User's Manual

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Note d’étude / Technical document : URD1– OTL 5665.1– 002 / 70 884 Edition 03
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Sagem Communications document. Reproduction and disclosure prohibited
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Please note available PWM frequencies are too high to be used to make LEDs blinking. If purpose is to
make LEDs blinking (for network states indication for example), GPIO usage is more accurate.
3.3.2 PWM for Buzzer connection
The HiloNC module can manage a dedicate PWM output to drive a buzzer. The buzzer can be used to alarm for
abnormal state.
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Resistors should be added to protect the buzzer. The value of these resistors depends on the buzzer and
the transistor. Normally, they can be set as 1K ohm.
Figure 7: Buzzer connection
3.4 POWER SUPPLY
The HiloNC module can be supplied by a battery or any DC/DC converter compliant with the module supply
range 3.2V to 4.5V 2.2 A.
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The PCB tracks must be well dimensioned to support 2.2 A maximum current. The voltage ripple caused
by resistance of power supply path (Battery internal resistance, tracks and contact resistance) could result
in the low voltage to the module.
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The HiloNC module does not manage the battery charging.
3.4.1.1 Burst conditions
- Communication mode (worst case: 2 continuous GSM time-slot pulse):
Figure 8: GSM/GPRS Burst
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A 47µF capacitor is highly recommended for VBAT and close to the module.
R1
R2
HiloNC
VBAT
PWM2