Semiconductor device
A semiconductor device connected to the display panel including the in-cell type touch sensor is configured as follows. The semiconductor device includes a driving circuit of the display panel, a touch sensing circuit of the touch sensor, a power supply circuit that supplies a power source to these circuits, and a bias control circuit that controls a bias current flowing through these circuits. The semiconductor device is able to perform a time-division operation in which one frame period of display is divided into a plurality of display driving periods and sensing periods. In the display driving periods, the supply of power to the touch sensing circuit is suppressed, and/or a bias current is reduced. In the sensing periods, the supply of power to the driving circuit is suppressed, and/or a bias current is reduced.
1. A semiconductor device capable of being connected to a display panel including a touch sensor,
wherein the display panel is a liquid crystal display panel, and
wherein the touch sensor is formed integrally with the liquid crystal display panel in an in-cell type using an arrangement of capacitors, and can detect a touch state and a position by detecting a change in capacitance,
the semiconductor device comprising:
a driving circuit configured to drive the liquid crystal display panel;
a touch sensing circuit configured to be connected to the integrally-formed touch sensor;
a power supply circuit that supplies a power source to the liquid crystal driving circuit and the touch sensing circuit; and
a bias control circuit that supplies a first control signal to the driving circuit to control a first bias current flowing through the liquid crystal driving circuit and a second control signal to the touch sensing circuit to control a second bias current flowing through the touch sensing circuit, the second control signal being separate and independent from the first control signal,
wherein the semiconductor device is able to perform a time-division operation including a display driving period in which the liquid crystal display panel is driven and a touch state is not detected and a sensing period in which a touch state is detected and a driving state of the liquid crystal display panel is not changed,
one or more display driving period and one or more sensing periods are included in one frame period of an image which is displayed by the liquid crystal display panel,
in the display driving period, the power supply circuit reduces power supply capability to the touch sensing circuit further than that in the sensing period, and/or the bias control circuit reduces the second bias current further than that in the sensing period by controlling a signal level output of the second control signal, and
in the sensing period, the power supply circuit reduces power supply capability to the liquid crystal driving circuit further than that in the display driving period, and/or the bias control circuit reduces the first bias current further than that in the display driving period by controlling a signal level output of the first control signal.
2. The semiconductor device according to claim 1 ,
the power supply circuit includes a first DCDC converter that generates a first internal power source from a power source which is supplied from an outside, a second DCDC converter that generates a second internal power source from the first internal power source, and a third DCDC converter that generates a third internal power source from the first internal power source,
the power supply circuit includes a first regulator that outputs a second stabilized power source, supplied to the driving circuit and the touch sensing circuit, from the second internal power source, and a second regulator that outputs a third stabilized power source, which is supplied to the driving circuit and is not supplied to the touch sensing circuit, from the third internal power source,
each of the first, second and third DCDC converters is configured to improve power supply capability by increasing a frequency and/or duty of a boost clock, and to reduce power supply capability by decreasing the frequency and/or duty thereof,
the first regulator is configured to improve power supply capability by increasing a third bias current controlled by the bias control circuit, and to reduce power supply capability by decreasing the third bias current,
the second regulator is configured to improve power supply capability by increasing a fourth bias current controlled by the bias control circuit, to reduce power supply capability by decreasing the fourth bias current, or to cut off a supply of power, and
in the sensing period, the power supply circuit reduces power supply capability by decreasing a frequency and/or duty of a boost clock of the first DCDC converter and the second DCDC converter and stops an operation of the third DCDC converter, and the bias control circuit stops a supply of power from the second regulator to the driving circuit by decreasing the fourth bias current.
3. The semiconductor device according to claim 2 ,
wherein the liquid crystal display panel is able to display an image frame constituted by a plurality of lines,
the display driving period is a period in which some of a plurality of lines within the image frame are displayed, and
the sensing period is set to an arbitrary period between the display driving period and a next display driving period.
4. The semiconductor device according to claim 3 , wherein
the liquid crystal display panel is able to display an image frame constituted by a plurality of lines,
the display driving period is a period in which some of a plurality of lines within the image frame are displayed, and
the waiting period is set to an arbitrary period between the display driving period and a next display driving period.
5. The semiconductor device according to claim 1 , wherein
the liquid crystal display panel is able to display an image frame constituted by a plurality of lines,
the display driving period is a period in which some of a plurality of lines within the image frame are displayed, and
the sensing period is set to an arbitrary period between the display driving period and a next display driving period.
