automotive engineering

1. 1
Sensing in Automotive -
Powertrain and Braking Systems

2. 2
Agenda
• Brief Introduction
• Automotive electronics & sensors
• Capabilities available from ON Semiconductor
• Powertrain Systems
• Gasoline and diesel engines
• Main powertrain sensors
• Braking and Stability Control Systems
• Basic systems: ABS, EBD, TCS, ESC
• Sensors for dynamic braking
• Examples of automotive sense interface ICs
• Sensing interface IP from ON Semiconductor

3. 3
Automotive Electronics
• Value added by ON Semiconductor APG
– Proprietary High-Voltage Processes
– Innovative Solutions: Sensor Interfaces,
IVN, High-Voltage System-on-Chip
– Harsh Environment Applications
– Extensive Automotive Portfolio
• Key Successes in sensing
– Steering/Pedal Angle Sensor
– Pressure sensors for Powertrain / Braking
– Position Sensors for Headlight Control
– Gyro Sensors for Stability Control
• Main drivers for new electronics
– Safety
– Emissions
– Fuel consumption
• Regulation plays a key role
← focus area for green electronics

4. 4
Modern Automotive Sensors
• External sensing element or MEMS
• Built-in protections (shorts, EMI, ESD…)
• Diagnostic modes / redundancy
• Accuracy / linearity reaching ~0.1% to 1%
• NVM for trimming and calibration
• Nonlinear temperature compensation
• TJ at IC: from –40 oC up to +125~200 oC
• Target failure rate: zero ppm

5. 5
Automotive Technologies Portfolio
I3T50
I3T80
C035
ABX
VoltageVoltage
Gate CountGate Count1K 5K 100K 500K
100 V
80 V
50 V
25 V
5 V
3.3 V
1.8 V
HBIMOS
I2T100
C3,C035U
C07
FeaturesFeatures
(OTP, EEPROM, etc.)(OTP, EEPROM, etc.)
C018
I3T25
>1.5 u 0.7 u 0.6 u 0.35 u 0.18 u Geometry
(drawn poly)
D3C5X
I4T
I2T30(E)

6. 6
Non-volatile Memory (NVM) IP
• EEPROM
– Long experience, started with C5 NASTEE release in 1999
– Non-added-steps EEPROMS available today for C5 / C3 / I3T50
– I3T50 EEPROM is capable of 175 oC operation (reading)
– EE being released for I3T25U (Q4 2009)
– Development for 0.18 u ongoing
• OTP
– OTP is Zener diode zap
– Available in I2T100, I3T25, I3T50, I3T80
• Flash
– Requires 5 added process steps
– Special technology developed only for I3T80
– Technology is qualified to 150 oC read (50 oC for write)

7. 7
I3T Example
S/H
Diag-
nostics
DAC
ADCPGA
AMUX
EEPROM
OTP
Temp sense
HV
BUF
Logic Control
Block
RAM
ROM or
Flash
JTAG
Timer
PWM
GPIO
Comm.
Control
UnitHV
LIN
Transceiver
LIN
BSD
RS-232
…Drivers :
Motor
Relay
Lamp
Heat
…
Sensor Int. :
HV / LV
Inductive
Capacitive
Resistive
Temperature
…
Analog Control
and Signal Processing :
Voltage regulators
Amplifiers, comparators
ADC, DAC
Filters (SC, GMC, RC) …
Vbat 5 V
Regulator
ARM7
R8051
PeripheralExtension
PeripheralExtension
Digital Signal Processing
and Control :
State Machine or
uController based
Vdc < 65V/36V/18V

8. 8

9. 9
Gasoline Engine System Concept
Source: Continental

10. 10
Diesel Engine

11. 11
The Internal Combustion Engine
Nikolaus Otto Rudolf Diesel
HeatOH
y
xCOO
y
xHC yx +⎟
⎠
⎞
⎜
⎝
⎛
+→⎟
⎠
⎞
⎜
⎝
⎛
++ 222
24
Chemical equation for
stoichiometric hydrocarbon burning
Partial combustion
Fuel evaporation
Nitrogen from air
Sulfur from fuel
HC – Hydrocarbons (unburned)
CO – Carbon monoxide
NO, NO2 – Nitrogen oxides (NOx)
SO2 – Sulfur dioxide
Diesel particulate matter (DPM)

12. 12
Electronic Fuel Injection (EFI)
• Stringent emission regulations
obsoleted the carburetor (~80’s)
• Advantages of EFI
– Precise and accurate fuel measurement
– Improved cylinder-to-cylinder fuel
distribution (MPFI, GDI, DDI)
– Predictable exhaust composition
– Enables use of optimized catalytic
converters
• Net benefits
– #1: Lower emissions
– #2: Higher efficiency
– #3: Increased power

