SHT31 evaluation + extended lithium battery power supply

hujj

SHT31 evaluation + extended lithium battery power supply [Copy link]

 

 

Previously, in order to bring out the relevant signal lines, a matching expansion board for SHT31 was specially drawn. At the same time, the space on the expansion board was used to add a lithium battery-powered circuit, which just made use of the lithium battery of the original feature phone. At the same time, a wiring port for an external battery was also reserved to facilitate the connection of other external power sources.

A lithium battery charging and discharging module is also added to the expansion board, and a Micro USB female socket is also added, which is convenient for USB charging and reserved for serial communication through the CH340 level conversion chip. Currently, the CH340 level conversion circuit has not been soldered.

The mobile phone charger tests the lithium battery on the expansion board through the Micro USB port. The following figure shows the charging process, and the red charging light is on:

When fully charged, the green light comes on:

The voltage coming out of the charge and discharge module is about 4V, and after passing through an S117 power conversion chip, it outputs about 3.25V to power SHT31 (this 117 power conversion chip originally outputs 3.3V, but because the input here is only about 3.7V, the output is slightly lower than 3.3V).

After the lithium battery is installed, I took out the 3V battery on the SHT31 evaluation board and installed it on the expansion board through the card holder. The evaluation board runs normally, indicating that the lithium battery power supply on the expansion board is completely fine:

Because it is powered by a rechargeable lithium battery, there is no need to worry about power consumption, so I turned on the Bluetooth.

At this point, the lithium battery power supply test has been successfully completed. The next step is to prepare to analyze the program to see if the serial communication test can be completed.

In addition, the nRF51822 upgrade package has not yet been installed in KEIL, and I don't know if I can use ST-LINK to download and burn it? I hope experienced people can give me some advice.

This content is originally created by EEWORLD forum user hujj . If you want to reprint or use it for commercial purposes, you must obtain the author's consent and indicate the source

qwqwqw2088

Can the short circuit and overcurrent protection be tested?

dcexpert

ST-Link only supports STM32, not nRF chips. You can use jlink or jlink-OB. jlink-ob is cheaper, and some jlink-ob hardware is almost the same as stlink.

hujj

qwqwqw2088 posted on 2020-1-11 19:50 Can the short circuit and overcurrent protection be tested?

I will remove the evaluation board tomorrow and test the charge and discharge management module alone.

hujj

dcexpert Published on 2020-1-11 19:59 ST-Link only supports STM32, not nRF chips. You can use jlink or jlink-OB. jlink-ob is cheaper. Some jlink-ob hardware is compatible with st ...

Then you must buy JLink before you can test it. Also, I would like to ask where to download KIEL's pack that supports nRF51822?

dcexpert

hujj posted on 2020-1-11 20:55 Then you must buy JLink before you can test it. In addition, I would like to ask where to download the KIEL pack that supports nRF51822?

You can download the keil package manager, or go to the keil official website to download it.

caizhiwei

I built an mdk project myself, but I can't burn it with jlink, which is very strange

hujj

caizhiwei posted on 2020-1-12 21:32 I built an mdk project myself, but I can't burn it with jlink, which is very strange

Could it be that the version of jlink is too low?

I haven't downloaded the pack upgrade yet.

littleshrimp

What solution is used to reduce the voltage of lithium batteries? Is the IQ high?

hujj

littleshrimp posted on 2020-1-13 17:55 What solution is used to reduce the voltage of lithium batteries? Is the IQ high?

I used an AMS1117 power conversion chip, which originally output 3.3V, but I used a lithium battery directly, and the input was only about 4V, so the actual output was 3.25V. After a few days of testing, it was proved that the 3.25V power supply can be used normally.

xuezehui

After reading your evaluation report, I feel that your operation is very good. I feel that I am not familiar with electronics in depth. If I can't get close to your level in half a year or a year, it would be a waste of time and youth.

hujj

xuezehui posted on 2020-3-25 18:27 After reading your evaluation report, I feel that this operation is very smooth. I feel that I am not in-depth in electronics. If I can't get close to your level in half a year or a year...

During the exploration, I found that there are double-row pins with SMD horns, which can be directly soldered on the back of the board, which is more convenient and practical.