User's Guide

LE910Cx HW User Guide
Doc#: 1VV0301298
Rev. 13.0 Page 57 of 124 2019-07-15
Figure 13 and Figure 14 show an example of switching regulator with 12V input.
Figure 11: Example of Switching Regulator with 12V Input – Part 1
Figure 12: 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
allowed voltage 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 100μF tantalum capacitor is usually suitable.
• Make sure that the low ESR capacitor (usually a tantalum one) is rated at least
10V.
• A protection diode must be inserted close to the power input to protect the
LE910Cx module from power polarity inversion. Otherwise, the battery connector
must 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.