13. 13
The ECU Control Loop
Throttle position
Intake air temperature
Manifold air pressure
Mass air flow (MAF)
Fuel pressure
In-cylinder pressure
Coolant temperature
Crankshaft position
Camshaft position
Engine speed
Engine knocking
Exhaust gas oxygen
╠ Fuel injection
╠ Idle speed control
╠ Ignition timing
╠ Multispark timing
╠ Dwell angle
╠ Valve timing (VVT)
╠ Camless valve actuation
╠ Exhaust gas recirc. (EGR)
╠ Turbo boost
╠ Transmission control
PROCESS
CONTROL LOOPSSENSORS
ACTUATORS
Engine Control Unit
(ECU)

14. 14
Mass Air Flow (MAF) Sensors
Source:
“Air Flow Sensor - Key Device of A/F ratio control Engine”
Engine Technology No.48 (February, 2007)
Sankaido Publishing Co., Ltd, Japan

15. 15
Oxygen (lambda) Sensors
(ZrO2)0.92 (Y2O3)0.08 Pt
Basic electrochemical cell
“Nernst Cell”
Wideband Universal Exhaust
Gas Oxygen (UEGO) Sensor
O2 + 4 e-
= 2 O2-
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
⋅=
2
2
ln
4 O
ref
O
S
P
P
F
RT
E
(lean-burn / diesel engines)
Potentiometric sensor characteristics
λ=1 equals A/F~14.7 (stoichiometric ratio) Sources: Damien Chazal, Bosch
Amperometric UEGO sensor
High sensitivity for a wide range of λ

16. 16
Environmental Effects
Source: NOAA
Global concentrations of major greenhouse gases
← smog
internal combustion engines
contribute to CO2 and NOx

17. 17
Engine Management - Market Drivers
Source: CAS
0.00
0.10
0.20
0.30
0.40
EPA(US)
('83)
TLEV
(~'99)
LEV
(~'00)
ULEV
(~'04)
SULEV
(~'07)
HC (g/mile)
NOx (g/mile)
Source: Hitachi, Ltd., Automotive Systems Group
SULEV*：Super Ultra Low Emission Vehicle
California Air Resources Board (CARB) Ratings
US NHTSA Corporate Average Fuel Economy (CAFE)

18. 18
Reducing NOx in Lean-burn Engines
NOx adsorption Urea selective catalytic
(SCR) reduction
Source: Honda Motor
AdBlue™ is a registered trademark by Verband der
Automobilindustrie (VDA) for AUS32 (Aqueous Urea Solution 32%)
Source: VDA

19. 19
Urea SCR needs strict control
Electronics used to:
Sense urea solution level in tank
Check quality and concentration
Inject known amount of urea
Low urea level warning
Engine shut-off
Source: Mitsui

20. 20

21. 21
The ABS Principle
During emergency braking, ABS automatically cycles
tire slip around point of maximum braking efficiency
( ) ( ) %100
_
__
×⎟⎟
⎠
⎞
⎜⎜
⎝
⎛ −
speedVehicle
speedWheelspeedVehicle

22. 22
First ABS-like Automotive System
Sure-Brake System supplied by Bendix
for the 1971 Chrysler Imperial
First ABS supplied by Bosch for 1978 S-class Mercedes and BMW 7

23. 23
Two Generations of ABS
Source: Robert Bosch GmbH

24. 24
Electronic Brake-Force Distribution (EBD)
• Braking causes a dynamic weight transfer to the front
wheels depending on:
– Vehicle construction / geometry
– Deceleration
• Consequence: rear wheels tend to lock first
• EBD reduces rear pressure to avoid rear wheel locking
– Similar to mechanical brake proportioning valves
• EBD bases rear wheel control on slip rather than pressure
• Wheel control kicks in before ABS in the low-G region
– EBD events occur frequently and are transparent to the driver
• ABS and EBD usually share the same hardware
– Brake proportioning valve is eliminated
– Better braking performance independent of vehicle loading

25. 25
Traction Control Systems (TCS)
• Limits torque applied to wheels to prevent spinning
– Also known as Anti-Slip Regulation (ASR)
• Usually shares the electro-hydraulic brake actuator and
the wheel speed sensors with the ABS
• Methods to achieve traction control:
– Brake one or more wheels
– Retard or suppress spark to one or more cylinders
– Reduce fuel supply to one or more cylinders
– Close throttle (with drive-by-wire throttle) or sub-throttle
– Actuate boost control solenoid in turbocharged engines
• Brake-only systems are simpler, but less functional

