CN-122018724-A - Driving circuit of touch screen, touch chip and vehicle-mounted terminal equipment

CN122018724ACN 122018724 ACN122018724 ACN 122018724ACN-122018724-A

Abstract

The application discloses a driving circuit of a touch screen, a touch chip and vehicle-mounted terminal equipment. The touch screen comprises a plurality of transmitting electrodes, a driving circuit comprises a first voltage domain circuit and a second voltage domain circuit, the second voltage domain circuit is connected with the first voltage domain circuit and the transmitting electrodes, the first voltage domain circuit is used for generating and outputting a first reference voltage and a first sine wave signal, the second voltage domain circuit is used for amplifying the first reference voltage into a second reference voltage according to a first multiple, proportional amplification is carried out on the first sine wave signal according to the second reference voltage, and a second sine wave signal is generated and output, wherein the second sine wave signal is used for driving the transmitting electrodes, and the amplitude of the second sine wave signal is larger than that of the first sine wave signal. The application can ensure that the touch screen can meet the anti-electromagnetic interference standard of the vehicle when being applied to the vehicle-mounted terminal, and can also effectively detect the touch point in the scene that the user needs to wear gloves.

Inventors

Sun tianqi
JIANG XINXI
ZHANG JINGKAI
SHEN HONGJU
XIE XUBIN

Assignees

敦泰电子（深圳）有限公司

Dates

Publication Date: 20260512
Application Date: 20260130

Claims (11)

1. The driving circuit of the touch screen is characterized by comprising a plurality of transmitting electrodes; the driving circuit comprises a first voltage domain circuit and a second voltage domain circuit, and the second voltage domain circuit is connected with the first voltage domain circuit and the transmitting electrode; The first voltage domain circuit is used for generating and outputting a first reference voltage and a first sine wave signal; The second voltage domain circuit is used for amplifying the first reference voltage into a second reference voltage according to a first multiple, and performing proportional amplification processing on the first sine wave signal according to the second reference voltage to generate and output a second sine wave signal; The second sine wave signal is used for driving the transmitting electrode, and the amplitude of the second sine wave signal is larger than that of the first sine wave signal.
2. The drive circuit of claim 1, wherein the first voltage domain circuit comprises an adjustable op-amp unit connected to the second voltage domain circuit; The adjustable operational amplifier unit is used for receiving a reference voltage source and an adjusting instruction, amplifying the reference voltage source to the first reference voltage according to the adjusting instruction and outputting the first reference voltage.
3. The drive circuit of claim 2, wherein the first voltage domain circuit further comprises a digital-to-analog converter, a programmable gain amplifier, and a low pass filter, the programmable gain amplifier being coupled to the digital-to-analog converter and the low pass filter, the low pass filter being coupled to the second voltage domain circuit; the digital-to-analog converter is used for receiving the digital signal and generating a step wave signal according to the digital signal; The programmable gain amplifier is used for receiving the step wave signal and amplifying the step wave signal according to a second multiple; The low-pass filter is used for carrying out smoothing filtering processing on the step wave signal to generate the first sine wave signal.
4. The drive circuit of claim 1, wherein the second voltage domain circuit comprises a voltage amplifying unit, a proportional amplifying unit, and a drive unit, the voltage amplifying unit being connected to the first voltage domain circuit, the proportional amplifying unit being connected to the voltage amplifying unit, the drive unit, and the first voltage domain circuit; The voltage amplifying unit is used for receiving the first reference voltage and amplifying the first reference voltage into the second reference voltage according to a first multiple; The proportional amplifying unit is used for carrying out proportional amplifying processing on the first sine wave signal according to the second reference voltage to generate and output the second sine wave signal; the driving unit is used for transmitting the second sine wave signal to the transmitting electrode and enabling the second sine wave signal to be matched with the capacitive reactance of the transmitting electrode.
5. The drive circuit of claim 2, wherein the adjustable operational amplifier unit comprises a first operational amplifier, a first resistor, and an adjustable resistor; the positive input end of the first operational amplifier is used for receiving the reference voltage source, the negative input end of the first operational amplifier is grounded through the first resistor, the negative input end of the first operational amplifier is also connected with the output end of the first operational amplifier through the adjustable resistor, and the output end of the first operational amplifier is connected with the second voltage domain circuit; The adjustable resistor is used for adjusting to a corresponding resistance value according to the adjusting instruction.
6. The driving circuit as recited in claim 4 wherein said voltage amplifying unit comprises a second operational amplifier, a second resistor and a third resistor; the positive input end of the second operational amplifier is used for receiving the first reference voltage, the reverse input end of the second operational amplifier is grounded through the second resistor, the reverse input end of the second operational amplifier is also connected with the output end of the second operational amplifier through the third resistor, and the output end of the second operational amplifier is connected with the proportional amplifying unit.
7. The driving circuit as recited in claim 4 wherein said proportional amplifying unit comprises a third operational amplifier, a first capacitor, a second capacitor, a fourth resistor, a first switch and a second switch; The positive input end of the third operational amplifier is used for receiving the second reference voltage, the negative input end of the third operational amplifier is used for receiving the first sine wave signal through the first capacitor, the negative input end of the third operational amplifier is further connected to the output end of the third operational amplifier through the first switch, the negative input end of the third operational amplifier is further connected to the output end of the third operational amplifier in series through the second switch and the fourth resistor, the output end of the third operational amplifier is connected with the driving unit, and the second capacitor is connected with the first switch in parallel.
8. The driving circuit as recited in claim 4 wherein said driving unit comprises a fourth operational amplifier, said fourth operational amplifier having a forward input for receiving said second sine wave signal, an inverse input connected to an output of said fourth operational amplifier, and an output connected to said transmitting electrode.
9. The drive circuit of claim 3, wherein the first voltage domain circuit further comprises an analog multiplier connected to the output of the low pass filter and the second voltage domain circuit, respectively; the analog multiplier is used for receiving a time domain window function, multiplying the time domain window function with the signal output by the low-pass filter, and obtaining and outputting the first sine wave signal.
10. A touch chip comprising the drive circuit of any one of claims 1 to 9.
11. A vehicle-mounted terminal device, comprising a touch screen and the touch chip of claim 10.

