Overvoltage protection circuit, control method, touch screen, wire controller and air conditioning unit

Abstract

The invention discloses an overvoltage protection circuit, a control method, a touch screen, a wire controller and an air conditioning unit, the overvoltage protection circuit comprises a threshold switching module, the input end of the threshold switching module is connected with a main power supply, and the threshold switching module is used for generating reference voltage according to voltage provided by the main power supply; the first input end of the comparator is connected with the output end of the threshold switching module; the first end of the sampling module inputs the actual input voltage of the touch chip, the second end of the sampling module is grounded, and the third end of the sampling module is connected with the second input end of the comparator; the input end of the D trigger is connected with the output end of the comparator; the input end of the first switching tube inputs the actual input voltage of the touch chip, the output end of the first switching tube is connected with the touch chip, and the control end of the first switching tube is connected with the output end of the D trigger and used for being switched on or switched off according to the switching signal output by the D trigger. According to the overvoltage protection circuit, the situation that overvoltage protection is triggered in advance or triggered in a delayed mode can be avoided, and the reliability of the overvoltage protection circuit is improved.

Description

Technical Field

[0001] This invention relates to the field of electronic power technology, and more specifically, to an overvoltage protection circuit, a control method, a touch screen, a wired controller, and an air conditioning unit. Background Technology

[0002] In smart home appliances, industrial control equipment, and household appliances, wired controllers (such as air conditioner remote controls, water heater control panels, and smart switches) widely adopt touch-based human-machine interfaces. Their core component is the touch chip (TouchIC), which is responsible for collecting user touch signals and communicating with the main control system wirelessly or via wired means. However, touchscreens typically operate in complex electromagnetic environments, and their input voltage is easily affected by the following factors, leading to overvoltage: 1. Electrostatic discharge (ESD): When a user touches a button in a dry environment, the static electricity from the human body can reach thousands of volts, easily damaging the chip's input terminals; 2. Power supply fluctuations: When battery power or external power supply is unstable, the input voltage may momentarily exceed the chip's rated range; 3. External interference: Electromagnetic interference (EMI) or signal crosstalk can cause abnormal voltages on the input pins; 4. Incorrect power connection: Users or maintenance personnel may reverse the power supply polarity when replacing batteries or connecting wiring. In existing technologies, current-limiting resistors are generally used to solve the overvoltage problem. However, current-limiting resistors can only limit current and cannot dynamically adjust the protection threshold according to the supply voltage, easily causing false triggering or protection delays.

[0003] The existing technology that uses current-limiting resistors to solve overvoltage problems can only limit the current and cannot dynamically adjust the protection threshold according to the supply voltage, which can easily cause false triggering or protection delay. There is currently no effective solution. Summary of the Invention

[0004] This invention provides an overvoltage protection circuit, control method, touch screen, wired controller, and air conditioning unit to solve the problem that the existing technology uses current-limiting resistors to solve overvoltage problems, which can only limit the current and cannot dynamically adjust the protection threshold according to the power supply voltage, easily causing false triggering or protection delay.

[0005] To address the aforementioned technical problems, this invention provides an overvoltage protection circuit applied to a touchscreen, wherein the touchscreen includes a touch chip, and the overvoltage protection circuit includes:

[0006] A threshold switching module, whose input is connected to the main power supply, is used to generate a reference voltage based on the voltage provided by the main power supply.

[0007] The comparator has its first input connected to the output of the threshold switching module;

[0008] The sampling module has its first terminal receiving the actual input voltage of the touch chip, its second terminal grounded, and its third terminal connected to the second input terminal of the comparator.

[0009] The D flip-flop has its input connected to the output of the comparator and is used to generate a switching signal based on the signal output by the comparator, and then output it to the first switching transistor. The D flip-flop is also used to latch the switching signal.

[0010] The first switching transistor has the actual input voltage of the touch chip input at its input terminal, its output terminal connected to the touch chip, and its control terminal connected to the output terminal of the D flip-flop, and is used to turn on or off according to the switching signal.

[0011] Furthermore, the threshold switching module includes:

[0012] A first resistor and a second resistor are connected in series, with the first resistor connected to the main power supply and the second resistor grounded.

