An anti-interference acoustic wave touch screen analog signal conditioning circuit

Abstract

The invention discloses an anti-interference acoustic wave touch screen analog signal conditioning circuit, belonging to the technical field of acoustic wave touch screen, which comprises an LC filter differential amplifier circuit and a VGA circuit, the LC filter differential amplifier circuit is used for gain amplification of input signals, and When the input signal is gain-amplified, the amplified signal is filtered and frequency-selected, so that the interference signal is suppressed; the VGA circuit is respectively connected with the LC filter differential amplifier circuit and the control voltage to form a public negative feedback network of the LC filter differential amplifier circuit, It is used to adjust the gain multiple. The present invention can further improve the anti-interference ability of the acoustic wave touch screen, and at the same time can satisfy high filter frequency selection characteristics in a large dynamic range.

Description

technical field [0001] The invention belongs to the technical field of touch screens, and relates to an anti-interference acoustic wave touch screen analog signal conditioning circuit. Background technique [0002] Acoustic touch screen occupies an important position in the touch screen industry due to its inherent characteristics, such as high light transmittance, high durability and other advantages. Since the acoustic wave touch screen uses surface ultrasonic waves for positioning, it can also be immune to electromagnetic wave interference and light interference in complex external environments, so it can be widely used in various industries. However, when the acoustic wave touch screen is actually used, the electromagnetic interference introduced to the controller through sensor signal lines, communication lines, power lines, etc., may affect the stable operation of the acoustic wave touch screen. [0003] Strengthening the anti-interference ability of the controller ca...

AI Technical Summary

Problems solved by technology

From the perspective of the electromagnetic interference source, this method has great limitations. Its assumption is that the interference source comes from the digital circuit interference on the touch screen controller, and it is useful to separate it; but if the electromagnetic interference comes from the sensor The analog small signal path has no relation to the digital circuitry of the controller, this separation will have no effect

And from the perspective of actual product application, there are more and more serious cases of interference sources simulating small signal paths

Therefore, the technique is less practical

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