Touch chip, touch screen and boosting method

Abstract

Embodiments of the present application provide a touch chip, a touch screen and a boosting method. The touch chip comprises a boosting control circuit having a power supply end, a high-voltage end and a switch end. The power supply end is electrically connected with an external medium-voltage power supply. The high-voltage end receives a high-voltage signal fed back by an external high-voltage power supply. The switch end outputs a driving voltage signal to an external circuit. The boosting control circuit is used to adjust the driving voltage signal based on the fed back high-voltage signal to control the voltage of the high-voltage power supply. A touch medium-voltage domain circuit is electrically connected with the medium-voltage power supply and drives a low-power-consumption area circuit. A touch high-voltage domain circuit is electrically connected with the high-voltage power supply and drives a high-power-consumption area circuit under the cooperation of the touch medium-voltage domain circuit to output a touch sensing signal. By integrating the boosting control circuit inside the touch chip, the number of chips and the size of the flexible circuit board are reduced, thereby reducing the cost of the touch screen.

Description

Technical Field

[0001] This application relates to the field of touch technology, and in particular to a touch chip, a touch screen, and a boost method. Background Technology

[0002] In existing capacitive touch technology for automotive electronics, the transmitter (TX) of the touchscreen in an in-vehicle touch panel (TP) system requires a high voltage (HV), such as 12V to 32V, for the touchscreen to accurately respond to user touch operations. However, the system power supply voltage of an in-vehicle touchscreen system is typically medium voltage (MV), such as 2.7V to 3.6V, therefore, the system power supply voltage cannot be directly used to power the transmitter.

[0003] In related technologies, a charge pump can be used to double the system power supply voltage. However, a standalone charge pump can typically only achieve a voltage multiplication of 1.5 to 2 times, which is insufficient to double the system power supply voltage to a high voltage. To use a charge pump to double the system power supply voltage to a high voltage, it needs to be used in conjunction with a boost control chip.

[0004] However, this solution requires two chips in the touch screen: a touch chip and a boost control chip. In addition, to accommodate the two chips, the area of ​​the flexible printed circuit board (FPC) in the touch screen needs to be increased. The increase in the number of chips and the increase in the area of ​​the flexible printed circuit board will lead to an increase in the cost of the touch screen. Summary of the Invention

[0005] The purpose of this application is to provide a touch chip, a touch screen, and a boost converter method to reduce the number of chips in the touch screen and the area of ​​the flexible circuit board, thereby reducing the cost of the touch screen. The specific technical solution is as follows:

[0006] In a first aspect of this application, a touch chip is provided, comprising:

[0007] A boost control circuit has a power supply terminal, a high voltage terminal, and a switching terminal. The power supply terminal is electrically connected to an external medium-voltage power supply. The high voltage terminal receives a high voltage signal fed back from the external high voltage power supply. The switching terminal outputs a drive voltage signal to an external circuit. The boost control circuit is used to adjust the drive voltage signal based on the feedback high voltage signal to control the voltage of the high voltage power supply.

[0008] The touch-sensitive medium-voltage domain circuit is electrically connected to the medium-voltage power supply and drives the low-power domain circuit.

[0009] The high-voltage domain circuit for touch control is electrically connected to the high-voltage power supply. With the cooperation of the high-voltage domain circuit in the touch control, it drives the high-power area circuit and outputs touch sensing signals.

[0010] In one possible embodiment, the boost control circuit includes a voltage divider circuit and a feedback control circuit;

[0011] The input terminal of the voltage divider circuit is electrically connected to the high voltage terminal, and the output terminal is electrically connected to the feedback terminal of the feedback control circuit.

[0012] The power supply terminal of the feedback control circuit is electrically connected to the power supply terminal of the boost control circuit. The input terminal is configured with a preset reference voltage, and the output terminal is electrically connected to the switching terminal of the boost control circuit. The feedback control circuit is used to adjust the driving voltage signal output by the output terminal based on the voltage of the feedback terminal, so that the voltage of the feedback terminal tends to the reference voltage.

[0013] In one possible embodiment, the feedback control circuit includes: an error amplifier circuit, a pulse width modulation comparator, a ramp generator, and a drive circuit;

[0014] The inverting input terminal of the error amplifier circuit is electrically connected to the feedback terminal of the feedback control circuit, the non-inverting input terminal of the error amplifier circuit is electrically connected to the input terminal of the feedback control circuit, the power supply terminal of the error amplifier circuit is electrically connected to the power supply terminal of the feedback control circuit, and the output terminal of the error amplifier circuit is electrically connected to the non-inverting input terminal of the pulse width modulation comparator.

[0015] The inverting input of the pulse width modulation comparator is electrically connected to the ramp generator, and the output of the pulse width modulation comparator is electrically connected to the input of the driving circuit.

[0016] The output terminal of the drive circuit is electrically connected to the output terminal of the feedback control circuit.

[0017] In one possible embodiment, the boost control circuit further includes a feedback terminal that is electrically connected to an external source;

[0018] The output terminal of the voltage divider circuit is electrically connected to the feedback terminal of the boost control circuit.

[0019] In one possible embodiment, the touch chip further includes:

[0020] The voltage divider register is electrically connected to each resistor in the voltage divider circuit. By changing the resistance value written into the voltage divider register, the resistance value of each resistor is adjusted to change the voltage division ratio of the voltage divider circuit.

[0021] In one possible embodiment, the touch chip further includes:

[0022] An overvoltage protection circuit is provided, wherein the voltage detection terminal of the overvoltage protection circuit is electrically connected to the output terminal of the voltage divider circuit, and the output terminal of the overvoltage protection circuit is electrically connected to the feedback control circuit.

[0023] An overvoltage protection register is electrically connected to the overvoltage protection circuit. The overvoltage protection threshold of the overvoltage protection circuit is adjusted by changing the voltage threshold written to the overvoltage protection register.

[0024] In one possible embodiment, the touch chip further includes:

[0025] An overcurrent protection circuit is provided, wherein the current detection terminal of the overcurrent protection circuit is electrically connected to an external source, and the output terminal of the overcurrent protection circuit is electrically connected to the feedback control circuit.

[0026] An overcurrent protection register is electrically connected to the overcurrent protection circuit. The overcurrent protection threshold of the overcurrent protection circuit is adjusted by changing the current threshold written to the overcurrent protection register.

[0027] In one possible embodiment, the touch chip further includes:

[0028] Temperature sensor;

[0029] An over-temperature protection circuit is provided, wherein the temperature detection terminal of the over-temperature protection circuit is electrically connected to the output terminal of the temperature sensor, and the output terminal of the over-temperature protection circuit is electrically connected to the feedback control circuit.

[0030] An over-temperature protection register is electrically connected to the over-temperature protection circuit. The over-temperature protection threshold of the over-temperature protection circuit can be adjusted by changing the temperature threshold written in the over-temperature protection register.

[0031] In one possible embodiment, the touch chip further includes:

[0032] An undervoltage lockout circuit, wherein the input terminal of the undervoltage lockout circuit is electrically connected to the medium-voltage power supply, and the output terminal of the undervoltage lockout circuit is electrically connected to other circuits in the touch chip;

[0033] An undervoltage lockout register, electrically connected to the undervoltage lockout circuit, adjusts the enable and disable voltage thresholds of the undervoltage lockout circuit by changing the voltage threshold written to the undervoltage lockout register.

[0034] In one possible embodiment, the touch chip further includes:

[0035] A frequency register, electrically connected to the ramp generator, is used to adjust the frequency or upper frequency limit of the ramp signal generated by the ramp generator by changing the frequency written to the frequency register.

[0036] In one possible embodiment, the driving circuit includes a plurality of cascaded driving stages;

[0037] The touch chip also includes a driver management register, which is electrically connected to each of the driver stages. The switching status of each driver stage is adjusted by changing the driver stage size written in the driver management register, thereby changing the equivalent driver size of each driver stage.

[0038] In one possible embodiment, the feedback control circuit further includes:

[0039] The superposition circuit has two input terminals that are electrically connected to the ramp generator and an external source, respectively, and its output terminal that is electrically connected to the inverting input terminal of the pulse width modulation comparator.

[0040] In a second aspect of this application, a touchscreen is provided, the touchscreen comprising:

[0041] Touch chips as described in any of the first aspects above;

[0042] A medium-voltage power supply, which is electrically connected to the power supply terminal of the boost control circuit and the power supply terminal of the touch medium-voltage domain;

[0043] A boost circuit is provided, wherein the input terminal of the boost circuit is electrically connected to the medium-voltage power supply to boost the medium-voltage power supply to a high-voltage power supply, and the output terminal of the boost circuit outputs the high-voltage power supply to feed back the high-voltage power supply to the touch chip.

[0044] In a third aspect of the application, a boost method is provided, applied to a touch chip as described in any of the first aspects, the method comprising:

[0045] The high-voltage terminal receives the high-voltage signal fed back from the external high-voltage power supply.

[0046] Based on the feedback high-voltage signal, the driving voltage signal is adjusted to control the voltage of the high-voltage power supply.

