Patent ID: 8487908

Claim:
A detector circuit of a capacitive touch panel having a plurality of traces, the detector circuit comprising: an analog-to-digital converter for converting an analog signal of a selected trace taken from the plurality of traces to a digital value, the selected trace selected m times to generate m digital values, where m is a natural number; a low-pass filter connected to the analog-to-digital converter, the low-pass filter including: m+n registers for storing the m digital values sequentially, where n is a natural number; and an arithmetic unit connected to the m+n registers; and a threshold comparator connected to the low-pass filter for comparing the first m digital values in the m+n registers with a threshold value, wherein when the m digital values are below the threshold value, the threshold comparator triggers an abort signal for aborting detection of the selected trace prior to a shifting of the digital values of said selected trace to said n registers in said m+n registers, whereby said analog-to-digital converter shifts to a next selected trace of said plurality of traces; and when the m digital values are above the threshold value, the analog-to-digital converter further detects the selected trace for n times to generate n digital values, said n digital values not compared with said threshold value before being stored into said m+n registers for the arithmetic unit to average the m+n digital values.