[0013] An AND gate arithmetic unit, whose first input is connected between the first resistor and the second resistor, and whose second input is connected to the control terminal of the main control chip, is used to output a control signal based on the voltage between the first resistor and the second resistor.

[0014] A digital potentiometer, whose input is connected to the output of the AND gate arithmetic unit and whose output is connected to the first input of the comparator, is used to generate a reference voltage based on the control signal output by the AND gate arithmetic unit.

[0015] Furthermore, the overvoltage protection circuit also includes:

[0016] A first capacitor, the first end of which is connected between the output terminal of the digital potentiometer and the first input terminal of the comparator, and the second end of which is grounded;

[0017] The resistance of the digital potentiometer is variable.

[0018] Furthermore, the overvoltage protection circuit also includes:

[0019] The fifth resistor is disposed between the output of the comparator and the input of the D flip-flop;

[0020] The second capacitor has its first end connected between the fifth resistor and the input of the D flip-flop, and its second end grounded.

[0021] Furthermore, the overvoltage protection circuit also includes:

[0022] The second switch is connected in parallel with the first switch, and its control signal is opposite to that of the first switch.

[0023] The NOT gate arithmetic unit has its input connected to the output of the D flip-flop, and its output connected to the control terminal of the second switching transistor.

[0024] Furthermore, the overvoltage protection circuit also includes:

[0025] The first clamping diode has its positive terminal receiving the actual input voltage of the touch chip, and its negative terminal grounded.

[0026] Furthermore, the overvoltage protection circuit also includes:

[0027] The second clamping diode has its positive terminal connected to the main power supply and its negative terminal grounded.

[0028] Furthermore, the sampling module includes:

[0029] A third resistor and a fourth resistor are connected in series. The third resistor is connected to the input power supply of the touch chip, and the fourth resistor is grounded. The second input terminal of the comparator is connected between the third resistor and the fourth resistor.

[0030] The present invention also provides a touch screen, including a touch chip and the overvoltage protection circuit described above.

[0031] The present invention also provides a wired controller, including the above-described touch screen.

[0032] The present invention also provides an air conditioning unit, including the above-mentioned wired controller.

[0033] The present invention also provides a control method applied to the above-mentioned overvoltage protection circuit, the control method comprising:

[0034] The comparator output signal determines whether the touch chip's input power supply has experienced overvoltage.

[0035] After an overvoltage occurs, the resistance of the digital potentiometer in the D flip-flop decreases.

[0036] The line between the output terminal of the digital potentiometer and the first input terminal of the comparator is connected to the first terminal of the first capacitor, and the second terminal of the first capacitor is grounded.

[0037] The present invention also provides a computer-readable storage medium having a computer program stored thereon, characterized in that the program, when executed by a processor, implements the above-described control method.

[0038] The present invention also provides an electronic device, comprising:

[0039] One or more processors;

[0040] A storage device for storing one or more programs, which, when executed by one or more processors, cause the one or more processors to implement the above-described control method.

[0041] Applying the technical solution of this invention, the threshold switching module generates a reference voltage based on the voltage provided by the main power supply. When the voltage provided by the main power supply is low, a lower reference voltage is generated; when the voltage provided by the main power supply is high, a higher reference voltage is generated. Based on this, the overvoltage protection threshold (i.e., the aforementioned reference voltage) can be flexibly adjusted according to the supply voltage, thereby matching the reference voltage with the chip's operating voltage. This avoids premature or delayed triggering of overvoltage protection, improving the reliability of the overvoltage protection circuit. Furthermore, the comparator generates high and low level signals based on the actual input voltage of the touch chip and the reference voltage. The D flip-flop generates a switching signal based on the high and low level signals output by the comparator, and then outputs it to the switching transistor M1, thereby controlling the on / off state of the switching transistor M1. This ensures timely disconnection of the input voltage from the touch chip in the event of overvoltage, protecting the touch chip and improving safety. Using a D flip-flop for latching results in a simple circuit implementation and significant effect. All functional modules are independent of the touch chip, requiring no modification to the chip's internal structure, offering strong compatibility and supporting various touch chip models. Attached Figure Description

[0042] Figure 1 This is a structural block diagram of an overvoltage protection circuit according to an embodiment of the present invention;

[0043] Figure 2 This is a structural diagram of an overvoltage protection circuit according to another embodiment of the present invention;

