silicon sensors final_prsentation
DESCRIPTION
A summary of the workshop on ¨Smart Sensors Systems 2012" that I attented at TU/DelftTRANSCRIPT
WelcomeSpecificaitons, Design & Development of smart
silicon sensor systemsMayur Sarode
Engineer at INCAS3Assen, The Netherlands
About the workshop
Smart Sensor Systems 2012 by Delft Institute of Microelectronics (DIMES)
Lectures , demonstrations, visit to clean room at TU/Delft.
Lectures
1. Silicon sensors: Applications and Future Perspectives by Paddy French,
TU/Delft.
2. Designing Smart Sensors and Smart Sensor Systems by Kofi Makinwa, TU/Delft.
3. Measurement techniques for smart sensor systems by Gerard Meijer, TU/Delft.
4. Calibration and Self-Calibration of Smart Sensors by Michiel A.P Pertijs, TU/Delft.
5. Integrated Hall Magnetic sensors by Pavel Keijk EPFL Lausanne, Switzerland.
6. Capacitive Sensors by Xiujin Li, TU/Delft.
7. Smart temperature sensors by Gerard Meijer, TU/Delft.
8. Optical Sensors Based on Photon Detection by Reinoud Wolffenbuttel , TU/Delft.
9. Physical chemosensors by Michel Velekoop, TU/Vienna.
10. Dynamic offset-cancellation techniques by Kofi Makinwa, TU/Delft.
11. Precision Instrumentation Amplifiers by Johan Huijsing , TU/Delft.
12. Universal asynchronous sensor interfaces by Gerard Meijer, TU/Delft.
13. Implantable Smart Sensors for Advanced Medical Devices by Tim Dension,
Medtronics
14. Interface electronics and A/D converters by Frank Reidijk, Xensor Integrartion
15. Introduction to CMOS-based DNA Microarrays by Jan Bosiersm Dalasa
16. Energy harvesting Sensor Systems by Ruud Vullers
What are Smart sensors?
Sensors ~“Smart sensor”o Low cost, Small size, Multi-sensingo Self-test, digital output, bus interface, RF, energy scavening
Transducers ~ self generating, modulating MEMS + CMOS design ~ a smart sensor
Silicon SensorsMEMS sensors~good planar processing technologySilicon not the best in class!Package design & analog designSignal processing to compensate for silicon defects
ThermalResistors, transistors,
thermopiles(temperature, wind sensor)
MechanicalDiaphram,
(micromachiened devices)
Radiant Photo diodes
(CMOS image sensors, optical sensors)
MagneticHall-plates, magFET’s, coil
(Hall sensors)
ElectricalResistors,capacitors, inductors,
(Capacitive sensors)
ChemicalISFETS
DNA detector, chemeosensors
Silicon Sensors Radition Domain
• P-N junction depletion layer• Shorter wavelentgth is absorbed by silicon• CCD’s, position sensors
Mechanical Domain• can introduce self test• Pressure and accelerartion sensors
Thermal domain• Silicon sensitive to temperature• Temperature and flow measurement
Magnetic Domain• Based on Hall effect• Magnetic field measurement, current, rotation and position
Chemical Domain• Physical chemeosensors
Smart Sensor Systems: System specs.
On Silicon Output format
Sensor bandwidth ~ 10 KHz Errors: offset, drift, noise, cross sensitivity, linearity, impedance, multipath Measurement techniques to solve these problems
• nested chopping•Dynamic element matching•Auto calibration
Smart Sensor Systems: functionality
Hardware
SoftwareoSelf test in accelerometerAuto-CalibrationoTransducer electronic data sheet (TEDS)oThree signal measurement
Sensing element
SignalConditioning
A/Dconverter
BusIntefacing
Processor
General hybrid solution
One chip solution
Universal transducer interface
Self testing Data evaluation
Auto-calibration identificaiton
Reducing errors• Random, Systematic, multi-path error• Auto zeroing vs Chopping
• Reduces 1/f noise , offset,
Autocalibration What is Mx ??
High accuracy ~high dynamic range
5 Kg
55 Kg
100 Kg
25 Kg
Mx Kg
Rotating Resistors
Sense1
Sense2
Compensating for parasitic effects
Cross and parasitic effects
Use of additonal sensorsExcitation signal, DC vs square vs sinusoidal vs pulsed, frequency
Zs1 Zs3
Zs2 Zs4
ZXIforce Vsense
Yp1 Y
p2
YX
Vforce Isense
Low ohmic impedance ( current) High ohmic impedance ( voltage)
Cable and wire impedance
Cx RpRx Cp
Zp
VxIx Yp
Capacitve sensors(humdity sensors)
resistive sensors (thermistors/photoresistors)
Votlage generating sensors(thermopiles/PH)
Current generating sensors(photo detectors)
Smart sensor Systems: A/D converters
Conventional system
Smart A/D conversion
AnalogFrontend
Off the shelfA/D
converter
processor
MUXcontrol
Period converter
processorSensing element reference element
Offset elementMUX
S/H circuitQuantizationDigital filteringΣΔ converter
capacitve
Tsense Treference Toffset
•Also used with resistive sensors
Universal Sensor Interface
System Setup
Sensing, signal conditioning , A/D conversionUniversal interface for interfacing sensor element to the processor
Smart sensor systems design
Wind sensor design at TU/Delft
System design~ sensor biasingDigitize early, modulation techniques for siliconlimitationsCharacteristics
oSlow, use dynamic techniquesoSmall output voltage, spreads, thermal balancingoThermal offset due to placement
Auto-zeroing of comparator~ low thermopile output1.6 μm technology10 bit ΣΔ ADC .
Smart temperature Sensors
Absolute temp sensorsThermistors( cheap, non linear, sensitive,
-80 to 200 ºCPlatinum resistors (expensive, stable, -260 to 1000 ºC)Thermocouple (reference junction and measurement
JunctionsSilicon Vbe ~ temperature
On silicon chipsIntegrated thermistors
1.Comparable to Pt resistors2.Stress dependent3.Voltage dependent non linear behaviour
Thermocouples1.No offset, no calibration
Measuring absolute temperature.
Microcontroller
Sensor Interface
Smart Temperature
Sensor
Temperature Sensingelements
Smart tempearature SensorsDesign considerations
Accuracy
Triple point of water ~ defined fixed point Absolute accuracy vs drift
Drift (1 mK ~ 10 mK)
Cross sensitivity to mechanical stress accuracy noise and resolution Reduced to 100 mK with packaging
Self heating
Dynamic behaviour Thermal design considerations Long term stability
So how to design it? Problem statement
Microrganism detection in milk products.
System level design
Circuit level design
DC DC
Milk carton
Im Is
Sensor Milk carton
Conclusions
Thank you