Telit Communications S.p.A. HE910 Benutzerhandbuch
HE910 Hardware User Guide
1vv0300925 Rev.9
– 07-02-2012
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved
page 35 of 80
5.3.1.3 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 suited for supplying the
power to the Telit HE910 module.
WARNING:
The three cells Ni/Cd or Ni/MH 3,6 V Nom. battery types or 4V PB types
MUST NOT BE
USED DIRECTLY
since their maximum voltage can rise over the absolute maximum
voltage for the HE910 and damage it.
NOTE:
DON'T USE any Ni-Cd, Ni-MH, and Pb battery types directly connected with HE910.
Their use can lead to overvoltage on the HE910 and damage it. USE ONLY Li-Ion battery
types.
Their use can lead to overvoltage on the HE910 and damage it. USE ONLY Li-Ion battery
types.
A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the
current absorption peaks, a 100μF tantalum capacitor is usually suited.
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, in order to save the
HE910 from power polarity inversion. Otherwise the battery connector should be done
in a way to avoid polarity inversions when connecting the battery.
in a way to avoid polarity inversions when connecting the battery.
The battery capacity must be at least 500mAh in order to withstand the current peaks
of 2A; the suggested capacity is from 500mAh to 1000mAh.