| 摘要 |
PURPOSE: A charge quantity sensing device of a multi touch panel is provided to secure a dynamic range of a system to the max and to guarantee enough sensitivity even in a small charge quantity change while minimizing low frequency noise which is generated by a touch of a panel and conductive material as well as noise which is included in a signal. CONSTITUTION: A charge quantity sensing device(100) of a multi touch panel includes a signal delivering unit(110) which outputs a sensing signal which includes data about a sampling point to a corresponding input terminal among input terminals of a capacitance sensor in response to an input selection signal; the capacitance sensor(120) which includes multiple output terminals which successively and repeatedly output a first charge quantity which has a positive value and a second charge quantity which has a negative value which are sensed in response to a sensing signal which is received through a corresponding input terminal; a signal receiving unit(130) which outputs first accumulated voltages and second accumulated voltages in parallel by sampling and accumulating the first charge quantities and the second charge quantities which are outputted from the output terminals of the capacitance sensor and controlling a gain; a noise removing unit(140) which outputs voltage differences in which a generated low frequency noise is removed in case a conductive material touches a multi touch panel by calculating the voltage difference of the first accumulated voltage and the second accumulated voltage which correspond by successively receiving the first accumulated voltages and the second accumulated voltages; a MUX(155) which successively selects voltage differences which are outputted in parallel one by one and outputs the voltage differences; and an AD[analog to digital]converter(150) which converts the voltage difference which is successively outputted from the MUX into a digital signal and successively outputs the digital signal. [Reference numerals] (110) Signal delivering unit; (131_1,131_k) Sampling unit; (133_1,133_k) First charge amount accumulating unit; (134_1,134_k) Second charge amount accumulating unit; (135) Gain control unit; (143) CDS control unit; (145_1,145_k) CDS unit |