6. A semiconductor device capable of being connected to a display panel including a touch sensor, comprising:
a driving circuit configured to drive the display panel;
a touch sensing circuit configured to be connected to the touch sensor;
a power supply circuit that supplies a power source to the driving circuit and the touch sensing circuit; and
a bias control circuit that controls a first bias current flowing through the driving circuit and a second bias current flowing through the touch sensing circuit,
wherein
the semiconductor device is able to perform a time-division operation including a display driving period in which the display panel is driven and a touch state is not detected and a sensing period in which a touch state is detected and a driving state of the display panel is not changed,
one or more display driving period and one or more sensing periods are included in one frame period of an image which is displayed by the display panel,
in the display driving period, the power supply circuit reduces power supply capability to the touch sensing circuit further than that in the sensing period, and/or the bias control circuit reduces the second bias current further than that in the sensing period,
in the sensing period, the power supply circuit reduces power supply capability to the driving circuit further than that in the display driving period, and/or the bias control circuit reduces the first bias current further than that in the display driving period,
the power supply circuit includes a DCDC converter that generates an internal power source from a power source which is supplied from an outside, a first regulator that outputs a first stabilized power source, supplied to the driving circuit, from the internal power source, a second regulator that outputs a second stabilized power source, supplied to the touch sensing circuit, from the internal power source,
the DCDC converter is configured to improve power supply capability by increasing a frequency of a boost clock, and to reduce power supply capability by decreasing the frequency thereof,
the first regulator is configured to improve power supply capability by increasing a third bias current controlled by the bias control circuit, and to reduce power supply capability by decreasing the third bias current,
the second regulator is configured to improve power supply capability by increasing a fourth bias current controlled by the bias control circuit, and to reduce power supply capability by decreasing the fourth bias current,
in the display driving period, the power supply circuit decreases the frequency of the DCDC converter further than that in the sensing period, and the bias control circuit reduces the fourth bias current and the second bias current further than those in the sensing period, and
in the sensing period, the power supply circuit controls decreasing the frequency of the DCDC converter further than that in the display driving period, and the bias control circuit controls reducing the third bias current and the first bias current further than those in the display driving period.
7. The semiconductor device according to claim 6 ,
wherein the display panel is able to display an image frame constituted by a plurality of lines,
the display driving period is a period in which some of a plurality of lines within the image frame are displayed, and
the sensing period is set to an arbitrary period between the display driving period and a next display driving period.
8. The semiconductor device according to claim 7 , wherein
the display panel is able to display an image frame constituted by a plurality of lines,
the display driving period is a period in which some of a plurality of lines within the image frame are displayed, and
the waiting period is set to an arbitrary period between the display driving period and a next display driving period.
9. A semiconductor device capable of being connected to a display panel including a touch sensor, comprising:
a driving circuit configured to drive the display panel;
a touch sensing circuit configured to be connected to the touch sensor;
a power supply circuit that supplies a power source to the driving circuit and the touch sensing circuit; and
a bias control circuit that controls a first bias current flowing through the driving circuit and a second bias current flowing through the touch sensing circuit,
wherein
the semiconductor device is able to perform a time-division operation including a display driving period in which the display panel is driven and a touch state is not detected and a sensing period in which a touch state is detected and a driving state of the display panel is not changed,
one or more display driving period and one or more sensing periods are included in one frame period of an image which is displayed by the display panel,
in the display driving period, the power supply circuit reduces power supply capability to the touch sensing circuit further than that in the sensing period, and/or the bias control circuit reduces the second bias current further than that in the sensing period,
in the sensing period, the power supply circuit reduces power supply capability to the driving circuit further than that in the display driving period, and/or the bias control circuit reduces the first bias current further than that in the display driving period,
the power supply circuit includes a DCDC converter that generates an internal power source from a power source which is supplied from an outside, a first regulator that outputs a first stabilized power source, supplied to the driving circuit, from the internal power source, a second regulator that outputs a second stabilized power source, supplied to the touch sensing circuit, from the internal power source,
the DCDC converter is configured to improve power supply capability by increasing a duty of a boost clock, and to reduce power supply capability by decreasing the duty thereof,
the first regulator is configured to improve power supply capability by increasing a third bias current controlled by the bias control circuit, and to reduce power supply capability by decreasing the third bias current,
the second regulator is configured to improve power supply capability by increasing a fourth bias current controlled by the bias control circuit, and to reduce power supply capability by decreasing the fourth bias current,
in the display driving period, the power supply circuit controls decreasing the duty of the DCDC converter further than that in the sensing period, and the bias control circuit controls reducing the fourth bias current and the second bias current further than those in the sensing period, and
in the sensing period, the power supply circuit controls decreasing the duty of the DCDC converter further than that in the display driving period, and the bias control circuit controls reducing the third bias current and the first bias current further than those in the display driving period.
