Autonomous Cars: Radar, Lidar, Stereo Cameras · Infineon RRN7745P & RTN7735P eWLB Fan-out Package - 77GHz Radar Dies The radar receiver die is packaged in an eWLB (embedded Wafer

Autonomous Cars:Radar, Lidar, Stereo Cameras

1 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

CAMERAS FOR AUTONOMOUS DRIVING

2 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Role of Cameras in Automotives

� Camera module market ~$25B in 2015, expected to double by 2025 (Yole)� Machine Vision integration with multiple sensors for ADAS and partial

autonomous driving� Disadvantages of cameras

• Environmental conditions can introduce problems• Difficulty in detecting non- illuminated and varying lighting conditions• Computer vision limitations for reliable detection

3 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

CMOS image sensors for Automotive are quite different from Consumer Electronics

Source: Yole

� Improved Low light sensitivity by larger pixel size� Lower resolution (it’s not about Mega pixels)� Fast response time (significantly faster than smartphone cameras

� Packaging Differences• Embedded logic in image sensor package• Ceramic packages for higher functional safety requirements

4 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Challenges� Fast image acquisition� Stereo camera for depth and distance of the object in image plane� High resolution AND high speed

• Resolution: greater than 1k x 1k pixels, aim for 4k x 4k• Frame rate: 60 fps and higher for shorter reaction time

� Zoom into image area for a greater detail � Efficient image processing for real-time analysis� Wider field of view than radar or laser systems

5 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Cameras in Current Cars (Bosch)

� Bosch‘s mono and stereo camera system: smallest currently available in the market. Has a 50-degree horizontal field of view for 50m distance.

Bosch’s stereo camera system

6 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Cameras in Current Cars (Panasonic)

� Stacked CMOS imaging chip and processing electronics in one package� Compact enough to fit within rearview mirror assembly or behind the windshield� Low cost high resolution cameras, but limited speed� High speed cameras limited resolution� Circuits for efficient image processing for real-time analysis� Can be implemented with multiple units for stereo vision

Panasonic CMOS 34227 Sensor

7 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Prior Work at GT: 1st CIS DEMONSTRATOR on LOW COST 3D GLASS PACKAGE

� 100um Thin Glass Substrate

� Wafer Level Camera on Top Side

� Thin Logic Emulator IC on bottom side

� Solder reflow at chip level

� Passed initial tests at Georgia Tech

� <1mm total thickness (3x reduction from

PWB integration)

� 10x higher I/Os for integrating multiple

sensors, logic, memory etc.

8 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Thermal Control Using Glass Package� Glass limits lateral thermal spreading by design� Junction temperatures can be reduced by vertical copper vias� Heating of image sensor with IC stacking or silicon interposers

Without copper With copper

Glass

38C 58C 48C 50C

49.1C 49.4C 49.1C 49.4C

Silicon10mm x 10mm Test Chipon Glass or Si Interposer

9 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

RADAR

10 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Why RADAR in NAE?

• Above functions Require radar sensors due to their robustness in varying environmental conditions like rain, dust, or sunlight

(J. Hasch, "Driving towards 2020: Automotive radar technology trends," Microwaves for Intelligent Mobility (ICMIM), 2015 IEEE MTT-S International Conference on, Heidelberg, 2015, pp. 1-4.)

Roadmap for driver assistance functions

• Short, Medium and Long Range RADAR Modules

Critical to Fully Autonomous Driving

11IEEE-CPMT Workshop – Autonomous Cars

Automotive RADAR – Brief Intro

• Basic Architecture and Requirements- Frequency Modulated Continuous Wave (FMCW) Doppler Radar- 76 GHz – 81 GHz- Severe Environment Conditions- Long Term Reliability

Many challenges to device and design !!

TxRx

fr

Freq

uenc

y

fb

fd

fb fd

fr

Transmit FMCW Signal76-81 GHz

Compare Received Signal with Transmitted Signal to Extract

Distance and Velocity

PROF. JOHN CRESSLER

12 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Automotive RADAR Evolution

1999 Mercedes-Benz • First manufacturer to use radar

for autonomous cruise control (ACC) system in S-class

Active Components Evolution

Pack

agin

g Ev

olut

ion

GaAs Technology

• Discrete semiconductor components ÆMMIC blocks or even complete

transceiver circuits

Silicon-based SiGe technology• Improved RF performance at high freq.• Destined to be the mainstream

semiconductor technology millimeter-wave

(J. Hasch, E. Topak, R. Schnabel, T. Zwick, R. Weigel and C. Waldschmidt, "Millimeter-Wave Technology for Automotive Radar Sensors in the 77 GHz Frequency Band," in IEEE Transactions on Microwave Theory and Techniques, vol. 60, no. 3, pp. 845-860, March 2012.)

