Five-wire resistance touch screen identification circuit

Abstract

The utility model relates to a five-wire resistance touch screen identification circuit which comprises a five-wire resistance touch screen driving power supply sub-circuit, a five-wire resistance touch screen driving sub-circuit, an identification circuit power supply sub-circuit, an ADC (Analog to Digital Converter) reference voltage sub-circuit, an operational amplifier sub-circuit and an ADC sub-circuit. The five-wire resistance touch screen is high in touch precision, fast in response, strong in anti-interference capability, high in reliability, long in service life and free of driving through simple component construction.

Description

Technical Field

[0001] The utility model relates to a resistive touch screen recognition technology, in particular to a five-wire resistive touch screen recognition circuit. Background Art

[0002] Whether in home appliances, cars, factory machines, etc., there are fewer and fewer devices without human-computer interaction, and the proportion of devices with human-computer interaction and touch function is increasing. But at the same time, new technical bottlenecks have also emerged. The size of touch screens is getting larger and larger, and the requirements for recognition accuracy, anti-interference ability, service life, reliability, cost, etc. are getting higher and higher. In this context, the application of five-wire resistive touch screens is becoming more and more widespread. Compared with traditional four-wire resistive touch screens, five-wire resistive touch screens have inherent advantages in physical structure, working principle, surface structure, reliability, anti-scratch, surface hardness, etc. However, the five-wire resistive touch screen with these inherent advantages is equivalent to the four-wire resistive touch screen. It also has a weakness - the touch screen drive circuit is more complex, the algorithm is more cumbersome, and the development is more difficult. Summary of the invention

[0003] The technical problem to be solved by the utility model is to provide a five-wire resistive touch screen recognition circuit, which has high touch accuracy, fast response, strong anti-interference ability, high reliability, long service life and is driver-free.

[0004] The utility model solves the above technical problems with the following technical solutions: A five-wire resistive touch screen recognition circuit comprises a five-wire resistive touch screen drive power subcircuit, a five-wire resistive touch screen drive subcircuit, a recognition circuit power subcircuit, an ADC reference voltage subcircuit, an operational amplifier subcircuit, and an ADC subcircuit. The 5-wire resistive touch screen driving power subcircuit is connected to the 5-wire resistive touch screen driving subcircuit, the 5-wire resistive touch screen driving subcircuit is connected to the 5-wire resistive touch screen driving power subcircuit, the operational amplifier subcircuit, and the identification circuit power subcircuit, the operational amplifier subcircuit is connected to the 5-wire resistive touch screen driving subcircuit, the ADC subcircuit, and the identification circuit power subcircuit, the identification circuit power subcircuit is connected to the 5-wire resistive touch screen driving subcircuit, the operational amplifier subcircuit, and the ADC subcircuit, the ADC subcircuit is connected to the operational amplifier subcircuit, the identification circuit power subcircuit, and the ADC reference voltage subcircuit; the 5-wire resistive touch screen driving power subcircuit supplies power to the 5-wire resistive touch screen driving subcircuit, the identification circuit power subcircuit supplies power to the 5-wire resistive touch screen driving subcircuit, the operational amplifier subcircuit, and the ADC subcircuit, the signal generated by the 5-wire resistive touch screen driving subcircuit is sent to the operational amplifier subcircuit, the signal generated by the operational amplifier subcircuit is sent to the ADC subcircuit, and the ADC reference voltage subcircuit provides a reference source for the ADC subcircuit.

[0005] On the basis of the above technical solution, the present invention can also be improved as follows.

[0006] Furthermore, the 5-wire resistive touch screen driving power supply sub-circuit includes chip U5, capacitors C10, C11, C9, and resistor R7; further, the resistor R7 in the 5-wire resistive touch screen driving power supply sub-circuit provides an enable level for chip U5 so that U5 can start working; capacitor C10 provides filtering and bypass functions for the 5V input power supply for chip U5; capacitor C9 provides the converted +3.3VTP power supply output filtering and bypass capacitor functions for chip U5; capacitor C11 provides chip U5 with a chip internal bypass capacitor function; through the functions of the above discrete devices, a stable power supply is provided for the 5-wire resistive touch screen driving power supply.

[0007] Furthermore, the 5-wire resistive touch screen driving sub-circuit includes analog switches SW1, SW2, SW3, SW4, and capacitors C8, C7, C6, and C5.

