CC2640 Button Battery Powered Design Tips

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CC2640 Button Battery Powered Design Tips [Copy link]

CC2640 is a low-power Bluetooth chip with a wide voltage input range (1.8-3.8V). It supplies the internal digital core and circuit after stepping down through the internal DCDC or LDO. Because of its wide voltage input characteristics, it can be directly powered by a battery that supports this voltage range, such as the commonly used CR2032 button battery, thus saving an external power chip. This paper analyzes the impact of the battery characteristics on CC2640 in the later period of the service life of the button battery through experiments, and proposes a method to extend the battery life with a small amount of external devices and software code, and conducts experimental verification.

CC2640 can be powered by an external 1.8-3.8V battery directly through the internal DCDC or LDO, as shown in Figure 1. Usually, we use a button battery to directly power it.

The impact of the battery life in the later period Taking the CR2032 lithium manganese button battery as an example, the battery voltage gradually decreases with the extension of the use time, and it is also accompanied by a sharp increase in the battery internal resistance. In the early stage when the battery is fully charged or the voltage is relatively high, the internal resistance of the battery is relatively small and can be basically ignored. However, in the later stage of the battery life, the impact of the battery internal resistance cannot be ignored. The following figure is a test curve of one of the CR2032 button batteries under continuous load discharge. The blue corresponds to the battery voltage and the green is the battery internal resistance. We can see at point A that the battery voltage is about 2.6V at this moment, but the internal resistance has reached 100 ohms.

CC2640 纽扣电池供电设计技巧.pdf (1013.41 KB, downloads: 17)

2020-8-27 20:54 上传

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