[0047] In one possible embodiment, the method further includes:

[0048] When the touch chip is started, the duty cycle of the driving voltage signal is adjusted to a preset safety value;

[0049] After the touch chip is activated, the duty cycle of the driving voltage signal is increased every preset time interval;

[0050] Until the duty cycle of the driving voltage signal reaches the preset target value, the step of receiving the high-voltage signal fed back from the external high-voltage power supply through the high-voltage terminal is executed.

[0051] In one possible embodiment, where the touch chip includes the voltage divider register and the overvoltage protection register, the method further includes:

[0052] When the touch chip is started, a resistance value is written into the voltage divider register to adjust the voltage division ratio of the voltage divider circuit to the initial voltage division ratio, and a voltage threshold is written into the overvoltage protection register to adjust the overvoltage protection threshold of the overvoltage protection circuit to the initial overvoltage protection threshold.

[0053] After the touch chip is started, every preset time interval, the resistance value in the voltage divider register is modified to increase the voltage division ratio of the voltage divider circuit, and the voltage threshold in the overvoltage protection register is modified to increase the overvoltage protection threshold of the overvoltage protection circuit.

[0054] Until the voltage at the high-voltage terminal reaches a preset voltage value, the step of receiving the high-voltage signal fed back from the external high-voltage power supply through the high-voltage terminal is executed.

[0055] In one possible embodiment, where the touch chip includes the voltage divider register, the method further includes: writing the resistance values ​​configured for each resistor in the voltage divider circuit into the voltage divider register to adjust the resistance values ​​of each resistor to change the voltage division ratio of the voltage divider circuit.

[0056] In one possible embodiment, where the touch chip includes the overvoltage protection register, the method further includes: writing a first voltage threshold configured for the touch chip into the overvoltage protection register to adjust the overvoltage protection threshold of the overvoltage protection circuit.

[0057] In one possible embodiment, where the touch chip includes the overcurrent protection register, the method further includes: writing a current threshold configured for the touch chip into the overcurrent protection register to adjust the overcurrent protection threshold of the overcurrent protection circuit.

[0058] In one possible embodiment, where the touch chip includes the over-temperature protection register, the method further includes: writing a temperature threshold configured for the touch chip into the over-temperature protection register to adjust the over-temperature protection threshold of the over-temperature protection circuit.

[0059] In one possible embodiment, where the touch chip includes the undervoltage lockout register, the method further includes: writing a second voltage threshold configured for the touch chip into the undervoltage lockout register to adjust the on-state voltage threshold and the off-state voltage threshold of the undervoltage lockout circuit.

[0060] In one possible embodiment, where the touch chip includes the frequency register, the method further includes: writing a frequency configured for the touch chip into the frequency register to adjust the frequency or upper frequency limit of the ramp signal generated by the ramp generator.

[0061] In one possible embodiment, where the touch chip includes the drive management register, the method further includes: writing the drive level size configured for the touch chip into the drive management register to change the equivalent drive size of each of the drive levels.

[0062] Beneficial effects of the embodiments in this application:

[0063] This application provides a touch chip, a touch screen, and a boost method for the touch chip. The touch chip includes: a boost control circuit, whose power supply terminal is electrically connected to an external medium-voltage power supply, whose high-voltage terminal receives a high-voltage signal feedback from the external high-voltage power supply, and whose switching terminal is electrically connected to an external circuit, outputting a drive voltage signal. The boost control circuit is used to adjust the drive voltage signal based on the feedback high-voltage signal to control the voltage of the high-voltage power supply; a touch medium-voltage domain circuit, electrically connected to the medium-voltage power supply, drives a low-power region circuit; and a touch high-voltage domain circuit, electrically connected to the high-voltage power supply, drives a high-power region circuit in cooperation with the touch medium-voltage domain circuit, outputting a touch sensing signal. The touch chip, touch screen, and boost method provided in this application integrate the boost control circuit inside the touch chip, enabling the touch chip itself to control the voltage of the high-voltage power supply. This reduces the number of chips in the touch screen and also reduces the area of ​​the flexible circuit board in the touch screen, thereby lowering the cost of the touch screen.

[0064] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0065] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0066] Figure 1 This is a schematic diagram of the structure of the touchscreen provided in this application;

[0067] Figure 2a The equivalent circuit diagram of the boost circuit provided in this application when the switching transistor is turned on;

[0068] Figure 2bThe equivalent circuit diagram of the boost circuit provided in this application when the switching transistor is off;

[0069] Figure 3a A circuit diagram of a boost control circuit and a boost circuit according to an embodiment of this application;

[0070] Figure 3b A circuit diagram of a boost control circuit and a boost circuit according to another embodiment of this application;

[0071] Figure 4 A circuit diagram of a boost control circuit and a boost circuit according to another embodiment of this application;

[0072] Figure 5 A circuit diagram of a boost control circuit and a boost circuit according to another embodiment of this application;

[0073] Figure 6 A circuit diagram of a boost control circuit and a boost circuit according to another embodiment of this application;

[0074] Figure 7 A circuit diagram of the touch screen provided in this application;

[0075] Figure 8a A circuit diagram of a boost control circuit and a boost circuit according to another embodiment of this application;

[0076] Figure 8b A circuit diagram of a boost control circuit and a boost circuit according to another embodiment of this application;

[0077] Figure 9 Comparison of energy spectra before and after enabling the spread spectrum function;

[0078] Figure 10 A circuit diagram of the driving circuit provided in this application;

[0079] Figure 11a Waveforms of driving voltage signals with different slopes;

[0080] Figure 11b A comparison of the energy spectra of driving voltage signals with different slopes;

[0081] Figure 12a A schematic flowchart of a pressure boosting method provided in this application;

[0082] Figure 12b A schematic diagram of another boosting method provided in this application;

[0083] Figure 12c A schematic diagram of another boosting method provided in this application.

[0084] Explanation of reference numerals in the attached figures:

[0085] Touch chip-1; Boost control circuit-11; Touch medium voltage domain circuit-12; Touch high voltage domain circuit-13; Voltage divider register-14; Voltage divider circuit-111; Feedback control circuit-112; Error amplifier circuit-1121; Pulse width modulation comparator-1122; Ramp generator-1123; Driver circuit-1124; Driver stage-11241; First energy spectrum-91; Second energy spectrum-92; Third energy spectrum-93; Fourth energy spectrum-94; Fifth energy spectrum-95; First curve-1101; Second curve-1102; Third curve-1103. Detailed Implementation

[0086] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0087] For ease of description, in this application, the port electrically connected to the medium-voltage power supply is denoted as VDDA, the port electrically connected to the high-voltage power supply is denoted as VDDH, the port for output / feedback voltage is denoted as FB, and the port for output / input drive voltage signal is denoted as SW.

[0088] The touch chip provided in this application can be found in [reference]. Figure 1 , Figure 1 The diagram shows the structure of a touchscreen. The part outlined by the dashed line is the touch chip 1, and the part outlined by the dotted line is the boost circuit. The touch chip 1 includes:

[0089] The boost controller circuit 11 has a power supply terminal VDDA, a high voltage terminal VDDH, and a switching terminal SW. The power supply terminal VDDA is electrically connected to an external medium voltage power supply. The high voltage terminal VDDH receives a high voltage signal from the feedback of the external high voltage power supply. The switching terminal SW is electrically connected to an external circuit and outputs a drive voltage signal. The boost controller circuit 11 is used to adjust the drive voltage signal based on the feedback high voltage signal to control the voltage of the high voltage power supply.

[0090] The touch-sensitive medium voltage domain (TP MV Power Domain) circuit 12 is electrically connected to the medium voltage power supply and drives the low power consumption area circuit;

[0091] The touch high voltage domain (TP HV Power Domain) circuit 13 is electrically connected to the high voltage power supply. With the cooperation of the touch high voltage domain circuit 12, it drives the high power consumption area circuit and outputs touch sensing signals.

[0092] By integrating the boost control circuit 11 into the touch chip 1 in this embodiment, the touch chip 1 itself has the ability to control the voltage of the high-voltage power supply. Therefore, the number of chips in the touch screen can be reduced, and the area of ​​the flexible circuit board in the touch screen can also be reduced, thereby reducing the cost of the touch screen.

[0093] For ease of description, the voltage of the medium-voltage power supply is denoted as Vdda, and the voltage of the high-voltage power supply is denoted as Vddh. The high-voltage power supply is obtained by boosting Vdda to Vddh using a boost circuit. The feedback control circuit 112 controls the boost circuit by adjusting the drive voltage signal, thereby controlling the specific value of Vddh. Figure 1 In the example shown, the circuit consisting of inductor L1, diode D1, capacitor C1, resistor R1 and switch SW1 is a boost circuit.

[0094] Figure 1 The boost circuit shown is only one possible boost circuit; other boost circuit structures may also be used in other possible embodiments. For ease of description, the following will only use the example shown. Figure 1 Taking the boost circuit shown in the figure as an example, this paper illustrates how the boost control circuit 11 controls the boost circuit by adjusting the drive voltage signal. The principle is the same for other boost circuit structures, so it will not be described in detail here.

