Other Parts Discussed in Thread: TPS61236EVM-676,
We are using BQ25606EVM-772 and TPS61236EVM-676 to build a UPS.
The required output is 5V with a max current Iout=2.5A .
Sys pin of BQ25606EVM is connected to Vin of TPS61236EVM, no battery connected, /CE-GND jumper on the BQ25606EVM not installed (charger disabled).
The input power supply can provide 5V-2.5A (we tested it and it can go up to 3A without issues).
Connecting a electronic load in CC mode on the Vout pin of the TPS61236EVM, we can’t reach 2.5A. The BQ25606 shut the output down at about 1.3A (current out from the TPS61236)
R11, which is connected to ILIM, has been set to 170Ω, considering that KLIM/ILIM=500/3=166.7Ω
Placing a Fluke 87V in different points to check the current, we noticed the following:
With no battery connected, when a current of 1.3A from Vout of the TPS61236 is reached:
1. current out from Sys pin is 2.185A
2. current out from the power supply is 1.934A
Connecting a 1400mAh battery, the system can provide 1.6A before it starts discharging the battery (tested with charging disabled). At 1.7A there are 0.136A coming out from the battery.
Connecting the electronic load directly to Sys pin of the BQ25606EVM, with no TPS61236, we can go over 2.5A without any problem. When a current of 2.5A is coming out Sys pin, the power supply is at 2A.
Is this behavior related to the inductor on the BQ25606EVM (from the BOM, 1 μH, 3.2 A, 0.028 ohm)?
How could we fix it and take 2.5A from Vout of the TPS61236?