CAPACITIVE TOUCH SYSTEM AND FREQUENCY SELECTION METHOD THEREOF

摘要

There is provided a capacitive touch system including a touch panel, a plurality of amplification units, a plurality of anti-aliasing filters and a control unit. The touch panel includes a plurality of driving electrodes and a plurality of sensing electrodes configured to form inductive capacitance. The amplification units have a high-pass cutoff frequency. The anti-aliasing filters have a low-pass cutoff frequency. The control unit is configured to control the high-pass cutoff frequency and the low-pass cutoff frequency to form an equivalent bandpass filter in a frequency scanning interval and adjust a center frequency of the equivalent bandpass filter to correspond to a plurality of predetermined driving frequencies.

主权项

1. A capacitive touch system comprising:
a touch panel comprising a plurality of driving electrodes and a plurality of sensing electrodes configured to form inductive capacitance; a driving unit, coupled to one of the driving electrodes, configured to output a driving signal at one of a plurality of predetermined driving frequencies in a driving interval and not output the driving signal to the driving electrode coupled thereto in a frequency scanning interval; a plurality of amplification units, respectively coupled to the sensing electrodes, configured to amplify a detecting signal outputted by the sensing electrode coupled thereto, and having a high-pass cutoff frequency; a plurality of filters, respectively coupled to the amplification units, configured to output an amplified and filtered detecting signal, and having a low-pass cutoff frequency; and a scan control unit configured to
control the high-pass cutoff frequency and the low-pass cutoff frequency in the frequency scanning interval to form an equivalent bandpass filter, andadjust a center frequency of the equivalent bandpass filter to correspond to the predetermined driving frequencies.