Touch capacitor type sensor with AC power immunity

Abstract

The invention provides a contact-by-finger capacitance-type sensor with AC power immunological competence including an induction electrode, a control unit, a first and a second comparators, wherein the induction electrode including a first and a second conductor parts. The positive input end of the first comparator and the negative input end of the second comparator are coupled to the first conductor part, and the negative input of the first comparator and the positive input end of the second comparator are coupled to the second conductor part. The first comparator output a first comparison signal based on the voltage of the positive input end, and the second comparator outputs a second comparison signal based on the voltage of the negative input end. When the first and the second comparison signals are a first and a second logic standard bit, the control unit controls the first conductor part to be charged and the second conductor part to be discharged; otherwise, the control unit complements the opposite operation.

Description

Touch Capacitive Sensor with AC Power Immunity technical field The present invention relates to a technology related to a touch sensor, and in particular to a touch capacitive sensor with immunity to AC power. Background technique In recent years, due to the advancement of technology, many control buttons, such as elevator buttons or buttons of electronic amusement equipment, have also changed from the previous spring mechanical buttons to touch sensors. FIG. 1 is a circuit diagram of a prior art capacitive sensor. Please refer to FIG. 1 , the circuit includes a sensing electrode 101 , a resistor 102 and a sensing-control terminal 103 . In this circuit, the sensing electrode 101 is equivalent to a grounded capacitor. FIG. 2 is an operation waveform of the capacitive sensor in the prior art at the coupling node A between the sensing electrode 101 and the resistor 102 . Please refer to FIG. 1 and FIG. 2 at the same time. The sensing-control terminal 103 initially charges...

AI Technical Summary

Problems solved by technology

When AC power interference comes in, the relative relationship between the ground of the battery and the ground of the environment will start to fluctuate due to the interference of the AC power, or the external environment observed by the battery system is an environment that fluctuates due to AC power interference , so the measurement result of the equivalent capacitance will be distorted

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