[0008] Furthermore, the capacitors C8, C7, C6, and C5 in the 5-wire resistive touch screen driving subcircuit are used to provide power supply filtering and bypass for the analog switches SW1, SW2, SW3, and SW4, respectively; the analog switches are turned on or off the CTUL, CTUR, CTLR, and CTLL signals under different timing conditions and loaded onto the driving signals UL, UR, LR, and LL of the RTP-5W 5-wire resistive touch screen to generate an analog voltage coordinate signal RTPOUT, thereby realizing the coordinate drive recognition of the 5-wire resistive touch screen.

[0009] Furthermore, the identification circuit power subcircuit includes a chip U4, capacitors C12, C13, C14, and a resistor R7.

[0010] Furthermore, the resistor R8 in the power subcircuit of the identification circuit provides an enable level for the chip U4 so that its U5 can start working; the capacitor C12 provides the chip U5 with a filtering and bypass function for the 5V input power supply; the capacitor C14 provides the chip U4 with a converted +3.3VCC power supply output filtering and bypass capacitor function; the capacitor C13 provides the chip U4 with an internal chip bypass capacitor function; through the action of the above discrete devices, a stable power supply is provided for the identification-related circuits.

[0011] Furthermore, the ADC reference voltage subcircuit includes resistors R1, R2, R3, and a voltage regulator U3.

[0012] Furthermore, R1 in the ADC reference voltage subcircuit is used to limit the current of the voltage regulator U3, so as to limit the excessive current flowing through U3 and causing excessive heat; resistors R2 and R3 are used to configure the output voltage of the voltage regulator U3 as the reference voltage; the voltage regulator U3 finally converts the 5V power supply into a precise VREF analog signal, which is used as the voltage reference source of the ADC conversion chip U2.

[0013] Furthermore, the operational amplifier sub-circuit includes an operational amplifier chip U1-A, resistors R6, R5, R4, and capacitors C4, C3.

[0014] Furthermore, the resistor R6 in the operational amplifier sub-circuit provides a certain level state for the positive input terminal of the operational amplifier chip U1-A when there is no load; the resistors R4 and R5 are resistors for configuring the same-direction amplification factor of the operational amplifier chip; the capacitor C4 provides bypass and filtering for the power supply terminal of the operational amplifier chip U1-A, and the capacitor C3 provides bypass and filtering for the output terminal of the operational amplifier chip U1-A; the operational amplifier chip converts the input signal RTPOUT into the ADCIN signal after amplification.

[0015] Furthermore, the ADC sub-circuit includes an ADC conversion chip U2 and capacitors C1 and C2.

[0016] Furthermore, the ADC conversion chip U2 included in the ADC subcircuit converts the ADCIN analog voltage into an I2C digital signal; the capacitor C1 provides bypass and filtering for the power supply end of the ADC conversion chip U2; the capacitor C1 provides bypass and filtering for the reference voltage source interface of the ADC conversion chip U2.

[0017] The beneficial effect of taking the above steps is that the functions of driving the 5-wire resistive touch screen and converting the coordinate analog quantity into a digital signal are realized through the combination of the 5-wire resistive touch screen driving power subcircuit, the 5-wire resistive touch screen driving subcircuit, the identification circuit power subcircuit, the ADC reference voltage subcircuit, the operational amplifier subcircuit, and the ADC subcircuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The utility model is a five-wire resistive touch screen recognition circuit of the overall structure diagram.

[0019] Figure 2 The utility model is a circuit structure schematic diagram of a five-wire resistive touch screen recognition circuit.

[0020] Figure 3 The utility model is a five-wire resistive touch screen recognition circuit working flow chart. DETAILED DESCRIPTION

