Touch detection chip and touch screen detection method

A touch detection chip, comprising:

• a signal output unit, configured to output a driving signal to a first channel of a touch screen in a water drop detection mode;
• a first analog front end circuit, comprising an inverting input end connected to the first channel, wherein the first analog front end circuit is configured to receive a detection signal from the first channel, and outputs a detected value of the first channel according to the detection signal received from the first channel;
• a second analog front end circuit, comprising an inverting input end connected to a second channel of the touch screen, wherein the second channel is adjacent to the first channel and the second channel is floating in the water drop detection mode, wherein the second analog front end circuit is configured to receive a detection signal from the second channel, and outputs a detected value of the second channel according to the detection signal received from the second channel;
• an impedance-adjustable circuit, connected between a non-inverting input end of the first analog front end circuit and the signal output unit, wherein the impedance-adjustable circuit comprises a preset impedance value;
• a DC voltage unit, connected to a non-inverting input end of the second analog front end circuit;
• and
• a processing unit, wherein the signal output unit, an output end of the first analog front end circuit, and an output end of the second analog front end circuit are connected to the processing unit respectively, wherein the processing unit is configured to process the detected value of the first channel and the detected value of the second channel to obtain a water drop detection result.