10. The semiconductor device according to claim 9 ,
wherein the display panel is able to display an image frame constituted by a plurality of lines,
the display driving period is a period in which some of a plurality of lines within the image frame are displayed, and
the sensing period is set to an arbitrary period between the display driving period and a next display driving period.
11. The semiconductor device according to claim 10 , wherein
the display panel is able to display an image frame constituted by a plurality of lines,
the display driving period is a period in which some of a plurality of lines within the image frame are displayed, and
the waiting period is set to an arbitrary period between the display driving period and a next display driving period.
12. A semiconductor device capable of connecting to a display panel, comprising:
a driving circuit configured to drive the display panel;
a power supply circuit that supplies a power source to the driving circuit; and
a bias control circuit that controls a bias current flowing through the driving circuit,
wherein
the semiconductor device is able to perform a time-division operation including a display driving period in which the display panel is driven and a waiting period in which a driving state is not changed,
one or more display driving periods and one or more waiting periods are included in one frame period of an image which is displayed by the display panel,
in the waiting period, the power supply circuit controls reducing power supply capability further than that in the display driving period, and/or the bias control circuit controls reducing the bias current further than that in the display driving period,
the power supply circuit includes a DCDC converter that generates an internal power source from a power source which is supplied from an outside, and a regulator that outputs a stabilized power source from the internal power source,
the DCDC converter is configured to improve power supply capability by increasing a frequency of a boost clock, and to reduce power supply capability by decreasing the frequency thereof,
the bias current is set to a first bias current,
the regulator is configured to improve power supply capability by increasing a second bias current controlled by the bias control circuit, and to reduce power supply capability by decreasing the second bias current, and
in the waiting period, the power supply circuit controls decreasing the frequency of the DCDC converter further than that in the display driving period, and the bias control circuit controls reducing the second bias current and the first bias current further than those in the display driving period.
13. The semiconductor device according to claim 12 , wherein
the display panel is able to display an image frame constituted by a plurality of lines,
the display driving period is a period in which some of a plurality of lines within the image frame are displayed, and
the waiting period is set to an arbitrary period between the display driving period and a next display driving period.
14. A semiconductor device capable of connecting to a display panel, comprising:
a driving circuit configured to drive the display panel;
a power supply circuit that supplies a power source to the driving circuit; and
a bias control circuit that controls a bias current flowing through the driving circuit,
wherein
the semiconductor device is able to perform a time-division operation including a display driving period in which the display panel is driven and a waiting period in which a driving state is not changed,
one or more display driving periods and one or more waiting periods are included in one frame period of an image which is displayed by the display panel,
in the waiting period, the power supply circuit controls reducing power supply capability further than that in the display driving period, and/or the bias control circuit controls reducing the bias current further than that in the display driving period,
the power supply circuit includes a DCDC converter that generates an internal power source from a power source which is supplied from an outside, and a regulator that outputs a stabilized power source from the internal power source,
the DCDC converter is configured to improve power supply capability by increasing a duty of a boost clock, and to reduce power supply capability by decreasing the duty thereof,
the bias current is set to a first bias current,
the regulator is configured to improve power supply capability by increasing a second bias current controlled by the bias control circuit, and to reduce power supply capability by decreasing the second bias current, and
in the waiting period, the power supply circuit controls decreasing the duty of the DCDC converter further than that in the display driving period, and the bias control circuit controls reducing the second bias current and the first bias current further than those in the display driving period.
15. A semiconductor device capable of connecting to a display panel,
wherein the display panel is a liquid crystal display panel, and
wherein the touch sensor is formed integrally with the liquid crystal display panel in an in-cell type using an arrangement of capacitors, and can detect a touch state and a position by detecting a change in capacitance,
the semiconductor device comprising:
a driving circuit configured to drive the liquid crystal display panel;
a power supply circuit that supplies a power source to the driving circuit; and
a bias control circuit that supplies a first control signal to the driving circuit to control a bias current flowing through the driving circuit,
wherein the semiconductor device is able to perform a time-division operation including a display driving period in which the liquid crystal display panel is driven and a waiting period in which a driving state is not changed,
wherein one or more display driving periods and one or more waiting periods are included in one frame period of an image which is displayed by the liquid crystal display panel,
wherein, in the waiting period, the power supply circuit controls reducing power supply capability further than that in the display driving period, and/or the bias control circuit controls reducing the bias current further than that in the display driving period, by controlling a signal level output of the first control signal,
wherein the power supply circuit includes a DCDC converter that generates an internal power source from a power source which is supplied from an outside, and a regulator that outputs a stabilized power source from the internal power source,
wherein the DCDC converter is configured to improve power supply capability by increasing a frequency or a duty of a boost clock, and to reduce power supply capability by decreasing the frequency or the duty thereof,
wherein the bias current is set to a first bias current,
wherein the regulator is configured to improve power supply capability by increasing a second bias current controlled by the bias control circuit, and to reduce power supply capability by decreasing the second bias current, and
wherein, in the waiting period, the power supply circuit controls fixing a signal level of the boost clock of the DCDC converter, and the bias control circuit controls reducing the second bias current and the first bias current further than those in the display driving period.
