TOUCH DISPLAY DEVICE, PEN, TOUCH SYSTEM, TOUCH CIRCUIT, AND PEN RECOGNITION METHOD

A touch display device (10) may include: a panel (110) including a plurality of touch electrodes (TE), and a touch circuit (300) configured to: transfer a panel driving signal (PDS1, PDS2, PDS3) to the panel (110), and receive a pen information signal (PINFO), output from a pen (20) in response to the panel driving signal (PDS1, PDS2, PDS3), through the panel (110), each of the panel driving signal (PDS1, PDS2, PDS3) and the pen information signal (PINFO) including a plurality of pulses, the pen information signal (PINFO) including one or more state sections among: an in-phase state section including pulses in phase with the pulses of the panel driving signal (PDS1, PDS2, PDS3), an antiphase state section including pulses having a different phase from the pulses of the panel driving signal (PDS1, PDS2, PDS3), and a passive state section distinguished from the in-phase state section and the antiphase state section.