Power Supply; Eeprom; Rf Front End Shield; Figure 7 Block Diagram - Power Supply Concept - Infineon BGT24LTR11 Manual

Distance2GoL (Software-Controlled FMCW) low-power radar shield using
BGT24LTR11 for range detection and human tracking
Hardware description: BGT24LTR11 Shield
4.3

Power supply

The Radar Baseboard XMC4700 is powered via micro-USB connector, external 7 V power supply or LiPo battery.
It also provides the supply for the BGT24LTR11 Shield via the connectors. An LDO (U6) is used on the
BGT24LTR11 Shield to supply all the components. Figure 7 shows the power supply concept used in the system.
Micro USB /
5 V
External supply /
LiPo battery
Figure 7 Block diagram – power supply concept
4.4

EEPROM

The BGT24LTR11 Shield contains an EEPROM (U7) to store data such as a board identifier. The Serial Data (SDA)
is a bi-directional pin that is used to transfer addresses and data into and out of the device. The Serial Clock
(SCL) is an input that is used to synchronize the data from and to the device.
When the Shield is plugged into the Radar Baseboard XMC4700, the sensor's supplies are initially deactivated.
Only the EEPROM is powered. The MCU reads the content of the EEPROM's memory to determine which Shield
is plugged into the interface. Only when the board has been correctly identified are the sensor's supplies
activated.
Figure 8 EEPROM block diagram
4.5

RF front end Shield

Figure 9 shows the top view of the RF front end. The RF front end has a cover with absorber material to get the
best RF performance. The transmitter and receiver inputs of the BGT24LTR11 are single-ended. The TX output
and RX input are connected over a matching structure, a DC block and a feed-through via to the antennas on
the other side of the board. The isolation between the RX and TX ports is improved by adding a grounded
length of line at the ground pins next to the TX output pin, as shown in Figure 9.
Application Note
R
shunt
VCC1
Current sensors
XMC4700
USIC
page 15 of 32
VCC1
C41
4.7 µF
VCC
VCC VSS
EEPROM
I2C_EEPROM.SCL
SDA
SCL
R83
VCC
I2C_EEPROM.SDA
IN OUT
LDO
EN
R84
VCC = 3.3 V
C42
1 µF
V1.0
2021-03-31