CN112947790B - Touch control driving circuit, driving chip and touch control display device - Google Patents

Abstract

The application provides a touch driving circuit, a driving chip and a touch display device. The touch control driving circuit is used for outputting a driving signal to drive a touch control electrode of the touch control display device; the touch control driving circuit comprises: the power supply comprises a power supply voltage generating circuit, a switching circuit and a first energy storage capacitor; the first input end of the switch circuit is connected to the power supply voltage generating circuit; the second input end of the switch circuit is connected to the ground end GND through the first energy storage capacitor; the third input end of the switch circuit is connected to the ground end GND; the output end of the switching circuit is connected to the touch electrode; the power supply voltage generating circuit is used for generating a first positive voltage; the switch circuit is used for controlling the touch electrode to be connected to the power voltage generating circuit in a first period, controlling the touch electrode to be connected to the first energy storage capacitor in a second period, and controlling the touch electrode to be connected to the ground terminal GND in a third period. The touch control driving circuit has lower driving power consumption.

Description

Touch control driving circuit, driving chip and touch control display device

Technical Field

The embodiment of the application relates to the technical field of electronic circuits, in particular to a touch driving circuit, a driving chip and a touch display device.

Background

The capacitive touch display device generally includes a display, a touch electrode and a touch driving circuit. The touch control driving circuit is used for charging and discharging the touch control electrode, so that when a human body or other conductors touch the display, the capacitance variation on the corresponding coordinate position of the display is detected, and the operation of a user is further determined.

Fig. 1 is a schematic structural diagram of a conventional touch driving circuit. The touch driving circuit provides a driving signal by using the inverter INV to drive the touch electrode. Wherein, the voltage V_DDIs a power supply voltage, a capacitor C_LRepresenting the equivalent capacitance, resistance R, of the touch electrode_LRepresenting the equivalent impedance (i.e., the drive impedance) at the time of coding. The power consumption of the touch control driving circuit is mainly divided into two parts, wherein one part is a pair capacitor C_LResistance R during charging_LAnother part is the capacitance C_LResistance R during discharge_LLoss in the optical fiber; in one period T of the driving signal (T:)Hereinafter referred to as a period T), the losses of both parts are 1/2 × C_L*V_DD ²F, the driving power consumption of the touch driving circuit shown in fig. 1 in one period T is C_L*V_DD ²F. Where f is 1/T, which is the frequency of the driving signal.

At present, the OLED (Organic Light Emitting Display) technology has many obvious advantages in Display performance compared with the conventional LCD (Liquid Crystal Display) technology, for example, the OLED screen is more Light and thin, and has the characteristics of wide viewing angle, low temperature resistance, ecological environment protection and the like, so the OLED screen is widely applied. However, the load capacitance of an OLED screen (equivalent capacitance C) is compared to an LCD screen_L) The capacitance value is obviously larger, so that the power consumption of the OLED screen is increased, and the requirement of low-power-consumption touch detection is difficult to meet.

Disclosure of Invention

In view of this, embodiments of the present disclosure provide a touch driving circuit, a driving chip and a touch display device to reduce driving power consumption.

In a first aspect, an embodiment of the present application provides a touch driving circuit, configured to output a driving signal to drive a touch electrode of a touch display device, where the touch driving circuit includes: the power supply comprises a power supply voltage generating circuit, a switching circuit and a first energy storage capacitor; a first input end of the switching circuit is connected to the power supply voltage generating circuit; the second input end of the switch circuit is connected to a ground end GND through the first energy storage capacitor; a third input end of the switch circuit is connected to the ground end GND; the output end of the switch circuit is connected to the touch electrode; the power supply voltage generating circuit is used for generating a first positive voltage; the switch circuit is used for controlling the touch electrode to be connected to the power supply voltage generating circuit within a first period, and the first positive voltage charges the touch electrode so that the voltage at two ends of the touch electrode is equal to the first positive voltage; controlling the touch electrode to be connected to the first energy storage capacitor in a second time period, wherein the first energy storage capacitor is used for storing charges released by the touch electrode, so that the voltage at two ends of the touch electrode is equal to a second positive voltage; controlling the touch electrode to be connected to the ground terminal GND in a third time period, and discharging the touch electrode to the ground terminal GND so that the voltage at two ends of the touch electrode is equal to zero voltage; the second positive voltage is lower than the first positive voltage and higher than the zero voltage.

By arranging the first energy storage capacitor and utilizing the first energy storage capacitor to store the charges released by the touch electrode, and introducing the second positive voltage between the first positive voltage and the zero voltage as an intermediate level, the loss of the driving impedance in the process (namely the discharging process) that the voltage at the two ends of the touch electrode is reduced from the first positive voltage to the zero voltage is reduced, so that the driving power consumption of the touch driving circuit is reduced.

Optionally, the touch driving circuit further includes: a second energy storage capacitor; a fourth input end of the switch circuit is connected to the ground end GND through the second energy storage capacitor; a fifth input terminal of the switching circuit is connected to the power supply voltage generating circuit; the power supply voltage generating circuit is further used for generating a first negative voltage; the switch circuit is further used for controlling the touch electrode to be connected to the second energy storage capacitor in a fourth time period, and the second energy storage capacitor is used for transferring stored charges to the touch electrode, so that the voltage at two ends of the touch electrode is equal to a second negative voltage; controlling the touch electrode to be connected to the power supply voltage generating circuit in a fifth time period, and charging the touch electrode by the first negative voltage so that the voltage at two ends of the touch electrode is equal to the first negative voltage; the second negative voltage is higher than the first negative voltage and lower than the zero voltage.

Optionally, the switch circuit is further configured to control the touch electrode to be connected to the second energy storage capacitor in a sixth time period, where the second energy storage capacitor is configured to store the charge released by the touch electrode, so that the voltage across the touch electrode is equal to the second negative voltage; controlling the touch electrode to be connected to the ground terminal GND in a seventh time period, and discharging the touch electrode to the ground terminal GND so that the voltage at two ends of the touch electrode is equal to the zero voltage; and controlling the touch electrode to be connected to the first energy storage capacitor in an eighth time period, wherein the first energy storage capacitor is used for transferring stored charges to the touch electrode, so that the voltage at two ends of the touch electrode is equal to the second positive voltage.

Optionally, the switching circuit further comprises: the first switch circuit, the second switch circuit, the third switch circuit, the fourth switch circuit and the fifth switch circuit; the input end of the first switch circuit is the first input end of the switch circuit, and the output end of the first switch circuit is connected to the output end of the switch circuit; the input end of the second switch circuit is the second input end of the switch circuit, and the output end of the second switch circuit is connected to the output end of the switch circuit; the input end of the third switching circuit is a third input end of the switching circuit, and the output end of the third switching circuit is connected to the output end of the switching circuit; the input end of the fourth switching circuit is the fourth input end of the switching circuit, and the output end of the fourth switching circuit is connected to the output end of the switching circuit; the input end of the fifth switch circuit is a fifth input end of the switch circuit, and the output end of the fifth switch circuit is connected to the output end of the switch circuit.

Optionally, in the first period, the first switch circuit is turned on; in the second period, the second switch circuit is conducted; during the third period, the third switch circuit is turned on; during the fourth period, the fourth switching circuit is turned on; during the fifth period, the fifth switch circuit is turned on; in the sixth period, the fourth switch circuit is turned on; in the seventh period, the third switch circuit is turned on; in the eighth time period, the second switch circuit is turned on; and when any one of the switch circuits is switched on, the other four switch circuits are switched off.

