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What should we do to eliminate the interference of the power supply?

Q: About the capacitive screen we are using now, the power supply interference problem is very serious. What should we do to eliminate the interference of the power supply? Apart from scanning frequency to avoid the noise frequency of the power supply, improve the signal-to-noise ratio of the screen? Is there any other way?

A: Seeing from all current cases, power supply interference is mainly concentrated in large-size TP (7inch or above), and we have the following solutions:
(1) Choose a quality power supply. This is very important and the most effective and fundamental way to solve power disturbances;

(2) Frequency hopping. Use the spectrum analyzer to find the area where the common mode interference strength of the adapter is small, and then set the TX scan frequency to this area through software setting, which can effectively control the interference. If there is interference in the full frequency band, it is recommended to abandon the adapter;

(3) Improve the signal to noise ratio. In the initial design of TP (7.0inch or above), consider using the low-impedance surface-rent material for the RX signal channel and using the design of the double-sided trace. Try to control all the channel resistances within 10K, which can effectively control the power supply interference. ;

(4) It is also possible to change the charger, increase the algorithm filtering, and adopt Cypress, EETI, ILI schemes with strong anti-interference performance.


Post time: Mar-15-2022