MB39C831 Datasheet, PDF (12/40 Pages) Cypress Semiconductor – Ultra Low Voltage Boost Power Management IC for Solar/Thermal Energy Harvesting Datasheet

MB39C831
[6] The VOUT voltage reaches 2.55V (lower threshold of VOUT detection voltage 2: VOUTDETL2) or the VCC voltage reaches
2.55V (lower threshold of VCC detection voltage 2: VCCDETL2, and then the internal switch SW1 between VCC and VOUT is
turned off, and the VCC and the VOUT are disconnected internally to protect the Li-ion battery from an over-discharge.
7.3 MPPT Control
In general, the voltage of a solar cell varies depending on the load current. The operating point where the power becomes the
maximum is called the optimum operating point. The control which tracks the optimum operating point is called the MPPT
(Maximum Power Point Tracking) control.
MPPT Values Setting
The voltage where the power becomes the maximum is called the power maximum voltage, and the voltage with no load is
called the release voltage. The comparison between the power maximum voltage and the release voltage is defined as the
MPPT values.
In the charge mode, the input voltage (VDD) is adjusted and the DC/DC converter operates while tracking the MPPT value
setting by the S2, S1 and S0 pins.
When in use, set the MPPT value after confirming the voltage dependency of the solar cell power.
Figure 7-3 MPPT Control
Voltage depedence of Solar
cell_Current
Power
maximum
voltage
Voltage(V)
Release
voltage
Voltage depedence of Solar
cell_Power
Optimum
operating point
Voltage(V)
MPPT values[%] = Power maximum voltage/Open voltage×100
Document Number: 002-08404 Rev *A
Page 12 of 40