Optionally, the touch driving circuit further comprises a first pressure-bearing pipe and a second pressure-bearing pipe; the first switch circuit further comprises a first MOS tube; the second switching circuit further comprises a second MOS tube; the fourth switching circuit further comprises a fourth MOS transistor; the fifth switching circuit further comprises a fifth MOS transistor; the third switch circuit further comprises a third MOS transistor and a sixth MOS transistor; the first MOS tube, the sixth MOS tube and the first pressure-bearing tube are P-type MOS tubes, and the second MOS tube, the third MOS tube, the fourth MOS tube, the fifth MOS tube and the second pressure-bearing tube are N-type MOS tubes; the source electrode of the first MOS tube is connected to the first positive voltage, and the drain electrode of the first MOS tube is connected to the source electrode of the first pressure bearing tube; the source electrode of the second MOS tube is connected to the source electrode of the first pressure-bearing tube, and the drain electrode of the second MOS tube is connected to the first end of the first energy storage capacitor; the source electrode of the third MOS tube is connected to the ground end GND, and the drain electrode of the third MOS tube is connected to the source electrode of the first pressure-bearing tube; the source electrode of the fourth MOS tube is connected to the first end of the second energy storage capacitor, and the drain electrode of the fourth MOS tube is connected to the source electrode of the second pressure-bearing tube; the source electrode of the fifth MOS tube is connected to the first negative voltage, and the drain electrode of the fifth MOS tube is connected to the source electrode of the second pressure-bearing tube; the source electrode of the sixth MOS tube is connected to the ground end GND, and the drain electrode of the sixth MOS tube is connected to the source electrode of the second pressure-bearing tube; the second ends of the first energy storage capacitor and the second energy storage capacitor are connected to the ground end GND; the drain electrodes of the first pressure-bearing pipe and the second pressure-bearing pipe are connected to the touch electrode; the first pressure bearing pipe is used for preventing the voltages at two ends of the first MOS pipe, the second MOS pipe and the third MOS pipe from exceeding a withstand voltage value; the second pressure-bearing pipe is used for preventing the voltage at two ends of the fourth MOS pipe, the fifth MOS pipe and the sixth MOS pipe from exceeding a withstand voltage value.

Optionally, in the first period, the first MOS transistor is turned on, the gates of the first voltage-bearing transistor and the second voltage-bearing transistor are connected to the ground GND, and the other five MOS transistors are turned off; in the second time period, the second MOS tube is conducted, the grids of the first pressure-bearing tube and the second pressure-bearing tube are connected to the ground end GND, and the other five MOS tubes are cut off; in the third time period, the third MOS transistor is turned on, the voltage accessed by the gate of the first pressure-bearing transistor is equal to the difference between the second positive voltage and the first positive voltage, the gate of the second pressure-bearing transistor is connected to the ground terminal GND, and the other five MOS transistors are turned off; in the fourth time period, the fourth MOS tube is switched on, the grids of the first pressure-bearing tube and the second pressure-bearing tube are connected to the ground end GND, and the other five MOS tubes are switched off; in the fifth time period, the fifth MOS tube is conducted, the grids of the first pressure-bearing tube and the second pressure-bearing tube are connected to the ground end GND, and the other five MOS tubes are cut off; in the sixth time period, the fourth MOS tube is switched on, the grids of the first pressure-bearing tube and the second pressure-bearing tube are connected to the ground end GND, and the other five MOS tubes are switched off; in the seventh time period, the sixth MOS transistor is turned on, the gate of the first pressure-bearing transistor is connected to the ground GND, the voltage applied to the gate of the second pressure-bearing transistor is equal to the difference value obtained by subtracting the first negative voltage from the second negative voltage, and the other five MOS transistors are turned off; in the eighth time period, the second MOS transistor is turned on, the gates of the first and second pressure-bearing transistors are connected to the ground GND, and the other five MOS transistors are turned off.

Optionally, the signal amplitude of the driving signal in one period is equal to the first positive voltage, the second positive voltage, the zero voltage, the second negative voltage, the first negative voltage, the second negative voltage, the zero voltage, and the second positive voltage in sequence.

Optionally, the power supply voltage generating circuit further comprises a positive-negative voltage converting circuit; the positive and negative voltage conversion circuit is used for converting the first positive voltage into the first negative voltage.

Optionally, a capacitance value of the first energy storage capacitor or the second energy storage capacitor is greater than 50 times an equivalent capacitance value of the touch electrode.

Optionally, the second positive voltage is equal to 1/2 of the first positive voltage, and the second negative voltage is equal to 1/2 of the first negative voltage.

In a second aspect, an embodiment of the present application provides a touch driving chip, including the touch driving circuit provided in the first aspect or any optional manner of the first aspect.

In a third aspect, an embodiment of the present application provides a touch display device, including the touch driving chip provided in the third aspect.

It can be understood that, the touch driving chip of the second aspect and the touch display device of the third aspect both employ the corresponding touch driving circuit provided above, and therefore, the beneficial effects achieved by the touch driving chip of the second aspect and the touch display device of the third aspect can refer to the beneficial effects of the corresponding touch driving circuit provided above, and are not repeated herein.

Drawings

One or more embodiments are illustrated by the corresponding figures in the drawings, which are not meant to be limiting. The following description refers to the accompanying drawings in which like numerals in different drawings represent like elements. The drawings in the drawings are not to scale unless specifically noted.

Fig. 1 is a schematic structural diagram of a conventional touch driving circuit;

fig. 2 is a schematic structural diagram of a touch driving circuit according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of another touch driving circuit according to an embodiment of the present disclosure;

fig. 4 is a waveform diagram of a driving signal according to an embodiment of the present disclosure;

FIG. 5 is a first time period provided by an embodiment of the present application

And a second period of time

A schematic diagram of charging and discharging of the touch electrode by the internal touch driving circuit;

FIG. 6 is a seventh time period provided in the embodiments of the present application

And an eighth period

The principle schematic diagram of charging and discharging the touch electrode by the internal touch driving circuit;

fig. 7 is a schematic structural diagram of another touch driving circuit according to an embodiment of the present disclosure;

fig. 8 is a schematic structural diagram of another touch driving circuit according to an embodiment of the present disclosure;

fig. 9 is a waveform diagram of another driving signal according to an embodiment of the present disclosure.

Detailed Description

The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

Furthermore, the terms "first," "second," and the like, are used solely to distinguish between similar objects and are not intended to indicate or imply relative importance or to implicitly indicate a number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature.

The embodiment of the application provides a touch drive circuit, a drive chip and a touch display device. The touch driving circuit can be applied to a touch display device, and outputs a driving signal to drive a touch electrode of the touch display device. The touch display device can also comprise a display, and a user can touch icons or characters on the display by using fingers or other conductors to realize corresponding touch operation; examples of displays include, but are not limited to, Liquid Crystal (LCD) displays, Organic Light Emitting (OLED) displays, Plasma Display Panels (PDP) displays, and Cathode Ray Tube (CRT) displays.

Fig. 2 is a schematic structural diagram of a touch driving circuit according to an embodiment of the present disclosure. Wherein, the resistance R_LRepresenting the driving impedance (including the equivalent impedance of the touch electrode and the touch driving circuit); capacitor C_LRepresenting the equivalent capacitance of the touch electrode. The touch driving circuit 10 includes a switch circuit 101, and a first input terminal of the switch circuit 101 is connected to a first positive voltage V_DDThe second input end passes through the first energy storage capacitor C_S1The third input end is connected to the ground end GND, and the output end is connected to the touch electrode. A first positive voltage V_DDMay be a power supply voltage generated by a power supply voltage generating circuit. The switching circuit 101 may control the connection object of the touch electrodes in the following order: controlling the touch control electrode to be connected to the power voltage generating circuit in a first period, and charging the touch control electrode by a first positive voltage to make the voltage at two ends of the touch control electrode equal to a first positive voltage V_DD(ii) a Controlling the touch electrode to be connected to the first energy storage capacitor C in the second time period_S1A first energy storage capacitor C_S1The charges discharged by the touch electrode can be stored so that the voltage across the touch electrode is equal to the second positive voltage V_C1(ii) a And controlling the touch electrode to be connected to the ground end GND in a third time period, and discharging the touch electrode to the ground so that the voltage at the two ends of the touch electrode is equal to zero voltage.

The power supply voltage generating circuit may be separately provided for supplying the power supply voltage to the touch driving circuit, or may be shared with other circuit modules in the touch detection chip.

