JP2015135706A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch sensor panel capable of comparatively easily enhancing the touch detection sensitivity.SOLUTION: A semiconductor device includes: a touch sensor panel controller that drives Y electrodes of a touch sensor panel in which capacitors are formed at a plurality of intersections by a plurality of Y electrodes and X electrodes, inputs a signal from the X electrodes, and detects signals corresponding to the capacitors of the intersections; and a display driver that supplies a display drive voltage to a display panel in which display cells are arranged at intersections of a plurality of scanning electrodes and signal electrodes. The touch sensor panel controller includes a first drive circuit that applies a first pulse waveform for pulse driving of the Y electrodes, and the display driver includes a second drive circuit that applies a second pulse waveform for pulse driving of the scanning electrodes. The change timing of the second pulse waveform is shifted from a period of pulse driving by the first pulse waveform, and a fall timing at which the pulse driving by the first pulse waveform ends is shifted from a fall timing at which the pulse driving of the second pulse waveform ends.

Description

  The present invention relates to a touch sensor panel controller and a semiconductor device using the same, and relates to a technique effectively applied to, for example, a liquid crystal display panel unit in which a touch sensor panel unit is incorporated.

  A touch sensor panel corresponding to a multi-point touch by a mutual capacitance method is arranged such that, for example, a Y electrode as a drive electrode and an X electrode as a detection electrode are orthogonal to each other with a dielectric interposed therebetween, and a capacitance (intersection capacitance) at each intersection. ) Is configured. When there is a finger or hand capacitance in the vicinity of the intersection capacitance, the mutual capacitance of the node decreases by the combined capacitance of the finger or hand. In order to detect at which intersection capacitance the change in mutual capacitance occurs, the touch sensor panel controller performs pulse-by-pulse charging operation by sequentially driving the drive electrodes, and the change in the charge charge is detected by each detection electrode. The signal detected according to the change in the mutual capacitance of the intersection capacitances arranged in matrix is obtained by sequentially repeating the operation detected from (1). For example, Patent Document 1 discloses a controller that detects a signal by driving a touch sensor panel using such a mutual capacitance method. In Patent Document 1, the detection circuit for detecting the signal of the X electrode is configured by an integration circuit using an operational amplifier. In the integration circuit, charges defined by the product of the drive voltage of the Y electrode and the capacitance value of the intersection capacitance are sequentially accumulated according to the AC pulse drive. The coordinate point of the position where the finger or hand is approached is determined based on the difference in charge amount between when the capacitance value of the intersection capacity decreases due to the approach of the finger or hand and when it does not.

US Patent Publication No. 2007 / 0257890A1

  The present inventor has studied the noise source of the detection circuit in the touch sensor panel controller. When a finger touches the touch sensor panel, the capacitance change of the intersection capacitance is about 1 pF at most. In order to accurately determine the presence or absence of the change from the X electrode signal, it is necessary to block the influence of noise from the surroundings. Become. In a portable terminal such as a PDA (Personal Digital Assistant), the touch sensor panel is overlaid on the surface of the liquid crystal display. Patent Document 1 describes the relationship between a touch sensor panel and a liquid crystal display panel. However, Patent Document 1 does not sufficiently study measures for improving the S / N ratio (signal noise ratio) of contact detection by the touch sensor panel in relation to the liquid crystal display panel.

  An object of the present invention is to provide a touch sensor panel that can improve detection sensitivity by contact relatively easily.

  Another object of the present invention is to provide a semiconductor device capable of relatively easily improving detection sensitivity due to contact with a touch sensor panel in relation to display driving of a display panel.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  The following is a brief description of an outline of typical inventions disclosed in the present application.

  That is, as a first mode, the touch sensor panel controller is driven by applying an AC drive signal having a low level as a negative voltage to the drive electrodes of the touch sensor panel.

  As a second form, the change timing of the drive waveform for the drive electrode of the touch sensor panel is shifted from the change timing of the drive waveform for the scan electrode of the display.

  As a third mode, the touch sensor panel controller generates a drive voltage for driving the drive electrodes of the touch sensor panel by a charge pump that synchronizes with the clock signals of a plurality of phases, and the clock of the plurality of phases is generated every time AC pulse driving for the drive electrodes. Initialize the signal.

  The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

  That is, the detection sensitivity due to contact can be improved relatively easily.

  The detection sensitivity due to contact with the touch sensor panel can be improved relatively easily in relation to the display drive of the display panel.