[0095] When the switching transistor SW1 is turned on, the equivalent circuit diagram of the boost circuit is as follows: Figure 2a As shown, the capacitor placed between the medium-voltage power supply and the analog ground is called capacitor Cin, and the resistor RL represents the load of the high-voltage power supply. Figure 2a The capacitor Cin and resistor RL in the circuit do not belong to the boost circuit, and because Figure 1 C1 is located at the output terminal of the boost circuit, therefore in Figure 2a as well as Figure 2b In this context, C1 is referred to as Cout.

[0096] like Figure 2a As shown, when the switching transistor SW1 is turned on, the inductor L1 is grounded, therefore the diode D1 is turned off. At this time, the current output from the medium voltage power supply will flow along... Figure 2a The direction indicated by the dashed arrow is from the medium voltage power supply into the inductor L1. It can be seen that the medium voltage power supply will charge the inductor L1 at this time, and the voltage difference across the inductor L1 is Vdda.

[0097] When the switching transistor SW1 is off, the equivalent circuit of the boost circuit is as follows: Figure 2bAs shown, since inductor L1 has been charged during the conduction of switch SW1, and the current across inductor L1 cannot change abruptly, inductor L1 will induce a voltage in response to the current output from the medium voltage power supply, thereby pulling up the voltage at the anode of diode D1 and causing diode D1 to conduct.

[0098] If the voltage drop across diode D1 is denoted as Vd, then Figure 2b The voltage across the right end of inductor L1 is Vddh + Vd, and the voltage across the left end is Vdda. Since Vddh + Vd > Vdda, the inductor will discharge, and the resulting discharge current will flow along... Figure 2b The current flows through capacitor Cout and resistor RL in the direction indicated by the dashed arrow, thereby charging capacitor Cout and supplying power to the load of the high-voltage power supply. Filtering of this current is achieved by charging capacitor Cout.

[0099] The switching transistor SW1 is turned on and then turned off within one cycle. The duration of the on-time and the duration of the off-time of the switching transistor SW1 within one cycle are denoted as Ton and Toff, respectively, and the total duration of one cycle is denoted as T. Then the duty cycle D of the switching transistor SW1 is Ton / T.

[0100] When the boost circuit is in equilibrium, the current rising during the charging process of inductor L1 follows the same trend as the current falling during the discharging process. That is, the amount of charge stored in inductor L1 will remain constant. From this, the volt-second principle can be derived, namely formula (1):

[0101] Von Ton=Voff Toff (1)

[0102] Where Von is the voltage difference across inductor L1 when switch SW1 is turned on, and Voff is the voltage difference across inductor L1 when switch SW1 is turned off. From the aforementioned... Figure 2a and Figure 2b As can be seen from the explanation, Von = Vdda, Voff = Vddh + Vd - Vdda, therefore formula (1) can be rewritten as formula (2):

[0103] Vdda Ton = (Vddh + Vd - Vdda) Toff (2)

[0104] Since Vd is much smaller than Vddh and Vdda, Vd in formula (2) can be ignored, resulting in formula (3):

[0105] Vddh = Vdda / (1-D) (3)

[0106] As can be seen from formula (3), Vddh can be changed by controlling the duty cycle D of the switching transistor SW1, and Vddh is larger when Vdda remains unchanged and the duty cycle D is larger. The boost control circuit 11 can control the duty cycle D of the switching transistor by adjusting the drive voltage signal, thereby controlling the specific value of Vddh.

[0107] For example, assuming that the switch SW1 is an N-channel metal-oxide-semiconductor field-effect transistor (NMOSFET), the boost control circuit 11 increases Vddh by increasing the duty cycle of the high level in the drive voltage signal and decreases Vddh by decreasing the duty cycle of the high level in the drive voltage signal.

[0108] The structure of the boost control circuit 11 will be illustrated below with reference to the boost circuit:

[0109] See Figure 3a , Figure 3a The diagram shows a boost control circuit 11 and a boost circuit according to one embodiment. The portion enclosed by the dashed box represents the boost control circuit 11, and the portion enclosed by the dotted-dash box represents the boost circuit. The boost control circuit 11 includes a voltage divider circuit 111 and a feedback control circuit 112.

[0110] The input terminal VDDH of the voltage divider circuit 111 is electrically connected to the high voltage terminal VDDH of the boost control circuit 11, and the output terminal FB of the voltage divider circuit 111 is electrically connected to the feedback terminal FB of the feedback control circuit 112.

[0111] The power supply terminal VDDA of the feedback control circuit 112 is electrically connected to the power supply terminal VDDA of the boost control circuit 11. The input terminal VREF_EA of the feedback control circuit 112 is configured to a preset reference voltage Vref_EA. The output terminal SW of the feedback control circuit 112 is electrically connected to the switching terminal SW of the boost control circuit 11. The feedback control circuit 112 is used to adjust the drive voltage signal output by the output terminal SW based on the voltage of the feedback terminal FB, so that the voltage of the feedback terminal 112a tends to Vref_EA.

[0112] exist Figure 3aIn the example shown, the feedback control circuit 112 controls the voltage (hereinafter referred to as the feedback voltage) obtained by the voltage divider circuit 111, so that the feedback voltage tends towards Vref_EA. Let the voltage division ratio of the voltage divider circuit 111 be K. Then, when the feedback voltage is controlled at Vref_EA, Vddh = Vref_EA / K. It can be seen that by configuring different voltage division ratios for the voltage divider circuit 111, Vddh can be controlled to different values, that is, different boost ratios can be achieved. The voltage division ratio of the voltage divider circuit 111 depends on the resistance values ​​of each resistor in the voltage divider circuit 111. Therefore, selecting... Figure 3a The boost control circuit 11 shown can control the boost ratio by simply changing the resistance values ​​of each resistor in the voltage divider circuit 111. It does not require a complex circuit structure to control the boost ratio, which effectively reduces the complexity of the boost control circuit 11, thereby reducing the cost of the touch chip 1 and further reducing the cost of the touch screen.

[0113] See Figure 3b , Figure 3b The diagram shown is a circuit diagram of a boost control circuit 11 and a boost circuit according to another embodiment, compared to... Figure 3a The example shown, Figure 3b In the example shown, a feedback terminal FB for external electrical connection is added to the boost control circuit 11.

[0114] The part enclosed in the dashed box is the boost control circuit 11, and the part enclosed in the dotted-line box is the boost circuit. The output terminal FB of the voltage divider circuit 111 is electrically connected to the feedback terminal FB of the boost control circuit 11.

[0115] By using this embodiment, the user can obtain the feedback voltage through the feedback terminal FB of the boost control circuit 11, thereby performing fault detection on the boost control circuit 11, so as to quickly locate and resolve the fault when the touch chip 1 fails.

[0116] See Figure 4 , Figure 4 The diagram shown is a circuit diagram of a boost control circuit 11 and a boost circuit according to another embodiment, compared to... Figure 3a The example shown, Figure 4 The example shown further refines the feedback control circuit 112, where the dashed box encloses the boost control circuit 11, and the dotted-line box encloses the boost circuit. Figure 4In the example shown, the boost control circuit 11 includes a voltage divider circuit 111 and a feedback control circuit 112; the feedback control circuit 112 includes: an error amplifier circuit (EA) 1121, a pulse width modulation comparator 1122, a ramp generator 1123, and a driver circuit (DRV) 1124.

[0117] The inverting input terminal of the error amplifier circuit 1121 is electrically connected to the feedback terminal FB of the feedback control circuit 112. The non-inverting input terminal of the error amplifier circuit 1121 is electrically connected to the input terminal VREF_EA of the feedback control circuit 112. The power supply terminal VDDA of the error amplifier circuit 1121 is electrically connected to the power supply terminal VDDA of the feedback control circuit 112. The output terminal EAO of the error amplifier circuit 1121 is electrically connected to the non-inverting input terminal of the pulse width modulation comparator 1122.

[0118] The inverting input of the pulse width modulation comparator 1122 is electrically connected to the ramp generator 1123, and the output CMP_OUT of the pulse width modulation comparator 1122 is electrically connected to the input of the drive circuit 1124.

[0119] The output terminal SW of the drive circuit 1124 is electrically connected to the output terminal SW of the feedback control circuit 112.

[0120] The following will discuss... Figure 4 The following describes the error amplifier circuit 1121, pulse width modulation comparator 1122, ramp generator 1123, and drive circuit 1124:

[0121] Error amplifier circuit 1121 is the core calculation unit in feedback control circuit 112. Its inputs are feedback voltage and reference voltage. It is used to continuously compare the difference between the two, and amplify the difference as an error signal (Verror) and perform phase compensation. The output is an analog compensation voltage, which will be denoted as Vcomp below. Vcomp can be expressed by formula (4):

[0122] Vcomp=Aol (Vref_EA-Vfb) (4)

[0123] Where Vfb is the feedback voltage and Aol is the open-loop gain of the error amplifier circuit 1121.

