Chargers and common mode noise

Capacitive touch screen devices is a major problem is that the charger emits high-frequency noise intensity touch performance will decline. Some mobile devices plugged into the charger only provide limited touch capabilities, or connect the charger does not apply when the device can not use the charger display information, in order to cope with high noise charger issue. The best solution to say it is not perfect.graphic lcd display module A quick look online forums and message boards related information, we can find a touchscreen device by charger noise problem is widespread and has made some consumers feel a headache.
Just as a standard USB charging interface rapid promotion in mobile devices, which also spawned a large number of low-cost aftermarket option market charger. Many chargers are more concerned about cost issues, without attention to performance, these chargers using inexpensive components, or the lack of common-mode noise can help reduce specific components.
The power and ground supply voltage with respect to ground voltage fluctuation, but between maintaining the same pressure, it will form a common mode noise. Such fluctuations only in the ground-coupled fingers touch screen that can affect the performance of the touch screen. Finger pressed with the same electric potential, mobile power and ground relative to its volatility will lead to noise injected by a finger touch screen. The amount of charge injected depends on the peak-to-peak voltage of noise.
In addition, the amount of the charge transport is also affected by two factors significantly affect: the fingers and the contact area between the touch screen and the touch screen overlay thickness of the lens.
The higher the capacitance, means injection of the touch screen, the greater the noise. In this case, the capacitance of a parallel plate is formed on one side by the finger contact area, the other side of the reception by the touch screen sensor electrode. First, TFT Display Module with the finger in contact with the touch screen area increases, the capacitance also increases accordingly proportional. However, since the receiving electrode from extremely narrow row or column form, the actual function of the diameter of the fingers.