FIG. 1 is an explanatory diagram showing the overall configuration of a display and input device to which the present invention is applied. FIG. 2 is an explanatory diagram illustrating the electrode configuration of the touch sensor panel. FIG. 3 is an explanatory diagram illustrating the electrode configuration of the display panel. FIG. 4 is a block diagram illustrating the overall configuration of the touch sensor panel controller. FIG. 5 is a circuit diagram showing an example of an equivalent circuit of the touch sensor panel and an integration circuit as a detection circuit. FIG. 6 is a waveform diagram showing an example of an input waveform to the Y electrodes Y1 to YM. FIG. 7 is a timing chart illustrating the input pulse voltage to the Y electrodes Y1 to YM and the timing of the detection operation by the integration circuit. FIG. 8 is a circuit diagram illustrating an equivalent circuit of a liquid crystal display panel and a driving circuit of a liquid crystal driver. FIG. 9 is a waveform diagram illustrating input waveforms to the gate electrodes G1 to G640. FIG. 10 is a timing chart illustrating the timing waveforms of the gate pulse applied to the gate electrode and the gradation voltage applied to the drain electrode. FIG. 11 is a waveform diagram illustrating drive waveforms for the gate electrode and drain electrode of the liquid crystal display and drive waveforms for the Y electrode of the touch sensor panel. FIG. 12 is an explanatory diagram illustrating the correspondence between register values and voltages when the drive pulse voltage of the Y electrode is made variable by register setting. FIG. 13 is a block diagram illustrating a power supply system to the liquid crystal driver and the touch sensor panel controller. FIG. 14 is a block diagram illustrating a case where the liquid crystal driver and the touch sensor panel controller are separately provided with a booster circuit. FIG. 15 is a block diagram illustrating a driver device in which a display driver and a touch sensor panel controller are configured by a single chip. FIG. 16 is a block diagram illustrating a touch sensor panel controller including a booster circuit. FIG. 17 is a block diagram showing a specific example of the driver device of FIG. FIG. 18 is a timing chart illustrating the relationship between the drive waveform of the liquid crystal display panel and the Y electrode drive pulse waveform of the touch sensor panel. FIG. 19 is an explanatory diagram exemplifying setting registers for parameters t1, t2, and t3 and setting times according to the setting values. FIG. 20 is a circuit diagram showing an example of a booster circuit. FIG. 21 is a timing chart illustrating the timing of the detection operation by the touch sensor panel controller and the boost operation by the boost circuit.

1. First, an outline of a typical embodiment of the invention disclosed in the present application will be described. Reference numerals in the drawings referred to in parentheses in the outline description of the representative embodiments merely exemplify what are included in the concept of the components to which the reference numerals are attached.

[1] <Low level of AC drive pulse for TP is negative voltage>
A touch sensor panel controller (3) according to a representative embodiment of the present invention includes a touch sensor panel in which capacitors are formed at a plurality of intersections by a plurality of Y electrodes (Y1 to YM) and X electrodes (X1 to XN). A drive circuit (300) for driving the Y electrode, a detection circuit (301) for detecting a capacitance value of the capacitance at the intersection by inputting a signal from the X electrode, and controlling the drive circuit and the detection circuit And a control unit (308). The drive circuit applies a pulsed AC drive voltage with a low level being a negative voltage to the Y electrode.

  According to this, by driving the Y electrode with a high-voltage pulsed AC drive voltage, the amount of charge accumulated in the capacitance at the intersection is increased by one pulse drive, so that the signal component can be enlarged and high S / N ratio can be obtained. Further, by setting the low level of the AC drive voltage to a negative voltage, it becomes possible to easily obtain a high voltage by using an operation power source of a circuit that uses a negative voltage as the drive voltage, for example, a display panel.

[2] <Negative voltage level selectable from outside>
In the touch sensor panel controller according to item 1, the control circuit determines the level of the negative voltage based on selection data (VGLVL data) given from the outside.

  According to this, when it is assumed that the touch sensor panel controller is disposed in the vicinity of another circuit such as a display driver, for example, the AC drive voltage becomes noise given to the other circuit and the other It is possible to select an optimum level of negative voltage in consideration of both resistance to noise given from the circuit.

[3] <Voltage of AC driving pulse of TP in consideration of LCD driving voltage>
A semiconductor device according to another embodiment of the present invention includes a touch sensor panel controller (3) and a display driver (4). The touch sensor panel controller drives the Y electrode of the touch sensor panel (1) in which capacitors (Cxy) are formed at a plurality of intersections by a plurality of Y electrodes (Y1 to YM) and X electrodes (X1 to XN). A signal is input from the X electrode, and the capacitance value of the capacitance at the intersection is detected. The display driver supplies a display driving voltage to an active matrix display panel (2) in which display cells are arranged at intersections between the plurality of scanning electrodes (G1 to G640) and the signal electrodes (D1 to D1440). The touch sensor panel controller includes a drive circuit (300) that applies a pulsed AC drive voltage having a negative low level to the Y electrode.

  According to this, by driving the Y electrode with a high-voltage pulsed AC drive voltage, the amount of charge accumulated in the capacitance at the intersection is increased by one pulse drive, so that the signal component can be expanded and the S / N ratio is high. Can be obtained. Further, by setting the low level of the AC drive voltage to a negative voltage, it is possible to easily obtain a high voltage for AC drive by diverting the operation power supply of a circuit that uses a negative voltage as the drive voltage, such as a display driver. become.

[4] <Applying voltage from display driver booster circuit to AC drive voltage>
In the semiconductor device according to Item 3, the display driver includes a booster circuit (400) that generates a plurality of voltages used to drive the scan electrodes and the signal electrodes. The drive circuit uses the voltage (VYL) generated by the booster circuit for both or one of the high and low levels of the AC drive voltage.

  According to this, by using the boost voltage of the display driver, AC drive can be easily performed without providing a dedicated boost circuit for the touch sensor panel controller or without providing a drive voltage supply circuit outside. The voltage can be obtained.

[5] <Negative voltage level selectable from outside>
The touch sensor panel controller according to Item 3 further includes a control unit that determines the level of the negative voltage based on selection data (VGLVL data) given from the outside.

  According to this, it is possible to select an optimum level of negative voltage in consideration of the magnitude of noise given to the display driver by the AC drive voltage and the resistance against noise given from the display driver.

[6] <Single chip or multi chip>
In the semiconductor device according to Item 3, the touch sensor panel controller (3) and the display driver (4) include a single chip formed on a common semiconductor substrate or a multichip formed on separate semiconductor substrates.

  The multi-chip configuration increases the selection range of the touch sensor panel controller and the display driver for the touch sensor panel and the display panel to be controlled, and the single-chip configuration contributes to downsizing.

