LE910Cx HW User Guide
1VV0301298 Rev. 33
Page 56 of 128
2021-06-29
Not Subject to NDA
Figure 16: Example of Switching Regulator with 12V Input – Part 2
6.3.1.3.
Battery Source Power Supply – Design Guidelines
•
The desired nominal output for the power supply is 3.8V, and the maximum voltage
allowed is 4.2V. Hence, a single 3.7V Li-Ion cell battery type is suitable for
supplying the power to the LE910Cx module.
Note: Do not use any Ni-Cd, Ni-MH, and Pb battery types directly
connected to the LE910Cx module. Their use can lead to overvoltage
on the LE910Cx and damage it. Use only Li-Ion battery types.
•
A bypass low ESR capacitor of adequate capacity must be provided to cut the
current absorption peaks; a 100
μ
F tantalum capacitor is usually suitable.
•
Make sure the low ESR capacitor (usually a tantalum one) is rated at least 10V.
•
A protection diode should be inserted close to the power input to protect the
LE910Cx module from power polarity inversion. Otherwise, the battery connector
should be done in a way to avoid polarity inversions when connecting the battery.
•
The battery capacity must be at least 500 mAh to withstand the current peaks of
2A.
6.3.2.
Thermal Design Guidelines
The thermal design for the power supply heat sink must be done with the following
specifications:
•
Average current consumption during RF transmission @PWR level max in LE910Cx
as shown in
Table 20: LE910Cx Current Consumption
•
Average current consumption during Class10 GPRS transmission @PWR level max
as shown in
