Touch sensing system and method of controlling power consumption thereof

Patent metadata

Field	Value
Publication number	US-10120432-B2
Application number	US-201615096016-A
Country	US
Kind code	B2
Filing date	Apr 11, 2016
Priority date	Nov 13, 2012
Publication date	Nov 6, 2018
Grant date	Nov 6, 2018

Abstract

A touch sensing system and a method of controlling power consumption thereof are disclosed. The touch sensing system includes a plurality of sensing units, which sample a voltage received from a touch screen and accumulate the sampled voltage, and a plurality of analog-to-digital converters converting an output of the sensing units into digital data. The sensing units and the analog-to-digital converters are divided into a plurality of groups in an idle state. Each of the plurality of groups includes at least two sensing units and one analog-to-digital converter. At least one sensing unit included in at least one group is powered down in the idle state. An analog-to-digital converter is powered on during the group it belongs to is powered on.

First claim

What is claimed is:

1. A touch sensing system, comprising:
a plurality of sensing units configured to:
sample a voltage received from a touch screen; and
accumulate a sampled voltage; and

a plurality of analog-to-digital converters configured to convert an output of the sensing units into digital data,
wherein the sensing units and the analog-to-digital converters are divided into a plurality of groups and driven in a time division manner,
wherein each of the plurality of groups includes:
at least one of the sensing units, and
at least one of the analog-to-digital converters,

wherein one of sensing units that is included in a group other than a group that is powered on is powered down, and
wherein the analog-to-digital converters are powered on, sequentially, on a per group basis.

2. The touch sensing system of claim 1 , wherein a plurality of sensing units are connected to one analog-to-digital converter in each of the plurality of groups.

3. The touch sensing system of claim 2 , wherein, among the analog-to-digital converters, only an analog-to-digital converter included in the group that is powered on is driven.

4. The touch sensing system of claim 3 , wherein only the group that is powered on among the plurality of groups outputs touch raw data.

5. The touch sensing system of claim 2 , wherein the sensing units connected to the one analog-to-digital converter included in the group that is powered on are driven sequentially.

6. The touch sensing system of claim 1 , wherein the plurality of groups comprise:
a first group including first and third sensing units and a first analog-to-digital converter that converts an output of the first and third sensing units into digital data to generate touch raw data; and
a second group including second and fourth sensing units and a second analog-to-digital converter configured to convert an output of the second and fourth sensing units into digital data to generate touch raw data,
wherein, after the first sensing unit and the first analog-to-digital converter are driven, the second sensing unit and the second analog-to-digital converter are driven, and
wherein, subsequently, after the third sensing unit and the first analog-to-digital converter are driven, the fourth sensing unit and the second analog-to-digital converter are driven.

7. The touch sensing system of claim 1 , further comprising:
a timing generator configured to control drive timings of the sensing units and drive timings of the analog-to-digital converters;
a buffer memory configured to store touch raw data output from the analog-to-digital converters;
a first controller configured to:
analyze the touch raw data in an active state; and
calculate a coordinate of each touch input to output coordinate information;

a second controller connected to the first controller; and
a clock generator configured to:
receive a first clock from an oscillator and a second external clock from the first controller; and
transmit the first clock to the timing generator, the buffer memory, and the second controller in an idle state.

8. The touch sensing system of claim 7 , wherein:
when the touch raw data is equal to or greater than a predetermined threshold value, the timing generator is further configured to generate an interrupt signal; and
the first controller is further configured to:
be converted to an active state in response to the interrupt signal; and
output coordinate information in the active state.

9. The touch sensing system of claim 8 , wherein:
the first controller comprises an interrupt receiving circuit configured to receive the interrupt signal; and
the interrupt receiving circuit of the first controller alone is configured to be driven in the idle state so that the coordinate information is not output from the first controller.

10. The touch sensing system of claim 9 , wherein the timing generator is further configured to:
receive an operation mode command from the first controller; and
drive the plurality of groups in a time division manner when the operation mode command indicates an idle state.

11. The touch sensing system of claim 10 , wherein:
the timing generator is further configured to:
control power of each of the plurality of sensing units in the idle state; and
generate a plurality of power-down signals indicating a power-down timing of each of the plurality of analog-to-digital converters; and

the plurality of power-down signals are respectively supplied to the sensing units and the analog-to-digital converters.

12. The touch sensing system of claim 11 , wherein:
after generating the operation mode command, the first controller is converted to the idle state; and
the first controller is further configured to turn off a power applied to circuits other than the interrupt receiving circuit.

13. The touch sensing system of claim 12 , wherein the second controller is further configured to:
transmit data received from the first controller to the timing generator;
read the touch raw data stored in the buffer memory;
transmit the touch raw data; and
in response to receipt of an operation mode command indicating the idle state, control the clock generator by generating a clock selection signal for selecting the first clock.

14. The touch sensing system of claim 9 , wherein:
the first controller is converted to the active state in response to receipt of the interrupt signal;
all the circuits in the first controller are driven in the active state; and
all the sensing units and all the analog-to-digital converters are driven in the active state under control of the timing generator.

15. The touch sensing system of claim 7 , wherein the clock generator is further configured to transmit the second clock received from the first controller to the timing generator, the buffer memory, and the second controller in the active state.

16. The touch sensing system of claim 1 , wherein each touch sensor of the touch screen comprises a self-capacitance type or a mutual capacitance type.

17. A touch sensitive display device, comprising:
a display driving circuit configured to:
apply video data of an input image to pixels of a display panel; and
accumulate a sampled voltage;

a plurality of sensing units configured to sample a voltage received from touch sensors coupled to the display panel; and
a plurality of analog-to-digital converters configured to convert an output of the plurality of sensing units into digital data,
wherein the sensing units and the analog-to-digital converters are divided into a plurality of groups and driven in a time division manner,
wherein each of the plurality of groups comprises:
at least one sensing unit, and
at least one analog-to-digital converter,

wherein at least one sensing unit included in a group other than a group that is powered on is powered down, and
wherein the analog-to-digital converters are powered on, sequentially, on a per group basis.

18. The touch sensitive display device of claim 17 , wherein:
the touch sensors are embedded in the display panel; and
each of the touch sensors comprises a self-capacitance type or a mutual capacitance type.

19. A touch sensing system, comprising:
a plurality of sensing units configured to:
sample a voltage received from a touch screen; and
accumulate a sampled voltage;

a plurality of analog-to-digital converters configured to convert an output of the sensing units into digital data; and
a touch screen driving circuit configured to drive the sensing units and

Assignees

• Lg Display Co Ltd

Inventors

• Jang Kyungjin

Classifications

• G06F1/3262 Primary

  Power saving in digitizer or tablet · CPC title

• G06F3/05

  Digital input using the sampling of an analogue quantity at regular intervals of time {, input from a/d converter or output to d/a converter} · CPC title

• Y02D50/20

  Cross-Sectional Technologies · mapped topic

• G06F3/044

  by capacitive means · CPC title

• G06F3/0416

  Control or interface arrangements specially adapted for digitisers · CPC title