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System Description
1
System Description
To detect an object behind the car during reverse motion, a park assist system should cover the entire
rear side and blind spots. For the low-cost implementation in this reference design, a three-sensor system
is used. However, the same concept can easily be extended to four sensors.
For PAS, the maximum detection range requirement from the vehicle can extend up to 1.5 m or 2 m. In
addition, it is also important to be able to detect objects at very close distances, less than 20 cm from
vehicle. Object distance information is then sent over OWI to an ECU where data is aggregated.
In the case of the rear sonar, two to four transformer-driven ultrasonic sensors are mounted on the rear
bumper to detect an obstacle up to 2 to 2.5 m away. The main characteristics of ultrasonic sensors for
rear sonar are directivity, ringing time, sensitivity and sound pressure. Directivity of an ultrasonic sensor
corresponds to the size and shape of the vibrating surface (that is, emitting the ultrasound) and the
frequency at which it vibrates.
Being an automotive application, it is also important to have a solution which can provide sensor
diagnostic information. The solution should also detect and report failures of individual sensors for
passenger safety. Here, the PGA460-Q1 device can provide sensor, supply, and transceiver diagnostics.
2
System Overview
2.1
Block Diagram
TIDA-01597
Transformer
MA58M
F14-7N
TIDA-01597
Transformer
MA58M
F14-7N
TIDA-01597
Transformer
MA58M
F14-7N
2
Automotive Ultrasonic Sensing Module Reference Design for Park Assist
PGA460-Q1
IO
PGA460-Q1
PGA460-Q1
Figure 1. TIDA-0597 Block Diagram
Copyright © 2018, Texas Instruments Incorporated
Local ECU/Main ECU
TX
SN65HVDA100-Q1
RX
OWI Transceiver
12 V Load Dump Protected
GND
www.ti.com
MSP430F5529
Launchpad
CC2640F128
TIDUDO4 – May 2018
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