[0124] The pulse width modulation comparator 1122 converts Vcomp into a pulse signal that determines the on-time of the switch SW1. Its inputs are Vcomp and the ramp signal Vramp generated by the ramp generator 1123. When Vramp is lower than Vcomp, the pulse width modulation comparator 1122 outputs a logic "1" to drive the switch SW1 to turn on; when Vramp is higher than Vcomp, the pulse width modulation comparator 1122 outputs a logic "0" to drive the switch SW1 to turn off. When the switch SW1 is an N-channel metal-oxide-semiconductor field-effect transistor, logic "1" is high and logic "0" is low; when the switch SW1 is a P-channel metal-oxide-semiconductor field-effect transistor (PMOSFET), logic "1" is low and logic "0" is high.

[0125] The ramp generator 1123 is used to generate a sawtooth wave or triangular wave signal with a period of T, and outputs the generated sawtooth wave or triangular wave signal as a Vramp to the pulse width modulation comparator 1122.

[0126] The driving circuit 1124 amplifies the logic signal output from the pulse width modulation comparator 1122, enabling the logic signal to drive the switch SW1 to turn on and off at a sufficiently fast speed and with a sufficiently large current. When the switch SW1 is a metal-oxide-semiconductor field-effect transistor (MOSFET), the amplified logic signal is output to the gate of the MOSFET; when the switch SW1 is a transistor, the amplified logic signal is output to the base of the transistor.

[0127] Figure 4 In the example shown, Vcomp is obtained by comparing Vfb and Vref_EA through the error amplifier circuit 1121. This allows the pulse width modulation comparator 1122 to change the duty cycle of the drive voltage signal based on Vcomp, thereby controlling Vddh. Vddh, in turn, affects Vfb, thus forming a voltage control loop to control Vfb within Vref_EA. Therefore, the selected... Figure 4 The boost control circuit 11 shown can implement feedback control with a relatively simple circuit, which can further reduce the cost of the touch chip 1 and also further reduce the cost of the touch screen.

[0128] See Figure 5 , Figure 5 The diagram shown is a circuit diagram of a boost control circuit 11 and a boost circuit according to another embodiment, compared to... Figure 4 The example shown, Figure 5The example shown additionally includes a superposition circuit 1125 in the feedback control circuit 112, where the dashed box encloses the boost control circuit 11, and the dotted-line box encloses the boost circuit. Figure 5 In the example shown, the boost control circuit 11 includes a voltage divider circuit 111 and a feedback control circuit 112; the feedback control circuit 112 includes: an error amplifier circuit 1121, a pulse width modulation comparator 1122, a ramp generator 1123, a drive circuit 1124, and a superposition circuit 1125.

[0129] The two input terminals of the superposition circuit 1125 are electrically connected to the ramp generator 1123 and an external source, respectively, and the output terminal of the superposition circuit 1125 is electrically connected to the inverting input terminal of the pulse width modulation comparator 1122.

[0130] like Figure 5 As shown, the input terminal of the superposition circuit 1125, which is electrically connected to the external circuit, is connected to the switching transistor SW1. This allows the superposition circuit 1125 to sample the peak value Vrs of the current flowing from the inductor L1, and superimpose the obtained signal with Vramp to compensate for Vramp. The superimposed signal is then output as a ramp signal to the inverting input terminal 1122b of the pulse width modulation comparator 1122. In this way, the pulse width modulation comparator 1122 can compare Vcomp as the inner loop current reference value with Vrs and generate a drive voltage signal, thereby realizing feedback control of Vrs, which forms a current control loop.

[0131] Select Figure 5 The boost control circuit 11 in the example shown can additionally form a current control loop to make the boost control circuit 11 more sensitive to changes in the load of the high voltage power supply and changes in Vddh, thereby improving the transient response rate of the boost control circuit 11 to the load of the high voltage power supply and the response rate to changes in Vddh. Therefore, the boost control circuit 11 can control Vddh more accurately.

[0132] See Figure 6 , Figure 6 The diagram shown is a circuit diagram of a boost control circuit 11 and a boost circuit according to another embodiment, compared to... Figure 5 The example shown, Figure 6 The diagram shows additional logic circuitry, where the dashed box encloses the boost control circuit 11, and the dotted-line box encloses the boost circuit. Figure 6 In the example shown, the boost control circuit 11 includes a voltage divider circuit 111 and a feedback control circuit 112; the feedback control circuit 112 includes: an error amplifier circuit 1121, a pulse width modulation comparator 1122, a ramp generator 1123, a drive circuit 1124, and a superposition circuit 1125.

[0133] The voltage divider circuit 111 consists of feedback resistors RFB1 and RFB2.

[0134] The error amplifier circuit 1121 consists of an error amplifier EA, a comparator COMP, a resistor R4, capacitors C3 and C4, and a resistor Rcomp. The inverting input, non-inverting input, and power supply of the error amplifier EA are the same as those of the error amplifier EA. The error amplifier EA1 generates and amplifies an error signal by continuously comparing Vfb and VREF_EA. The comparator COMP1, resistor R4, capacitors C3 and C4, and resistor Rcomp form a resistance-capacitance (RC) compensation loop to compensate for the amplified error signal.

[0135] Figure 6 In the example shown, the driver circuit 1124 is integrated with the logic circuit, which implements one or more of various protection functions, such as overvoltage protection (OVP), overcurrent protection (OCP), overtemperature protection (OTP), and undervoltage lockout (UVLO). The specific implementation of these protection functions will be illustrated below and will not be repeated here.

[0136] The circuit structure of the boost control circuit 11 has been illustrated above with five examples. The circuit structures of the touch-sensitive medium-voltage domain circuit 12 and the touch-sensitive high-voltage domain circuit 13 in the touch chip 1 will now be illustrated. See [link to documentation]. Figure 7 , Figure 7 The circuit diagrams of the touch-sensitive high-voltage domain circuit 12 and the touch-sensitive high-voltage domain circuit 13 are shown in detail. Figure 7 In the example shown, the touch mid-voltage domain circuit 12 includes a TX mid-voltage domain circuit 121 and an analog front end (AFE) mid-voltage domain circuit 122, and the touch high-voltage domain circuit 13 includes a TX high-voltage domain circuit 131.

[0137] The TX mid-voltage domain circuit 121 includes: a digital-to-analog converter (DAC), a programmable gain amplifier (PGA), a low-pass filter (LPF), and a mid-voltage domain regulator (MV regulator). Although Figure 7The boost control circuit 11 is drawn in the TX intermediate voltage domain circuit 121. However, this only means that the boost control circuit 11 and the TX intermediate voltage domain circuit 121 are integrated in the touch chip 1 using the same intermediate voltage process. It does not mean that the boost control circuit 11 is located in the TX intermediate voltage domain circuit 121.

[0138] The digital-to-analog converter module converts digital signals into analog sine waves. A gain-programmable amplifier amplifies this analog sine wave according to a configured gain. A low-pass filter performs low-pass filtering on the amplified analog sine wave to remove high-frequency noise. The intermediate voltage regulator serves as the pre-amplifier for the high-voltage regulator (HVRegulator) in the TX high-voltage circuit 131, providing a drive signal of 0.25V to 1V to the high-voltage regulator.

[0139] The TX high-voltage domain circuit 131 includes: a high-voltage amplifier (HV Amplifier), a high-voltage driver circuit (HV Driver), and a high-voltage domain regulator.

[0140] The high-voltage amplifier, driven by the high-voltage domain regulator, boosts the analog sine wave output from the voltage domain circuit 121 in TX into a high-voltage sine wave. The boost ratio can be changed by adjusting the amplification factor of the high-voltage amplifier. For example, the peak-to-peak voltage of the analog sine wave is 0.4V to 1.4V, and the peak-to-peak voltage of the high-voltage sine wave obtained after boosting by the high-voltage amplifier is 8V to 28V. The high-voltage drive circuit is used to improve the driving capability of the high-voltage sine wave so that it can drive an external large-capacitor load.

[0141] The analog front-end voltage domain circuit 122 includes: a charge amplifier, an analog-to-digital converter (ADC), a digital filter, an amplitude calculation module, and a code division multiplexing decoder module. The digital filter, amplitude calculation module, and code division multiplexing decoder module together constitute an in-phase quadrature (IQ) demodulator.

[0142] A charge amplifier converts a high-voltage sine wave into an output voltage Vout, which is then sent to an analog-to-digital converter (ADC). The ADC converts Vout into a digital code value. A quadrature demodulator demodulates the digital code value and uploads it to the touchscreen's processor for further processing.

[0143] The principle of a charge amplifier will be briefly explained below. (See also...) Figure 7, Figure 7 In the example shown, due to the virtual short characteristic of the op-amp, the non-inverting and inverting inputs of the op-amp are approximately equal, while Figure 7 In the example shown, the voltage at the non-inverting input of the operational amplifier in the charge amplifier is configured as VREF, so the voltage at the inverting input of the operational amplifier will also be close to VREF. In this case, the voltage VTX emitted by TX is converted into current IRX through capacitor Cm, and the current IRX is converted into Vsig through capacitor Cfb in the integrator. According to circuit common sense, at this time, formula (5) should be satisfied:

[0144] Vsig=IRX / Cfb (5)

[0145] Since IRX = VTX Therefore, formula (5) can be rewritten as formula (6):

[0146] Vsig=VTX Cm / Cfb (6)

[0147] When a finger touches the touchscreen, Cm will decrease, and according to formula (6), Vsig will change. It can be seen that finger contact will cause a change in Vsig. Therefore, by monitoring whether Vsig changes, it can be determined whether there is a finger touch, and thus touch control can be achieved.