[7] <Preventing interference between Y electrode drive waveform of TP and scan electrode drive waveform of display panel>
A semiconductor device according to still another embodiment of the present invention includes a touch sensor panel controller (3) and a display driver (4). The touch sensor panel controller drives the Y electrodes of the touch sensor panel (1) in which capacitors (Cxy) are formed at a plurality of intersections by a plurality of Y electrodes (Y1 to YM) and X electrodes (X1 to XN). A signal is input from the X electrode to detect a capacitance value of the capacitance at the intersection. The display driver supplies a display driving voltage to an active matrix display panel (2) in which display cells are arranged at intersections between the plurality of scanning electrodes (G1 to G640) and the signal electrodes (D1 to D1440). The touch sensor panel controller has a first drive circuit (300) for applying a first pulse waveform to the Y electrode, and the display driver applies a second pulse waveform to the scan electrode of the liquid crystal display panel. A second drive circuit (AMPvf) to be applied is included. The first driving circuit and the second driving circuit have a high level period of the first pulse waveform within a high level period of the second pulse waveform, and a high level width of the first pulse waveform. It is made smaller than the high level width of the second pulse waveform (see FIG. 18).

  According to this, in the control by the touch sensor panel controller, when paying attention to the voltage change timing of the scan electrode of the display panel, the Y electrode is set to the non-pulse driving period, that is, the non-detection period (charge period) by the X electrode. Therefore, the noise caused by the voltage change of the scan electrode does not affect the X electrode detection operation performed during the Y electrode pulse drive period. In the control by the display driver, paying attention to the voltage change timing of the Y electrode of the touch sensor panel, the falling timing of the drive pulse (first pulse waveform) of the Y electrode scans the signal voltage applied to the display cell. Since the driving pulse (second pulse waveform) of the electrode is shifted from the falling timing, noise caused by the voltage change of the Y electrode does not affect the signal voltage determined in the display cell. In short, it is possible to avoid a situation in which the touch detection capability using the touch sensor panel controller is reduced or the display performance of the display driver is deteriorated.

[8] <Control of TP Y electrode drive waveform based on display panel drive timing reference>
In the semiconductor device according to Item 7, the second drive circuit generates a second pulse waveform based on the drive timing of the display panel. The first driving circuit sets a high level period of the first pulse waveform within a high level period of the second pulse waveform with reference to a driving timing of the display panel, A second pulse waveform is generated in which the high level width is set smaller than the high level width of the second pulse waveform (see FIG. 8).

  According to this, since the second pulse waveform is used as a reference, the first pulse waveform corresponding to the second pulse waveform can be easily generated.

[9] <Setting of change timing for drive pulse waveform of scan electrode>
In the semiconductor device according to Item 8, the change timing of the first pulse waveform is a time (t1) when a wait time has elapsed with respect to a rise timing of the second pulse waveform, and a rise time of the second pulse waveform. The first drive circuit is set by the time (t3) before the set time elapses with respect to the falling timing.

  According to this, the first pulse waveform with respect to the second pulse waveform can be easily determined using the parameters.

[10] <Initialize charge pump charge clock for each Y electrode>
In the touch sensor panel controller (3A) according to yet another embodiment of the present invention, capacitors (Cxy) are formed at a plurality of intersections by a plurality of Y electrodes (Y1 to YM) and X electrodes (X1 to XN). A drive circuit (300) for driving the Y electrode of the touch sensor panel (1), a detection circuit (301) for inputting a signal from the X electrode to detect a capacitance value of the capacitance at the intersection, the drive circuit, And a booster circuit (309) for generating a power supply voltage for operating the detection circuit. The drive circuit applies a plurality of pulse waveforms to the Y electrodes to drive the Y electrodes. The booster circuit performs a charge pump operation in synchronization with a pulse change of the charge clock signals (CCK1 to CCK4) of a plurality of phases. The multi-phase charge clock signals are initialized in drive cycle units (YNSCAN_ST) based on a plurality of pulse waveforms for each Y electrode.

  According to this, since the number of clock changes of the charge clock signal of a plurality of phases that determines the number of charge pump operations of the booster circuit becomes constant every constant pulse drive period for the Y electrode, noise due to the boost operation of the booster circuit The amount of superimposing is constant every time, and it is possible to prevent the touch detection accuracy from being lowered due to noise variations. When a boost circuit of a simple feedback control mode is used, the number of charge pump operations that occur every fixed pulse drive period for the Y electrode becomes indefinite and is affected by noise variations.

[11] <Initialization of counter for generating charge clock>
In the touch sensor panel controller according to item 10, the booster circuit includes a counter (410) that counts a clock signal and generates the charge clock signal of the plurality of phases based on a required plurality of digits of output. Initialization is performed in units of drive cycles (YNSCAN_ST) with a plurality of pulse waveforms for each Y electrode.

  According to this, generation and initialization of a required charge clock signal can be easily realized by using the counter.

[12] <Initialize charge pump charge clock for each Y electrode>
A semiconductor device according to still another embodiment of the present invention includes a touch sensor panel controller (3), a display driver (4), and a booster circuit (700). The touch sensor panel controller drives the Y electrodes of the touch sensor panel (1) in which capacitors (Cxy) are formed at a plurality of intersections by a plurality of Y electrodes (Y1 to YM) and X electrodes (X1 to XN). A detection circuit (301) that detects a capacitance value of the capacitance at the intersection by inputting a signal from the drive circuit (300) and the X electrode. The display driver supplies a display driving voltage to an active matrix display panel (2) in which display cells are arranged at intersections of a plurality of scanning electrodes (G1 to G640) and signal electrodes (D1 to D1440). The drive circuit applies a plurality of pulse waveforms to the Y electrodes to drive the Y electrodes. The booster circuit generates a power supply voltage for operating the drive circuit, the detection circuit, and the display driver, and performs a charge pump operation in synchronization with a pulse change of a plurality of charge clock signals (CCK1 to CCK4). . The multi-phase charge clock signals are initialized in drive cycle units (YNSCAN_ST) by a plurality of pulses for each Y electrode.