[0044] Figure 3 This is a structural diagram of an overvoltage protection circuit according to another embodiment of the present invention;

[0045] Figure 4 This is a structural diagram of an overvoltage protection circuit according to another embodiment of the present invention;

[0046] Figure 5 This is a structural diagram of an overvoltage protection circuit according to another embodiment of the present invention;

[0047] Figure 6 This is a structural diagram of an overvoltage protection circuit according to another embodiment of the present invention;

[0048] Figure 7 This is a structural diagram of an overvoltage protection circuit according to another embodiment of the present invention;

[0049] Figure 8 This is a schematic diagram illustrating the specific working process of the overvoltage protection circuit in this embodiment;

[0050] Figure 9A flowchart of a control method according to an embodiment of the present invention;

[0051] Figure 10 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0053] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0054] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0055] It should be understood that although the terms first, second, third, etc., may be used to describe resistors in the embodiments of the present invention, these resistors should not be limited to these terms. These terms are only used to distinguish different resistors. For example, without departing from the scope of the embodiments of the present invention, a first resistor may also be referred to as a second resistor, and similarly, a second resistor may also be referred to as a first resistor.

[0056] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0057] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0058] The optional embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0059] Example 1

[0060] In smart home appliances, industrial control equipment, and household appliances, wired controllers (such as air conditioner remote controls, water heater control panels, and smart switches) widely adopt touch-based human-machine interfaces. Their core component is the touch IC, responsible for collecting user touch signals and communicating with the main control system wirelessly or via wired means. However, touchscreens typically operate in complex electromagnetic environments, and their input voltage is susceptible to overvoltage due to the following factors: 1. Electrostatic Discharge (ESD): When a user touches a button in a dry environment, the static electricity from the human body can reach thousands of volts, easily damaging the chip's input terminals; 2. Power Fluctuations: When battery power or external power supply is unstable, the input voltage may momentarily exceed the chip's rated range; 3. External Interference: Electromagnetic interference (EMI) or signal crosstalk can cause abnormal voltages on the input pins; 4. Incorrect Power Connection: Users or maintenance personnel may reverse the power polarity when replacing batteries or connecting wiring. Current-limiting resistors are generally used to address overvoltage issues, but they only limit current and cannot dynamically adjust the protection threshold based on the supply voltage, easily leading to false triggering or protection delays.

[0061] To address the problem that existing technologies using current-limiting resistors to solve overvoltage issues can only limit current and cannot dynamically adjust the protection threshold based on the supply voltage, easily leading to false triggering or protection delays, this embodiment provides an overvoltage protection circuit applied to a touchscreen, which includes a touch chip. Figure 1 This is a structural block diagram of an overvoltage protection circuit according to an embodiment of the present invention, such as... Figure 1As shown, the overvoltage protection circuit includes: a threshold switching module 10, whose input is connected to the main power supply; the threshold switching module is used to generate a reference voltage V_ref based on the voltage VDD provided by the main power supply; a comparator 20, whose first input is connected to the output of the threshold switching module 10; a sampling module 30, whose first end is connected to the input power supply of the touch chip 50, its second end is grounded, and its third end is connected to the second input of the comparator 20; a D flip-flop 40, whose input is connected to the output of the comparator 20, the D flip-flop 40 generates a switching signal based on the signal output by the comparator 20, and then outputs it to the first switching transistor M1. The D flip-flop also latches the above switching signal. For example, after the comparator 20 outputs a high-level signal, the D flip-flop outputs a high-level signal and latches the high-level signal at the same time. In this way, even if the comparator 20 no longer outputs a signal, the D flip-flop can still continuously output a high-level signal; the input of the first switching transistor M1 is the actual input voltage of the touch chip, the output is connected to the touch chip 50, and its control end is connected to the output of the D flip-flop 40, which is used to turn on or off according to the above switching signal, thereby controlling whether the touch chip has a voltage input.

