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Smart Machine Smart Decision
SIM5360_Hardware Design_V1.06
2016-11-17
23
Vin
Vout
GND
FB
3
+
PWR_CTRL
R102
R101
VBAT
100K
47K
+
C103
330uF
C104
100nF
U101 MIC29302
5
4
1
2
C101
C102
100uF
1uF
DC INPUT
R103
470R
On/Off
Figure 9: Reference circuit of the LDO power supply
If there is a big difference between the input voltage and the desired output (VBAT), a switching converter
power will be preferable because of its better efficiency, especially at the high current situation. The
following figure is the reference circuit. Note that DCDC may deprave RF performance because of ripple
current intrinsically.
Vin
Vout
FB
U101
1
2
3
4
5
LM2596-ADJ
+
100uH
MBR360
L101
C101
+
C102
D102 C103
R102
R101
FB101
330uF
VBAT
2.2K
1K
100uF
1uF
C104
100nF
270 ohm@100Mhz
DC INPUT
PWR_CTRL
GND
On/Off
Figure 10: Reference circuit of the DCDC power supply
Voltage monitor
To monitor the power supply voltage, user can use the AT command “AT+CBC”, this command has two
parameters: the battery status and the voltage value (mV). It will return the capacity percentage and actual
value of battery (at the VBAT pin). The voltage is continuously measured at intervals, whenever the
measured battery voltage is lower than a specific value set by the AT command “AT+CVALARM”. For
example, if the voltage value is set to be 3.4V, the following URC will be presented: “warning! voltage is
low: 3.3v”.
If the voltage is lower than a specific value which is set by the AT command “AT+CPMVT”, the module
will be powered off automatically and AT commands cannot be executed any more.
Note: Under-voltage warning function is disabled by default, user can enable it by the AT command
“AT+CVALARM”. Please refer to Document [1].
SIMCOM
CONFIDENTIAL
FILE