  According to this, there exists an effect similar to item 10. However, the booster circuit mentioned here is not limited to the one dedicated to the touch sensor panel controller, and may be used also for supplying the operation power to the display driver.

[13] <Initialization of counter for generating charge clock>
Item 12. The semiconductor device according to Item 12, wherein the booster circuit includes a counter (410) that counts a clock signal and generates the charge clock signal of a plurality of phases based on outputs of a plurality of required digits. The count value is initialized in units of drive cycles with a plurality of pulse waveforms for each Y electrode.

  According to this, it has the same effect as the item 11.

2. Details of Embodiments Embodiments will be further described in detail.

<< Embodiment 1 >>
FIG. 1 is an explanatory diagram showing the overall configuration of a display and input device to which the present invention is applied. The display and input device shown in FIG. 1 constitutes a part of a portable terminal such as a PDA or a mobile phone, and includes a touch sensor panel (TP) 1, a liquid crystal display panel (DSP) 2 as a display panel, and a touch sensor panel controller. (TPC) 3 and a liquid crystal driver (DSPD) 4 as a display driver.

  The touch sensor panel controller 3 drives the touch sensor panel 1 based on the control of the subsystem microprocessor (SMPU) 5 and sequentially acquires and accumulates signals from the capacitance array at the intersection of the X electrode and the Y electrode. Then, the accumulated signal is returned to the microprocessor 5 for the subsystem. The subsystem microprocessor 5 means a microprocessor for constituting a subsystem with respect to the host processor 6.

  The touch sensor panel 1 is configured using a transmissive (translucent) electrode or a dielectric film, and is disposed, for example, on the display surface of the liquid crystal display 2 in a bitmap display form. The host processor (HMPU) 6 generates display data, and the liquid crystal display driver 4 performs display control for displaying the display data received from the host processor 6 on the liquid crystal display 2.

  The microprocessor 5 of the subsystem performs a digital filter operation on the signal received from the touch sensor panel controller 3, and the coordinates when a touch event occurs on the touch sensor panel 3 based on the signal from which the noise has been removed by this operation. Is calculated and given to the host processor 6. For example, the host processor 6 analyzes the input from the touch sensor panel 1 from the relationship between the display screen given to the liquid crystal display driver 4 and the coordinate data given from the microprocessor 5 of the subsystem.

  FIG. 2 illustrates an electrode configuration of the touch sensor panel. The touch sensor panel 1 is configured such that a large number of Y electrodes Y1 to YM formed in the horizontal direction and a large number of X electrodes X1 to XN formed in the vertical direction are electrically insulated from each other. Each electrode is formed in a rectangular shape in the middle of its extending direction to constitute a capacitive electrode. The capacitance at the intersection (intersection capacitance) is formed by the capacitance electrode connected to the X electrode and the capacitance electrode connected to the Y electrode. The Y electrodes Y1 to YM are driven by applying pulses in line order.

  FIG. 3 illustrates an electrode configuration of the display panel 2. The display size of the display panel 2 shown in the figure is, for example, a scale of 480 RGB × 640. In the display panel 2, gate electrodes G1 to G640 as scanning electrodes formed in the horizontal direction and drain electrodes D1 to D1440 as signal electrodes formed in the vertical direction are arranged, and selection terminals correspond to the intersections. A large number of display cells connected to the scan electrodes and having input terminals connected to the corresponding signal electrodes are arranged. The gate electrodes G1 to G640 are driven by applying pulses in the order of electrode arrangement.

  FIG. 4 illustrates the overall configuration of the touch sensor panel controller 3. The touch sensor panel controller 1 includes a drive circuit (YDRV) 300, an integration circuit (INTGR) 301 as a detection circuit, a sample hold circuit (SH) 302, a selector (SLCT) 303, an AD conversion circuit (ADC) 304, a RAM 305, and a bus interface. A circuit (BIF) 306 and a sequence control circuit (SQENC) 308 are included.

  The drive circuit 300 drives the Y electrodes Y1 to YM with a pulsed AC drive voltage in the order of electrode arrangement. In short, the capacitance formed at the intersection of the X electrode and the Y electrode is scan-driven. The integration circuit 301 inputs detection signals sequentially from the intersection capacitance driven by scanning and accumulates the signal charges. The selector 303 selects the charge signal integrated by the integration circuit for each X electrode (X1 to XN), and the selected charge signal is converted into detection data by the AD conversion circuit 304. The converted detection data is stored in the RAM 305. The detection data stored in the RAM 305 is supplied to the microprocessor 5 of the subsystem via the bus interface circuit 306 and used for digital filter calculation and coordinate calculation.

  The sequence control circuit 308 uses the control signals Csig1 to Csig6 to control the operations of the drive circuit 300, the integration circuit 301, the sample hold circuit 302, the selector 303, the AD conversion circuit 304, and the bus interface circuit 306, and also according to the control signal Csig7. Access control of the RAM 305 is performed. Although not particularly limited, a plurality of drive voltages Vbst output by the drive circuit 300 to the Y electrode, an initialization voltage VHSP of the X electrode input by the integration circuit 301, and other power supply voltages VIC are supplied from the outside of the touch sensor panel controller 3. Is done.

