Dear all
I use an STEVAL-ISV019V1 (Boost Mode) with a KXOB25-05X3F PV cell.
When I connect a 330mF supercap to BATT, working at low light (200Lux) Store is being charged withing 30s. Not the SPV1050 tries to switch to the Supercap and restarts because the voltage at STORE drops below the 2.5V.
So far so good (or at least I expected that to happen).
In the datasheet there is "Figure 4. Implementations examples of larger UVP hysteresis". I don't fully understand the paragrap above:
"For some applications (typically with battery or super-cap connected to BATT pin) it could be necessary to
implement a reactivation hysteresis after under-voltage event (pass transistors status changes from closed to
open): it avoids the undesired continuous system reset loop due to full discharge of the CSTORE at every triggering
of the over-voltage threshold. The application solution is simply based on a diode (or p-channel MOSFET driven
by BATT_CONN) between STORE and BATT pins."
It sounds like this (circuit in figure 4) should solve my problem. However, it does not. When I use the MOSFET version, I build exactly the same issue, that occurs due to the switching of the PASS TRANSITIOR for a second time at the ouside of the SPV1050, don't I?
Just to mention, the system works when there's enough light (30000Lux) on the solar cell.
What do you propose to do? The output voltage of the PV cell is about 900mV at low light and there's very little current available.
Any help appreciated
Christian
