STEVAL-ISV020V1 - min required voltage to be operated

[rsmqu]

Hi ST Community / @Peter BENSCH 

I use my solar panel connected to the STEVAL-ISV020V1 to charge my LiPo battery. Everything works fine and it charges the battery. However since I am trying to charge it indoors, during night-time, my solar panel doesn't reach the min required voltage of 2.6 to operate the STEVAL-ISV020V1. 

Now I am wondering if the STEVAL-ISV020V1 becomes a load instead of being a charge controller when this happens because it drains the battery with a very low voltage at a certain time. 

[Peter BENSCH · Accepted solution]

1. As the data sheet of the SPV1050 states and as I have already mentioned, the LDOs are also connected to STORE. As long as the battery voltage is between UVP and EOC, the battery is connected to STORE via the pass transistor, so that the LDOs are also supplied - either from the input, if it supplies enough energy, or from the battery. Only when VSTORE falls below UVP is STORE and therefore the LDOs disconnected.
2. The second bullet should be answered by the first.
3. Bullet three was also answered by the first, you cannot change that behavior if the input source doesn't supply enough energy.
4. The LDOs do not charge the battery, but are intended to supply external circuits, as the data sheet also mentions: two fully independent LDOs (1.8 V and 3.3 V) are embedded for powering other companion ICs like MCU, sensors or RF transceivers.

Regards
/Peter