In the second time interval, the touch electrode faces the first energy storage capacitor C_S1Part of positive charges are transferred until the voltage at the two ends of the touch electrode and the first energy storage capacitor C_S1The voltages at the two ends are equal, so that the voltages at the two ends of the touch electrode are controlled by a first positive voltage V_DDBecomes a second positive voltage V_C1Therefore, it is possible toA second positive voltage V_C1Lower than a first positive voltage V_DDAnd above zero voltage, i.e. satisfies V_DD>V_C1>0。

When the first energy storage capacitor C_S1Is much larger than the capacitance C_LAt the capacitance value of (2), a second positive voltage V_C1Is approximately equal to V_DD/2, so that during the discharge of the touch electrode, the resistance R_LThe loss above is approximately equal to 1/4C_L*V_DD ²F is only 50% of the conventional touch driving circuit shown in fig. 1, specifically, if the first energy storage capacitor C is used_S1Is greater than the capacitance C_L30 times of the capacitance value of the first capacitor C, the first energy storage capacitor C can be determined_S1Is much larger than the capacitance C_LThe capacitance value of (a); preferably, the first energy storage capacitor C may be made_S1Is larger than the capacitance C_L50 to 100 times of the capacitance value of (A).

In addition, when the first energy storage capacitor C_S1Is not much larger than the capacitance C_LAt the capacitance value of (C), the first energy storage capacitor C_S1It is also possible to introduce a voltage V lower than the first positive voltage_DDAnd is higher than the middle level of zero voltage, thereby reducing the resistance R in the discharge process of the touch electrode_LI.e. the loss can be made to be less than 1/2C_L*V_DD ²F, but since the intermediate level is not approximately equal to V _DD2, so that this loss value is greater than 1/4C_L*V_DD ²*f。

Fig. 3 is a schematic structural diagram of another touch driving circuit according to an embodiment of the present disclosure. The touch driving circuit 20 includes a switch circuit 201, and a first input terminal of the switch circuit 201 is connected to a first positive voltage V_DDThe second input end passes through the first energy storage capacitor C_S1Is connected to the ground end GND, the third input end is connected to the ground end GND, and the fourth input end passes through the second energy storage capacitor C_S2Is connected to ground GND, and the fifth input end is connected to a first negative voltage-V_DDAnd the output end is connected to the touch electrode. A first positive voltage V_DDAnd a first negative voltage-V_DDAre all generated by a power supply voltage generating circuitThe resulting supply voltage. The switching circuit 201 may control the connection object of the touch electrodes in the following order: controlling the touch control electrode to be connected to the power voltage generating circuit in a first period, and charging the touch control electrode by a first positive voltage to make the voltage at two ends of the touch control electrode equal to a first positive voltage V_DD(ii) a Controlling the touch electrode to be connected to the first energy storage capacitor C in the second time period_S1A first energy storage capacitor C_S1The charges discharged by the touch electrode can be stored so that the voltage across the touch electrode is equal to the second positive voltage V_C1(ii) a Controlling the touch electrode to be connected to a ground end GND in a third time period, and discharging the touch electrode to the ground to enable the voltage at two ends of the touch electrode to be equal to zero voltage; controlling the touch electrode to be connected to the second energy storage capacitor C in the fourth period_S2A second energy storage capacitor C_S2Transferring the stored charge to the touch electrode such that the voltage across the touch electrode equals a second negative voltage V_C2(ii) a Controlling the touch electrode to be connected with the first negative voltage-V in the fifth time period_DDFirst negative voltage-V_DDCharging the touch electrode so that the voltage across the touch electrode is equal to a first negative voltage-V_DD。

The power supply voltage generating circuit may include a positive-negative voltage converting circuit, and the positive-negative voltage converting circuit may convert the first positive voltage V_DDIs converted into a first negative voltage-V_DDAn example of the positive-negative voltage conversion circuit includes a negative voltage charge pump circuit.

The charge transfer process in the fourth period is based on the second energy storage capacitor C_S2A certain negative charge situation has been stored. Since in the fifth period the first negative voltage-V_DDFurther charging the touch electrode to make the voltage at two ends of the touch electrode from a second negative voltage V_C2Becomes a first negative voltage-V_DDSo that the second negative voltage V_C2Higher than the first negative voltage-V_DDAnd is lower than zero voltage, i.e. satisfies 0>V_C2>-V_DD，│V_DD│>│V_C2│>0。

By setting a first negative voltage-V_DDThe signal of the driving signal output by the touch driving circuit can be enabledAmplitude from V_DDIs increased to 2V_DDThe resolution of touch detection is improved. For the conventional touch driving circuit shown in fig. 1, if the signal amplitude of the driving signal is increased to 2V_DDThe drive power consumption in one period T will increase to 4 x C_L*V_DD ²F, f; wherein, the resistance R in the discharging process of the touch electrode_LLoss in is equal to 2 x C_L*V_DD ²F. However, in this embodiment, the first energy storage capacitor C is utilized_S1And a second energy storage capacitor C_S2The charges transferred out by the touch electrode in the discharging process are recycled, and extra power consumption is not generated in the process, so that the resistor R in the discharging process of the touch electrode_LLoss in is equal to 1/2C_L*V_DD ²F, which is only 25% of the conventional touch driving circuit.

Based on the disclosure of the above embodiments, in the present embodiment, the switch circuit may further control the touch electrode to be connected to the second energy-storing capacitor C in the sixth time period_S2A second energy storage capacitor C_S2Storing the charges discharged by the touch electrode so that the voltage across the touch electrode is equal to the second negative voltage V_C2(ii) a Controlling the touch electrode to be connected to the ground end GND in a seventh time period, and discharging the touch electrode to the ground to enable the voltage at the two ends of the touch electrode to be equal to zero voltage; controlling the touch electrode to be connected to the first energy storage capacitor C in the eighth time period_S1A first energy storage capacitor C_S1Transferring the stored charges to the touch electrode so that the voltage across the touch electrode is equal to a second positive voltage V_C1. To this end, the switching circuit completes the operation in one duty cycle, and then the first positive voltage V may be controlled again in accordance with the operation in the first period_DDAnd charging the touch electrode, and continuously and periodically circulating to ensure that the signal amplitude of the driving signal output by the touch driving circuit in one period is sequentially equal to a first positive voltage, a second positive voltage, a zero voltage, a second negative voltage, a first negative voltage, a second negative voltage, a zero voltage and a second positive voltage.

When the touch control driving circuit is in an initial state, the first energy storage capacitor C_S1And a second energy storage capacitor C_S2The stored charge amount is zero, and at this time, the switch circuit can be sequentially controlled according to the operation sequence from the first period to the eighth period: a first positive voltage V_DDCharging the touch electrode until the voltage at the two ends of the touch electrode is equal to a first positive voltage V_DD(ii) a Touch electrode and first energy storage capacitor C_S1Connected to a first energy storage capacitor C_S1Transferring a part of positive charges until the voltage across the touch electrode is equal to a second positive voltage V_C1(ii) a Grounding the touch electrode and discharging to the ground until the voltage at the two ends of the touch electrode is equal to 0; touch electrode and second energy storage capacitor C_S2Connected but due to a second energy-storage capacitor C_S2The stored charge amount is 0, so the touch electrode and the second energy-storing capacitor C_S2No charge transfer occurs therebetween; a first negative voltage-V_DDCharging the touch electrode until the voltage at the two ends of the touch electrode is equal to the first negative voltage-V_DD(ii) a The touch electrode is connected with the second energy storage capacitor C again_S2Connected and touch-control electrode is coupled to the second energy-storage capacitor C_S2Discharging, second energy-storage capacitor C_S2Storing the charges released by the touch electrode until the voltage across the touch electrode is equal to the second negative voltage V_C2(ii) a The touch electrode is grounded again and discharges to the ground until the voltage at the two ends of the touch electrode is equal to 0; touch electrode and first energy storage capacitor C_S1Connected to a first energy storage capacitor C_S1Transferring the stored charges to the touch electrode, and charging the touch electrode until the voltage at the two ends of the touch electrode is equal to a second positive voltage V_C1(ii) a Then, the above process is periodically cycled, and when the touch electrode is controlled to be switched from the ground to be connected to the second energy storage capacitor C again_S2While, the second energy storage capacitor C_S2The stored charge can be transferred to the touch electrode to charge the touch electrode until the voltage across the touch electrode equals the second negative voltage V_C2. Thus, the first energy storage capacitor C_S1And a second energy storage capacitor C_S2The amount of stored charge may gradually tend to be stable, thereby making the second positive voltage V_C1And a second negative voltage V_C2Gradually becomes stable when the first stored energy is reachedCapacitor C_S1And a second energy storage capacitor C_S2Is much larger than the capacitance C_LAt the capacitance value of (C)_LBefore and after charge transfer, the first energy storage capacitor C_S1And a second energy storage capacitor C_S2The amount of stored charge hardly changes.