  FIG. 5 shows an example of an equivalent circuit of the touch sensor panel 1 and an integration circuit 301 as a detection circuit. In the touch sensor panel, Y electrodes Y1 to YM and X electrodes X1 to XN are arranged in a matrix, and an intersection capacitance Cxy is formed at the intersection.

  The integration circuit 301 resets the power supply VHSP for charging the X electrodes X1 to XN, the switch SW2 for controlling the charging of the power supply VHSP to the X electrodes X1 to XN, the operational amplifier AMPit, the integration capacitor Cs, and the integration capacitor Cs. Switch SW1. The switch SW1 is a switch for resetting the electric charge superimposed on the capacitor Cs used for detection, and the switch SW2 is a switch for charging the power supply VHSP to the X electrodes X1 to XN.

  FIG. 6 shows an example of an input waveform to the Y electrodes Y1 to YM. As illustrated in the figure, an AC drive voltage is input to the Y electrodes Y1 to YM in the form of pulses in the order of electrode arrangement. Here, for the sake of convenience, an example in which the AC drive voltage is changed by nine pulses per Y electrode is shown.

  FIG. 7 illustrates the input pulse voltage to the Y electrodes Y1 to YM and the timing of the detection operation by the integration circuit 301. First, the switch SW2 is turned on to make a transition to the non-detection state a in which the X electrode Xn (n = 1 to N) is charged to the power supply VHSP, the switch SWS1 is turned on, and the capacitor Cs is reset. Next, the switch SW1 and the switch SW2 are turned off, and a transition is made to the detection standby state b. In the detection standby state b, the X electrode Xn is not connected to the power supply VHSP, and the voltage level is held in the integrating circuit 301 having a virtual ground configuration. Then, after transitioning to the detection standby state b, a rising pulse having an amplitude Vy is input to the Y electrode Y1 (the other Y electrodes Y2 to YM are fixed at a low level). As a result, the charge (= Vy × Cxy) is moved to the X electrode Xn via the intersection capacitance Cxy on the Y electrode Y1 and input to the detection circuit 301, and the output VOUTn of the operational amplifier AMPit changes. Since the corresponding intersection capacitance Cxy is reduced by the capacitance value Cf by touching with a finger, for example, if the touched X electrode is X2, the charge input to the operational amplifier AMPit of the X electrode X2 is Vy × (Cxy −Cf), and the output VOUT2 of the operational amplifier AMPit becomes a high potential. This VOUTn (n = 1 to N) is converted into detection data of a digital value by the AD conversion circuit 304 and used for coordinate calculation or the like.

  FIG. 8 illustrates an equivalent circuit of the liquid crystal display panel 2 and a liquid crystal driver 4 drive circuit. In the liquid crystal display panel 2, gate electrodes G1 to G640 and drain electrodes D1 to D1440 are arranged in a matrix, and TFT (Thin Film Transistor) switches are formed at the intersections. A liquid crystal pixel electrode S of a liquid crystal capacitor LCD serving as a subpixel is connected to the source side of the TFT switch, and an electrode on the opposite side of the liquid crystal capacitor LCD is a common electrode (COM). The drain electrodes D1 to D1440 are coupled to the output of an operational amplifier AMPvf that constitutes a voltage follower. For example, the gradation voltage VDR1 corresponding to red is supplied to the operational amplifier AMPvf of the drain electrode D1, and the gradation voltage VDG1 corresponding to green is supplied to the operational amplifier AMPvf of the drain electrode D2.

  FIG. 9 illustrates input waveforms to the gate electrodes G1 to G640. Gate pulses are input to the gate electrodes G1 to G640 in the order of electrode arrangement.

  FIG. 10 illustrates timing waveforms of the gate pulse applied to the gate electrode and the gradation voltage applied to the drain electrode. For example, a gate pulse with an amplitude Vg is input to the gate electrode G1, and the TFT switch on the gate electrode G1 is turned on. Thereafter, the gradation voltage VDR1 is applied from the drain electrode D1 to the selected liquid crystal pixel electrode S through the TFT switch. The input voltage of the liquid crystal pixel electrode S is determined at the timing when the gate pulse falls. A reference voltage is applied to the common electrode COM, and after the TFT switch is turned off, the reference voltage COM and the gradation voltage VDR1 are held in the liquid crystal capacitor LCD for one frame to define display luminance.

  FIG. 11 illustrates drive waveforms for the gate electrode and the drain electrode of the liquid crystal display 2 and drive waveforms for the Y electrode of the touch sensor panel 1. In the touch sensor panel 1, it is known that when the pulse amplitude of the drive voltage supplied to the Y electrode is larger, the signal component can be expanded and a higher S / N ratio (signal noise ratio) can be obtained. . Here, the drive waveform for the gate electrode of the liquid crystal driver 4 is focused on the fact that the high level VGH is 9 V and the low level VGL is −15. In this embodiment, the power supply voltage generated inside the liquid crystal driver 4 The drive pulse voltage of the touch sensor panel 1 is generated based on Vbst. For example, the power supply voltage Vbst is -15V, -5V, 5V, 9V. The drive pulse voltage of the touch sensor panel 1 is, for example, -15V for the low level VYL and 9V for the high level VYH. As a result, the power supply circuit or booster circuit of the touch sensor panel 1 and the liquid crystal driver 4 can be shared, and the number of external components such as a stabilization capacitor or a booster capacitor for each power supply voltage can be reduced. .