[0062] Different models of touch chips operate at different voltages. For example, some touch chips operate at 3.3V. When the actual input voltage of the touch chip exceeds 3.3V by a certain value, the touch chip is in an overvoltage state. If the set reference voltage threshold is high at this time, it will cause the overvoltage protection to be delayed in triggering, which may easily lead to damage to the touch chip due to prolonged high voltage. On the other hand, some touch chips operate at 5V. The touch chip is only in an overvoltage state when the actual input voltage exceeds 5V by a certain value. If the set reference voltage threshold is low at this time, it will cause the overvoltage protection to be triggered prematurely. Therefore, to avoid a mismatch between the reference voltage threshold and the chip's operating voltage, the threshold switching module 10 generates a reference voltage V_ref based on the voltage VDD provided by the main power supply. For example, when VDD=3.3V, it outputs a "low threshold mode" signal; when VDD=5V, it outputs a "high threshold mode" signal. The corresponding reference voltage V_ref is generated according to the above threshold modes: for example, when VDD=3.3V, V_ref=4.2V; – when VDD=5V, V_ref=6.0V.

[0063] During normal operation, the voltage output by sampling module 30 is lower than the reference voltage V_ref, and the voltage at the non-inverting input of comparator 20 is greater than the voltage at the inverting input. Comparator 20 outputs a high level, the D flip-flop is set, and outputs a high-level signal. The first switch M1 is turned on, connecting the input voltage VIN to the touch chip, thus powering the touch chip. In the event of overvoltage, the voltage output by sampling module 30 is higher than the reference voltage V_ref, and the voltage at the non-inverting input of comparator 20 is less than the voltage at the inverting input. Comparator 20 outputs a low level, the D flip-flop outputs a low-level signal, the first switch M1 is turned off, disconnecting the input voltage VIN from the touch chip, and powering off the touch chip, thereby achieving overvoltage protection. Due to the latching effect of the D flip-flop, once triggered, the state is latched, and even if the high level output by comparator 20 disappears, the output of the D flip-flop remains high.

[0064] In this embodiment, the overvoltage protection circuit uses a threshold switching module 10 to generate a reference voltage V_ref based on the voltage VDD provided by the main power supply. When VDD is low, a lower reference voltage V_ref is generated; when VDD is high, a higher reference voltage V_ref is generated. This flexibly adjusts the overvoltage protection threshold according to the supply voltage, ensuring the reference voltage matches the chip's operating voltage. This prevents premature or delayed overvoltage protection triggering, improving the reliability of the overvoltage protection circuit. Furthermore, comparator 20 generates high and low level signals based on the actual input voltage to the touch chip and the reference voltage. D flip-flop 40 generates a switching signal based on the signal output from comparator 20 and outputs it to switch transistor M1, controlling the switching on and off of M1. This ensures timely disconnection of the input voltage from the touch chip during overvoltage, protecting the touch chip and improving safety. Using D flip-flops for latching is simple and effective; all functional modules are independent of the touch chip, requiring no modification to the chip's internal structure, offering strong compatibility and supporting various touch chip models. Meanwhile, the D flip-flop 40 can also latch the output signal. For example, after the comparator 20 outputs a high-level signal, the D flip-flop outputs a high-level signal and latches the high-level signal at the same time. In this way, even if the comparator 20 no longer outputs a signal, the D flip-flop can still continuously output a high-level signal, thereby realizing the continuous conduction state of the switch.

[0065] Figure 2 This is a structural diagram of an overvoltage protection circuit according to another embodiment of the present invention. To achieve flexible switching of the output reference voltage V_ref, as shown... Figure 2As shown, the threshold switching module 10 includes: a first resistor R1 and a second resistor R2 connected in series, the first resistor R1 being connected to the main power supply and the second resistor R2 being grounded; an AND gate arithmetic unit U1, the first input of which is connected between the first resistor R1 and the second resistor R2, and the second input of which is connected to the control terminal of the main control chip, for outputting a control signal based on the voltage between the first resistor R1 and the second resistor R2; and a digital potentiometer U2, the input of which is connected to the output of the AND gate arithmetic unit U1, and the output of which is connected to the first input of the comparator 20, for generating a reference voltage V_ref according to the control signal output by the AND gate arithmetic unit.

[0066] like Figure 2 As shown, the sampling module 30 includes a third resistor R3 and a fourth resistor R4 connected in series. The third resistor R3 is used to input the input voltage of the touch chip 50, and the fourth resistor R4 is grounded. The second input terminal of the comparator 20 is connected between the third resistor R3 and the fourth resistor R4.