Based on the disclosure of the above embodiments, in this embodiment, the switch circuit may further include a first switch circuit, a second switch circuit, a third switch circuit, a fourth switch circuit, and a fifth switch circuit. Specifically, the input end of the first switch circuit is the first input end of the switch circuit, and the output end of the first switch circuit is connected to the output end of the switch circuit; the input end of the second switch circuit is the second input end of the switch circuit, and the output end of the second switch circuit is connected to the output end of the switch circuit; the input end of the third switching circuit is the third input end of the switching circuit, and the output end of the third switching circuit is connected to the output end of the switching circuit; the input end of the fourth switching circuit is the fourth input end of the switching circuit, and the output end of the fourth switching circuit is connected to the output end of the switching circuit; the input end of the fifth switching circuit is the fifth input end of the switching circuit, and the output end of the fifth switching circuit is connected to the output end of the switching circuit.

When any one of the switch circuits is turned on, the other four switch circuits are all kept off, namely, only one switch circuit is turned on at a single moment. In this embodiment, the five switching circuits may be periodically turned on in the following order:

in the first period, only the first switch circuit is conducted, and the first positive voltage V_DDCharging the touch electrode to make the voltage at two ends of the touch electrode equal to a first positive voltage V_DD. In the second time interval, only the second switch circuit is conducted, and the touch electrode is connected to the first energy storage capacitor C_S1A first energy storage capacitor C_S1Storing the charges released by the touch electrode to make the voltage at both ends of the touch electrode equal to a second positive voltage V_C1(ii) a In a third time period, only the third switch circuit is conducted, the touch electrode is connected to the ground end GND, and the touch electrode discharges to the ground, so that the voltage at the two ends of the touch electrode is equal to that at the ground endZero voltage; in a fourth time period, only the fourth switch circuit is conducted, and the touch electrode is connected to the second energy storage capacitor C_S2A second energy storage capacitor C_S2Transferring the stored charges to the touch electrode to make the voltage across the touch electrode equal to a second negative voltage V_C2(ii) a In a fifth time period, only the fifth switch circuit is conducted, and the touch electrode is connected with the first negative voltage-V_DDFirst negative voltage-V_DDCharging the touch electrode so that the voltage across the touch electrode is equal to a first negative voltage-V_DD(ii) a In the sixth time period, only the fourth switch circuit is conducted, and the touch electrode is connected to the second energy storage capacitor C_S2A second energy storage capacitor C_S2Storing the charges discharged by the touch electrode so that the voltage across the touch electrode is equal to the second negative voltage V_C2(ii) a In a seventh time period, only the third switch circuit is turned on, the touch electrode is connected to the ground terminal GND, and the touch electrode discharges to the ground, so that the voltage at the two ends of the touch electrode is equal to zero voltage; in the eighth time period, the touch electrode is connected to the first energy storage capacitor C_S1A first energy storage capacitor C_S1Transferring the stored charges to the touch electrode so that the voltage across the touch electrode is equal to a second positive voltage V_C1。

In addition, when the touch electrode is charged and discharged, the voltage at the two ends of the touch electrode often needs to reach a stable value after a certain period of time, so as to ensure that the touch electrode can be sufficiently charged and discharged in a corresponding period of time, the on-time of the first switch circuit, the second switch circuit, the third switch circuit, the fourth switch circuit and the fifth switch circuit is set to be greater than or equal to the time for the voltage at the two ends of the electrode to reach the stable value in the corresponding period of time, thereby ensuring that the signal amplitude of the driving signal output by the touch driving circuit and the driving power consumption of the touch driving circuit can reach the designed target value. For example, in a first time period, the first switch circuit is turned on, and the touch driving circuit outputs a first positive voltage to charge the electrode, so that when the voltage across the electrode rises to a stable value, or after the voltage across the electrode rises to a stable value, the first switch circuit is controlled to be turned off, and the second switch circuit is turned on; if at both ends of the electrodeWhen the voltage is not increased to a stable value, the first switch circuit is turned off and the second switch circuit is turned on, so that the positive voltage amplitude of the driving signal does not reach V_DDAnd further the signal amplitude of the driving signal can not reach 2V_DD(ii) a For another example, in the fourth time period, the fourth switching circuit is turned on, the voltage across the touch electrode starts to decrease from zero voltage, and if the voltage across the touch electrode does not decrease to a stable value, the fourth switching circuit is turned off, and the fifth switching circuit is turned on, that is, the power supply voltage generating circuit starts to provide the power supply voltage to drive the touch electrode, which is equivalent to that the voltage variation across the touch electrode increases when the touch electrode is directly driven by the power supply voltage, thereby causing large driving power consumption.

As shown in fig. 4, a waveform diagram of a driving signal provided by the embodiment of the present application, the driving signal can be generated by the touch driving circuit shown in fig. 3, and the second positive voltage V is shown_C1And a second negative voltage V_C2The values of (A) have all substantially stabilized. It can be seen that the waveform of the driving signal is stepped, and the signal amplitude is 2V_DDAnd in one period T, only the first period

And a fifth period

The touch electrode is directly charged by the power voltage, thus corresponding to only the first period

And a fifth period

Actual driving power consumption is generated. In the working process of the touch control driving circuit, the first energy storage capacitor C_S1Equivalent capacitance C with touch electrode_LThere is a charge transfer between them, so that before and after the charge transfer, the first energy-storing capacitor C_S1And the voltage value at two ends of the charge quantity is constantIn order to calculate the driving power consumption of the touch driving circuit, the first period is described below

Inner first energy storage capacitor C_S1The value of the voltage at both ends after the voltage becomes stable is recorded as V_{C1_1}For a second period of time

Inner first energy storage capacitor C_S1The value of the voltage at both ends after the voltage becomes stable is recorded as V_{C1_2}。

As shown in fig. 5, a first time period is provided for the embodiment of the present application

And a second period of time

The principle schematic diagram of charging and discharging the touch electrode by the internal touch driving circuit; a first energy storage capacitor C_S1The voltage values across the terminals have already substantially stabilized. It can be seen that during the first period of time

Internal, first positive voltage V_DDEquivalent capacitance C to touch electrode_LCharging is carried out, and the first energy storage capacitor C_S1The voltage at both ends is stabilized at a voltage value V_{C1_1}(ii) a During the second period

Inner, equivalent capacitance C of touch electrode_LTo the first energy storage capacitor C_S1Transfer positive charge so that the equivalent capacitance C_LAnd a first energy storage capacitor C_S1The voltages at both ends are stabilized at a voltage value V_{C1_2}And a voltage value V_{C1_2}Slightly above voltage value V_{C1_1}. According to the law of conservation of charge, the voltage values and the capacitance values satisfy the following relations:

V_DD*C_L+V_{C1_1}*C_S1＝V_{C1_2}*(C_L+C_S1) (formula 1)

As shown in fig. 6, a seventh time interval is provided for the embodiment of the present application

And an eighth period

And the inner touch driving circuit is used for charging and discharging the touch electrode. It can be seen that in the seventh period

Inner, equivalent capacitance C of touch electrode_LDischarging to ground, the first energy-storage capacitor C_S1The voltage at both ends is stabilized at a voltage value V_{C1_2}(ii) a In the eighth period

Inner, equivalent capacitance C of touch electrode_LTo the first energy storage capacitor C_S1Transfer negative charges to make the equivalent capacitance C_LAnd a first energy storage capacitor C_S1The voltages at both ends are stabilized at a voltage value V_{C1_1}. According to the law of conservation of charge, the voltage value and the capacitance value satisfy the following relation:

V_{C1_2}*C_S1＝V_{C1_1}*(C_L+C_S1) (formula 2)

Combining equation 1 and equation 2, we can calculate:

V_{C1_1}＝V_DD*C_S1/(2C_S1+C_L) (formula 3)

V_{C1_2}＝V_DD*(C_L+C_S1)/(2C_S1+C_L) (formula 4)

When the first energy storage capacitor C_S1Is much larger than the capacitance C_LCapacitance value (i.e. C)_S1>>C_L) Then, it is possible to obtain: v_{C1_1}≈V_{C1_2}≈1/2V_DD. In particular, the first energy storage capacitor C_S1Is greater than the capacitance C_LWhen the capacitance value is 50-100 times, the first energy storage capacitor C is determined_S1Is much larger than the capacitance C_LThe capacitance value of (2).

