LEON-G100 / LEON-G200 - System Integration Manual
GSM.G1-HW-09002-G3
Preliminary
System description
Page 23 of 125
1.5.3
Current consumption profiles
During operation, the current consumed by LEON-G100/LEON-G200 through
VCC
pin can vary by several orders
of magnitude. This is applied to ranges from the high peak of current consumption during the GSM transmitting
bursts at maximum power level in connected mode, to the low current consumption in idle mode when power
saving configuration is enabled.
1.5.3.1
Current consumption profiles – Connected mode
When a GSM call is established, the
VCC
consumption is determined by the current consumption profile typical
of the GSM transmitting and receiving bursts.
The current consumption peak during a transmission slot is strictly dependent on the transmitted power, which
is regulated by the network. If the module transmits in GSM talk mode in the GSM 850 or in the EGSM 900
band at the maximum power control level (32.2 dBm typical transmitted power in the transmit slot/burst), the
current consumption can reach up to 2500 mA (with highly unmatched antenna) for 576.9 µs (width of the
transmit slot/burst) with a periodicity of 4.615 ms (width of 1 frame = 8 slots/bursts), so with a 1/8 duty cycle,
according to GSM TDMA.
During a GSM call, current consumption is in the order of 100-200 mA in receiving or in monitor bursts and is
about 30-50 mA in the inactive unused bursts (low current period). The more relevant contribution to determine
the average current consumption is set by the transmitted power in the transmit slot.
Figure 10 shows an example of current consumption profile of the data module in GSM talk mode.
Time [ms]
RX
slot
unused
slot
unused
slot
TX
slot
unused
slot
unused
slot
MON
slot
unused
slot
RX
slot
unused
slot
unused
slot
TX
slot
unused
slot
unused
slot
MON
slot
unused
slot
GSM frame
4.615 ms
(1 frame = 8 slots)
Current [A]
200 mA
~170 mA
2500 mA
Peak current
depends on
TX power
GSM frame
4.615 ms
(1 frame = 8 slots)
1.5
1.0
0.5
0.0
2.5
2.0
~170 mA
~40 mA
Figure 10: Description of the VCC current consumption profile versus time during a GSM call (1 TX slot)
When a GPRS connection is established there is a different VCC current consumption profile also determined by
the transmitting and receiving bursts. In contrast to a GSM call, during a GPRS connection more than one slot
can be used to transmit and/or more than one slot can be used to receive. The transmitted power depends on
network conditions and sets the peak of current consumption, but following the GPRS specifications the
maximum transmitted power can be reduced if more than one slot is used to transmit, so the maximum peak of
current consumption is not as high as can be the case in a GSM call.
If the module transmits in GPRS class 10 connected mode in the GSM 850 or in the EGSM 900 band at the
maximum power control level (30.5 dBm typical transmitted power in the transmit slot/burst), the current
consumption can reach up to 1800 mA (with highly unmatched antenna) for 1.154 ms (width of the 2 transmit