[0067] Figure 3 This is a structural diagram of an overvoltage protection circuit according to another embodiment of the present invention. To achieve rapid energy dissipation and active response to overvoltage surges in the event of an overvoltage, thereby improving the withstand level, such as... Figure 3 As shown, the above overvoltage protection circuit also includes: a first capacitor C1, whose first end is connected between the output terminal of the digital potentiometer U2 and the first input terminal of the comparator 20, and whose second end is grounded; the resistance value of the digital potentiometer U2 is variable.

[0068] After an overvoltage occurs, the main control chip MCU controls the AND gate arithmetic unit U1 through the control terminal MCU_CONTRUL, which in turn controls the digital potentiometer U2 in the D flip-flop to switch the operation of reducing the resistance value to priority, and no longer outputs the reference voltage V_ref. The resistance value of the digital potentiometer U2 decreases rapidly, for example from 10kΩ to 1kΩ, so that the RC time constant decreases from 1ms to 0.1ms; the first capacitor C1 charges rapidly to absorb the energy generated by the overvoltage.

[0069] Figure 4 This is a structural diagram of an overvoltage protection circuit according to another embodiment of the present invention. To obtain a delay time of approximately 10 ns, noise is filtered out, and glitches are prevented from triggering the protection. Figure 4 As shown, the above overvoltage protection circuit also includes: a fifth resistor R5, which is disposed between the output terminal of the comparator and the input terminal of the D flip-flop; and a second capacitor C2, the first terminal of which is connected between the fifth resistor R5 and the input terminal of the D flip-flop 40, and the second terminal of which is grounded.

[0070] Figure 5The diagram shows the structure of an overvoltage protection circuit according to another embodiment of the present invention. If the first switching transistor M1 is damaged, the protection circuit will fail, requiring the circuit to be disassembled and the switching transistor replaced, increasing maintenance costs. To solve the above problem, such as... Figure 5 As shown, the above overvoltage protection circuit also includes: a second switch M2, which is connected in parallel with the first switch M1, and its type is opposite to that of the first switch M1, so the control signal is opposite to that of the first switch; and a NOT gate arithmetic unit U3, whose input is connected to the output of the D flip-flop 40, and whose output is connected to the control terminal of the second switch M2.

[0071] Figure 6 The diagram below shows the structure of an overvoltage protection circuit according to another embodiment of the present invention. To achieve multi-level overvoltage protection, the overvoltage protection circuit further includes: a first clamping diode D1, whose positive terminal is connected to the actual input voltage of the touch chip and whose negative terminal is grounded; and a second clamping diode D2, whose positive terminal is connected to the main power supply and whose negative terminal is grounded. Voltage clamping is achieved through the clamping diodes, thereby realizing an additional layer of overvoltage protection.

[0072] Example 2

[0073] Figure 7 This is a structural diagram of an overvoltage protection circuit according to another embodiment of the present invention, as shown below. Figure 7 As shown, in this embodiment, the AND gate U1 is model 74HC08, the digital potentiometer is model MCP41010, the D flip-flop is model 74HC74, and the NOT gate is model 74HC04. Figure 8 This is a schematic diagram illustrating the specific working process of the overvoltage protection circuit in this embodiment, as shown below. Figure 8 As shown, the specific working process is as follows:

[0074] 1. After the system is powered on, the value of the main power supply voltage VDD is detected through the first resistor R1 and the second resistor R2. Based on the value of VDD, the digital potentiometer is controlled to output the corresponding reference voltage V_ref.

[0075] First, the threshold switching module is connected to VDD via resistors R1 (100kΩ) and R2 (10kΩ) to detect the main supply voltage VDD. When VDD = 3.3V, it outputs a "low threshold mode" signal; when VDD = 5V, it outputs a "high threshold mode" signal. The adjustable reference source consists of a digital potentiometer (such as MCP41010), which generates a corresponding reference voltage V_ref based on the control signal.

[0076] – When VDD=3.3V, V_ref=4.2V;

[0077] – When VDD=5V, V_ref=6.0V.

[0078] The reference voltage accuracy is better than ±1%, and the temperature drift is less than 50ppm / ℃.

[0079] 2. The actual voltage V_sample input to the touch chip is detected by the third resistor R3 and the fourth resistor R4.