Similarly, when the second energy storage capacitor C_S2Is much larger than the capacitance C_LWith a capacitance value of (c), a second negative voltage V can be obtained_C2Approximately equal to-1/2V_DD. In particular, the second energy storage capacitor C can be arranged_S2Is larger than the capacitance C_LWhen the capacitance value of the second energy storage capacitor C is 50-100 times, the second energy storage capacitor C is determined_S2Is far larger than the capacitance C_LThe capacitance value of (2).

Since only the first period of time is within one period T

And a fifth period

Since driving the touch electrode directly by the power voltage corresponds to generating the actual driving power consumption only in the two periods, when the frequency of the driving signal is f, the actual driving power consumption of the touch driving circuit shown in fig. 3 in one period T can be calculated as P (1/2V)_DD)*C_L*f*V_DD*2＝C_L*V_DD ²F and the signal amplitude of the drive signal is 2V_DD(ii) a Where f is 1/T, which is the frequency of the driving signal. However, for the conventional touch driving circuit, when the signal amplitude of the output driving signal is 2V_DDWhile, the driving power consumption in one period T is 4 × C_L*V_DD ²F. Therefore, the touch driving circuit provided by the embodiment of the application obviously has lower driving power consumption while providing high driving voltage.

It should be noted that the driving power consumption of the touch driving circuit can also be divided into two parts, wherein one part is the resistance R when the touch electrode is charged_LThe other part is a resistance R when the touch electrode discharges_LThe loss of each part is 1/2 × C in a period T_L*V_DD ²F, the driving power consumption of the touch driving circuit in one period T is C_L*V_DD ²*f。

In addition, in this embodiment, a first energy storage capacitor C may be provided_S1And a second energy storage capacitor C_S2The capacitance values are equal and far larger than the equivalent capacitance value C of the touch electrode_LI.e. setting C_S1＝C_S2>>C_L。

Specifically, each of the switch circuits in the embodiments of the present application may be composed of one or more MOS (Metal-Oxide-Semiconductor) field effect transistors, and for convenience of description, the MOS transistors are simply referred to below.

Fig. 7 is a schematic structural diagram of another touch driving circuit provided in the embodiment of the present application. Based on the disclosure of the above embodiments, in this embodiment, the first switch circuit further includes a first MOS transistor S_A1The second switch circuit further comprises a second MOS transistor S_A2The fourth switching circuit further comprises a fourth MOS transistor S_B1The fifth switch circuit further includes a fifth MOS transistor S_B2The third switch circuit further comprises a third MOS transistor S_A3And a sixth MOS transistor S_B3(ii) a Wherein, the first MOS transistor S_A1And a sixth MOS transistor S_B3And a first pressure bearing pipe S_CAAre all P-type MOS tubes, the second MOS tube S_A2And a third MOS transistor S_A3And the fourth MOS transistor S_B1The fifth MOS transistor S_B2And a second pressure bearing pipe S_CBAre all N-type MOS tubes.

Referring to fig. 7, the specific connection relationship among the elements in the touch driving circuit 30 is as follows: first MOS transistor S_A1Is connected to a first positive voltage V_DDThe first MOS transistor S_A1Is connected to the first pressure bearing pipe S_CAA source electrode of (a); second MOS transistor S_A2Is connected to the first pressure bearing pipe S_CASource electrode of the second MOS transistor S_A2Is connected to the first energy storage capacitor C_S1A first end of (a); third MOS transistor S_A3The source of the first MOS transistor is connected to the ground terminal GND, and the third MOS transistor S_A3Is connected to the first pressure bearing pipe S_CASource electrode of(ii) a Fourth MOS transistor S_B1Is connected to the second energy storage capacitor C_S2First terminal of (1), fourth MOS tube S_B1Is connected to the second pressure-bearing pipe S_CBA source electrode of (a); fifth MOS transistor S_B2Source electrode of the first transistor is connected to a first negative voltage-V_DDFifth MOS transistor S_B2Is connected to the second pressure-bearing pipe S_CBA source electrode of (a); sixth MOS transistor S_B3The source of the sixth MOS transistor S is connected to the ground end GND_B3Is connected to the second pressure-bearing pipe S_CBA source electrode of (a); a first energy storage capacitor C_S1And a second energy storage capacitor C_S2The second ends of the first and second terminals are connected to a ground end GND; first pressure bearing pipe S_CAAnd a second pressure bearing pipe S_CBThe drain electrodes are all connected to the touch electrode.

The voltage withstanding value of the MOS transistor element processed by the CMOS process is generally equal to the power supply voltage V_DDHowever, in a part of the time period, the voltage value across several MOS transistors in the switching circuit may exceed the withstand voltage value, so the problem of burning out of the MOS transistors is easily caused. Therefore, the first pressure bearing pipe S can be respectively subjected to pressure difference of two ends of each MOS pipe in different time periods_CAAnd a second pressure bearing pipe S_CBThe voltage value connected to the grid electrode is set, so that the situation that the voltage at two ends of the MOS tube exceeds the withstand voltage value of the MOS tube is prevented, and the normal charging and discharging of the touch electrode by the touch driving circuit can not be influenced. Specifically, the first bearing pipe S_CACan prevent the first MOS transistor S_A1A second MOS transistor S_A2And a third MOS transistor S_A3The voltage at the two ends exceeds the withstand voltage value; second bearing pipe S_CBCan prevent the fourth MOS transistor S_B1The fifth MOS transistor S_B2And a sixth MOS transistor S_B3The voltage across the terminals exceeds its withstand voltage. The voltage at two ends of the MOS tube is specifically the voltage between the source and the drain of the MOS tube, namely the source-drain voltage V_SDOr drain-source voltage V_DS。

In this embodiment, in order to make the signal amplitude of the driving signal output by the touch driving circuit 30 sequentially equal to the first positive voltage, the second positive voltage, the zero voltage, the second negative voltage, the first negative voltage, the second negative voltage, the zero voltage, and the second positive voltage in one period, each MOS transistor in the switching circuit may be controlled to periodically and cyclically turn on in the following order, and when any one MOS transistor in the switching circuit is turned on, the other five MOS transistors are all kept off, that is, only one MOS transistor in the switching circuit is turned on at a single time:

in a first time interval, a first MOS tube S_A1Conducting the first pressure bearing pipe S_CAAnd a second pressure bearing pipe S_CBThe grid of the transistor is connected to the ground end GND, and the other five MOS transistors are cut off.

During this period, due to the first pressure-bearing pipe S_CAGate voltage V of_aEqual to 0, source voltage higher than gate voltage V_aTherefore, the first pressure bearing pipe S_CAConducting without affecting the output of the first positive voltage V by the touch driving circuit 30_DDTo the capacitor C_LCharging until the capacitor C_LThe voltage at both ends is equal to the first positive voltage V_DD. And due to the second bearing pipe S_CBGate voltage V of_bEqual to 0, so only when the second pressure-bearing pipe S_CBWhen the source voltage of the second pressure-bearing pipe S is less than 0_CBCan be conducted when the second bearing pipe S_CBWhen the source voltage of (S) is higher than or equal to 0, the second pressure-bearing tube S_CBIs stopped so that the second pressure-bearing pipe S is in this period_CBCut-off, the fourth MOS transistor S can be avoided_B1The fifth MOS transistor S_B2And a sixth MOS transistor S_B3The drain-source voltage of (2) exceeds a withstand voltage value V_DDThereby preventing the fourth MOS transistor S_B1The fifth MOS transistor S_B2And a sixth MOS transistor S_B3And burning out.

In the second time interval, the second MOS transistor S_A2Conducting the first pressure bearing pipe S_CAAnd a second pressure bearing pipe S_CBThe grid of the transistor is connected to the ground end GND, and the other five MOS transistors are cut off.

