An touch input electronic device includes: a touch input device; a clock generation circuit, generating a first clock and a second clock; a touch sensing circuit, coupled to the touch input device, the touch sensing circuit operated under the first clock; a logic circuit, receiving a sensing output signal from the touch sensing circuit, the logic circuit operated under the second clock; and a conversion circuit, outputting an output voltage under control of the logic circuit, the output voltage coupled to the touch sensing circuit, the conversion circuit operated under the second clock. In response to the sensing output signal from the touch sensing circuit, the logic circuit controls the conversion circuit to adjust the output voltage to detect a capacitance variance of the touch input device.