  FIG. 12 illustrates the correspondence between register values and voltages when the drive pulse voltage of the Y electrode is made variable by register setting. Here, an example of a register for setting a low level VYL and a voltage level among drive pulses of an AC drive voltage for driving the Y electrode is shown. The high level VYH of the drive pulse is fixed at 9V, for example, and the low level VYL of the drive pulse can be set programmable by a 2-bit register VGLVL. The register VGLVL is configured as a part of the control register (CREG) 320 provided in the sequence control circuit 308 illustrated in FIG. 4, and the setting content of the register VGLVL is given to the drive circuit 300 as a part of the control signal Csig1. .

  If it is in the above-mentioned voltage range, the touch sensor panel controller 3 can be configured by the existing transistor process employed in the liquid crystal driver 4, and no cost increase due to unnecessary process development or the like is required. Naturally, the power supply voltage generated by the power supply circuit or the booster circuit of the liquid crystal driver 4 can be shared by all or part of the power supply voltage of the drive pulse for driving the Y electrode. In the example of FIG. 12, a voltage of −9 V is generated inside the touch sensor panel controller 3 using −5 V and −15 V.

  Furthermore, as illustrated in FIGS. 11 and 12, the high voltage drive pulse of the Y electrode having a potential difference of 24 V at the maximum can be expected to have a high S / N ratio for the touch sensor panel 1 as described above. On the other hand, the liquid crystal display 2 used in combination with the touch sensor panel 1 may be a noise source. Here, paying attention to the fact that the influence on the display of the liquid crystal display 2 as a noise source differs depending on the mounting method of the touch sensor panel 1 and the liquid crystal display 2, and in the present embodiment, the setting for the register VGLVL as described above. Accordingly, it is possible to adjust the pulse amplitude Vy (= VYH−VYL) that achieves both a high S / N ratio and avoidance of display deterioration.

  FIG. 13 illustrates a power supply system to the liquid crystal driver 4 and the touch sensor panel controller 3. In the figure, the driving voltages of the liquid crystal driver 4 and the touch sensor panel controller 3 formed on different semiconductor chips are shared as described above. As described above, the liquid crystal driver 4 includes the booster circuit 400 that generates a high voltage. The voltage AVDD (5 V) is used for the power supply for generating VHSP described with reference to FIG. Compared to the case where the liquid crystal driver 4 and the touch sensor panel controller 3 are separately provided with the booster circuits 400 and 309 as shown in FIG. 14, the number of external parts typified by the stabilizing capacitor Cp can be reduced.

  FIG. 16 shows an example of a touch sensor panel controller 3A provided with a booster circuit 309. 4 is different from FIG. 4 in that a booster circuit (VBST) 309 is provided, and the other configurations are the same as those in FIG. 4, and the same reference numerals are assigned to the same and detailed description thereof is omitted. The booster circuit 309 generates boosted voltages Vbst and VHSP from the external voltage VCI according to the control signal Csig8 supplied from the sequence control circuit 308. Since the touch sensor panel controller 3A includes the dedicated booster circuit 309, the selection range of the drive pulse voltage of the Y electrode is widened without being limited by the booster voltage by the booster circuit 400 of the liquid crystal driver 4.

  FIG. 15 illustrates a driver device 7 in which the display driver 4 and the touch sensor panel controller 3 are configured as a single chip. The driver device 7 includes a booster circuit 700 that is shared by the display driver 4 and the touch sensor panel controller 3. The booster circuit 700 generates 5V, −5V, and 9V−15V and supplies them to the display driver 4 and the touch sensor panel controller 3. In consideration of the register setting of the pulse voltage for the Y electrode described with reference to FIG. 12, the booster circuit 700 may further have a voltage output function of −9V.

  FIG. 17 shows a specific example of the driver device 7 of FIG. Compared to FIG. 4, the difference is that the booster circuit (VBST) 700 and the liquid crystal driver 4 are provided, and the other configurations are the same as those in FIG. . The booster circuit 700 generates boosted voltages Vbst and VHSP from the external voltage VCI according to the control signal Csig10 supplied from the liquid crystal driver 7. The device driver 7 is a device having a property called a liquid crystal driver if the function is mainly a liquid crystal driver and a touch sensor panel controller if the function is mainly a touch sensor panel controller. By constituting with one chip, it is possible to contribute to miniaturization of a system to which this is applied.

<< Embodiment 2 >>
Next, as Embodiment 2 of the present invention, the relationship between the drive waveform of the liquid crystal display and the drive pulse waveform of the touch sensor panel will be described. In the first embodiment, the detection sensitivity is improved or the S / N ratio is increased by increasing the voltage of the drive pulse to the Y electrodes Y1 to YM of the touch sensor panel 1. It is assumed that the drive pulse with high voltage applied to the Y electrodes Y1 to YM becomes noise for the liquid crystal display panel 2 and the liquid crystal driver 4. In the second embodiment, a control timing suitable for achieving both a high S / N ratio of the touch sensor panel and avoiding display deterioration of the liquid crystal display panel by increasing the drive pulse voltage to the Y electrode is provided. It is.

  FIG. 18 illustrates the relationship between the drive waveform of the liquid crystal display panel and the Y electrode drive pulse waveform of the touch sensor panel.

  In the control of the touch sensor panel, attention is paid to the voltage change timing of the gate electrode and the drain electrode of the liquid crystal display, and the X electrode is controlled to transit to the non-detection period (VHSP charge period) at that timing. In the control of the liquid crystal display, paying attention to the voltage change timing of the Y electrode of the touch sensor panel, the falling timing of the Y electrode drive pulse is a certain period before the gate pulse falling timing at which the gradation voltage is determined. Set to be.

