Intelligent wearable products as a more popular form of products in recent years, more and more people pay attention to it. Although it can’t be accepted by all people, it does make some changes in the electronic product market.
An intelligent wearable product is usually composed of RF circuit unit, clock circuit unit, memory circuit unit, sensor circuit unit and main control MCU unit, while circuit PCB is usually concentrated in a small range and assembled on one side or two sides. The circuit board is mainly composed of 4 or 6 layers. Since so many functions are concentrated on a small PCB, we should pay special attention to the PCB layout
and wiring of wearable products. Now we summarize some precautions for reference.
First of all, partition layout, pay attention to wiring protection
From the above PCB circuit board, we can see that each part of the circuit of the intelligent wearable device (marked by different color boxes) has a good partition: because the intelligent bracelet is a collection of digital circuit components, in the circuit design, as long as the matching resistance and capacitance distribution is done, the circuit module with certain functions can be completed, which makes the circuit design more concise and easy to find. Although some sensor circuit units use analog circuit technology for data acquisition, once the module is designed as a module, the data communication and information transmission can be completed through the corresponding interface.
In the layout of circuit modules, on the one hand, it is necessary to pay attention to the clock circuit and crystal oscillator circuit to reach the target training through the shortest path, on the other hand, in the clock wiring, we should also pay attention to avoid data lines to prevent interference from affecting the stability of the system.
In the wiring, it is necessary to protect the key wiring, such as whether the clock generation circuit, crystal oscillator circuit, etc. are copper coated protection, and whether the ring ground protection is carried out. Generally, the protection will be carried out in the design, and the crystal oscillator part needs to be excavated copper.
Second, deal with the RF circuit
Intelligent wearable products need to be linked with mobile phones when they are in use. Therefore, the radio frequency part is the key part. In the design of this part, we must pay special attention to it. Now the intelligent wearable products on the market are all based on Bluetooth wireless data transmission, so the focus is on Bluetooth PCB RF processing. If the smart wearable product is only used for data transmission without the transmission of sound and music, then low-power Bluetooth is the best choice. In the design, the shape of Bluetooth antenna, the antenna layout and the shell material of smart wearable products are all important factors affecting the performance of the smart bracelet. In the PCB design process of intelligent wearable products, an excellent RF antenna engineer is particularly important.
Third, do ESD protection
In the previous article, I also wrote some technology and knowledge of circuit ESD. Today, I will talk about the importance of ESD to smart Bracelet products. Different countries and regions have different standards for ESD requirements of different products or the same products. In order to make the products pass the relevant tests, ESD protection design should be carried out during the design, and ESD testing should be carried out after the completion of the design to ensure that the products can adapt to the electronic testing of the local market.
Finally, the system upgrade interface is reserved
Whether the function upgrade of an intelligent wearable product is convenient or not is of great significance to users or fans of intelligent wearable products. If the software of a product is upgraded at an appropriate time (it may be that the hardware is designed to some functions in the early stage and the software fails to catch up with the market, or it may be that some software bugs have been fixed), this indicates that the product is still in the process of continuous development, which is a good psychological compensation for users. Now there are two ways to upgrade the software of smart Bracelet: through USB interface and wireless push. As for which method to adopt, it needs to be determined in the preliminary planning and software and hardware planning.