16. The semiconductor device according to claim 15 , wherein
the liquid crystal display panel is able to display an image frame constituted by a plurality of lines,
the display driving period is a period in which some of a plurality of lines within the image frame are displayed, and
the waiting period is set to an arbitrary period between the display driving period and a next display driving period.
17. A semiconductor device capable of connecting to a display panel,
wherein the display panel is a liquid crystal display panel, and
wherein the touch sensor is formed integrally with the liquid crystal display panel in an in-cell type using an arrangement of capacitors, and can detect a touch state and a position by detecting a change in capacitance,
the semiconductor device comprising:
a driving circuit configured to drive the liquid crystal display panel;
a power supply circuit that supplies a power source to the driving circuit; and
a bias control circuit that supplies a first control signal to the driving circuit to control a bias current flowing through the driving circuit,
wherein the semiconductor device is able to perform a time-division operation including a display driving period in which the liquid crystal display panel is driven and a waiting period in which a driving state is not changed,
wherein one or more display driving periods and one or more waiting periods are included in one frame period of an image which is displayed by the liquid crystal display panel,
wherein, in the waiting period, the power supply circuit controls reducing power supply capability further than that in the display driving period, and/or the bias control circuit controls reducing the bias current further than that in the display driving period, by controlling a signal level output of the first control signal,
wherein the power supply circuit includes a first DCDC converter that generates a first internal power source from a power source which is supplied from an outside, a second DCDC converter that generates a second internal power source from the first internal power source, and a regulator that outputs a stabilized power source from the second internal power source,
wherein each of the first and second DCDC converters is configured to improve power supply capability by increasing a frequency or a duty of a boost clock, and to reduce power supply capability by decreasing the frequency or the duty thereof,
wherein the bias current is set to a first bias current,
wherein the regulator is configured to improve power supply capability by increasing a second bias current controlled by the bias control circuit, and to reduce power supply capability by decreasing the second bias current, and
wherein, in the waiting period, the power supply circuit controls decreasing the frequency of the first DCDC converter further than that in the display driving period, and/or decreasing the duty further than that in the display driving period, and fixing a signal level of the boost clock of the second DCDC converter, and the bias control circuit controls reducing the second bias current and the first bias current further than those in the display driving period.
18. The semiconductor device according to claim 17 , wherein
the liquid crystal display panel is able to display an image frame constituted by a plurality of lines,
the display driving period is a period in which some of a plurality of lines within the image frame are displayed, and
the waiting period is set to an arbitrary period between the display driving period and a next display driving period.
19. A semiconductor device capable of connecting a display panel including a touch sensor, comprising:
a touch sensing circuit which is configured to be connected to the touch sensor;
a power supply circuit that supplies a power source to the touch sensing circuit; and
a bias control circuit that controls a bias current flowing through the touch sensing circuit,
wherein the semiconductor device is able to perform a time-division operation including a sensing period in which a touch state is detected and a waiting period in which the touch state is not detected,
one or more sensing periods and one or more waiting period are included in one frame period of an image which is displayed by the display panel,
in the waiting period, the power supply circuit controls reducing power supply capability, and/or the bias control circuit controls reducing the bias current,
the power supply circuit includes a DCDC converter that generates an internal power source from a power source which is supplied from an outside, and a regulator that outputs a stabilized power source from the internal power source,
the DCDC converter is configured to improve power supply capability by increasing a frequency and/or duty of a boost clock, and to reduce power supply capability by decreasing the frequency and/or duty thereof,
the bias current is set to a first bias current,
the regulator is configured to improve power supply capability by increasing a second bias current controlled by the bias control circuit, and to reduce power supply capability by decreasing the second bias current, and
in the waiting period, the power supply circuit controls decreasing the frequency and/or duty of the DCDC converter further than that in the display driving period, and the bias control circuit controls reducing the second bias current and the first bias current further than those in the display driving period.