Touch screen driver and method for driving touch screen
A touch screen driver includes a touch screen including Tx channels, Rx channels crossing the Tx channels, and sensor nodes formed at crossings of the Tx channels and the Rx channels, a Tx driving circuit supplying a driving pulse to the Tx channels, an Rx driving circuit which samples voltages of the sensor nodes supplied through the Rx channels in response to Rx sampling clocks and converts the sampled voltages into digital data, and a touch controller which modulates the Rx sampling clocks based on an RC delay deviation between the Rx channels, supplies the modulated Rx sampling clocks to the Rx driving circuit, differently controls sampling times of the Rx channels, and analyzes the digital data using a previously determined touch recognition algorithm.
1. A touch screen driver, comprising:
a touch screen including:
transmission (Tx) channels;
receiving (Rx) channels crossing the Tx channels; and
sensor nodes formed at crossings of the Tx channels and the Rx channels;
a Tx driving circuit configured to supply a driving pulse to the Tx channels;
an Rx driving circuit configured to:
sample voltages of the sensor nodes supplied through the Rx channels in response to Rx sampling clocks; and
convert the sampled voltages of the sensor nodes into digital data; and
a touch controller configured to:
modulate the Rx sampling clocks based on an RC delay deviation between the Rx channels;
supply the modulated Rx sampling clocks to the Rx driving circuit;
differently control sampling times of the Rx channels;
analyze the digital data received from the Rx driving circuit using a previously determined touch recognition algorithm;
output touch data including coordinate information of a touch position;
further widen an on-duty of an Rx sampling clock of an Rx channel having a large RC delay, rather than an Rx channel having a small RC delay; and
synchronize rising edges of the Rx sampling clocks of the Rx channels, falling edges of the Rx sampling clocks of the Rx channels, or on-period center points of the Rx sampling clocks of the Rx channels.
2. The touch screen driver of claim 1 , wherein the touch controller is further configured to differently control on-duties of the Rx sampling clocks of the Rx channels based on the RC delay deviation.
3. The touch screen driver of claim 1 , wherein the touch controller is further configured to differently control on-period start points of the Rx sampling clocks of the Rx channels based on the RC delay deviation.
4. A method for driving a touch screen including transmission (Tx) channels, receiving (Rx) channels crossing the Tx channels, and sensor nodes formed at crossings of the Tx channels and the Rx channels, the method comprising:
supplying a driving pulse to the Tx channels;
modulating Rx sampling clocks to differently control sampling times of the Rx channels based on an RC delay deviation between the Rx channels;
sampling voltages of the sensor nodes supplied through the Rx channels in response to the Rx sampling clocks;
converting the sampled voltages of the sensor nodes into digital data; and
analyzing the digital data using a previously determined touch recognition algorithm to output touch data including coordinate information of a touch position,
wherein the modulating of the Rx sampling clocks includes further widening an on-duty of an Rx sampling clock of an Rx channel having a large RC delay, rather than an Rx channel having a small RC delay, and
wherein the modulating of the Rx sampling clocks includes synchronizing rising edges of the Rx sampling clocks of the Rx channels, falling edges of the Rx sampling clocks of the Rx channels, or on-period center points of the Rx sampling clocks of the Rx channels.
5. The method of claim 4 , wherein the modulating of the Rx sampling clocks includes differently controlling on-duties of the Rx sampling clocks of the Rx channels based on the RC delay deviation.
6. The method of claim 4 , wherein the modulating of the Rx sampling clocks includes differently controlling on-period start points of the Rx sampling clocks of the Rx channels based on the RC delay deviation.