[0148] Assuming the mutual capacitance Cm is Cm when there is no finger contact, and the decrease in mutual capacitance between TX and the receiving electrode RX when there is finger contact is denoted as ΔCm, then from formula (6), it can be deduced that the change in Vsig caused by finger contact, Vsig_diff_sine, should satisfy formula (7):

[0149] Vsig_diff_sine=VTX △Cm / Cfb (7)

[0150] Compared to direct finger contact with the touchscreen, when a user wears gloves thicker than 5mm, ΔCm decreases significantly, leading to a smaller Vsig_diff_sine. This makes changes in Vsig more difficult to detect, impacting touch control. Furthermore, for touchscreens using indium tin oxide (ITO), such as glass-based organic light-emitting diode (GOLED) and liquid crystal display (LCD) touchscreens, Cfb can often reach hundreds of pF to 1 nF. In large-size plastic-based organic light-emitting diode (POLED) touchscreens, Cfb can even reach 2 nF. The larger Cfb in these touchscreens also makes changes in Vsig more difficult to detect, further affecting touch control.

[0151] The touch chip 1 provided in this application can control Vddh at a high voltage. Therefore, as long as Vddh is used as VTX, even if ΔCm is small or Cfb is large, Vsig_diff_sine will still be large because VTX is large. That is, the change of Vsig can be easily detected and will not affect the implementation of touch control. In other words, the touch chip 1 provided in this application can improve the load capacity of the touch chip 1.

[0152] Please watch it again. Figure 6 The following will provide an exemplary description of how the logic circuit implements the aforementioned overvoltage protection, overcurrent protection, overtemperature protection, and undervoltage lockout functions.

[0153] For overvoltage protection, in one example, touch chip 1 also includes:

[0154] The overvoltage protection circuit has its voltage detection terminal electrically connected to the output terminal FB of the voltage divider circuit 111, and its output terminal electrically connected to the feedback control circuit 112.

[0155] The overvoltage protection register is electrically connected to the overvoltage protection circuit. The overvoltage protection threshold VOVP of the overvoltage protection circuit is adjusted by changing the voltage threshold written to the overvoltage protection register.

[0156] The overvoltage protection circuit, as a logic circuit, can be integrated with the driver circuit 1124. In other possible examples, the overvoltage protection circuit can also be independent of the driver circuit 1124.

[0157] The overvoltage protection circuit's input Vfb is used to compare the magnitudes of Vfb and VOVP. When Vfb exceeds VOVP, it controls the drive circuit 1124 to stop outputting the drive voltage signal, effectively shutting down the drive circuit 1124. It is understandable that under conditions such as an open voltage loop or a sudden reduction in the load of the high-voltage power supply, Vfb may rise abnormally, potentially damaging the load of the high-voltage power supply and power components in the boost circuit, such as switching transistors and capacitors. The overvoltage protection circuit can shut down the drive circuit 1124 when Vfb rises abnormally, causing Vfb to drop back to its normal value, thus effectively preventing damage to the load and power components.

[0158] Meanwhile, since VOVP can be changed by writing different voltage thresholds into the overvoltage protection register, this embodiment can be used to flexibly adjust VOVP according to the user's actual needs, so that the overvoltage protection circuit can effectively realize the overvoltage protection function in different scenarios, thus improving the applicability of the overvoltage protection function.

[0159] Understandably, VOVP should be higher than Vfb under normal conditions. Therefore, users can first determine the peak value of Vfb, and then select a voltage threshold greater than that peak value and write it into the overvoltage protection register to adjust VOVP to that voltage threshold.

[0160] For overcurrent protection, in one example, touch chip 1 also includes:

[0161] The overcurrent protection circuit has its current detection terminal connected to an external power source and its output terminal connected to the feedback control circuit 112.

[0162] The overcurrent protection register is electrically connected to the overcurrent protection circuit. The overcurrent protection threshold VOCP of the overcurrent protection circuit is adjusted by changing the current threshold written to the overcurrent protection register.

[0163] The overcurrent protection circuit, as a logic circuit, can be integrated with the driver circuit 1124. In other possible examples, the overcurrent protection circuit can also be independent of the driver circuit 1124. Furthermore, the current sensing terminal of the overcurrent protection circuit should be electrically connected to the switching transistor SW1 to sample Vrs.

[0164] The overcurrent protection circuit's input Vrs is used to compare Vrs with VOCP. When Vrs is greater than VOCP, the drive circuit 1124 is shut down. Understandably, in situations like a short circuit or overload on a high-voltage power supply, Vrs is larger. Since Vrs flows through inductor L1, switching transistor SW1, and some traces on the circuit board, a larger Vrs could burn out inductor L1, switching transistor SW1, and these traces. The overcurrent protection circuit shuts down the drive circuit 1124 when Vrs is large, causing Vrs to drop back to a normal value, thus effectively preventing the inductor L1, switching transistor SW1, and these traces from burning out.

[0165] Meanwhile, since VOCP can be changed by writing different current thresholds into the overcurrent protection register, this embodiment can be used to flexibly adjust VOCP according to the user's actual needs, so that the overcurrent protection circuit can effectively realize the overcurrent protection function in different scenarios, thus improving the applicability of the overcurrent protection function.

[0166] For over-temperature protection, in one example, the touch chip 1 also includes:

[0167] Temperature sensor;

[0168] The over-temperature protection circuit is electrically connected to the output terminal of the temperature sensor 16 and to the feedback control circuit 112.

[0169] The over-temperature protection register is electrically connected to the over-temperature protection circuit. The over-temperature protection threshold VOTP of the over-temperature protection circuit is adjusted by changing the temperature threshold written to the over-temperature protection register.

[0170] The over-temperature protection circuit, as a logic circuit, can be integrated with the driver circuit 1124. In other possible examples, the over-temperature protection circuit can also be independent of the driver circuit 1124.

[0171] The over-temperature protection circuit takes the temperature signal Vt sensed by the temperature sensor as its input and compares it with VOTP. When Vt is greater than VOTP, the drive circuit 1124 is shut down. Under conditions of overload, high ambient temperature, or poor heat dissipation, the internal temperature of the touch chip 1 may become too high, potentially burning it out. The over-temperature protection circuit shuts down the drive circuit 1124 when the internal temperature of the touch chip 1 is high, thus stopping the touch chip from working and reducing heat generation. This prevents the touch chip 1 from overheating further and effectively prevents it from burning out due to excessive temperature.

[0172] Meanwhile, since VOTP can be changed by writing different temperature thresholds into the over-temperature protection register, this embodiment can be used to flexibly adjust VOTP according to the user's actual needs, so that the over-temperature protection circuit can effectively realize the over-temperature protection function in different scenarios, thus improving the applicability of the over-temperature protection function.

[0173] For the undervoltage lockout function, in one possible example, touch chip 1 also includes:

[0174] The undervoltage lockout circuit has its input terminal electrically connected to the medium-voltage power supply, and its output terminal electrically connected to other circuits in the touch chip 1; wherein, other circuits refer to all circuits in the touch chip 1 other than the undervoltage lockout circuit.

[0175] The undervoltage lockout register is electrically connected to the undervoltage lockout circuit. The enable voltage threshold Vstart and disable voltage threshold Vstop of the undervoltage lockout circuit are adjusted by changing the voltage threshold written to the undervoltage lockout register, wherein Vstop is less than Vstart.

[0176] The undervoltage lockout circuit, as a logic circuit, can be integrated with the driver circuit 1124. In other possible examples, the undervoltage lockout circuit can also be independent of the driver circuit 1124.

[0177] The input of the undervoltage lockout circuit is VDDA, which is used to compare the magnitude of VDDA with Vstart and Vstop. When VDDA drops below Vstop, the undervoltage lockout circuit shuts down other circuits, which means that the touch chip 1 stops working; when VDDA rises above Vstart, the undervoltage lockout circuit turns on other circuits, which means that the touch chip 1 restarts.

[0178] Understandably, the boost controller 11 and the touch-intermediate voltage domain circuit 12 in touch chip 1 rely on VDDA for power. However, VDDA may be low due to voltage fluctuations. If VDDA is used to power the boost controller 11 and the touch-intermediate voltage domain circuit 12 in touch chip 1 at this time, abnormalities will occur due to insufficient voltage, such as startup failure or overheating and damage to the switching transistor SW1 due to incomplete conduction. The undervoltage lockout circuit can drive touch chip 1 to stop working when VDDA is low and drive touch chip 1 to restart after VDDA recovers to a higher value. This avoids using a low VDDA to power touch chip 1, thereby avoiding abnormalities caused by insufficient voltage.

[0179] Meanwhile, since Vstart and Vstop can be changed by writing different voltage thresholds into the undervoltage lockout circuit, this embodiment can flexibly adjust Vstart and Vstop according to the user's actual needs, so that the undervoltage lockout circuit can effectively realize the undervoltage lockout function in different scenarios, thus improving the applicability of the undervoltage lockout function.