[0021] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0022] like Figure 1As shown, a five-wire resistive touch screen recognition circuit includes a five-wire resistive touch screen drive power subcircuit, a five-wire resistive touch screen drive subcircuit, a recognition circuit power subcircuit, an ADC reference voltage subcircuit, an operational amplifier subcircuit, and an ADC subcircuit. The 5-wire resistive touch screen driving power subcircuit is connected to the 5-wire resistive touch screen driving subcircuit, the 5-wire resistive touch screen driving subcircuit is connected to the 5-wire resistive touch screen driving power subcircuit, the operational amplifier subcircuit, and the identification circuit power subcircuit, the operational amplifier subcircuit is connected to the 5-wire resistive touch screen driving subcircuit, the ADC subcircuit, and the identification circuit power subcircuit, the identification circuit power subcircuit is connected to the 5-wire resistive touch screen driving subcircuit, the operational amplifier subcircuit, and the ADC subcircuit, the ADC subcircuit is connected to the operational amplifier subcircuit, the identification circuit power subcircuit, and the ADC reference voltage subcircuit; the 5-wire resistive touch screen driving power subcircuit supplies power to the 5-wire resistive touch screen driving subcircuit, the identification circuit power subcircuit supplies power to the 5-wire resistive touch screen driving subcircuit, the operational amplifier subcircuit, and the ADC subcircuit, the signal generated by the 5-wire resistive touch screen driving subcircuit is sent to the operational amplifier subcircuit, the signal generated by the operational amplifier subcircuit is sent to the ADC subcircuit, and the ADC reference voltage subcircuit provides a reference source for the ADC subcircuit.

[0023] like Figure 2 The invention discloses a five-wire resistive touch screen recognition circuit, a five-wire resistive touch screen driving power subcircuit, a five-wire resistive touch screen driving subcircuit, a recognition circuit power subcircuit, an ADC reference voltage subcircuit, an operational amplifier subcircuit, and an ADC subcircuit.

[0024] Further, in the 5-wire resistive touch screen driving power supply sub-circuit, the IN pin of chip U5 is connected to one end of capacitor C10 and 5V power supply, and the other end of C10 is grounded; the GND pin of chip U5 is grounded; the BP / FB pin of chip U5 is connected to one end of capacitor C11, and the other end of C11 is grounded; the OUT pin of chip U5 is connected to one end of capacitor C9 and +3.3VTP, and the other end of capacitor C9 is grounded; further, in the 5-wire resistive touch screen driving sub-circuit, the COM pin of analog switch SW1 is connected to the UL pin of the 5-wire resistive touch screen; the analog switch The IN pin of SW1 is connected to CTUL; one end of the VCC pin of the analog switch SW1 is connected to one end of the capacitor C8 and the power supply +3.3VCC, and the other end of the capacitor C8 is grounded; the NC and GND pins of the analog switch SW1 are grounded; the NO pin of the analog switch SW1 is connected to +3.3VTP; further, in the 5-wire resistive touch screen driving sub-circuit, the COM pin of the analog switch SW2 is connected to the UR pin of the 5-wire resistive touch screen; the IN pin of the analog switch SW2 is connected to CTUR; one end of the VCC pin of the analog switch SW2 is connected to one end of the capacitor C7 and the power supply +3.3VCC, the other end of capacitor C7 is grounded; the NC and GND pins of analog switch SW2 are grounded; the NO pin of analog switch SW2 is connected to +3.3VTP; further, in the 5-wire resistive touch screen driving sub-circuit, the COM pin of analog switch SW3 is connected to the LR pin of the 5-wire resistive touch screen; the IN pin of analog switch SW3 is connected to CTLR; one end of the VCC pin of analog switch SW3 is connected to one end of capacitor C6 and the power supply +3.3VCC, and the other end of capacitor C6 is grounded; the NC and GND pins of analog switch SW3 are grounded; the analog switch The NO pin of switch SW3 is connected to +3.3VTP; further, in the 5-wire resistive touch screen driving subcircuit, the COM pin of analog switch SW4 is connected to the LL pin of the 5-wire resistive touch screen; the IN pin of analog switch SW4 is connected to CTLL; one end of the VCC pin of analog switch SW4 is connected to one end of capacitor C5 and the power supply +3.3VCC, and the other end of capacitor C5 is grounded; the NC and GND pins of analog switch SW4 are grounded; the NO pin of analog switch SW4 is connected to +3.3VTP; further, in the 5-wire resistive touch screen driving subcircuit, the WIPER of RTP-5W 5-wire resistive touch screen is connected to RTPOUT; further, in the identification circuit power supply subcircuit, the IN pin of chip U4 is connected to one end of capacitor C12 and the 5V power supply, and the other end of C12 is grounded; the GND pin of chip U4 is grounded; the BP / FB pin of chip U4 is connected to one end of capacitor C3, and the other end of C13 is grounded; the OUT pin of chip U4 is connected to one end of capacitor C14 and +3.3VCC, the other end of capacitor C14 is grounded; further, in the ADC reference voltage sub-circuit, one end of resistor R1 is connected to 5V, and the other end is connected to pin 1 of U3, VREF is connected to one end of resistor R2 and pin 1 of U3; the common connection point of resistors R2 and R3 is connected to pin 2 of U3; the other end of resistor R3 and pin 3 of U3 are both grounded; further, pin 1 of op amp sub-circuit chip U1-A is connected to +3.3VCC and one end of capacitor C4, and the other end of capacitor C4 is grounded; pin 2 of chip U1-A is connected to RTPOUT and one end of resistor R6, and the other end of resistor R6 is grounded; pin 3 of chip U1-A is connected to one end of resistor R5 and one end of resistor R4, and the other end of resistor R5 is grounded , the other end of resistor R4 is connected to pin 4 of U1-A and ADCIN and one end of capacitor C3, and the other end of capacitor C3 is grounded; pin 5 of chip U1-A is grounded; further, the ADCIN pin of ADC conversion chip U2 in the ADC subcircuit is connected to ADCIN; the REF+ pin of ADC conversion chip U2 is connected to VREF and one end of capacitor C1, and the other end of capacitor C1 is grounded; the GND pin of ADC conversion chip U2 is grounded; the VCC pin of ADC conversion chip U2 is connected to +3.3VCC and one end of capacitor C2, and the other end of capacitor C2 is grounded; the RST, INT, SCL, and SDA pins of ADC conversion chip U2 should be connected to RST, INT, SCL, and SDA signals respectively. .

