Touch Sensing Device Phase Error Compensation for Active Pen

The patent merges the synchronization function with the existing downlink signal transmission. Instead of using a separate synchronization signal, the phase error compensator extracts timing information from the downlink signal that the active pen transmits during normal operation. This combines the synchronization task with the existing data transmission, eliminating the need for additional dedicated synchronization transmissions and thereby reducing power consumption while maintaining signal reception sensitivity.

The patent makes the existing timing signal generation unit multi-functional by enabling it to perform both its original timing signal generation task and the additional function of phase error compensation. The phase error compensator uses the same internal timing signal that is already generated for display operations and compares it with the downlink signal timing. This eliminates the need for a separate comparator dedicated solely to synchronization, reducing device complexity while maintaining phase error compensation accuracy.

The patent implements self-service synchronization where the display device autonomously adjusts its internal timing signal to match the downlink signal timing from the active pen. The phase error compensator continuously monitors the phase difference between the internal timing signal and the downlink signal, and automatically compensates for the phase error by adjusting the timing signal. This self-adjusting mechanism ensures reliable signal transmission while maintaining compatibility with various active pens that have different timing characteristics, thus preserving the degree of freedom in active pen selection.