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CYALKIT-E02 Solar-Powered BLE Sensor Beacon Reference Design Kit Guide, Doc. No. 002-11317 Rev. *C
84
E =
1
2
× C × (VH
2
− VL
2
)
VL = √ VH
2
−
2 × E
C
= √ 1.9V
2
−
2 × 200uJ
400uF
= 1.62V
Vdrop = VH − VL = 1.90V − 1.62V = 0.28V
E = 200 [uJ]
C = 400 [uF]
VH = 1.9 [V]
VL = Voltage after drop
Vdrop = Drop voltage
When the VOUT1 is 3.3 V to 1.9 V, S6AE103A constantly supplies the voltage. When the VOUT1 is under 1.9 V or reaches
1.62 V due to voltage drop, S6AE103A turns the voltage OFF and stops the BLE transmission.
A.4
Diode Connection Between Solar Cell and VDD
A diode is needed between the VDD pin and the solar cell to protect against reverse current from the input capacitor to the
solar cell. When the ambient light level is suddenly dark, the input capacitor voltage will be higher than the solar cell voltage.
S6AE103A
VSTORE1
400 µF
VSTORE2
200 mF
VOUT1
BLE current
3.3 V to 1.9
V
Read sensor
data
0.28-V drop
1.62 V
3.3 V to 1.9
V
Under 1.9 V
Turn the power off
BLE Transmit
