MB39C811 Datasheet, PDF (17/36 Pages) Cypress Semiconductor – Ultra Low Power Buck PMIC Solar/Vibrations Energy Harvesting

MB39C811
Figure 10. Application example using the power gating by the OPGOOD signal
Harvester
VUVLOH
VUVLOL
0V
OPGOOD
VIN
VOUT
Cin _MB39C811
VVOUT
VOPGL
Efficiency(η)
0V
Power
Gating
Cout
Appli.
Available Energy
+ Total Energy
VUVLOH : UVLO release voltage
VUVLOL : UVLO detection voltage
VVOUT : Preset output voltage
VUVLOL : Output power-good reset voltage
Before calculating the initial charging time (TInitial[s]), calculate the total energy (ECin and ECout) stored on both Cin and
Cout.
A PHarvester[W] is a power generation capability of a harvester. An initial charging time (TInitial[s]) is calculated by the
following equation.
A repeat charging time (TRepeat[s]) is calculated by the following equation. The TRepeat[s] become shorter than the
TInitial[s].
Additionally, waiting for a period of time after the OPGOOD signal goes high can store more energy on the capacitor
Cin Figure 11.
Document Number: 002-08401 Rev *A
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