MCU AD protection

tangwei8802429

MCU AD protection [Copy link]

ADC2 is the external ADC signal. The external environment may have radiation interference. I am afraid of overvoltage. Is it better to use a voltage regulator diode or TVS? Or is there any good circuit?

dcexpert

The choice of protection circuit depends mainly on the form of interference caused by the use environment.

chunyang

Use TVS and connect it at the line entrance.

qwqwqw2088

It is generally not recommended to use a voltage regulator diode for ADC port protection. When the voltage is close to the breakdown voltage, the leakage current is large, which affects the accuracy.

qwqwqw2088

TVS is mainly used for surge protection and communication port protection

Usually a diode clamp method

Fred_1977

Your circuit is also suitable for using a voltage regulator diode, the purpose is to protect the external high voltage from damaging the port

tangwei8802429

qwqwqw2088 posted on 2022-2-26 16:45 TVS is mainly for surge protection, and communication port protection is usually a diode clamping method

Diode clamp? If the radiated interference voltage is 6V, won't it return to the microcontroller power supply and burn out the microcontroller?

qwqwqw2088

tangwei8802429 posted on 2022-2-28 08:35 Diode clamp? If the radiation interference voltage is 6V, won’t it return to the microcontroller power supply and burn the microcontroller?

If the radiation interference voltage of AD is 6V, the voltage regulator tube is even worse, so you can consider TVS

There are many ways to protect the ADC input port, and the method used is determined by the characteristics of the signal source port.

chunyang

As electromagnetic radiation protection, the voltage regulator is not available, the conduction speed is too slow and it is ineffective. In addition, the MCU's IO itself has an internal clamp, so it is usually not necessary to add it. If you need to add it, you must use a Schottky diode with a lower junction voltage drop.

There is only one situation in which a Zener diode is used: when the input is a long-term DC voltage. This is completely different from the nature of electromagnetic radiation coupling, and the two cannot be confused.