During this period, due to the first pressure-bearing pipe S_CAGate voltage V of_aEqual to 0, source voltage higher than gate voltage V_aSo that the first pressure bearing pipe S_CAConducting without affecting the capacitance C_LFor the first energy storage capacitor C_S1Discharging until the capacitor C_LThe voltage at both ends and the first energy storage capacitor C_S1The voltages at both ends are equal, i.e.Get the capacitance C_LThe voltage at both ends is changed from a first positive voltage V_DDBecomes a second positive voltage V_C1(0<V_C1<V_DD). And due to the second bearing pipe S_CBGate voltage V of_bEqual to 0, so the second bearing pipe S_CBCut-off, the fourth MOS transistor S can be avoided_B1The fifth MOS transistor S_B2And a sixth MOS transistor S_B3The drain-source voltage exceeds the withstand voltage value V_DD。

In the third time interval, the third MOS transistor S_A3Conducting the first pressure bearing pipe S_CAIs equal to a second positive voltage V_C1Minus a first positive voltage V_DDDifference of (a), i.e. the first pressure-bearing pipe S_CAThe value of the voltage of the grid connection is equal to V_C1-V_DDSecond bearing pipe S_CBThe grid of the transistor is connected to the ground end GND, and the other five MOS transistors are cut off.

During this period, due to the first pressure-bearing pipe S_CAGate voltage V of_aIs equal to V_C1-V_DDSo that the gate voltage V_a<0, source voltage is higher than gate voltage V_aFirst bearing pipe S_CAConducting without affecting the capacitance C_LDischarge to ground to make the capacitor C_LThe voltage at both ends is changed from a second positive voltage V_C1Becomes 0. And due to the second bearing pipe S_CBGate voltage V of_bEqual to 0, so the second bearing pipe S_CBCut-off, the fourth MOS transistor S can be avoided_B1The fifth MOS transistor S_B2And a sixth MOS transistor S_B3The drain-source voltage exceeds the withstand voltage value V_DD. In addition, when the first energy storage capacitor C_S1Is much larger than the capacitance C_LAt a capacitance value of V_a＝V_C1-V_DD≈-1/2V_DD。

In the fourth time period, the fourth MOS transistor S_B1Conducting the first pressure bearing pipe S_CAAnd a second pressure bearing pipe S_CBThe grid of the transistor is connected to the ground end GND, and the other five MOS transistors are cut off.

During this period, due to the second pressure-bearing pipe S_CBGate voltage V of_bEqual to 0, source voltage is less than gate voltage V_bSo that the second bearing pipe S_CBIs conducted without influencing the second energy storage capacitor C_S2To the capacitor C_LCharging so that the capacitor C_LVoltage at two ends and a second energy storage capacitor C_S2The voltages at both ends are equal, i.e. the capacitance C is obtained_LThe voltage at two ends is changed from 0 to a second negative voltage V_C2(V_C2<0). And due to the first bearing pipe S_CAGate voltage V of_aEqual to 0, so only when the first pressure-bearing pipe S_CAWhen the source voltage of (2) is higher than 0, the first pressure bearing pipe S_CAIs conducted when the first bearing pipe S_CAWhen the source voltage of (2) is less than or equal to 0, the first pressure bearing pipe S_CAIs stopped, so that the first pressure-bearing pipe S is in this period_CACut-off, the first MOS transistor S can be avoided_A1A second MOS transistor S_A2And a third MOS transistor S_A3The source-drain voltage exceeds the withstand voltage value V_DD。

In the fifth period, the fifth MOS transistor S_B2Conducting the first pressure bearing pipe S_CAAnd a second pressure bearing pipe S_CBThe grid of the transistor is connected to the ground end GND, and the other five MOS transistors are cut off.

During this period, due to the second pressure-bearing pipe S_CBGate voltage V of_bEqual to 0, source voltage is less than gate voltage V_bSo that the second bearing pipe S_CBConducting without affecting the first negative voltage-V output by the touch driving circuit 30_DDTo the capacitor C_LCharging so that the capacitor C_LThe voltage at both ends is controlled by a second negative voltage V_C2Becomes a first negative voltage-V_DD. And due to the first bearing pipe S_CAGate voltage V of_aEqual to 0, so the first bearing pipe S_CACut-off, first MOS transistor S can be avoided_A1A second MOS transistor S_A2And a third MOS transistor S_A3The source-drain voltage exceeds the withstand voltage value V_DD。

In the sixth time period, the fourth MOS transistor S_B1Conducting the first pressure bearing pipe S_CAAnd a second pressure bearing pipe S_CBThe grid of the transistor is connected to the ground end GND, and the other five MOS transistors are cut off.

In this stage, due to the second pressure-bearing pipe S_CBGate voltage V of_bEqual to 0, source voltage is less than gate voltage V_bSo that the second bearing pipe S_CBConducting without affecting the capacitance C_LFor the second energy storage capacitor C_S2Discharging until the capacitor C_LVoltage at two ends and a second energy storage capacitor C_S2The voltages at both ends are equal, i.e. the capacitance C is obtained_LThe voltage at both ends is controlled by a first negative voltage-V_DDBecomes the second negative voltage V_C2. And due to the first pressure-bearing pipe S_CAGate voltage V of_aEqual to 0, so the first bearing pipe S_CACut-off, first MOS transistor S can be avoided_A1A second MOS transistor S_A2And a third MOS transistor S_A3The source-drain voltage exceeds the withstand voltage value V_DD。

In the seventh period, the sixth MOS transistor S_B3Conducting the first pressure bearing pipe S_CAThe grid electrode of the second pressure-bearing tube S is connected to the ground end GND_CBThe value of the voltage switched on by the grid is equal to the second negative voltage V_C2Minus a first negative voltage-V_DDBy difference, i.e. the second pressure-bearing pipe S_CBThe value of the voltage of the grid connection is equal to V_C2-(-V_DD)＝V_C2+V_DDAnd the other five MOS tubes are cut off.

During this period, due to the second pressure-bearing pipe S_CBGate voltage V of_bIs equal to V_C2+V_DDSo that the gate voltage V_b>0, source voltage is less than gate voltage V_bSecond bearing pipe S_CBConducting without affecting the capacitance C_LDischarge to ground to make the capacitor C_LThe voltage at both ends is controlled by a second negative voltage V_C2Becomes 0. And due to the first bearing pipe S_CAThe gate voltage of (1) is equal to 0, so that the first pressure-bearing pipe S_CACut-off, first MOS transistor S can be avoided_A1A second MOS transistor S_A2And a third MOS transistor S_A3The source-drain voltage exceeds the withstand voltage value V_DD. In addition, when the second energy storage capacitor C_S2Is much larger than the capacitance C_LAt a capacitance value of V_b＝V_C2+V_DD≈1/2V_DD。

In the eighth time period, the second MOS transistor S_A2Conducting the first pressure bearing pipe S_CAAnd a second pressure bearing pipe S_CBThe grid of the transistor is connected to the ground end GND, and the other five MOS transistors are cut off.

During this period, due to the first pressure-bearing pipe S_CAGate voltage V of_aEqual to 0, so the source voltage is higher than the gate voltage V_aFirst bearing pipe S_CAIs conducted without affecting the first energy storage capacitor C_S1To the capacitor C_LCharging so that the capacitor C_LThe voltage at two ends is changed from 0 to a second positive voltage V_C1. And due to the second bearing pipe S_CBGate voltage V of_bEqual to 0, so the second bearing pipe S_CBCut-off, the fourth MOS transistor S can be avoided_B1The fifth MOS transistor S_B2And a sixth MOS transistor S_B3The drain-source voltage exceeds the withstand voltage value V_DD。

Specifically, the first MOS transistor S_A1The control voltage for conduction can be set to 0, i.e. the first MOS transistor S can be set_A1Grid of the grid is connected to zero voltage (V)₁0) to turn it on; first MOS transistor S_A1The control voltage for the cutoff may be set to V_DDNamely, the first MOS transistor S can be connected_A1Gate access voltage value V_DD(V₁＝V_DD) So that it is cut off.

Second MOS transistor S_A2The conducting control voltage can be set to 0, that is, the second MOS transistor S can be set_A2Grid of the grid is connected to zero voltage (V)₂0) to turn it on; second MOS transistor S_A2The control voltage for the cutoff may be set to V_DDThat is, the second MOS transistor S can be connected_A2Gate access voltage value V_DD(V₂＝V_DD) So that it is cut off.