  According to the above timing relationship, the high level period of the drive pulse waveform (first pulse waveform) of the Y electrodes Y1 to YM is within the high level period of the gate electrodes G1 to G640 (second pulse waveform), and the first The high level width of the first pulse waveform is made smaller than the high level width of the second pulse waveform. According to this, in the control by the touch sensor panel controller 3, when paying attention to the voltage change timing of the scanning electrodes G1 to G640 of the display panel 2, the Y electrodes Y1 to YM are in the non-pulse driving period, that is, the X electrodes X1 to X1. Since it is a non-detection period (charge period) due to XN, noise generated by voltage changes of the scan electrodes G1 to G640 affects the detection operation of the X electrodes X1 to XN performed in the pulse drive period of the Y electrodes Y1 to YM. Absent. Further, in the control by the display driver 4, when attention is paid to the voltage change timing of the Y electrodes Y1 to YM of the touch sensor panel, the falling timing of the drive pulse (first pulse waveform) of the Y electrodes Y1 to YM is given to the display cell. It deviates from the fall timing (Ta in FIG. 18) of the drive pulse (second pulse waveform) of the scan electrode at which the signal voltage is determined. Therefore, noise caused by voltage changes of the Y electrodes Y1 to YM does not affect the signal voltage determined in the display cell. In short, it is possible to avoid a situation in which the touch detection capability using the touch sensor panel controller 3 is reduced or the display performance of the display driver 4 is deteriorated.

  The example of FIG. 18 shows a case where a driving pulse is applied to the Y electrode once in one scanning period for the liquid crystal display 2, and in this case, the high level period of the driving pulse of the Y electrode is the high level period of the gate pulse. It will be included and set. In this case, the drive pulse timing of the Y electrode includes a built-in reference clock (for example, 4 MHz), a signal for defining one scanning period (for example, a horizontal synchronization signal such as Hsync), and parameters t1 and t2 illustrated in FIG. , T3. The sequence control circuit 308 of the touch sensor panel controller 3 or 3A receives the reference clock (for example, 4 MHz), a horizontal synchronization signal such as Hsync, and parameters t1, t2, and t3 as illustrated in FIG. The pulse drive timing for the Y electrode can be controlled. The parameters t1, t2, and t3 may be initialized by the subsystem microprocessor 5 in the control register 320.

  FIG. 19 shows an example of setting registers Twait, Tydrv, Tset for parameters t1, t2, and t3 and setting times according to the setting values. The setting registers Twait, Tydrv, and Tset are part of the control register 320.

  Although illustration is omitted, all the configurations described in the first embodiment can be applied to the second embodiment. In that case, the sequence control circuit can acquire the parameters for controlling the pulse drive waveform of the Y electrode with respect to the drive waveform of the gate electrode, the horizontal synchronization signal, and the like in the first embodiment as exemplarily described in FIG. A signal path or the like may be provided.

<< Embodiment 3 >>
In the third embodiment, a configuration for optimizing the boost operation timing by the boost circuit to the detection operation by the touch sensor panel will be described.

  FIG. 20 shows an example of the booster circuit 400. The charge pump circuit 400 includes, for example, a counter 410 that counts a 4 MHz reference clock CLK and outputs a plurality of phases of the charge clock signals CCK1, CCK2, CCK3, and CCK4 based on a required multiple-digit output. Switch elements DC1_SW1 to DC1_SW4 and DC2_SW1 to DC2_SW4 that are switch-controlled by the output charge clock signals CCK1 to CCK4, and a capacitive element C11 that performs charge transfer in synchronization with the switch operations of the switch elements DC1_SW1 to DC1_SW4 and DC2_SW1 to DC2_SW4 C12. The counter 410 is initialized to 0 by the timing pulse YNSCAN_ST. The timing pulse YNSCAN_ST is generated by the timing control circuit 308 of the touch sensor panel controller 3 and supplied to the counter 410.

  FIG. 21 illustrates the timing of the detection operation by the touch sensor panel controller 3 and the boost operation by the boost circuit. The timing signal YNSCAN_ST is pulse-changed in synchronization with the heads of a plurality of drive pulse waveforms for each Y electrode. That is, the touch panel sensor controller 3 generates the timing signal YNSCAN_ST indicating the head of the drive pulse applied to the Y electrodes Y1 to YM of the touch sensor panel. The booster circuit 400 performs a boost operation in synchronization with changes in the charge clock signals CCK1, CCK2, CCK3, and CCK4 according to a count value obtained by the counter 410 counting a reference clock CLK of 4 MHz, for example. Each time the signal YNSCAN_ST is set to the high level, the count value of the counter 410 is initialized to zero. As a result, every time the timing signal YNSCAN_ST indicating the start of the touch detection operation transitions to a high level, the internal state of the booster circuit 400 is made identical, and the number of power supply voltage fluctuations (boost count) associated with the boost operation is determined by the Y electrode Y1. It can be made the same in any driving period of .about.YM. In FIG. 8, a case where the number of times of boosting in the detection period of each Y electrode Ym (m = 1 to M) is 16.5 is taken as an example. As a result, the amount of noise superimposed due to the boosting operation of the booster circuit is made uniform during the detection period of each Y electrode, and a high S / N ratio can be realized for the touch sensor panel 1.

  In the third embodiment, the boosting operation timing of the boosting circuit 400 has been described based on the relationship with the detection operation cycle of the touch sensor panel 1, but as described in the second embodiment, the detection of the touch sensor panel 1 is performed. If the drive control of the liquid crystal display panel 2 is synchronized with the operation, the operations of the liquid crystal display panel 2, the touch sensor panel 1, and the booster circuit 400 can be synchronized. This is useful in achieving both the N ratio and the avoidance of deterioration of display quality in the liquid crystal display panel 2.

