Touch screen sensor integrated circuit, a method of operating the same, and a system including the same

Patent metadata

Field	Value
Publication number	US-9727183-B2
Application number	US-201414477198-A
Country	US
Kind code	B2
Filing date	Sep 4, 2014
Priority date	Oct 10, 2013
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A method of operating a touch screen sensor integrated circuit includes: receiving a plurality of current signals through a plurality of pins, wherein each current signal is generated according to mutual capacitance in response to a modulation signal; sensing the current signals and generating a plurality of sensed current signals corresponding to each of the current signals; and generating a plurality of subtracted current signals, wherein each subtracted current signal is generated by performing a subtraction on sensed current signals corresponding to a pair of the pins.

First claim

What is claimed is:

1. A touch screen sensor integrated circuit, comprising:
a plurality of pins configured to receive a plurality of current signals, wherein each current signal is generated according to mutual capacitance in response to a modulation signal;
a current conveyor configured to receive the current signals from the pins, sense the current signals and generate a plurality of pairs of sensed current signals each pair corresponding to a respective one of the current signals, wherein each pair of the sensed current signals comprises first and second sense current signals;
a delay table configured to store phase delay information;
a control logic configured to generate a mixer control signal and control a timing of the mixer control signal using the phase delay information; and
a mixer configured to receive the plurality of pairs of sensed current signals from the current conveyor and generate a plurality of subtracted current signals, wherein each subtracted current signal is generated by performing a subtraction on sensed current signals corresponding to a pair of the pins, and wherein the mixer generates the plurality of subtracted current signals in response to the mixer control signal.

2. The touch screen sensor integrated circuit of claim 1 , wherein in each pair of the sensed current signals a phase of the first sensed current signal is opposite to a phase of the second sensed current signal.

3. The touch screen sensor integrated circuit of claim 2 , wherein the current conveyor comprises a plurality of unit current conveyors respectively corresponding to the pins, and each of the unit current conveyors comprises:
an operational amplifier configured to generate a first control voltage and a second control voltage according to one of the current signals; and
a current copy circuit configured to generate one of the first sensed current signals and one of the second sensed current signals according to the first control voltage and the second control voltage.

4. The touch screen sensor integrated circuit of claim 2 , wherein the mixer adds one of the first sensed current signals, which corresponds to one of two pins in a pair, and one of the second sensed current signals, which corresponds to the other one of the two pins, according to a demodulation signal.

5. The touch screen sensor integrated circuit of claim 4 , wherein the two pins correspond to adjacent channels.

6. The touch screen sensor integrated circuit of claim 4 , wherein the two pins correspond to peripheral channels.

7. The touch screen sensor integrated circuit of claim 1 , further comprising a sine-shape resampler configured to generate fine current signals by multiplying the subtracted current signals by a sine wave.

8. The touch screen sensor integrated circuit of claim 7 , wherein the sine-shape resampler comprises a plurality of unit sine-shape resamplers respectively corresponding to the subtracted current signals, and
each of the unit sine-shape resamplers is an R-2R ladder digital-to-analog converter comprising a plurality of transistors that operate according to digital sine-wave signals.

9. The touch screen sensor integrated circuit of claim 7 , further comprising a current-to-voltage converter configured to generate output voltage signals respectively corresponding to the fine current signals.

10. The touch screen sensor integrated circuit of claim 9 , further comprising:
an analog-to-digital converter (ADC) configured to convert the output voltage signals into digital voltage signals; and
a micro controller unit (MCU) configured to sequentially integrate the digital voltage signals and generate touch voltage signals respectively corresponding to the current signals.

11. The touch screen sensor integrated circuit of claim 10 , wherein the pins comprise first through m-th pins respectively connected to first through m-th sensing lines of a touch screen panel, and
the MCU compensates the sequentially integrated digital voltage signals using a result of integrating the digital voltage signals respectively corresponding to the first through m-th pins.

12. A touch screen sensor integrated circuit, comprising:
a plurality of pins configured to receive a plurality of current signals, wherein each current signal is generated according to mutual capacitance in response to a modulation signal;
a current conveyor configured to sense the current signals and generate a plurality of pairs of sensed current signals each pair corresponding to one of the current signals, wherein each pair of the sensed current signals comprises first and second sensed current signals;
a delay table configured to store phase delay information;
a control logic configured to generate a mixer control signal and control a timing of the mixer control signal using the phase delay information; and
a mixer configured to output the sensed current signals according to a mode selection signal, or generate a plurality of subtracted current signals, wherein each subtracted current signal is generated by performing a subtraction on sensed current signals corresponding to a pair of the pins, and wherein the mixer generates the plurality of subtracted current signals in response to the mixer control signal.

13. The touch screen sensor integrated circuit of claim 12 , wherein in each pair of the sensed current signals a phase of the first sensed current signal is opposite to a phase of the second sensed current signal.

14. The touch screen sensor integrated circuit of claim 13 , wherein the current conveyor comprises a plurality of unit current conveyors respectively corresponding to the pins, and each of the unit current conveyors comprises:
an operational amplifier configured to generate a first control voltage and a second control voltage according to one of the current signals; and
a current copy circuit configured to generate one of the first sensed current signals and one of the second sensed current signals according to the first control voltage and the second control voltage.

15. The touch screen sensor integrated circuit of claim 13 , wherein the mixer adds one of the first sensed current signals, which corresponds to one of two pins in a pair, and one of the second sensed current signals, which corresponds to the other one of the two pins, according to a demodulation signal.

16. The touch screen sensor integrated circuit of claim 15 , wherein the two pins correspond to adjacent channels.

17. A touch screen sensor integrated circuit, comprising:
a current conveyor configured to generate a pair of sensed current signals for each received current signal;
a delay table configured to store phase delay information;
a control logic configured to generate a mixer control signal and control a timing of the mixer control signal using the phase delay information;
a mixer configured to perform a subtraction operation on the pairs of sensed current signals to generate a plurality of subtracted current signals, wherein the mixer generates the plurality of subtracted current signals in response to the mixer control signal;
a sine-shape resampler configured to generate a plurality of fine current signals by multiplying the subtracted current signals by a sine wave; and
a current converter configured to generate a plurality of output voltage signals by removing a high-frequency component of the fine current signals.

18. The touch screen sensor integrated circuit of claim 17 , further comprising:
an analog-to-digital converter configured to convert the output voltage signals into digital voltage signal

Assignees

• Samsung Electronics Co Ltd

Inventors

• Byun San Ho
• Park Jun Chul
• Kim Ki Duk
• Choi Yoon Kyung

Classifications

• G06F3/0416

  Control or interface arrangements specially adapted for digitisers · CPC title

• G06F3/044 Primary

  by capacitive means · CPC title

• G06F3/0446

  using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes · CPC title

• G06F3/0443 Primary

  using a single layer of sensing electrodes · CPC title

• G06F3/04182

  Filtering of noise external to the device and not generated by digitiser components · CPC title