Other Parts Discussed in Thread: TPS25751
Tool/software:
1. System Configuration
1) TPS25751 (PD) + BQ25713
2) Battery config.: 2 cells(Charging stop temp 45 °C, discharging stop temp. 60 °C), 3350mAh
3) System: Bluetooth speaker with USB PD function with 30 watts
2. What is the required test
1) Reliability power test
a. Playback pink noise with unit volume max. condition
b. External PD adapter: 30W power
c. Tested environment temperature: Ambient 25 °C temp.
d. Tested playback time period: 100 hours
e. Tested unit total used power: around 23 watts with volume MAX. condition
3. What is the problem
1) If the battery temperature detected by the NTC resistor inside the battery pack is 45 °C or less, normal playback and charge discharge occur without any problems found.
2) The problem occurs after BQ25713 stops battery charging normally when the battery temperature detected by the NTC resistor inside the battery pack is 45 °C or higher.
a. Problem: The battery continues to discharge because the output voltage of BQ25713 is lower than the battery's output voltage. (*Of course, if the temperature drops below 45 degrees again, BQ25713 starts charging normally.)
At this time, if the temperature detected by the NTC remains above 45 °C, the battery continues to discharge. Eventually, it becomes fully discharged, causing the test unit to be shut down automatically.
--> Question 1: Is there a way to control the output voltage of BQ25713 to be higher than the output voltage of the Battery?
(This is required when the battery charging is stopped normally under the NTC sensing temperature of 45 °C or higher. The PD adapter, which supplies DC from the outside, has verified that there is no problem in supplying a power of 28 watts, and there is no need to use current from the battery under the above temperature condition of 45 degrees or higher.)
--> Question 2: To solve this problem, I would like to ask you for your opinion on whether the TPS25751(PD) side should also do control together.
