December 2017
DocID022816 Rev 3
1/17
www.st.com
AN4050
Application note
STEVAL-ISV012V1 lithium-ion solar battery charger
Domenico Ragonese; Alessandro Nicosia; Giovanni Conti
Introduction
The STEVAL-ISV012V1 evaluation board mounts an
(solar energy harvester) for the input
(Li-Ion battery charger) as the output stage. It targets any portable application
powered by lithium-ion batteries and merges the SPV1040 power extraction capacity of the solar
module with the linear regulation of the L6924D for optimum battery charging load protection while
reducing the power dissipation at the bottom.
Figure 1: STEVAL-ISV012V1 evaluation board
The board is designed to charge lithium-ion and lithium-polymer batteries with V
BATT_max
= 4.1 or 4.2 V
and it includes a 400 mWpk polycrystalline PV panel (SZGD6060-4P from NBSZGD) with V
OC
= 2.2 V
and I
SC
= 220 mA.
According to specific application requirements, some components may be replaced
a
:
The PV panel can be replaced as long as V
OC
< V
BATT_max
and I
S
< 1.65 A.
The inductor L1 can be replaced, but consider its effect on the maximum peak current to ensure
that the input overcurrent limit is not triggered.
The maximum output current can be limited by replacing the current sensing resistor R
S
(0
0Ω by
default).
Resistor R14, which limits the charge current threshold (500 mA by default).
a
For more deta
ils on component selection, refer to Application note AN3319, section “external component selection”