  The configuration of the booster circuit can be applied to other booster circuits 309 and 700. The initialization of the counter 410 may be performed in synchronization with a timing signal indicating the end of the detection operation for each Y electrode. Furthermore, any timing may be used as long as the timing is constant in units of driving cycles of a plurality of Y electrode pulse waveforms.

  Although the invention made by the present inventor has been specifically described based on the embodiments, it is needless to say that the present invention is not limited thereto and can be variously modified without departing from the gist thereof.

  For example, each embodiment can be implemented in combination with each other. The present invention can be applied to a touch sensor panel having a small size of about 5 inches or 7 inches to a large size of about 15 inches. The present invention can also be realized as a liquid crystal driver with a built-in touch sensor panel controller and a touch sensor panel controller with a built-in liquid crystal driver. The semiconductor device according to the present invention may be a single chip or a multichip, and in the case of a multichip, it may be realized as a module device such as a system-in-package.

  In the case of a single chip, not only the touch sensor panel controller and the liquid crystal driver but also a subsystem microprocessor 5 may be included. In the case of a multichip, the touch sensor panel controller 3 and the subsystem are included. For example, a two-chip configuration of a chip composed of the microprocessor 5 for the above and a liquid crystal driver may be used.

  Furthermore, in the present invention, the integration circuit has been described as an example of the detection circuit. However, the present invention is applicable to any detection system that inputs a pulse to the Y electrode.

1 Touch sensor panel (TP)
2 Liquid crystal display panel (DSP)
3 Touch sensor panel controller (TPC)
4 Liquid crystal driver (DSPD)
5 Microprocessor for subsystem (SMPU)
6 Host processor (HMPU)
Y1 to YM Y electrode X1 to XN X electrode G1 to G640 Gate electrode as scanning electrode D1 to D1440 Drain electrode as signal electrode 300 Drive circuit (YDRV)
301 Integration circuit (INTGR) as detection circuit
302 Sample hold circuit (SH)
303 Selector (SLCT)
304 AD conversion circuit (ADC)
305 RAM
306 Bus interface circuit (BIF)
308 Sequence control circuit (SQENC)
Csig1 to Csig7 Control signal Vbst Drive voltage VHSP X electrode initialization voltage AMPit Operational amplifier Cs Integration capacitor SW1 Reset switch 309, 400, 700 Booster circuit Twait, Tydrv, Tset Setting register CLK Reference clock CCK1, CCK2, CCK3, CCK4 Charge clock DC1_SW1 to DC1_SW4, DC2_SW1 to DC2_SW4 Switch element C11, C12 Capacitance element YNSCAN_ST Timing pulse

Claims (7)

A touch sensor panel that drives the Y electrode of a touch sensor panel in which capacitance is formed at a plurality of intersections by a plurality of Y electrodes and X electrodes, and detects a signal corresponding to the capacitance at the intersection by inputting a signal from the X electrode. A controller,
A display driver for supplying a display drive voltage to an active matrix display panel in which display cells are arranged at intersections of a plurality of scanning electrodes and signal electrodes,
The touch sensor panel controller has a first drive circuit that applies a first pulse waveform for driving the Y electrode in a pulsed manner,
The display driver has a second drive circuit that applies a second pulse waveform that drives the scan electrodes of the liquid crystal display panel.
The change timing of the second pulse waveform is shifted from the period of pulse driving by the first pulse waveform, and the falling timing at which the pulse driving by the first pulse waveform ends is the pulse driving by the second pulse waveform. A semiconductor device deviated from the end of falling.   The first driving circuit and the second driving circuit have a high level period of the first pulse waveform within a high level period of the second pulse waveform, and a high level width of the first pulse waveform. The semiconductor device according to claim 1, wherein the semiconductor device is made smaller than a high-level width of the second pulse waveform. The second driving circuit generates a second pulse waveform based on the driving timing of the display panel;
The first driving circuit sets a high level period of the first pulse waveform within a high level period of the second pulse waveform with reference to a driving timing of the display panel, The semiconductor device according to claim 2, wherein a second pulse waveform is generated in which a high level width is set smaller than a high level width of the second pulse waveform.   The change timing of the first pulse waveform is the time when the wait time has elapsed with respect to the rise timing of the second pulse waveform and the set time with respect to the fall timing of the second pulse waveform. 4. The semiconductor device according to claim 3, wherein the first driving circuit is set according to a time before starting. The touch sensor panel controller includes a drive circuit that drives the Y electrode;
A detection circuit that receives a signal from the X electrode and detects a voltage signal based on the capacitance of the intersection;
A control unit that controls the drive circuit and the detection circuit;
The drive circuit applies a pulse drive voltage that rises from a low level having a negative polarity to a high level having a positive polarity and falls from the high level to the low level to the Y electrode,
The semiconductor device according to claim 1, wherein the detection circuit detects the voltage signal in a high-level pulse period of the pulse drive voltage. The detection circuit has an integration amplifier that integrates the voltage signal of the X electrode,
The control unit precharges the X electrode using a low-level pulse period of the pulse drive voltage before detecting the capacitance,
The semiconductor device according to claim 5, wherein the integration amplifier performs an integration operation during a high-level pulse period of the pulse drive voltage.   The semiconductor device according to claim 5, wherein the control unit determines a low level of the pulse drive voltage based on selection data given from outside.

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