EVK-M101, EVK-M101C - User guide
5 Current measurement
5.1 GNSS current
At startup, the receiver starts in acquisition mode to search for available satellites and to download
GNSS orbital data, i.e., ephemeris and almanac. Once the data has been downloaded, the receiver
enters tracking mode. In continuous operation, the receiver typically remains in tracking mode once
entering it. The current consumption reduces when the receiver enters the tracking mode. The time
required to enter tracking mode can be reduced by downloading aiding data from the AssistNow
™
Online service.
On EVK-M101/C, the main supply voltage for the u-blox M10 GNSS receiver is 3.3 V. The EVK
contains an internal 3.3 V to 1.0 V DC-DC converter to reduce power consumption from the V_CORE
and V_RF power domains of the receiver. To measure the total GNSS supply current with EVK-M101/
C, follow these steps:
1.
Power up EVK-M101/C.
2.
Connect a true RMS voltmeter across GNSS I1 (pin 12) and GNSS I2 (pin 13) of the
.
3.
Read the voltage (and average if necessary) on the voltmeter and convert to current (1 mV
equals 10 mA).
4.
Perform the test with good signals and clear sky view to ensure that the receiver can acquire
the satellite signals.
The total GNSS current (I
VCC
) shows the current consumption from the V_CORE, V_RF, and V_IO
power domains. The I
V_IO
current includes the contribution from the TCXO current consumption of
around 1.5 mA.
The DC-DC has an average efficiency of 85 %, resulting in a higher power consumption than
the values defined in the M10050-KB data sheet.
The separate current contribution from I
V_IO
and I
V_RF
can be measured from
available test points on the EVK board that are connected to the I2C current sensors on the
EVK as shown in
.
5.2 Backup current
To measure the backup current (I
BCKP
) with EVK-M101/C, follow these steps:
1.
Connect a true RMS voltmeter across BCKP I1 (pin 11) and BCKP I2 (pin 10) of the
.
2.
Remove power supply (USB cable or other external power supply from the 14-pin connector).
3.
Read the voltage (and average if necessary) on the voltmeter and convert to current (1 mV
equals 10 µA).
UBX-21003949 - R04
5 Current measurement
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