[0180] The foregoing Figure 3a , Figure 3b , Figure 4 , Figure 5 as well as Figure 6 The touch chip 1 provided in this application has been described by way of example in terms of its circuit structure. The touch chip 1 provided in this application will be described by way of example in terms of its internal registers below.

[0181] See Figure 8a , Figure 8a The diagram shown is a circuit diagram of a boost control circuit 11 and a boost circuit according to another embodiment, compared to... Figure 6 The example shown is in Figure 8a The touch chip 1 in the example shown also includes:

[0182] A voltage divider register 14 is electrically connected to each resistor in the voltage divider circuit 111. The voltage division ratio of the voltage divider circuit 111 can be changed by changing the resistance value written into the voltage divider register 14 to adjust the resistance value of each resistor.

[0183] Using this embodiment, the voltage division ratio can be changed by writing different resistance values ​​into the voltage divider register 14. As mentioned above... Figure 3a As can be seen from the relevant description, the specific value of Vddh can be controlled by changing the voltage divider ratio. Therefore, in this embodiment, the specific value of Vddh can be controlled by writing different resistance values ​​into the voltage divider register 14, thereby flexibly controlling Vddh according to the application scenario and improving the applicability of the touch chip 1.

[0184] Additionally, assuming the voltage divider circuit 111 is as follows: Figure 6 The voltage divider circuit shown is formed by feedback resistors RFB1 and RFB2 connected in series. According to circuit principles, the voltage division ratio K of the voltage divider circuit 111 is K = 1 / (1 + RFB2 / RFB1), therefore Vddh = Vfb / K = Vfb. (1 + RFB2 / RFB1). Since RFB1 and RFB2 change with increasing temperature, according to circuit knowledge, considering this change, the actual resistance of RFB1 and RFB2 can be expressed as RFB1. (1+a1) △T1), RFB1 (1+a2) △T2), where a1 and a2 are the temperature coefficients of RFB1 and RFB2, respectively, and △T1 and △T2 are the temperature changes of RFB1 and RFB2, respectively. Furthermore, the actual Vddh = Vfb can be derived. {1+[ RFB1 (1+a1) △T1)] / [ RFB1 (1+a2) As can be seen from △T2)]}, Vddh will change with the temperature of RFB1 and RFB2, that is, Vddh will experience temperature drift.

[0185] Since RFB1 and RFB2 are both located inside touch chip 1, they are made of the same material and have the same temperature change. Furthermore, since the temperature coefficient depends on the material, a1 = a2 and ΔT1 = ΔT2. Substituting these into the aforementioned expression for the actual Vddh, we obtain the actual Vddh = Vfb. (1+RFB2 / RFB1). It can be seen that the actual Vddh no longer experiences temperature drift. Similarly, for the scenario where voltage divider circuit 111 is formed by a larger number of voltages connected in series, Vddh will also no longer experience temperature drift. In other words, choosing... Figure 8a The example shown can reduce or even eliminate the temperature drift of Vddh, thereby enabling more accurate control of Vddh.

[0186] See Figure 8b , Figure 8b The diagram shown is a circuit diagram of a boost control circuit 11 and a boost circuit according to another embodiment, compared to... Figure 6 The example shown is in Figure 8b The touch chip 1 in the example shown also includes:

[0187] Multiple voltage divider registers 14 are provided, each of which is electrically connected to a resistor in the voltage divider circuit 111. The voltage division ratio of the voltage divider circuit 111 can be changed by adjusting the resistance value of each resistor written into the voltage divider register 14.

[0188] exist Figure 8b In the example shown, each voltage divider register 14 is used to change the resistance value of the resistor electrically connected to it. Similarly... Figure 8a The embodiment shown uses Figure 8b The illustrated embodiment also improves the applicability of the touch chip 1 and enables more accurate control of Vddh.

[0189] Please watch it again. Figure 4 , Figure 5 As we know from basic circuit knowledge, in Figure 4 or Figure 5In the example shown, the frequency of the driving voltage signal is equal to the frequency of the ramp signal generated by the ramp generator 1123. Both will be denoted as fsw in the following text, and the upper limit of fsw will be denoted as fsw_max.

[0190] To control fsw or fsw_max, in one possible embodiment, the touch chip 1 also includes a frequency register electrically connected to the ramp generator 1123. The frequency of the ramp signal generated by the ramp generator 1123 is adjusted by changing the frequency written to the frequency register, thereby changing fsw; or, the upper limit of the frequency of the ramp signal generated by the ramp generator 1123 is adjusted by changing the frequency written to the frequency register, thereby changing fsw_max.

[0191] Using this embodiment, fsw or fsw_max can be dynamically adjusted by changing the frequency written to the frequency register. For the case of dynamically adjusting fsw, spread spectrum functionality can be achieved through dynamic adjustment of fsw, that is, controlling fsw to continuously change within the range of (fsw-Δfc, fsw+Δfc), where Δfc = (1%~10%). According to the principle of energy conversion, when fsw changes continuously within the range of (fsw-Δfc, fsw+Δfc), energy will be distributed across multiple frequencies, thus effectively reducing electromagnetic interference (EMI) in the voltage loop.

[0192] See Figure 9 , Figure 9 Comparison of energy spectra before and after enabling the spread spectrum function. Figure 9 The first energy spectrum 91 is the energy spectrum of the voltage loop before the spread spectrum function is enabled, and the second energy spectrum 92 is the energy spectrum of the voltage loop after the spread spectrum function is enabled. Figure 9 It is evident that after enabling the spread spectrum function, the energy peak of electromagnetic interference is significantly reduced, thus verifying that the spread spectrum function can effectively reduce electromagnetic interference.

[0193] It is evident that dynamically adjusting the fsw enables touch chip 1 to possess spread spectrum functionality, thereby reducing electromagnetic interference in the voltage loop and improving the operational stability of touch chip 1. Additionally, the following effects can also be achieved:

[0194] 1. No oscillator circuit is needed during the dynamic adjustment of fsw, so there is no need to set up an oscillator circuit in the touch chip 1, which simplifies the internal circuit of the touch chip 1.

[0195] 2. No external resistor Rosc is required during the dynamic adjustment of fsw, so there is no need to set an external resistor Rosc in the external circuit of touch chip 1, which simplifies the external circuit of touch chip 1.

[0196] 3. The fsw can be dynamically adjusted according to the application scenario to improve the applicability of touch chip 1.

[0197] Regarding the dynamic adjustment of fsw_max, on the one hand, fsw_max can be dynamically adjusted according to the application scenario, so that the touch chip 1 can work stably in different application scenarios, thus improving the stability of the touch chip 1. On the other hand, since fsw_max is controlled by changing the frequency of writing to the frequency register, there is no need to rely on analog circuits or external resistors Rosc. Therefore, fsw_max is not affected by non-ideal factors such as temperature drift and voltage drift of analog circuits or external resistors Rosc, which means that fsw_max can be stably controlled, thereby stably controlling Vddh.

[0198] See Figure 10 , Figure 10 The diagram shown is a circuit diagram of the drive circuit 1124 and the boost circuit in one embodiment. The portion enclosed by the dashed box represents the drive circuit 1124, and the portion enclosed by the dotted-dash box represents the boost circuit. Figure 10 In the example shown, the driving circuit 1124 is composed of a plurality of cascaded driving stages 11241. Each driving stage 11241 consists of a P-channel metal-oxide-semiconductor field-effect transistor and an N-channel metal-oxide-semiconductor field-effect transistor. In other possible embodiments, the driving stage 11241 may also have other constructions, and this application does not impose any restrictions on them.

[0199] Furthermore, in Figure 10 In the example shown, the touch chip 1 also includes a driver management register, which is electrically connected to each driver stage 11241. The switching status of each driver stage 11241 is adjusted by changing the driver stage size written to the driver management register, thereby changing the equivalent driver size of each driver stage 11241.

[0200] It is understandable that the stronger the driving capability of the driving circuit 1124, the shorter the transition time of the driving voltage signal from low / high level to high / low level. Therefore, the slope of the rising and falling edges of the driving voltage signal is larger, which in turn makes the switching transistor SW1 respond to the driving voltage signal faster, that is, the switching speed of the switching transistor SW1 is faster. And the faster the switching speed, the higher the control efficiency of Vddh. Therefore, it can be seen that when the driving capability of the driving circuit 1124 is too low, the control efficiency of Vddh is too low, which affects the working efficiency of the touch chip 1.

[0201] Additionally, see Figure 11a and Figure 11b , Figure 11a The figure shows the waveforms of the driving voltage signals with different slopes. Figure 11b The image shows a comparison of the energy spectra of driving voltage signals with different slopes. Figure 11a The first curve 1101 is the voltage change curve of the driving voltage signal with a transition time of 100ns, the second curve 1102 is the voltage change curve of the driving voltage signal with a transition time of 1000ns, and the third curve 1103 is the voltage change curve of the driving voltage signal with a transition time of 10000ns. Figure 11b The third energy spectrum 93 is the energy spectrum of the driving voltage signal with a transition time of 100 ns, the fourth energy spectrum 94 is the energy spectrum of the driving voltage signal with a transition time of 1000 ns, and the fifth energy spectrum 95 is the energy spectrum of the driving voltage signal with a transition time of 10000 ns. Figure 11a and Figure 11b It is evident that as the slopes of the rising and falling edges of the driving voltage signal increase, the high-frequency noise components of the driving voltage signal also increase, leading to stronger electromagnetic interference. In other words, when the driving capability of the driving circuit 1124 is too high, the electromagnetic interference is stronger.

