Telit Wireless Solutions GE863-QUAD Manual Do Utilizador

Página de 79
 
 
 
 
 
GE863-QUAD 
GE863-PY 
 
 1vv0300715 Rev. 1 - 19/09/06  
  
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Right reserved 
 
page 18 of 79 
 
 
An example of switching regulator with 12V input is: 
 
4.2.1.3  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 
GE863-QUAD/PY module. 
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 
GE863-QUAD/PY and damage it. 
 
NOTE: DON'T USE any Ni-Cd, Ni-MH, and Pb battery types directly connected with GE863-
QUAD/PY. Their use can lead to overvoltage on the GE863-QUAD/PY 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 GE863-
QUAD/PY 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 500mAh in order to withstand the current peaks of 2A; the 
suggested capacity is from 500mAh to 1000mAh.