[0080] A voltage divider network is formed by two high-resistance surface-mount resistors, R1 (90kΩ) and R2 (10kΩ), connected in series between the input terminal VIN and ground. The sampling point is located between R1 and R2, and the output sampling voltage V_sample is generated. This sampling voltage is 1 / 10 of the input voltage VIN (i.e., V_sample = VIN / 10) and is used for subsequent comparisons.

[0081] 3. The actual voltage V_sample input to the touch chip is compared with the reference voltage V_ref by comparator 20, and high and low level signals are output.

[0082] When V_sample is fed into the inverting input of comparator 20, and V_sample > V_ref, comparator 20 outputs a low-level signal “OV_flag”, indicating that an overvoltage event has occurred. Comparator 20 has built-in hysteresis to prevent oscillation.

[0083] 4. The D flip-flop triggers and latches the state.

[0084] like Figure 7 As shown, the delay circuit, composed of a digital potentiometer MCP41010, a fifth resistor R5, and a second high-voltage ceramic capacitor C2, can achieve a delay time of approximately 10ns, filtering out noise and preventing glitches from triggering protection. After the delay, the signal is sent to the D input of the D flip-flop. The clock signal (CLK) is provided by the system master clock or a dedicated trigger signal. When OV_flag is high, the D flip-flop is set, and the output signal Q is high. The output signal Q serves as a switch control signal, driving the first switching transistor M1. Once the D flip-flop is triggered, its state is latched; even if the OV_flag signal disappears, the output signal Q of the D flip-flop remains high.

[0085] 5. Drive switching transistors M1 and M2.

[0086] like Figure 7 As shown, the gate of M1 is connected to the control signal D flip-flop pin Q5, and the gate of M2 is connected to the inverting control signal NOT gate output pin. During normal operation, M1 and M2 are turned on, and VIN is connected to the internal circuitry. When OV_flag is low, the control signal is pulled low, and M1 and M2 are simultaneously turned off, cutting off the path between VIN and the internal circuitry, achieving physical isolation. The switching transistors M1 and M2 have low on-resistance (less than 1Ω) and high turn-off impedance (greater than 10^10Ω), ensuring protection effectiveness and signal integrity.

[0087] 6. The main control chip (MCU) detects overvoltage events.

[0088] The main control chip (MCU) uses the OV_flag signal to determine whether an overvoltage event has occurred.

[0089] 7. Control the resistance of the digital potentiometer to decrease.

[0090] When an overvoltage event is detected, the control logic forces the MCP41010 resistance to drop from 10kΩ to 1kΩ; the RC time constant to drop from 1ms to 0.1ms; C1 fast charging to absorb electrostatic energy, actively respond to electrostatic shocks, and improve the withstand level; the "resistance reduction operation" is set to have a higher priority than the "output reference voltage operation" to ensure that overvoltage events are handled first.

[0091] 8. Reset and then standby.

[0092] If VIN is normal, V_int will supply power and the touch chip will work normally; if VIN is overvoltage, V_int will power off and activate protection; the protection state is latched and cannot be automatically restored, and can only be restored by external reset or system restart.

[0093] In this embodiment, the voltage sampling unit acquires the input voltage in real time; the reference voltage generation unit dynamically generates an adjustable reference voltage based on the system supply voltage; the programmable comparator compares the sampled voltage with the dynamic reference voltage and outputs a judgment signal; the protection switch control logic controls the protection switch module to disconnect the input path based on the comparison result, achieving overvoltage protection; simultaneously, a dual-stage ESD protection structure is set at the input, with the first stage being an external clamping diode and the second stage being an adjustable RC network, working together to dissipate electrostatic energy. A latching logic circuit is used, resulting in a simple circuit implementation and significant effect; all functional modules are independent of the touch chip, requiring no modification to the chip's internal structure, exhibiting strong compatibility and supporting various touch chip models.

[0094] Example 3

[0095] This embodiment provides a touch screen, including a touch chip and an overvoltage protection circuit as described in the above embodiment.

[0096] Example 4

[0097] This embodiment provides a wired controller, including the touch screen described in the above embodiment.

[0098] Example 5

[0099] This embodiment provides an air conditioning unit, including the wired controller described in the above embodiment.

[0100] Example 6

[0101] This embodiment provides a control method applied to the overvoltage protection circuit of the above embodiment. Figure 9 A flowchart of a control method according to an embodiment of the present invention is shown below. Figure 9 As shown, the control method includes:

[0102] S101 determines whether the input power supply of the touch chip has been over-voltage based on the signal output by the comparator.