Description

Driving circuit of touch screen, touch chip and vehicle-mounted terminal equipment Technical Field The application relates to the technical field of touch control, in particular to a driving circuit of a touch screen, a touch chip and vehicle-mounted terminal equipment. Background At present, along with the high-speed development of the automobile industry, the application of the in-car touch screen is more and more extensive, the in-car touch screen is used as an instrument panel for display, functions such as car machine control and in-car entertainment are carried more, and the changes put forward higher requirements on the touch chip. In the existing vehicle-mounted touch screen, the transmitting electrode is generally driven by square wave or trapezoidal wave signals, so that harmonic components are large, and the vehicle-mounted anti-electromagnetic interference standard is difficult to meet. Moreover, the load of the vehicle-mounted touch screen is large, when a user touches a scene of the touch screen through thick gloves, insufficient signal quantity of touch detection of the touch screen can be caused, and effective detection of touch points cannot be realized. Disclosure of Invention In view of the above, the application provides a driving circuit of a touch screen, a touch chip and a vehicle-mounted terminal device. The technical scheme of the application is as follows: The first aspect of the application provides a driving circuit of a touch screen, which comprises a plurality of emitting electrodes, wherein the driving circuit comprises a first voltage domain circuit and a second voltage domain circuit, the second voltage domain circuit is connected with the first voltage domain circuit and the emitting electrodes, the first voltage domain circuit is used for generating and outputting a first reference voltage and a first sine wave signal, the second voltage domain circuit is used for amplifying the first reference voltage into a second reference voltage according to a first multiple, and the first sine wave signal is subjected to proportional amplification according to the second reference voltage to generate and output a second sine wave signal, wherein the second sine wave signal is used for driving the emitting electrodes, and the amplitude of the second sine wave signal is larger than that of the first sine wave signal. In an embodiment of the application, the first voltage domain circuit comprises an adjustable operational amplifier unit, wherein the adjustable operational amplifier unit is connected with the second voltage domain circuit, and is used for receiving a reference voltage source and an adjusting instruction, amplifying the reference voltage source to the first reference voltage according to the adjusting instruction and outputting the first reference voltage. In an embodiment of the application, the first voltage domain circuit further comprises a digital-to-analog converter, a programmable gain amplifier and a low-pass filter, wherein the programmable gain amplifier is connected with the digital-to-analog converter and the low-pass filter, the low-pass filter is connected with the second voltage domain circuit, the digital-to-analog converter is used for receiving a digital signal and generating a step wave signal according to the digital signal, the programmable gain amplifier is used for receiving the step wave signal and amplifying the step wave signal according to a second multiple, and the low-pass filter is used for conducting smooth filtering processing on the step wave signal and generating the first sine wave signal. In an embodiment of the application, the second voltage domain circuit comprises a voltage amplifying unit, a proportional amplifying unit and a driving unit, wherein the voltage amplifying unit is connected with the first voltage domain circuit, the proportional amplifying unit is connected with the voltage amplifying unit, the driving unit and the first voltage domain circuit, the voltage amplifying unit is used for receiving the first reference voltage and amplifying the first reference voltage into the second reference voltage according to a first multiple, the proportional amplifying unit is used for carrying out proportional amplifying processing on the first sine wave signal according to the second reference voltage to generate and output the second sine wave signal, and the driving unit is used for transmitting the second sine wave signal to the transmitting electrode and enabling the second sine wave signal to be matched with the capacitive reactance of the transmitting electrode. In an embodiment of the application, the adjustable operational amplifier unit comprises a first operational amplifier, a first resistor and an adjustable resistor, wherein a forward input end of the first operational amplifier is used for receiving the reference voltage source, a reverse input end of the first operational amplifier is grounded through the first resi