Chip on board wire bonding

Flip chip mounting on substrate

eWLB (embedded wafer level

BGA) package

Evolution of SiGe Device Technology

Courtesy of P. Chevalier

13 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Challenges in Automotive RADARPackage Challenges

� Low losses and reflections chip to substrateTransition

� Thermal dissipation� High Reliability� Low cost

• Generation of sufficient output power at high frequency

• LNA demonstration

Device Challenges

• No LNA: High NF → Low SNR → Lowmaximum detecting range of system

77GHz 4-channel automotive radar transceiver chip specification

(H. P. Forstner et al., "A 77GHz 4-channel automotive radar transceiver in SiGe," Radio Frequency Integrated Circuits Symposium, 2008. RFIC 2008. IEEE, Atlanta, GA, 2008, pp. 233-236. )

14 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Status of Automotive RADAR Products

Bosch LRR3 Sensor• SiGe MMICs instead of Gunn oscillators and discrete mixer diodes • Size and package complexity reduction

Bosch LRR3 SensorBosch LRR2 Sensor

15 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Latest Automotive RADAR Products

Bosch Mid Range Radar (MRR) Sensor• Frequency band 76-77 GHz• Distance range up to 160 meters • Integrates two electronic boards and STMicroelectronics devices• RF board with Hybrid PTFE/FR4 substrate and equipped with planar antennas• Infineon 77GHZ SiGe Monolithic Microwave Integrated Circuits (MMIC) used as High-Freqency

transmitter and receiver

16 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Recent Automotive RADAR Packaging Technologies Infineon RRN7745P & RTN7735P eWLB Fan-out Package - 77GHz Radar Dies

The radar receiver die is packaged in an eWLB (embeddedWafer Level BGA) package, Fan-Out technology fromInfineon.

Back view

Die3mm x 3mm

Package cross-section

17IEEE-CPMT Workshop – Autonomous Cars

Proposed High Linearity Low Noise RX

Block Diagram

�One of the first Radar modules to integrate LNA in front end

�Leading Edge SiGe Receiver9 Employ Advanced SiGe Node

9 Use Novel Circuit Design

9 Incorporate High Gain High Linearity

LNA

� Current Design Phase

9 LNA layout modificationPROF. JOHN CRESSLER

18IEEE-CPMT Workshop – Autonomous Cars

Proposed High-Linearity LNA

9 IBM 9HP 90nm technology9 3 cascaded cascode stages9 Fully differential to improve CMRR9 Input transformer balun:

- Provide RF ESD protection and differential signal

9 Inter-stage matching with transformers9 Variable gain

- Improve input P1dB

Area: 0.6mm x 1 mmVCC: 2.5V

IN

OUT

VCC

VB1_13

VB2_13

VB1_2

VB2_2

GND

GND

GND

PROF. JOHN CRESSLER

19IEEE-CPMT Workshop – Autonomous Cars

LNA Initial Design and Simulation� Transistor Sizing: 6um, 8um, 10um Simulation Results

S-param

NF

P1dB

Gain 17.3 dBNF 6.221 dB3dB Freq 56GHz-94GHzDC Power 91.5 mWInput P1dB -14.5 dBm

PROF. JOHN CRESSLER

IEEE-CPMT Workshop – Autonomous CarsSlide 20

CONFIDENTIAL

GT Program Focus� The research objective is to design and demonstrate an ultra miniaturized low cost

integrated 77GHz radar & high speed camera module applying the most advancedpanel-level glass fan-out (PGFO) packaging technologies to the following parameters:

77 GHz Radar Chip

Processor

Image sensor

Antenna Incident light

Glass

Cover glass

Active area Camera ModuleRadar Module

Properties Objectives Prior Art

Integrated Module

Package type GFO FO-WLP/ CeramicCost <1x 1.2x

Reliability AEC Q100 Grade 1 AEC Q100 Grade 3Thickness < 300 um > 500 um

RadarNoise Figure 6-7 dB > 20 dB

Gain 15 dB < 15 dBAntennas Integrated in package Integrated in PCB

CameraData Rate ~ 1 Gbps <1 Gb/s

Response time < 1 ms >1 ms

21 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

LIDAR

22 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Why Lidar for Automotive ?

� Cameras and radar cannot ensure 100 % safety� Radars provide no object detection� Cameras depend on environmental conditions.� Lidar enables high precision detection in real time � Time of Flight lasers in Lidar are the most accurate for real time and

long range detection.

23 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Basics of Lidar

Fired Laser Pulses

Reflected Laser Pulses

Starting a timer when the pulse goes out and stopping by the reflected pulse

24 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Challenges

� Cost reduction (see figure)� Miniaturization for easy integration in car body� High aperture angle – number of channels � Reliability by application of solid state lidar

25 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Lidar Products

� Velodyne lidar system VLP-16• Range: 100 m, • Power consumption: ~8 W, • Weight: 830 grams, • Footprint:~Ø103 mm x 72 mm,• 16 channels, ~300,000

points/sec, • 360° horizontal field of view,

30° vertical field• Accuracy: +/- 3 cm (typical)• Rotating mirror inside

assembly,• Laser: Class 1 – 903 nm

wavelength

26 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Lidar Products

� Quanergy Solid-state LIDAR system• Field of view is 120 degrees both horizontally and vertically. • The minimum range is 10 cm, and the maximum range is at least

150 m at 8 percent reflectivity. • At 100 meters, the distance accuracy is +/- 5 cm, and the

minimum spot size is just 9 cm.

Small (9 cm x 6 cm x 6 cm), no moving parts

27 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

Solid State Lidar

� Uses an optical phased array as a transmitter (no micro mirrors), which steers laser pulses by shifting the phase.