[0103] S102, after an overvoltage occurs, controls the resistance of the digital potentiometer in the D flip-flop to decrease; wherein, the line between the output terminal of the digital potentiometer and the first input terminal of the comparator is connected to the first terminal of the first capacitor, and the second terminal of the first capacitor is grounded.

[0104] To achieve rapid energy release and proactive response to overpressure shocks during overpressure events, thereby enhancing the tolerance level, such as... Figure 3 As shown, the above overvoltage protection circuit also includes: a first capacitor, the first end of which is connected between the output terminal of the digital potentiometer and the first input terminal of the comparator, and the second end of which is grounded; the resistance value of the digital potentiometer is variable.

[0105] After an overvoltage occurs, the main control chip MCU controls the AND gate arithmetic unit U1 through the control terminal MCU_CONTRUL, which in turn controls the digital potentiometer U2 in the D flip-flop to switch the operation of reducing the resistance value to priority, and no longer outputs the reference voltage V_ref. The resistance value of the digital potentiometer U2 decreases rapidly, for example from 10kΩ to 1kΩ, so that the RC time constant decreases from 1ms to 0.1ms; the first capacitor C1 charges rapidly to absorb the energy generated by the overvoltage.

[0106] In this embodiment, the control method reduces the resistance of the digital potentiometer in the D flip-flop after an overvoltage occurs. This reduces the RC time constant of the RC circuit formed by the first capacitor and the digital potentiometer, thereby enabling the first capacitor to charge quickly, absorb the energy generated by the overvoltage, and achieve the effect of protecting the circuit.

[0107] Example 7

[0108] This embodiment provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described control method.

[0109] Example 8

[0110] This embodiment provides an electronic device, including:

[0111] One or more processors;

[0112] A storage device for storing one or more programs, which, when executed by one or more processors, cause the one or more processors to implement the above-described control method.

[0113] Figure 10 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention, such as... Figure 10 As shown, the electronic device includes:

[0114] One or more processors 1010 and memory 1020, Figure 10 Take the 1010 processor as an example.

[0115] The aforementioned electronic device may further include: an input device 1030 and an output device 1040.

[0116] The processor 1010, memory 1020, input device 1030, and output device 1040 can be connected via a bus or other means. Figure 10 Taking the example of a connection between China and Israel via a bus.

[0117] The memory 1020, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as the program instructions / modules corresponding to the control method in this embodiment of the invention. The processor 1010 executes various functional applications and data processing of the server by running the non-volatile software programs, instructions, and modules stored in the memory 1020, thereby implementing the above-described method embodiments.

[0118] The memory 1020 may include a program storage area and a data storage area. The program storage area may store application programs required for operating the device and at least one function. The data storage area may store data created based on the use of the control method. Furthermore, the memory 1020 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device.

[0119] Input device 1030 can receive input digital or character information, and generate key signal inputs related to user settings and function control of the electronic device. Output device 1040 may include display devices such as a display screen.

[0120] The one or more modules are stored in the memory 1020, and when executed by the one or more processors 1010, they execute the control method in any of the above method embodiments.

[0121] The aforementioned electronic device product can execute the method provided in the embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the method. Technical details not described in detail in this embodiment can be found in the method provided in the embodiments of the present invention.

[0122] The electronic devices of this invention exist in various forms, including but not limited to:

[0123] (1) Mobile communication devices: These devices are characterized by their mobile communication capabilities and are primarily designed to provide voice and data communication. These terminals include smartphones (e.g., iPhones), multimedia phones, feature phones, and low-end phones.

[0124] (2) Ultra-mobile personal computer devices: These devices fall under the category of personal computers, have computing and processing functions, and generally also have mobile internet access capabilities. These terminals include: PDAs, MIDs, and UMPCs, such as iPads.

[0125] (3) Portable entertainment devices: These devices can display and play multimedia content. This category includes: audio and video players (such as iPods), handheld game consoles, e-books, as well as smart toys and portable car navigation devices.

[0126] (4) Server: A device that provides computing services. The components of a server include a processor, hard disk, memory, device bus, etc. Servers are similar to general computer architectures, but because they need to provide highly reliable services, they have higher requirements in terms of processing power, stability, reliability, security, scalability, and manageability.

