Touch display device, pen, touch system, touch circuit, and pen recognition method

A touch display device, comprising:

• a panel including:
• a plurality of touch electrodes;
• and
• a plurality of touch signal lines;
• and
• a touch circuit configured to:
• transfer a panel driving signal to the panel;
• and
• receive a pen information signal output from a pen,
• wherein the pen is configured to output the pen information signal through a pen tip during a pen driving period including a first state period, a second state period, and a third state period,
• wherein the pen information signal includes:
• a first state signal being transmitted from the pen tip during the first state period,
• a second state signal being transmitted from the pen tip during the second state period, and
• a third state signal being transmitted from the pen tip during the third state period,
• wherein the first state signal includes a plurality of first pulses,
• wherein the second state signal includes a plurality of second pulses having a inversed phase with the plurality of first pulses, and
• wherein the third state signal includes a predetermined DC voltage or a floating signal or a plurality of third pulses different from the plurality of first pulses and the plurality of second pulses.