[0025] like Figure 3 As shown, the working process of a five-wire resistive touch screen recognition circuit includes 6 steps; Step 1: 5-wire resistive touch screen drive power subcircuit works; Step 2: recognition circuit power subcircuit works; Step 3: ADC reference voltage subcircuit works; Step 4: 5-wire resistive touch screen drive subcircuit works; Step 5: op amp subcircuit works; Step 6: ADC subcircuit works.

[0026] Further, in step 1, the 5-wire resistive touch screen driving power supply subcircuit works, which means that the 5-wire resistive touch screen driving power supply subcircuit converts 5V power supply into +3.3VTP power supply, so that after the power conversion, the RTP-52 5-wire resistive touch screen and the +3.3VTP power supply required by the 5-wire resistive touch screen driving subcircuit can work normally; further, in step 2, the identification circuit power supply subcircuit works, which means that the 5V to +3.3VCC power supply circuit works, thus generating +3.3VCC, preparing for the circuit using +3.3VCC in the subsequent step; further, in step 3, the ADC reference voltage subcircuit works, which means that the voltage reference chip U3 generates a reference voltage source VREF; further, in step 4, the 5-wire resistive touch screen driving subcircuit works, which means that the 5-wire resistive touch screen driving subcircuit drives the 5-wire resistive touch screen under a fixed driving logic and obtains the coordinate original signal RTPOUT; further, in step 5, the operational amplifier subcircuit works, which means that the coordinate original signal RTPOUT is amplified by the operational amplifier subcircuit, and the original coordinate signal is converted into an ADCIN signal; further, in step 6 The operation of the ADC sub-circuit refers to the process in which the ADC conversion chip converts the ADCIN signal into an I2C digital signal, and finally realizes the driving of the 5-wire resistive touch screen and obtains the digital coordinate signal.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A five-wire resistive touch screen recognition circuit, characterized in that: The invention comprises a 5-wire resistive touch screen driving power subcircuit, a 5-wire resistive touch screen driving subcircuit, an identification circuit power subcircuit, an ADC reference voltage subcircuit, an operational amplifier subcircuit and an ADC subcircuit; the 5-wire resistive touch screen driving power subcircuit is connected to the 5-wire resistive touch screen driving subcircuit, the 5-wire resistive touch screen driving subcircuit is connected to the 5-wire resistive touch screen driving power subcircuit, the operational amplifier subcircuit and the identification circuit power subcircuit, the operational amplifier subcircuit is connected to the 5-wire resistive touch screen driving subcircuit, the ADC subcircuit and the identification circuit power subcircuit, the identification circuit power subcircuit is connected to the 5-wire resistive touch screen driving subcircuit, the operational amplifier subcircuit and the ADC subcircuit, the ADC subcircuit is connected to the operational amplifier subcircuit, the identification circuit power subcircuit and the ADC reference voltage subcircuit; the 5-wire resistive touch screen driving power subcircuit supplies power to the 5-wire resistive touch screen driving subcircuit, the identification circuit power subcircuit supplies power to the 5-wire resistive touch screen driving subcircuit, the operational amplifier subcircuit and the ADC subcircuit, the signal generated by the 5-wire resistive touch screen driving subcircuit is sent to the operational amplifier subcircuit, the signal generated by the operational amplifier subcircuit is sent to the ADC subcircuit, and the ADC reference voltage subcircuit provides a reference source for the ADC subcircuit.

