The touch panel includes a panel capacitor, a first circuit, a first capacitor, a second circuit and a controlling circuit. The first capacitor is coupled to the panel capacitor. The first circuit transmits a scan signal to the panel capacitor. The second circuit transmits an inverting signal to the first capacitor. The inverting signal is synchronized with the scan signal, a frequency of the inverting signal is identical to a frequency of the scan signal, and the inverting signal is phase-inverted from the scan signal. The controlling circuit outputs a touch signal in response to a voltage at a terminal of the panel capacitor, in which the touch signal is configured to estimate a capacitance of the panel capacitor.