1, so that M*VTX*Cm=ICOM*t0+IMS*t1, where t1 is the time the quantized output of the comparator CMP is logic high—the time the quantized output is logic low during the measurement cycle time tm, and M is an amplitude modulation coefficient of the GM module.