High speed CMOS image sensors - pdfs.semanticscholar.org · • 150 pin PGA • Mono and color. 30 ... LUPA-1300 LUPA-1300-2. 31 High speed CMOS image sensors – Vision 2006 Conclusion

P E R F O R M

High speed CMOS image sensors

Wim Wuyts – Sr. Staff Applications Engineer

Cypress Semiconductor Corporation Belgium

Vision 2006

2 High speed CMOS image sensors – Vision 2006

Outline

• Introduction• Architecture

• Analog high speed CIS• Digital high speed CIS

• 6T snapshot pixel type• Applications

• Holographic data storage• Line sensors

• Standard high speed products: LUPA-family• Conclusion


Why?

Why high speed?

High speed motion/data analysis for various application fields

e.g. military ballistics


• Cypress has huge experience in high-speed CMOS Image Sensor (CIS) design

• (almost) All big players works with us• Current max. pixel throughput of 13.2 Gpixels/s• Typical with multiple parallel analog output tabs• Now high-speed ADCs, LVDS output and on-chip

timing sequencer available• Both array and linear sensors• Typical applications: high-speed motion analysis

(crash and impact test), holographic data storage, digital film slow motion capture

Introduction


Introduction

• What’s high speed?• Typically > 100 MPixels/s

• Requirements for high speed sensor design:• High speed read out architecture

(> 50 MPixels / internal tab)• High sensitive snapshot shutter pixel with low

Parasitic Light Sensitivity (PLS)• High speed ADCs• High speed interface (LVDS)


Technology: architecture

• High-speed read out architecture: 60+ MPixels/s / internal analog tab

• Parallel analog outputs e.g. 128*60 Mhz = 7.68 Gpixels/s throughput @ output

• Windowing (ROI) to boost frame rate (both in X and Y e.g. 100*100 @ 768k fps)

• Two trends:• Analog ‘naked’ image sensor: no sequencing

or digital logic on-chip => requires complex camera system

• System-on-a-chip approach (as much integration as possible): on-chip ADC, sequencer, interface



Typical analog high speed image sensor:• 6T-pixel core (e.g. 1024 * 1024divided in multiple sections • pixel drivers and column buffers• parallel analog output tabs (128+)• no timing sequencer on-chip (full external control on pixel array and read out timing).

e.g. custom high-speed CIS architecture



Typical system-on-a-chip high speed image sensor:

• Timing sequencer on-board

• Multiple ADCs on-chip

• Single clock input

• Multiple parallel digital LVDS outputs

• Different read-out schemes possible to fit different needs

e.g. LUPA-1300-2 architecture


Technology: 3T pixel

PD

GND

T1

T2 T3

Ipd

Vpd

Cpd

Vout

VDD row select

column output

reset

PD node

reset

time

Vol

ts

Sample & Read Out

Classic 3T-pixel with rolling shutter


Technology: Pixel type: 6T

T1

T2

T3

T4

T5

T6

Vpix Vpix Vmem

Row-select

Sample

Precharge

Reset

Vpd

Vpd

Vpd - Vt

AB

High speed applications requires: snapshot shutter, high sensitivity, low PLS => solution: 6T-pixel architecture


Rolling vs. snapshot

Snapshot shutter

Rolling shutter

Distorted motion Freezed motionElectronic snapshot shutter required for high-speed motion analysis


Snapshot shutter

Reset frameIn parallel

x

y Integrate andSample frame In parallel

Burst readoutsequential

Time axis

Line number

Integration time Burst Readout time

CO

MM

ON

RES

ET

CO

MM

ON

SA

MPL

E&H

OLD

Flas

h co

uld

occu

r her

e


Snapshot shutter

True Snapshot Shutter: Pipelined and Triggered type

Integration frame I+1 Integration frame I+2

Readout frame I Readout frame I+1

Pipelined mode (6T-pixel):

Triggered mode (IBIS5 alike pixel):

Integration frame I Integration frame I+1Readout frame I Readout frame I+1


Frame rate calculation (fps)

The frame rate depends on: 1. Pixel throughput in MPixels/s2. Frame Overhead Time (FOT) typical 10us3. Row Overhead Time (ROT) typical 300ns4. Window size in X and Y

→ Frame period calculation:Frame period = FOT + Nr. Lines * (ROT + Nr. Pixels * clock period)

Example: LUPA-300 (VGA resolution at 80MPixels/s) Frame period = 7.8 µs + (480 * (400 ns + 12.5 ns * 640) = 4.039 ms => 247.6 fps.

