EGS5 Hardware Interface Description
3.3 Power Up / Power Down Scenarios
75
EGS5_HD_v02.004
Page 40 of 123
2012-02-09
Confidential / Released
3.3.4.3
Undervoltage Shutdown
IIf the measured battery voltage is no more sufficient to set up a call the following URC will be
presented:
^SBC: Undervoltage.
The message will be reported, for example, when you attempt to make a call while the voltage
is close to the shutdown threshold of 3.2V and further power loss is caused during the transmit
burst. In IDLE mode, the shutdown threshold is the sum of the module’s minimum supply volt-
age (3.2V) and the value of the maximum voltage drop resulting from earlier calls. This means
that in IDLE mode the actual shutdown threshold may be higher than 3.2V. Therefore, to prop-
erly calculate the actual shutdown threshold application manufacturers are advised to measure
the maximum voltage drops that may occur during transmit bursts.
To remind you that the battery needs to be charged soon, the URC appears several times be-
fore the module switches off.
This type of URC does not need to be activated by the user. It will be output automatically when
fault conditions occur.
3.3.4.4
Overvoltage Shutdown
The overvoltage shutdown threshold is 100mV above the maximum supply voltage V
BATT+
specified in
When the supply voltage approaches the overvoltage shutdown threshold the module will send
the URC
^SBC: Overvoltage warning.
This alert is sent once.
When the overvoltage shutdown threshold is exceeded the module will send the 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 EGS5 components are directly linked to BATT+ and, therefore, the
supply voltage remains applied at major parts of EGS5, even if the module is switched off. Es-
pecially the power amplifier is very sensitive to high voltage and might even be destroyed.
