Patent ID: 9697410
Date: 2017-07-04
CPC Classifications: G06K,H01L

Claim:
1. A capacitive fingerprint sensor comprising: a capacitive sensing array comprising a plurality of sensing units arranged in an array, wherein the capacitive sensing array individually outputs sensing signals measured by each the sensing unit; a row decoder and a column decoder electrically connected with the capacitive sensing array to address each the sensing unit; a compensation memory storing a direct current offset parameter and a gain compensation parameter of each the sensing unit; a controller electrically connected with the row decoder, the column decoder and the compensation memory, wherein the controller controls the capacitive sensing array to individually output the sensing signals measured by each the sensing unit and controls the compensation memory to output the direct current offset parameter and the gain compensation parameter corresponding to the sensing unit; a digital to analog converter electrically connected with the compensation memory and outputting a direct current offset compensation signal according to the direct current offset parameter; and a compensation circuit electrically connected with the capacitive sensing array, the compensation memory and the digital to analog converter and individually compensating the sensing signals measured by each the sensing unit to output compensated sensing signals according to the direct current offset compensation signal and the gain compensation parameter; wherein the compensation memory comprising: an external memory electrically connected with the controller and storing the direct current offset parameter and the gain compensation parameter of each the sensing unit; and a register electrically connected with the controller, the digital to analog converter and the compensation circuit and storing the direct current offset parameter and the gain compensation parameter of part of the sensing units, wherein the external memory and the register are arranged on the different dies.