Application Notes
MB39C831-EVB-02 Thermal Energy Harvesting Evaluation Board Operation Guide, Doc. No. 002-08635 Rev. *A
24
8.3
Waveform of VDD/VOUT Voltages in Start-up in Constant Voltage
Mode
The followings are the waveform of the VDD/VOUT voltages in start-up when a solar cell is connected.
Figure 8-2. Waveform of VDD/VOUT Voltage in Start-up
Waveforms with Solar Cell
200ms/DIV
VDD
200mV/DIV
VDD = 0.5V, L = 4.7µH, IOUT = 0A
Preset output voltage = 3.3V
VOUT
2V/DIV
DET1
2V/DIV
0.5V
3.3V
3.3V
The current requirements in start-up are shown in Table9-2 when the VDD current is applied from constant
current source (because a solar cell operates close to a constant current source). For each preset output
voltage, select a right harvester to satisfy the following current value in start-up.
Table 8-2. Current Requirement in Start-Up at VDD
Preset Output Voltage[V]
Current Requirement in Start-Upat VDD[mA]
3.0
8.4
3.3
23.8
3.6
42.2
4.1
51.9
4.5
63.6
5.0
87.9
VDD current is applied from constant current source.
