Power Consumption Analysis; Table 5 Power Consumption Overview; Table 6 Power Consumption Calculation - Infineon BGT24LTR11 Manual

Distance2GoL (Software-Controlled FMCW) low-power radar shield using
BGT24LTR11 for range detection and human tracking

Power consumption analysis

5 Power consumption analysis
The BGT24LTR11 Shield is designed for low power consumption.
• The MMIC is turned on with TX enabled for all N
checke and recalibration, while the influence of the TX status on the power consumption is neglectable.
In order to avoid out-of-band spurs, MMIC and TX are enabled and disabled for chirping only at center
frequency, for which reason the on-time per chirp t
repetition time (PRT) is smaller than or equal to 3 ms, the fast chirp mode is enabled and t
the PRT. If the PRT is larger than 3 ms, the power-saving mode is applied and t
• The PTAT and the divider are used for frequency checks and recalibration (with MMIC enabled). Each
frame a frequency check is performed, which requires around 1 ms. The recalibration is only performed
if the frequency fails takes around 2 ms. Thus, the mean total recalibration time per frame t
maximum.
•
The baseband section consists of the two stages of op-amps and the voltage divider. It is turned on
simultaneously with the MMIC and TX for chirping and is turned off shortly after the end of the up-chirp.
As shown in Table 5, the major contributors to the power consumption are the MMIC and the divider.
Table 5 Power consumption overview
Component
MMIC (BGT24LTR11)
MMIC+ Divider + PTAT
Baseband section
(op-amps and voltage divider)
The Distance2GoL power consumption can be computed after calculating the current consumption of the
BGT24LTR11 for chirping, the frequency check and recalibration, and the duty-cycling of the baseband section.
Some exemplary power consumption calculations are shown in the table below:
Table 6 Power consumption calculation
Frame period Pulse
(ms) repetition time
(ms)
100 (default) 5
100 5
150 5
150 10
200 5
200 10
For more information about the power consumption calculation please refer to the
"Power_consumption_sFMCW_D2GL" Excel calculator file.
Application Note
chirps per frame and with TX disabled during frequency
C
on
Current consumption (mA)
45
65.5 (45 + 19 + 1.5)
0.335
Chirps per Calibration
frame time (ms)
10 3
12 3
10 3
12 3
10 3
12 3
page 21 of 32
is larger than the pure up-chirp time t
On-time per frame (ms)
N * t
C on
t (~3)
calib
t + 0.6
up
Current
consumption
(mA)
13.3
15.5
8.9
10.4
6.64
7.8
. If the pulse
up
is equal to
on
is 2.5 ms.
on
is 3 ms at
calib
Power
consumption
(mW)
43.8
51.3
29.3
34.2
21.9
25.6
V1.0
2021-03-31