Position detection circuit, position detection method, and position detection system

A position detection method of using a touch sensor of a capacitance type including a plurality of sensor electrodes to detect a position indicated by a first indicator that communicates with the touch sensor to indicate the position indicated by the first indicator and a position indicated by a second indicator that indicates the position indicated by the second indicator without communicating with the touch sensor, the position detection method being performed by a position detection circuit connected to the touch sensor, the position detection method comprising:

• detecting a touch of the second indicator to an input surface arranged on the touch sensor;
• detecting the first indicator when proximity information indicating a proximity of the first indicator to the touch sensor is equal to or greater than a threshold;
• and
• changing the threshold to a larger value in a case where the touch is detected, wherein the larger value is larger than a value of the threshold in a case where the touch is not detected.

A position detection system, comprising:

• a first indicator that, in operation, communicates with a touch sensor of a capacitance type including a plurality of sensor electrodes to indicate a position indicated by the first indicator;
• and
• a position detection circuit that, in operation, uses the touch sensor to detect the position indicated by the first indicator and a position indicated by a second indicator that, in operation, indicates the position indicated by the second indicator without communicating with the touch sensor,
• the position detection circuit including:
• a first detection circuit that, in operation, detects a touch of the second indicator to an input surface arranged on the touch sensor,
• a second detection circuit that, in operation, detects the first indicator when proximity information indicating a proximity of the first indicator to the touch sensor is equal to or greater than a threshold, and
• a changing circuit that, in operation, changes the threshold to a larger value in a case where the first detection circuit detects the touch, wherein the larger value is larger than a value of the threshold in a case where the first detection circuit does not detect the touch.