Third MOS transistor S_A3The control voltage for conduction may be set to V_DDThat is, the third MOS transistor S can be connected_A3Gate access voltage value V_DD(V₃＝V_DD) To make it conductive; third MOS transistor S_A3Control voltage V of cut-off₃Can be set to 0, i.e. the third MOS transistor S can be set_A3Grid of the grid is connected to zero voltage (V)₃0) to turn it off.

Fourth MOS transistor S_B1The control voltage for conduction may be set to 0That is, the fourth MOS transistor S can be connected_B1Grid of the grid is connected to zero voltage (V)₄0) to turn it on; fourth MOS transistor S_B1Control voltage V of cut-off₄Can be set as-V_DDThat is, the fourth MOS transistor S can be connected_B1Gate access voltage value-V_DD(V₄＝-V_DD) So that it is cut off.

Fifth MOS transistor S_B2The control voltage for conduction can be set to 0, that is, the fifth MOS transistor S can be set_B2Grid of the grid is connected to zero voltage (V)₅0) to turn it on; fifth MOS transistor S_B2Control voltage V of cut-off₅Can be set as-V_DDThat is, the fifth MOS transistor S can be connected_B2Gate access voltage value (V)₅＝-V_DD) So that it is cut off.

Sixth MOS transistor S_B3The control voltage for conduction may be set to-V_DDThat is, the sixth MOS transistor S can be connected_B3Gate access voltage value-V_DD(V₆＝-V_DD) To make it conductive; sixth MOS transistor S_B3Control voltage V of cut-off₆Can be set to 0, i.e. the sixth MOS transistor S can be set_B3Grid of the grid is connected to zero voltage (V)₆0) to turn it off.

Similarly, when the first energy storage capacitor C_S1A second energy storage capacitor C_S2The capacitance value is far larger than the equivalent capacitance value C of the touch electrode_LWhen the frequency of the driving signal is f, the driving power consumption of the touch driving circuit provided in this embodiment is P ═ C in one period T_L*V_DD ²F, and the signal amplitude of the drive signal is 2V_DD(ii) a Wherein, f is 1/T.

It should be noted that the touch driving circuit provided in the embodiment of the present application may not only adopt two energy storage capacitors, but also adopt four or more than four paired energy storage capacitors, where each pair of energy storage capacitors is used to provide a positive voltage and a negative voltage, respectively, so as to introduce more intermediate levels and achieve lower driving power consumption, but with the increase in the number of the energy storage capacitors, more peripheral devices are also introduced, resulting in an increase in cost and complexity of the circuit.

As shown in fig. 8The disclosure is a schematic structural diagram of another touch driving circuit provided in the embodiments of the present application. Referring to fig. 8, the touch driving circuit 40 includes a switch circuit 401 and four energy storage capacitors; the four energy storage capacitors are respectively third energy storage capacitors C_S3A fourth energy storage capacitor C_S4A fifth energy storage capacitor C_S5And a sixth energy storage capacitor C_S6(ii) a The switching circuit 401 includes seven switches, respectively switch S₁Switch S₂Switch S₃Switch S₄Switch S₅Switch S₆And switch S₇. Wherein, the switch S₁First terminal of the power supply is connected to a power supply voltage V_DDSwitch S₁The second end of the first electrode is connected to the touch electrode; switch S₂Is connected to the third energy storage capacitor C_S3First terminal of (1), switch S₂The second end of the first electrode is connected to the touch electrode; switch S₃Is connected to the fourth energy storage capacitor C_S4First terminal of (1), switch S₃The second end of the first electrode is connected to the touch electrode; switch S₄Is connected to ground terminal GND, switch S₄The second end of the first electrode is connected to the touch electrode; switch S₅Is connected to the fifth energy-storing capacitor C_S5First terminal of (1), switch S₅The second end of the first electrode is connected to the touch electrode; switch S₆Is connected to the sixth energy storage capacitor C_S6First terminal of (1), switch S₆The second end of the first electrode is connected to the touch electrode; switch S₇First terminal of the power supply is connected to a power supply voltage-V_DDSwitch S₇The second end of the second electrode is connected to the touch electrode. Wherein the power supply voltage-V_DDCan be controlled by applying a supply voltage V_DDAnd connecting the positive and negative voltage conversion circuits to obtain the voltage-stabilizing circuit.

For convenience of description, the third energy storage capacitor C will be described below_S3The voltage across is denoted V_C3A fourth energy storage capacitor C_S4The voltage across is denoted V_C4A fifth energy storage capacitor C_S5The voltage across is denoted V_C5A sixth energy storage capacitor C_S6The voltage across is denoted V_C6。

In this embodiment, four energy storage capacitors are respectively introduced with four intermediate levels, and four intermediate levelsThe magnitude relationship of the flat satisfies: 0<V_C4<V_C3<V_DD，-V_DD<V_C6<V_C5<0, the touch control driving circuit can periodically and sequentially output the power voltage V by setting the conducting sequence of the seven switches_DDVoltage V_C3Voltage V_C4Zero voltage, voltage V_C5Voltage V_C6Supply voltage-V_DDVoltage V_C6Voltage V_C5Zero voltage, voltage V_C4Voltage V_C3。

In addition, the capacitance values of the four energy storage capacitors are far larger than that of the capacitor C_LCan further make V_C3≈2/3V_DD，V_C4≈1/3V_DD，V_C5≈-1/3V_DD，V_C6≈-2/3V_DD(ii) a Specifically, when the capacitance values of the four energy storage capacitors are larger than the capacitor C_LWhen the capacitance value is 50-100 times, the capacitance values of the four energy storage capacitors are far larger than that of the capacitor C_LThe capacitance value of (2). Since the actual driving power consumption is generated when only the power voltage directly drives the touch electrode in one period T, the driving power consumption generated by the touch driving circuit provided in this embodiment in one period T is P (1/3V)_DD)*C_L*f*V_DD*2＝2/3C_L*V_DD ²F and the signal amplitude of the drive signal is 2V_DD. Wherein, f is 1/T.

Specifically, in this embodiment, each switching circuit may also be implemented by an MOS transistor, and a voltage-bearing transistor may also be provided to prevent the voltage across each MOS transistor from exceeding the withstand voltage value, and the voltage-bearing transistor may also be implemented by an MOS transistor.

It should be noted that the touch driving circuit provided in the embodiment of the present application may further turn on only a part of the switching circuits or the MOS transistors according to a specific sequence to generate different driving signals, so as to adapt to different application scenarios. With the touch shown in fig. 3For example, the control driving circuit sequentially controls the touch electrode to access the first positive voltage V only in one period T_DDGrounded and connected to a first negative voltage-V_DDAnd grounded, the driving signal shown in fig. 9 can be generated, and the signal amplitude of the driving signal is 2V_DDDriving power consumption of 2C_L*V_DD ²*f。

The embodiment of the application provides a touch driving chip, which comprises the touch driving circuit provided by the embodiment.

It should be noted that the touch driving chip may further include other circuits, for example, a control circuit, configured to control the switch circuit to periodically and cyclically turn on according to the turn-on sequence provided in the foregoing embodiment.

The embodiment of the application provides a touch display device, which comprises the touch driving chip provided by the embodiment.

The touch display device may include a display such as a liquid crystal display, an organic light emitting display, a plasma display, a cathode ray display, and the like.

It should be understood that the detailed description in the embodiments of the present application is only for helping those skilled in the art better understand the embodiments of the present application, and not for limiting the scope of the embodiments of the present application, and those skilled in the art can make various modifications and variations on the above embodiments, and these modifications and variations fall into the protection scope of the present application.