2. The five-wire resistive touch screen recognition circuit according to claim 1, characterized in that: The 5-wire resistive touch screen driving power subcircuit includes chip U5, capacitors C10, C11, C9, and resistor R7; the resistor R7 in the 5-wire resistive touch screen driving power subcircuit provides an enable level for chip U5 so that U5 can start working; capacitor C10 provides chip U5 with filtering and bypass functions for the 5V input power supply; capacitor C9 provides chip U5 with the converted +3.3VTP power supply output filtering and bypass capacitor function; capacitor C11 provides chip U5 with the chip internal bypass capacitor function.

3. The five-wire resistive touch screen recognition circuit according to claim 1, characterized in that: The 5-wire resistive touch screen driving subcircuit includes analog switches SW1, SW2, SW3, SW4, and capacitors C8, C7, C6, and C5; the capacitors C8, C7, C6, and C5 in the 5-wire resistive touch screen driving subcircuit are used to perform power supply filtering and bypass functions for the analog switches SW1, SW2, SW3, and SW4, respectively.

4. The five-wire resistive touch screen recognition circuit according to claim 1, characterized in that: The identification circuit power subcircuit includes chip U4, capacitors C12, C13, C14, and resistor R7; the resistor R8 in the identification circuit power subcircuit provides an enable level for chip U4 so that U5 can start working; capacitor C12 provides chip U5 with filtering and bypass functions for the 5V input power supply; capacitor C14 provides chip U4 with the converted +3.3VCC power supply output filtering and bypass capacitor function; capacitor C13 provides chip U4 with the chip internal bypass capacitor function.

5. The five-wire resistive touch screen recognition circuit according to claim 1, characterized in that: The ADC reference voltage subcircuit includes resistors R1, R2, R3, and a voltage regulator U3; R1 in the ADC reference voltage subcircuit is used to limit the current of the voltage regulator U3, limiting the excessive current flowing through U3 and causing excessive heat; resistors R2 and R3 are used to configure the output voltage of the voltage regulator U3 as a reference voltage; the voltage regulator U3 ultimately converts the 5V power supply into a precise VREF analog signal, which serves as the voltage reference source of the ADC conversion chip U2.

6. The five-wire resistive touch screen recognition circuit according to claim 1, characterized in that: The operational amplifier sub-circuit includes an operational amplifier chip U1-A, resistors R6, R5, R4, and capacitors C4 and C3; the resistor R6 in the operational amplifier sub-circuit provides a certain level state for the positive input terminal of the operational amplifier chip U1-A when there is no load; the resistors R4 and R5 are resistors for configuring the same-direction amplification factor of the operational amplifier chip; the capacitor C4 provides bypass and filtering for the power supply terminal of the operational amplifier chip U1-A, and the capacitor C3 provides bypass and filtering for the output terminal of the operational amplifier chip U1-A; the operational amplifier chip converts the input signal RTPOUT into the ADCIN signal after amplification.

7. The five-wire resistive touch screen recognition circuit according to claim 1, characterized in that: The ADC subcircuit includes an ADC conversion chip U2, capacitors C1 and C2; the ADC conversion chip U2 included in the ADC subcircuit converts the ADCIN analog voltage into an I2C digital signal; the capacitor C1 provides bypass and filtering for the power supply end of the ADC conversion chip U2; Capacitor C1 provides bypass and filtering functions for the reference voltage source interface of the ADC conversion chip U2.

8. The five-wire resistive touch screen recognition circuit according to claim 1, characterized in that: The workflow includes 6 steps; Step 1: 5-wire resistive touch screen driver power subcircuit works; Step 2: identification circuit power subcircuit works; Step 3: ADC reference voltage subcircuit works; Step 4: 5-wire resistive touch screen driver subcircuit works; Step 5: op amp subcircuit works; Step 6: ADC subcircuit works.

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