Frame rate increases with reduced window size in X and Y


Packaged high speed CIS

Analog high speed CIS Digital high speed CIS


Applications

• Examples of high speed applications:• Motion analysis:

• Military ballistics and impact• Crash tests analysis• Sport analysis

• Machine vision – inspection• Slow motion digital movie capture• Holographic mass data storage


High speed motion analysis:

Example of applications

Crash test analysis:


FEATURES• Ultrahigh storage densities:

• Optical interference technique with coherent laser beams• Data storage in 3 dimensions! • Storage density > 31.5 Gbits/in2 => 200 GB on DVD disk)

• Parallel access to data using data matrix and matrix reader instead of conventional photo diode

• Fast data transfers upto 1 Gbps (high speed data read out with CMOS image sensor)

• Durable, reliable, low cost media (polymer media)• Possible due to technology breakthrough on: SLM,

CMOS image sensor technology, storage media

Application focus:Holographic data storage


RECORDING DATA• A single laser beam is split into two: the

signal beam that carries the data and a reference beam

• The data is encoded on the signal beam with a Spatial Light Modulator (SLM)

• Data is stored as a hologram that is recorded onto a light-sensitive storage medium at the point where the signal and reference beam intersect

• Angle of incidence reference beam sets depth of writing




Writing data


READING DATA• A laser with the properties as the reference

beam is trained on the media• By changing the angle of incidence a new

page is read out• The laser projects the entire hologram, or

page, onto a detector, a high speed CMOS image sensor

• Spinning disk is scanned similar to CD principle




High speed CMOS image sensor

Reading data Read out system



Custom high-speed sensor for holographic read out • Resolution: 1696 X * 1710 Y• Pixel size: 8 um * 8 um• Shutter type: Snapshot (6T-pixel)• Pixel rate: 13.2 GHz (using 32 LVDS outputs)• Frame rate: 485 fps• 10-bit on-chip ADC• Sensitivity: 650 V.m2 / W.s• Power dissipation: 1100 mWatt


Application focus (2):high-speed linear sensor

Key features on linear high-speed CISs:

• High speed pixel read out (> 200 MHz, with multiple outputs)

• Very high spatial resolution

• Large area imaging area (possible with stitching)

• Linear pixel array with high sensitivity

• Low power consumption

• High on-chip integration of digital logic (lower system cost)

• Typical applications: bar-code readers, dimensions measuring, position inspection devices


Custom high-speed linear sensor project:• Resolution: 8200 * 1 line sensor• Pixel size: 7 um * 7 um• Image area length: 57,4 mm• Chip size: 58.5 * 3.5 mm2• Snapshot shutter• Line rate: 28.5k / s• Data rate: 240 MHz• 10-bit ADC on-chip• Sensitivity: 21 V.cm2/uJ

CMOS IS

Application focus (2):high-speed linear sensor


Standard high speed sensors

3T

3T

6T

6T

6T

4T

3T

3T

3T

Pixel type

11 fps

29 fps

15 fps

442 fps

247 fps

27 fps

3 fps

5 fps

7 fps24 fps

Framerate

1”15 umRolling1 MPSTAR-1000

1”25 umRolling250kSTAR-250

F-mount12 umSnapshot4 MPLUPA-4000

1”14 umSnapshot1.3 MPLUPA-1300

1/2”9.9 umSnapshotVGALUPA-300

2/3”6.7 umRollingSnapshot1.3 MPIBIS5-B-1300

F-mount8 umRolling13.85 MPIBIS4-14000

1”3.5 umRolling6.6 MPIBIS4-A-6600

2/3”7 umRolling1.3 MPIBIS4-1300

Optical format

Pixel pitch

Shutter typeResolutionName


LUPA family sensorsLUPA-4000 – Traffic

monitoring and surveillanceLUPA-300 – Fast machine vision applications


LUPA-1300-2• Current LUPA-1300 has 16 parallel analog

output tabs + no on-chip ADCs => difficult and expensive system design

• Custom developed high speed technology = state-of-the-art (13.2 GPixels/s)

• New LUPA-1300-2 standard product:• Use of state-of-the-art high speed IP• High sensitive, high efficient snapshot shutter pixel• ADCs on chip for easy integration• High-speed LVDS interface


LUPA-1300-2

• Samples expected Q2 2007• Product brief available• Specs:

• Resolution: 1.3 MP: 1280 X *1024 Y • 14 um pixel: pipelined snapshot shutter (6T-

architecture)• 310 MHz master clock => > 500 fps @ 1.3MP• Frame rate increase with ROI read out (in X and Y) • 10-bit ADC on-chip• 12 LVDS output taps @ 480 Msps• < 700 mWatt (ADC power on) @ 500 fps• 150 pin PGA• Mono and color


LUPA-1300-2

1/3000 – 99.97%1/500 - 99.8%PLS - Shutter efficiency

< 700 mWatt900 mWattPower

14 * 14 um214 * 14 um2Pixel size

1280 * 10241280 * 1024Resolution

Multi slope + NDRMulti slope + NDRExt. dynamic range

12 10-bit LVDS tabs16 analog outputsOutput

10-bitNo ADC on-boardADC0-500+ fps0-450 fpsFrame rate

64.6 dB60.7dBS/N ratio

LUPA-1300-2LUPA-1300


Conclusion

• Very high speed imaging still necessary with increasing speeds and resolutions

• High speed imaging with on-board features for easier implementation

• Generic high speed image sensors for wide variety of applications

• New challenges on combining a very high data rate image with a lot of on-board features like LVDS and image processing


• Thank you for your attention• Questions?

Documents

High speed CMOS image sensors - pdfs.semanticscholar.org · • 150 pin PGA • Mono and color. 30 ... LUPA-1300 LUPA-1300-2. 31 High speed CMOS image sensors – Vision 2006 Conclusion