Claims (12)

1. A touch driving circuit for outputting a driving signal to drive a touch electrode of a touch display device, comprising: the power supply comprises a power supply voltage generating circuit, a switching circuit, a first energy storage capacitor and a second energy storage capacitor;

a first input end of the switching circuit is connected to the power supply voltage generating circuit; the second input end of the switch circuit is connected to a ground end GND through the first energy storage capacitor; a third input end of the switch circuit is connected to the ground end GND; a fourth input end of the switching circuit is connected to the ground end GND through the second energy storage capacitor; a fifth input terminal of the switching circuit is connected to the power supply voltage generating circuit; the output end of the switch circuit is connected to the touch electrode;

the power supply voltage generating circuit is used for generating a first positive voltage and a first negative voltage;

the switch circuit is used for controlling the touch electrode to be connected to the power supply voltage generating circuit within a first period, and the first positive voltage charges the touch electrode so that the voltage at two ends of the touch electrode is equal to the first positive voltage; controlling the touch electrode to be connected to the first energy storage capacitor in a second time period, wherein the first energy storage capacitor is used for storing charges released by the touch electrode, so that the voltage at two ends of the touch electrode is equal to a second positive voltage; controlling the touch electrode to be connected to the ground terminal GND in a third time period, and discharging the touch electrode to the ground terminal GND so that the voltage at two ends of the touch electrode is equal to zero voltage; controlling the touch electrode to be connected to the second energy storage capacitor in a fourth time period, wherein the second energy storage capacitor is used for transferring stored charges to the touch electrode, so that the voltage at two ends of the touch electrode is equal to a second negative voltage; controlling the touch electrode to be connected to the power supply voltage generating circuit in a fifth time period, and charging the touch electrode by the first negative voltage so that the voltage at two ends of the touch electrode is equal to the first negative voltage;

the second positive voltage is lower than the first positive voltage and higher than the zero voltage; the second negative voltage is higher than the first negative voltage and lower than the zero voltage.

2. The touch driving circuit of claim 1, wherein the switching circuit is further configured to control the touch electrode to be connected to the second energy storage capacitor during a sixth time period, and the second energy storage capacitor is configured to store the charge released by the touch electrode, so that the voltage across the touch electrode is equal to the second negative voltage; controlling the touch electrode to be connected to the ground terminal GND in a seventh time period, and discharging the touch electrode to the ground terminal GND so that the voltage at two ends of the touch electrode is equal to the zero voltage; and controlling the touch electrode to be connected to the first energy storage capacitor in an eighth time period, wherein the first energy storage capacitor is used for transferring stored charges to the touch electrode, so that the voltage at two ends of the touch electrode is equal to the second positive voltage.

3. The touch driving circuit according to claim 2, wherein the switching circuit further comprises: the first switch circuit, the second switch circuit, the third switch circuit, the fourth switch circuit and the fifth switch circuit;

the input end of the first switch circuit is the first input end of the switch circuit, and the output end of the first switch circuit is connected to the output end of the switch circuit;

the input end of the second switch circuit is the second input end of the switch circuit, and the output end of the second switch circuit is connected to the output end of the switch circuit;

the input end of the third switching circuit is a third input end of the switching circuit, and the output end of the third switching circuit is connected to the output end of the switching circuit;

the input end of the fourth switching circuit is the fourth input end of the switching circuit, and the output end of the fourth switching circuit is connected to the output end of the switching circuit;

the input end of the fifth switch circuit is a fifth input end of the switch circuit, and the output end of the fifth switch circuit is connected to the output end of the switch circuit.

4. The touch control driving circuit according to claim 3, wherein the first switch circuit is turned on during the first period; in the second period, the second switch circuit is conducted; during the third period, the third switch circuit is turned on; during the fourth period, the fourth switching circuit is turned on; during the fifth period, the fifth switch circuit is turned on; in the sixth period, the fourth switch circuit is turned on; in the seventh period, the third switch circuit is turned on; in the eighth time period, the second switch circuit is turned on;

and when any one of the switch circuits is switched on, the other four switch circuits are switched off.

5. The touch control driving circuit according to claim 4, further comprising a first pressure-bearing pipe and a second pressure-bearing pipe;

the first switch circuit further comprises a first MOS tube; the second switching circuit further comprises a second MOS tube; the fourth switching circuit further comprises a fourth MOS transistor; the fifth switching circuit further comprises a fifth MOS transistor; the third switch circuit further comprises a third MOS transistor and a sixth MOS transistor;

the first MOS tube, the sixth MOS tube and the first pressure-bearing tube are P-type MOS tubes, and the second MOS tube, the third MOS tube, the fourth MOS tube, the fifth MOS tube and the second pressure-bearing tube are N-type MOS tubes;

the source electrode of the first MOS tube is connected to the first positive voltage, and the drain electrode of the first MOS tube is connected to the source electrode of the first pressure bearing tube;

the source electrode of the second MOS tube is connected to the source electrode of the first pressure-bearing tube, and the drain electrode of the second MOS tube is connected to the first end of the first energy storage capacitor;

the source electrode of the third MOS tube is connected to the ground end GND, and the drain electrode of the third MOS tube is connected to the source electrode of the first pressure-bearing tube;

the source electrode of the fourth MOS tube is connected to the first end of the second energy storage capacitor, and the drain electrode of the fourth MOS tube is connected to the source electrode of the second pressure-bearing tube;

the source electrode of the fifth MOS tube is connected to the first negative voltage, and the drain electrode of the fifth MOS tube is connected to the source electrode of the second pressure-bearing tube;

the source electrode of the sixth MOS tube is connected to the ground end GND, and the drain electrode of the sixth MOS tube is connected to the source electrode of the second pressure-bearing tube;

the second ends of the first energy storage capacitor and the second energy storage capacitor are connected to the ground end GND; the drain electrodes of the first pressure-bearing pipe and the second pressure-bearing pipe are connected to the touch electrode;

the first pressure bearing pipe is used for preventing the voltages at two ends of the first MOS pipe, the second MOS pipe and the third MOS pipe from exceeding a withstand voltage value; the second pressure-bearing tube is used for preventing the voltage at two ends of the fourth MOS tube, the fifth MOS tube and the sixth MOS tube from exceeding a withstand voltage value.

6. The touch control driving circuit according to claim 5, wherein in the first time period, the first MOS transistor is turned on, gates of the first voltage-bearing transistor and the second voltage-bearing transistor are connected to the ground GND, and the other five MOS transistors are turned off;

in the second time period, the second MOS tube is conducted, the grids of the first pressure-bearing tube and the second pressure-bearing tube are connected to the ground end GND, and the other five MOS tubes are cut off;

in the third time period, the third MOS transistor is turned on, the voltage accessed by the gate of the first voltage-bearing transistor is equal to the difference value obtained by subtracting the first positive voltage from the second positive voltage, the gate of the second voltage-bearing transistor is connected to the ground terminal GND, and the other five MOS transistors are turned off;

in the fourth time period, the fourth MOS tube is switched on, the grids of the first pressure-bearing tube and the second pressure-bearing tube are connected to the ground end GND, and the other five MOS tubes are switched off;

in the fifth time period, the fifth MOS tube is conducted, the grids of the first pressure-bearing tube and the second pressure-bearing tube are connected to the ground end GND, and the other five MOS tubes are cut off;

in the sixth time period, the fourth MOS tube is switched on, the grids of the first pressure-bearing tube and the second pressure-bearing tube are connected to the ground end GND, and the other five MOS tubes are switched off;

in the seventh time period, the sixth MOS transistor is turned on, the gate of the first pressure-bearing transistor is connected to the ground GND, the voltage applied to the gate of the second pressure-bearing transistor is equal to the difference value obtained by subtracting the first negative voltage from the second negative voltage, and the other five MOS transistors are turned off;

in the eighth time period, the second MOS transistor is turned on, the gates of the first and second pressure-bearing transistors are connected to the ground GND, and the other five MOS transistors are turned off.

7. The touch driving circuit according to any one of claims 2 to 6, wherein the driving signal has a signal amplitude sequentially equal to the first positive voltage, the second positive voltage, the zero voltage, the second negative voltage, the first negative voltage, the second negative voltage, the zero voltage, and the second positive voltage in one period.

8. The touch control driving circuit according to any one of claims 1 to 6, wherein the power voltage generating circuit further comprises a positive-negative voltage converting circuit;

the positive and negative voltage conversion circuit is used for converting the first positive voltage into the first negative voltage.

9. The touch driving circuit according to any one of claims 1 to 6, wherein a capacitance value of the first energy storage capacitor or the second energy storage capacitor is greater than 50 times an equivalent capacitance value of the touch electrode.

10. The touch driver circuit of claim 9, wherein the second positive voltage is equal to 1/2 times the first positive voltage, and wherein the second negative voltage is equal to 1/2 times the first negative voltage.

11. A touch driving chip comprising the touch driving circuit according to any one of claims 1 to 10.

12. A touch display device comprising the touch driving chip according to claim 11.

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