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Method for determining active input elements of an input arrangement and input arrangement

  • US 9,876,510 B2
  • Filed: 02/21/2014
  • Issued: 01/23/2018
  • Est. Priority Date: 02/28/2013
  • Status: Active Grant
First Claim
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1. A method for determining active input elements (S1a, S2a) of input elements (S1a to S2b) of an input arrangement (10), comprising:

  • providing the input elements (S1a to S2b) such that they are connected according to a matrix arrangement (Ma),providing within the matrix arrangement (Ma) at least two drive lines (L1, L2) that are each connected to a respective driving circuit (2, 4),providing within the matrix arrangement (Ma) at least two sense lines (Ca, Cb) that are used to detect the active input elements (S1a, S2a),providing within the matrix arrangement (Ma) serial connections (SC1 to SC4) each comprising a respective input element (S1a to S2b) of the input elements (S1a to S2b) and a resistor (R1a to R2b) and each of the serial connections (SC1 to SC4) being connected to a respective one of the drive lines (L1, L2) and to a respective one of the sense lines (Ca, Cb),providing pull resistors (Ra, Rb) that connect the sense lines (Ca, Cb) to a first potential, andusing a control device and the driving circuits (2, 4) to selectively activate by driving a first drive line (L1) of the at least two drive lines (L1, L2) to a second potential that is different from the first potential and to selectively activate by driving a second drive line (L2) or other respective drive lines of the at least two drive lines (L1, L2) to the first potential or to a potential having an absolute offset value from the first potential that is at most 50 percent of the absolute value of the difference of the first potential and of the second potential,the method further comprising;

    activating the first drive line (L1) of the at least two drive lines (L1, L2), wherein only one drive line (L1, L2) of the at least two drive lines (L1, L2) is active at one time,detecting a first value of an electrical signal on a first sense line (Ca) of the at least two sense lines (Ca, Cb) during activating the first drive line (L1), anddetermining the respective activated input element (S1a, S2a) of the input elements (S1a to S2b) in the respective serial connection (SC1, SC2) of the serial connections (SC1 to SC4) between the first drive line (L1) and the first sense line (Ca) due to an undershoot or due to exceeding of a threshold value (SW) by the first value,whereby the threshold value (SW) is independent of a number of the active input elements (S1a, S2a) or independent of at least two, three or four different numbers of the active input elements (S1a, S2a) on the first sense line (Ca) and/or on the other sense lines (Ca, Cb) of the at least two sense lines (Ca, Cb),wherein the matrix arrangement (Ma) comprises a calibration line (Ccc),whereby reference resistors (R1cc, R2cc) are connected to the calibration line (Ccc) and to each of the at least two drive lines (L1, L2) respectively, andwherein the method comprises;

    detecting a calibration value using the calibration line (Ccc),using the calibration value to determine the threshold value (SW), andwhereby the calibration line (Ccc) is connected to the first potential by a further pull resistor (Rcc).

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