Touch Sensing Device for Compensating Phase Error of Active Pen and Method for Compensating Phase Error of Active Pen

Abstract

The invention relates to a touch sensing device for compensating phase errors of an active pen and a method for compensating phase errors of the active pen. The touch sensing device that compensates for a phase error of a downlink signal transmitted / received between a display device and an active pen. The touch sensing device includes a differential amplifier configured to amplify a difference between a first accumulated capacitance value for a first touch group and a second accumulated capacitance value for a second touch group, based on a first downlink signal generated during a pre-driving section, an ADC configured to convert an output signal of the differential amplifier into digital data, and a phase error compensator configured to detect an edge of the first downlink signal based on a difference value between current and previous values of the digital data and compensate for a phase error of the first downlink signal using the edge of the first downlink signal and an edge of an internal timing signal.

Description

technical field [0001] This specification relates to touch sensing devices, and more particularly, to touch sensing devices capable of sensing a touch by an active pen. Background technique [0002] Recently, stylus pens and fingers are used as input devices in various display devices. A stylus has the advantage of enabling more precise input than a finger. Styluses are separated into passive and active types. [0003] Passive type stylus pens (hereinafter, referred to as “passive pens”) have disadvantages in that it is difficult to detect a touch position because the change in capacitance that occurs at the point of contact of the passive pen with the display panel is small, while active Type stylus pens (hereinafter, referred to as "active pens") autonomously generate pen drive signals, and output the generated pen drive signals to the contact points between the active pen and the display panel, thus being different from passive pens. It has an advantage of being easy t...

AI Technical Summary

Problems solved by technology

However, when the synchronization between the active pen and the display device is performed by the transmission of the ping signal from the display device to the active pen, the display device has to represent a touch sensing period (during which time is performed for a finger or Each long horizontal blanking (LHB) of the touch sensing of the active pen sends a ping signal to the active pen, so there is a problem of large power consumption

[0006] In addition, since the synchronization itself cannot be done when the active pen cannot interpret the ping signal, the display device has to rely on the synchronization ability of the active pen, so there is also the problem that the freedom of choice of the active pen may be limited

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