[0202] And choose Figure 10 The example shown allows for dynamic adjustment of the equivalent drive size of the drive stage 11241 to change the drive capability of the drive circuit 1124. This enables dynamic adjustment of the drive capability of the drive circuit 1124 according to the application scenario, balancing the operating efficiency of the touch chip 1 with the intensity of electromagnetic interference. In other words, it reduces the likelihood of the touch chip 1 experiencing excessively low operating efficiency or excessively high electromagnetic interference.

[0203] Corresponding to the aforementioned touch chip 1, this application also provides a touch screen, including:

[0204] Touch chip 1 as described above;

[0205] Medium voltage power supply, which is electrically connected to the power supply terminal VDDA of the boost control circuit 11 and the power supply terminal VDDA of the touch medium voltage domain 12.

[0206] The boost circuit has its input terminal electrically connected to the medium-voltage power supply, which boosts the medium-voltage power supply to a high-voltage power supply. The output terminal VDDH of the boost circuit outputs a high-voltage power supply to feed back the high-voltage power supply to the touch chip 1.

[0207] By using this embodiment, the boost control circuit can be integrated into the touch chip 1, so that the touch chip 1 itself has the ability to control the voltage of the high-voltage power supply. Therefore, the number of chips in the touch screen can be reduced, and the area of ​​the flexible circuit board in the touch screen can also be reduced, thereby reducing the cost of the touch screen.

[0208] Corresponding to the aforementioned touch chip 1, this application also provides a boost method, applied to any of the aforementioned touch chips 1, wherein in one embodiment the method is as follows: Figure 12a As shown, it includes:

[0209] Step S1: Receive the high-voltage signal fed back from the external high-voltage power supply through the high-voltage terminal VDDH.

[0210] Step S2: Based on the feedback high voltage signal, adjust the drive voltage signal to control the voltage of the high voltage power supply.

[0211] By using this embodiment, the boost control circuit can be integrated into the touch chip, so that the touch chip itself has the ability to control the voltage of the high-voltage power supply. Therefore, the number of chips in the touch screen can be reduced, and the area of ​​the flexible circuit board in the touch screen can also be reduced, thereby reducing the cost of the touch screen.

[0212] In another embodiment, the boosting method is as follows: Figure 12b The above, compared to Figure 12a , Figure 12b The steps involved in a soft-start process that adds a touch chip 1 are as follows: Figure 12b The method in the example shown includes:

[0213] Step S3: When the touch chip 1 is started, the duty cycle of the driving voltage signal is adjusted to a preset safe value.

[0214] This safety value should be 0% or close enough to 0%, such as 1%, to avoid voltage loop oscillations caused by an excessively high duty cycle.

[0215] Step S4: After the touch chip 1 is started, the duty cycle of the driving voltage signal is increased every preset time interval until the duty cycle of the driving voltage signal reaches the preset target value, and then step S1 is executed.

[0216] For example, the duty cycle of the drive voltage signal could be increased by 1% every 1ms. The preset target value should not be lower than the duty cycle that allows the voltage loop to operate stably.

[0217] In this application, the touch chip 1 increases the duty cycle of the driving voltage signal through digital control, rather than controlling the duty cycle of the driving voltage signal through hardware circuitry. It is understood that the boost control circuit 11 is integrated inside the touch chip 1, therefore the touch chip 1 can change the duty cycle of the driving voltage signal output by the boost control circuit 11 through digital control.

[0218] Furthermore, the preset time interval, the increment when increasing the duty cycle each time, the preset safety value, and the preset target value can all be modified according to user needs.

[0219] Step S1: Receive the high-voltage signal fed back from the external high-voltage power supply through the high-voltage terminal VDDH.

[0220] When the duty cycle reaches the target value, it can be assumed that the voltage loop is working stably. Therefore, the voltage loop can be switched to control Vddh, that is, steps S1 and S2 are executed.

[0221] Step S2: Based on the feedback high voltage signal, adjust the drive voltage signal to control the voltage of the high voltage power supply.

[0222] In this embodiment, soft start is achieved by gradually increasing the duty cycle of the driving voltage signal of the touch chip 1. Since the soft start process is controlled by the touch chip 1 itself, the touch chip 1 can flexibly adjust the soft start time according to user needs, thus improving the flexibility of the soft start of the touch chip 1.

[0223] In yet another embodiment, the boosting method is as follows: Figure 12c The above, compared to Figure 12a , Figure 12c The example adds another soft-start process related to the touch chip 1, and in this example, the touch chip 1 internally includes the aforementioned voltage divider register 14 and overvoltage protection register. Figure 12c The method in the example shown includes:

[0224] Step S5: When the touch chip 1 is started, write a resistance value into the voltage divider register 14 to adjust the voltage division ratio of the voltage divider circuit 111 to the initial voltage division ratio, and write a voltage threshold into the overvoltage protection register to adjust the overvoltage protection threshold of the overvoltage protection circuit to the initial overvoltage protection threshold.

[0225] The initial voltage division ratio should be small enough to keep Vfb at a low voltage value. At the same time, the initial overvoltage protection threshold should also be small enough to satisfy Vddh > initial overvoltage protection threshold when Vddh is about to overshoot, so as to shut down the drive circuit 1124 in time to prevent Vddh from overshooting and thus avoid voltage loop oscillation.

[0226] Step S6: After the touch chip 1 is started, every preset time interval, modify the resistance value in the voltage divider register 14 to increase the voltage division ratio of the voltage divider circuit 111, and modify the voltage threshold in the overvoltage protection register to increase the overvoltage protection threshold of the overvoltage protection circuit, until the voltage of the high voltage terminal VDDH reaches the preset voltage value, and then execute step S1.

[0227] The preset target value should not be lower than the voltage value that enables the voltage loop to operate stably. Furthermore, the initial voltage division ratio, the initial overvoltage protection threshold, the increment when increasing the voltage division ratio and overvoltage protection threshold each time, and the preset voltage value can all be modified according to user needs.

[0228] When increasing the voltage division ratio and overvoltage protection threshold, the following should be followed: prevent Vddh from overshooting to avoid voltage loop oscillation.

[0229] Step S1: Receive the high-voltage signal fed back from the external high-voltage power supply through the high-voltage terminal VDDH.

[0230] When the voltage at the high-voltage end VDDH reaches the preset voltage value, it can be considered that the voltage loop can work stably. Therefore, the voltage loop can be switched to control Vddh, that is, steps S1 and S2 are executed.

[0231] Step S2: Based on the feedback high voltage signal, adjust the drive voltage signal to control the voltage of the high voltage power supply.

[0232] In this embodiment, soft start is achieved by gradually increasing Vfb and VOVP of the touch chip 1. Since the soft start process is controlled by the touch chip 1 itself, the touch chip 1 can flexibly adjust the soft start time according to user needs, thus improving the flexibility of the soft start of the touch chip 1.

[0233] In another possible embodiment, where the touch chip 1 includes the voltage divider register 14, the method further includes: writing the resistance values ​​configured for each resistor in the voltage divider circuit 111 into the voltage divider register 14 to adjust the resistance values ​​of each resistor to change the voltage division ratio of the voltage divider circuit 111.

[0234] In another possible embodiment, where the touch chip 1 includes the overvoltage protection register, the method further includes: writing a first voltage threshold configured for the touch chip 1 into the overvoltage protection register to adjust the overvoltage protection threshold of the overvoltage protection circuit.

[0235] In another possible embodiment, where the touch chip 1 includes the overcurrent protection register, the method further includes: writing a current threshold configured for the touch chip 1 into the overcurrent protection register to adjust the overcurrent protection threshold of the overcurrent protection circuit.

[0236] In another possible embodiment, where the touch chip 1 includes the over-temperature protection register, the method further includes: writing a temperature threshold configured for the touch chip 1 into the over-temperature protection register to adjust the over-temperature protection threshold of the over-temperature protection circuit.

[0237] In another possible embodiment, where the touch chip 1 includes the undervoltage lockout register, the method further includes: writing a second voltage threshold configured for the touch chip 1 into the undervoltage lockout register to adjust the on-state voltage threshold and the off-state voltage threshold of the undervoltage lockout circuit.

[0238] In another possible embodiment, where the touch chip 1 includes the frequency register, the method further includes: writing a frequency configured for the touch chip 1 into the frequency register to adjust the frequency or frequency upper limit of the ramp signal generated by the ramp generator 1123.

[0239] In another possible embodiment, where the touch chip 1 includes the drive management register, the method further includes: writing the drive level size configured for the touch chip 1 into the drive management register to change the equivalent drive size of each of the drive levels.

[0240] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0241] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0242] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the embodiments of the touchscreen and boost method are basically similar to the embodiments of the touch chip, so the description is relatively simple; relevant parts can be referred to in the description of the method embodiments.

