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LEXI-R422 - System integration manual
UBX-23007449 - R02 System description Page 19 of 108
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Figure 7 illustrates the current consumption profiles in GPRS connected mode, in 850 or 900 MHz
bands, with 4 slots used to transmit and 1 slot used to receive, as for the GPRS multi-slot class 12.
Time
[ms]
RX
slot
unused
slot
TX
slot
TX
slot
TX
slot
TX
slot
MON
slot
unused
slot
RX
slot
unused
slot
TX
slot
TX
slot
TX
slot
TX
slot
MON
slot
unused
slot
GSM frame
4.615 ms
(1 frame = 8 slots)
Current [A]
60-120mA
GSM frame
4.615 ms
(1 frame = 8 slots)
1.5
1.0
0.5
0.0
60-120mA
10-40mA
200mA
Peak current depends
on TX power and
actual antenna load
1600 mA
Figure 7: VCC current consumption profile versus time during a GPRS multi-slot class 12 connection (4 TX slots, 1 RX slot)
In case of EGPRS (i.e. EDGE) connections, the VCC current consumption profile is similar to that
during GPRS connections: the current consumption profile in GPRS multi-slot class 12 connected
mode illustrated in
Figure 7 is representative for the EDGE multi-slot class 12 connected mode.
1.5.1.4 VCC current consumption in ultra-low power deep-sleep mode
The UE power saving mode (PSM) defined in 3GPP Rel.13 is by default disabled, but can be enabled by
AT+CPSMS command (see the AT commands manual
[2] and the application development guide [3] ).
When PSM is enabled, the module automatically enters the PSM and the ultra-low power deep-sleep
mode whenever possible.
LEXI-R422 modules may automatically enter the ultra-low power deep-sleep mode in-between eDRX
cycles, whenever possible, if the functionality is enabled by the +UPSMVER AT command, see the AT
commands manual
[2] and the application development guide [3] .
In ultra-low power deep-sleep mode, the current consumption is reduced down to a steady value in the
µA range: only the RTC runs with internal reference clock frequency.
See detailed current consumption values in the LEXI-R422 data sheet [1] .
☞
Due to RTC running during PSM mode, the Cal-RC turns on the crystal every ~10 s to calibrate the
RC oscillator, as a consequence, a very low spike in current consumption will be observed.
Figure 8 shows VCC current consumption profile in ultra-low power deep-sleep mode, with PSM
enabled (AT+CPSMS
≠
0). The module is registered to the network and is in ultra-low power
deep-sleep mode, with no concurrent activities on. It does not periodically wake up for paging block
reception, but wakes up upon the expiration of the periodic update timer set by the network, or due to
proper toggling of the
PWR_CTRL input line.
DEEP SLEEP MODE
Time [h]
Current [mA]
0
100
Figure 8: Example of VCC current consumption profile in ultra-low power deep-sleep mode with PSM ( AT+CPSMS≠0 )