User's Manual
PCS3_HD_v01.000-03
Confidential / Preliminary
Page 31 of 101
2013-10-21
PCS3 Hardware Interface Description
3.3 Power-Up / Power-Down Scenarios
3.3.5.2
Under voltage Shutdown
If the measured battery voltage is no more sufficient to set up a call the following URC will be
presented:
^SBC: Under voltage.
The URC indicates that the module is close to the under voltage threshold. If under voltage
persists the module keeps sending the URC several times before switching off automatically.
This type of URC does not need to be activated by the user. It will be output automatically when
fault conditions occur.
3.3.5.3
Over voltage Shutdown
The overvoltage shutdown threshold is 100mV above the maximum supply voltage V
BATT+
specified in Table 22.
When the supply voltage approaches the overvoltage shutdown threshold the module will send
the following URC:
^SBC: Overvoltage warning
This alert is sent once.
When the overvoltage shutdown threshold is exceeded the module will send the following URC
^SBC: Overvoltage shutdown
before it shuts down cleanly:
This type of URC does not need to be activated by the user. It will be output automatically when
fault conditions occur.
Keep in mind that several PCS3 components are directly linked to BATT+ and, therefore, the
supply voltage remains applied at major parts of PCS3, even if the module is switched off.
Especially the power amplifier is very sensitive to high voltage and might even be destroyed.
3.3.6
Automatic Reset
An automatic reset takes effect if
•
A sudden momentary power loss (SMPL) occurs - e.g., a very brief battery disconnect - and
the power returns within 2 seconds.
The SMPL feature ensures that if VBATT+ drops out-of-range (< 2.55V nominal) and then re-
turns into range within 2 seconds, the power-on sequence is executed and the module switches
on again. Thus the SMPL feature achieves immediate and automatic recovery from momentary
power loss such as a brief battery disconnect.
To employ the SMPL feature the VDDLP line has to supplied for at least 2 seconds after a
possible power loss (e.g., by connecting a 10µF capacitor).