[0243] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A touch chip, characterized in that, The touch chip includes: A boost control circuit has a power supply terminal, a high voltage terminal, and a switching terminal. The power supply terminal is electrically connected to an external medium-voltage power supply. The high voltage terminal receives a high voltage signal fed back from the external high voltage power supply. The switching terminal outputs a drive voltage signal to an external circuit. The boost control circuit is used to adjust the drive voltage signal based on the feedback high voltage signal to control the voltage of the high voltage power supply. The touch-sensitive medium-voltage domain circuit is electrically connected to the medium-voltage power supply and drives the low-power domain circuit. The high-voltage domain circuit for touch control is electrically connected to the high-voltage power supply. With the cooperation of the high-voltage domain circuit in the touch control, it drives the high-power area circuit and outputs touch sensing signals.

2. The touch chip according to claim 1, characterized in that, The boost control circuit includes a voltage divider circuit and a feedback control circuit; The input terminal of the voltage divider circuit is electrically connected to the high voltage terminal, and the output terminal is electrically connected to the feedback terminal of the feedback control circuit. The power supply terminal of the feedback control circuit is electrically connected to the power supply terminal of the boost control circuit. The input terminal is configured with a preset reference voltage, and the output terminal is electrically connected to the switching terminal of the boost control circuit. The feedback control circuit is used to adjust the driving voltage signal output by the output terminal based on the voltage of the feedback terminal, so that the voltage of the feedback terminal tends to the reference voltage.

3. The touch chip according to claim 2, characterized in that, The feedback control circuit includes: an error amplifier circuit, a pulse width modulation comparator, a ramp generator, and a drive circuit; The inverting input terminal of the error amplifier circuit is electrically connected to the feedback terminal of the feedback control circuit, the non-inverting input terminal of the error amplifier circuit is electrically connected to the input terminal of the feedback control circuit, the power supply terminal of the error amplifier circuit is electrically connected to the power supply terminal of the feedback control circuit, and the output terminal of the error amplifier circuit is electrically connected to the non-inverting input terminal of the pulse width modulation comparator. The inverting input of the pulse width modulation comparator is electrically connected to the ramp generator, and the output of the pulse width modulation comparator is electrically connected to the input of the driving circuit. The output terminal of the drive circuit is electrically connected to the output terminal of the feedback control circuit.

4. The touch chip according to claim 2, characterized in that, The boost control circuit also includes a feedback terminal that is electrically connected to an external source. The output terminal of the voltage divider circuit is electrically connected to the feedback terminal of the boost control circuit.

5. The touch chip according to claim 2, characterized in that, The touch chip also includes: The voltage divider register is electrically connected to each resistor in the voltage divider circuit. By changing the resistance value written into the voltage divider register, the resistance value of each resistor is adjusted to change the voltage division ratio of the voltage divider circuit.

6. The touch chip according to claim 2, characterized in that, The touch chip also includes: An overvoltage protection circuit is provided, wherein the voltage detection terminal of the overvoltage protection circuit is electrically connected to the output terminal of the voltage divider circuit, and the output terminal of the overvoltage protection circuit is electrically connected to the feedback control circuit. An overvoltage protection register is electrically connected to the overvoltage protection circuit. The overvoltage protection threshold of the overvoltage protection circuit is adjusted by changing the voltage threshold written to the overvoltage protection register.

7. The touch chip according to claim 2, characterized in that, The touch chip also includes: An overcurrent protection circuit is provided, wherein the current detection terminal of the overcurrent protection circuit is electrically connected to an external source, and the output terminal of the overcurrent protection circuit is electrically connected to the feedback control circuit. An overcurrent protection register is electrically connected to the overcurrent protection circuit. The overcurrent protection threshold of the overcurrent protection circuit is adjusted by changing the current threshold written to the overcurrent protection register.

8. The touch chip according to claim 1, characterized in that, The touch chip also includes: Temperature sensor; An over-temperature protection circuit is provided, wherein the temperature detection terminal of the over-temperature protection circuit is electrically connected to the output terminal of the temperature sensor, and the output terminal of the over-temperature protection circuit is electrically connected to the feedback control circuit. An over-temperature protection register is electrically connected to the over-temperature protection circuit. The over-temperature protection threshold of the over-temperature protection circuit can be adjusted by changing the temperature threshold written in the over-temperature protection register.

9. The touch chip according to claim 1, characterized in that, The touch chip also includes: An undervoltage lockout circuit, wherein the input terminal of the undervoltage lockout circuit is electrically connected to the medium-voltage power supply, and the output terminal of the undervoltage lockout circuit is electrically connected to other circuits in the touch chip; An undervoltage lockout register, electrically connected to the undervoltage lockout circuit, adjusts the enable and disable voltage thresholds of the undervoltage lockout circuit by changing the voltage threshold written to the undervoltage lockout register.

10. The touch chip according to claim 3, characterized in that, The touch chip also includes: A frequency register, electrically connected to the ramp generator, is used to adjust the frequency or upper frequency limit of the ramp signal generated by the ramp generator by changing the frequency written to the frequency register.

11. The touch chip according to claim 3, characterized in that, The driving circuit includes multiple cascaded driving stages; The touch chip also includes a driver management register, which is electrically connected to each of the driver stages. The switching status of each driver stage is adjusted by changing the driver stage size written in the driver management register, thereby changing the equivalent driver size of each driver stage.

12. The touch chip according to claim 3, characterized in that, The feedback control circuit also includes: The superposition circuit has two input terminals that are electrically connected to the ramp generator and an external source, respectively, and its output terminal that is electrically connected to the inverting input terminal of the pulse width modulation comparator.

13. A touchscreen, characterized in that, The touchscreen includes The touch chip as described in any one of claims 1-12; A medium-voltage power supply, which is electrically connected to the power supply terminal of the boost control circuit and the power supply terminal of the touch medium-voltage domain; A boost circuit is provided, wherein the input terminal of the boost circuit is electrically connected to the medium-voltage power supply to boost the medium-voltage power supply to a high-voltage power supply, and the output terminal of the boost circuit outputs the high-voltage power supply to feed back the high-voltage power supply to the touch chip.

14. A method for boosting voltage, characterized in that, Applied to a touch chip as described in any one of claims 1-12, the method includes: The high-voltage terminal receives the high-voltage signal fed back from the external high-voltage power supply. Based on the feedback high-voltage signal, the driving voltage signal is adjusted to control the voltage of the high-voltage power supply.

15. The method according to claim 14, characterized in that, The method further includes: When the touch chip is started, the duty cycle of the driving voltage signal is adjusted to a preset safety value; After the touch chip is activated, the duty cycle of the driving voltage signal is increased every preset time interval; Until the duty cycle of the driving voltage signal reaches the preset target value, the step of receiving the high-voltage signal fed back from the external high-voltage power supply through the high-voltage terminal is executed.

16. The method according to claim 14, characterized in that, When the touch chip includes the voltage divider register and the overvoltage protection register, the method further includes: When the touch chip is started, a resistance value is written into the voltage divider register to adjust the voltage division ratio of the voltage divider circuit to the initial voltage division ratio, and a voltage threshold is written into the overvoltage protection register to adjust the overvoltage protection threshold of the overvoltage protection circuit to the initial overvoltage protection threshold. After the touch chip is started, every preset time interval, the resistance value in the voltage divider register is modified to increase the voltage division ratio of the voltage divider circuit, and the voltage threshold in the overvoltage protection register is modified to increase the overvoltage protection threshold of the overvoltage protection circuit. Until the voltage at the high-voltage terminal reaches a preset voltage value, the step of receiving the high-voltage signal fed back from the external high-voltage power supply through the high-voltage terminal is executed.

17. The method according to claim 14, characterized in that, In the case where the touch chip includes the voltage divider register; the method further includes: writing the resistance values ​​configured for each resistor in the voltage divider circuit into the voltage divider register to adjust the resistance values ​​of each resistor to change the voltage division ratio of the voltage divider circuit; and / or, When the touch chip includes the overvoltage protection register, the method further includes: writing a first voltage threshold configured for the touch chip into the overvoltage protection register to adjust the overvoltage protection threshold of the overvoltage protection circuit; and / or, In the case where the touch chip includes the overcurrent protection register, the method further includes: writing a current threshold configured for the touch chip into the overcurrent protection register to adjust the overcurrent protection threshold of the overcurrent protection circuit; And / or, In the case where the touch chip includes the over-temperature protection register, the method further includes: writing a temperature threshold configured for the touch chip into the over-temperature protection register to adjust the over-temperature protection threshold of the over-temperature protection circuit; And / or, When the touch chip includes the undervoltage lockout register, the method further includes: writing a second voltage threshold configured for the touch chip into the undervoltage lockout register to adjust the on-state voltage threshold and the off-state voltage threshold of the undervoltage lockout circuit; And / or, When the touch chip includes the frequency register, the method further includes: writing a frequency configured for the touch chip into the frequency register to adjust the frequency or upper frequency limit of the ramp signal generated by the ramp generator; And / or, If the touch chip includes the driver management register, the method further includes: writing the driver level size configured for the touch chip into the driver management register to change the equivalent driver size of each driver level.

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