[0127] (5) Other electronic devices with data interaction functions, such as televisions, in-vehicle screens, etc.

[0128] The circuit embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0129] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the control methods described in various embodiments or some parts of the embodiments.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An overvoltage protection circuit applied to a touchscreen, the touchscreen including a touch chip, characterized in that, The overvoltage protection circuit includes: A threshold switching module, whose input is connected to the main power supply, is used to generate a reference voltage based on the voltage provided by the main power supply. The comparator has its first input connected to the output of the threshold switching module; The sampling module has its first terminal receiving the actual input voltage of the touch chip, its second terminal grounded, and its third terminal connected to the second input terminal of the comparator. The D flip-flop has its input connected to the output of the comparator and is used to generate a switching signal based on the signal output by the comparator, and then output it to the first switching transistor. The D flip-flop is also used to latch the switching signal. The first switching transistor has the actual input voltage of the touch chip input at its input terminal, its output terminal connected to the touch chip, and its control terminal connected to the output terminal of the D flip-flop, and is used to turn on or off according to the switching signal.

2. The overvoltage protection circuit according to claim 1, characterized in that, The threshold switching module includes: A first resistor and a second resistor are connected in series, with the first resistor connected to the main power supply and the second resistor grounded. An AND gate arithmetic unit, whose first input is connected between the first resistor and the second resistor, and whose second input is connected to the control terminal of the main control chip, is used to output a control signal based on the voltage between the first resistor and the second resistor; A digital potentiometer, whose input is connected to the output of the AND gate arithmetic unit and whose output is connected to the first input of the comparator, is used to generate a reference voltage based on the control signal output by the AND gate arithmetic unit.

3. The overvoltage protection circuit according to claim 2, characterized in that, The overvoltage protection circuit also includes: A first capacitor, the first end of which is connected between the output terminal of the digital potentiometer and the first input terminal of the comparator, and the second end of which is grounded; The resistance of the digital potentiometer is variable.

4. The overvoltage protection circuit according to claim 1, characterized in that, The overvoltage protection circuit also includes: The fifth resistor is disposed between the output of the comparator and the input of the D flip-flop; The second capacitor has its first end connected between the fifth resistor and the input of the D flip-flop, and its second end grounded.

5. The overvoltage protection circuit according to claim 1, characterized in that, The overvoltage protection circuit also includes: The second switch is connected in parallel with the first switch, and its control signal is opposite to that of the first switch. The NOT gate arithmetic unit has its input connected to the output of the D flip-flop, and its output connected to the control terminal of the second switching transistor.

6. The overvoltage protection circuit according to claim 1, characterized in that, The overvoltage protection circuit also includes: The first clamping diode has its positive terminal receiving the actual input voltage of the touch chip, and its negative terminal grounded.

7. The overvoltage protection circuit according to claim 1, characterized in that, The overvoltage protection circuit also includes: The second clamping diode has its positive terminal connected to the main power supply and its negative terminal grounded.

8. The overvoltage protection circuit according to claim 1, characterized in that, The sampling module includes: A third resistor and a fourth resistor are connected in series. The third resistor is connected to the input power supply of the touch chip, and the fourth resistor is grounded. The second input terminal of the comparator is connected between the third resistor and the fourth resistor.

9. A touchscreen, comprising a touch chip, characterized in that, It also includes the overvoltage protection circuit according to any one of claims 1 to 8.

10. A wired controller, characterized in that, Includes the touchscreen as described in claim 9.

11. An air conditioning unit, characterized in that, Includes the wired controller as described in claim 10.

12. A control method applied to the overvoltage protection circuit according to any one of claims 1 to 8, characterized in that, The method includes: The comparator output signal determines whether the touch chip's input power supply has experienced overvoltage. After an overvoltage occurs, the resistance of the digital potentiometer in the D flip-flop decreases. The line between the output terminal of the digital potentiometer and the first input terminal of the comparator is connected to the first terminal of the first capacitor, and the second terminal of the first capacitor is grounded.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the control method as described in claim 12.

14. An electronic device, characterized in that, include: One or more processors; A storage device for storing one or more programs, which, when executed by one or more processors, cause the one or more processors to implement the control method as described in claim 12.

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