Touch sensing system including active stylus pen

A touch sensing system, in which one frame is time-divided into at least one touch driving period and a display driving period, the touch sensing system comprising:

• a display panel including a plurality of common electrodes implemented as touch sensors, the touch sensors being configured to apply a common voltage to the plurality of common electrodes during the display driving period;
• an active stylus pen configured to:
• generate:
• a first pen driving signal in synchronization with a touch driving signal, the first pen driving signal being related to a touch input of the active stylus pen;
• and
• a second pen driving signal related to one or more of:
• pen pressure information, information about whether to use a button function, and identification (ID) information of the active stylus pen;
• and
• output, to the display panel, the first pen driving signal in a first period and the second pen driving signal in a second period;
• and
• a touch driving device configured to:
• sense the first pen driving signal input through the display panel in the first period;
• and
• sense the second pen driving signal input through the display panel in the second period,
• wherein the first period and the second period are in different touch driving periods, with the display driving period between them,
• wherein a conductive tip of the active stylus pen is configured to output the first pen driving signal and the second pen driving signal to the display panel,
• wherein the second pen driving signal includes a plurality of state signals, the plurality of state signals including:
• a first state signal,
• a second state signal, and
• a third state signal, and
• wherein:
• the first state signal includes a plurality of pulses having a same phase as the touch driving signal,
• the second state signal includes a plurality of pulses having a phase opposite the touch driving signal, and
• the third state signal is a passive state of the second pen driving signal.

A display device, in which one frame is time-divided into at least one touch driving period and a display driving period and configured to operate in the at least one touch driving period, the display device comprising:

• a display panel including a plurality of common electrodes implemented as touch sensors, the touch sensors being configured to:
• during the display driving period, apply a common voltage to the plurality of common electrodes;
• and
• during the touch driving period, apply a touch driving signal, a first pen driving signal, and a second pen driving signal to the plurality of common electrodes;
• and
• a touch driving device configured to:
• sense the first pen driving signal output from an active stylus pen in a first touch driving period, and
• sense the second pen driving signal output from the active stylus pen in a second touch driving period,
• wherein the first pen driving signal and the second pen driving signal are synchronized with the touch driving signal,
• wherein the first pen driving signal is used to detect a touch input of the active stylus pen,
• wherein the second pen driving signal is used to detect an additional input related to an additional function of the active stylus pen, the additional input including one or more of:
• pen pressure information, information about whether to use a button function, and identification (ID) information of the active stylus pen,
• wherein a conductive tip of the active stylus pen is configured to output the first pen driving signal and the second pen driving signal to the display panel,
• wherein the second pen driving signal includes a plurality of state signals, the plurality of state signals including:
• a first state signal,
• a second state signal, and
• a third state signal, and
• wherein:
• the first state signal includes a plurality of pulses having a same phase as the touch driving signal,
• the second state signal includes a plurality of pulses having a phase opposite the touch driving signal, and
• the third state signal is a passive state of the second pen driving signal.