26. 26
A Complete ABS/TCS System
Source: LEXUS Technical Training Manual

27. 27
Electronic Stability Control (ESC)
• Enhances stability through
asymmetric braking (yaw)
• ESC may be required during
ABS, DRP or TCS events
• Sensors collect information
– Individual wheel speeds
– Steering angle
– Yaw rate
– Lateral acceleration…
• ECU runs algorithms to detect
and correct ESC events
• Mercedes W-140 S-Class had
first complete ESC in 1995
• Key precursors (no yaw rate):
Mitsubishi Diamante/Sigma 1990
BMW all model line in 1992
Source:IIHS

28. 28
Marketed Names for ESC
• Acura: Vehicle Stability Assist (VSA)
• Alfa Romeo: Vehicle Dynamic Control (VDC)
• Audi: Electronic Stability Program (ESP)
• Bentley: Electronic Stability Program (ESP)
• Bugatti: Electronic Stability Program (ESP)
• Buick: StabiliTrak
• BMW: Dynamic Stability Control (DSC) (including Dynamic Traction
Control)
• Cadillac: StabiliTrak & Active Front Steering (AFS)
• Chery: Electronic Stability Program (ESP)
• Chevrolet: StabiliTrak; Active Handling (Corvette only)
• Chrysler: Electronic Stability Program (ESP)
• Citroën: Electronic Stability Program (ESP)
• Dodge: Electronic Stability Program (ESP)
• Daimler: Electronic Stability Program (ESP)
• Fiat: Electronic Stability Program (ESP) and Vehicle Dynamic
Control (VDC)
• Ferrari: Controllo Stabilità (CST)
• Ford: AdvanceTrac with Roll Stability Control (RSC) and Interactive
Vehicle Dynamics (IVD) and Electronic Stability Program (ESP);
Dynamic Stability Control (DSC) (Australia only)
• General Motors: StabiliTrak
• Honda: Vehicle Stability Assist (VSA)
• Holden: Electronic Stability Program (ESP)
• Hyundai: Electronic Stability Program (ESP), Electronic Stability
Control (ESC), and Vehicle Stability Assist (VSA)
• Infiniti: Vehicle Dynamic Control (VDC)
• Jaguar: Dynamic Stability Control (DSC)
• Jeep: Electronic Stability Program (ESP)
• Kia: Electronic Stability Control (ESC), Electronic Stability Program
(ESP)
• Lamborghini: ESP - Electronic Stability Program
• Land Rover: Dynamic Stability Control (DSC)
• Lexus: Vehicle Dynamics Integrated Management (VDIM) with
Vehicle Stability Control (VSC)
• Lincoln: AdvanceTrac
• Maserati: Maserati Stability Program (MSP)
• Mazda: Dynamic Stability Control (DSC) (Including Dynamic Traction
Control)
• Mercedes-Benz (co-inventor): Electronic Stability Program (ESP)
• Mercury: AdvanceTrac
• MINI: Dynamic Stability Control
• Mitsubishi: Active Skid and Traction Control (ASTC) and Active
Stability Control (ASC)
• Nissan: Vehicle Dynamic Control (VDC)
• Oldsmobile: Precision Control System (PCS)
• Opel: Electronic Stability Program (ESP)
• Peugeot: Electronic Stability Program (ESP)
• Pontiac: StabiliTrak
• Porsche: Porsche Stability Management (PSM)
• Renault: Electronic Stability Program (ESP)
• Rover Group: Dynamic Stability Control (DSC)
• Saab: Electronic Stability Program (ESP)
• Saturn: StabiliTrak
• Scania: Electronic Stability Program (ESP)
• SEAT: Electronic Stability Program (ESP)
• Škoda: Electronic Stability Program (ESP)
• Smart: Electronic Stability Program (ESP)
• Subaru: Vehicle Dynamics Control (VDC)
• Suzuki: Electronic Stability Program (ESP)
• Toyota: Vehicle Dynamics Integrated Management (VDIM) with
Vehicle Stability Control (VSC)
• Vauxhall: Electronic Stability Program (ESP)
• Volvo: Dynamic Stability and Traction Control (DSTC)
• Volkswagen: Electronic Stability Program (ESP)
Source: Wikipedia

29. 29
Importance of ESC
• High visibility after “moose test” by a Swedish car magazine in 1997
• Today considered the most important safety feature since the seat belt,
studies show ESC reduces fatal car accidents by about 35%
• National Highway Traffic Safety Administration (NHTSA) will require
ESC on all new light passenger vehicles in US by 2012
– ABS will not be mandatory but usually comes “for free” with ESC
• ChooseESC! educational campaign across Europe
• United Nations working group for adopting ESC as a Global Technical
Regulation (GTR)
• What ESC cannot do:
– Improve tire traction characteristics (μ-slip curve)
– Increase vehicle lateral acceleration capacity
– Change any of the Laws of Physics

30. 30
ESC Systems Keep Evolving
Source: Continental Teves, Inc.

31. 31
Sensors and Actuators in ESC Control
Pressure
sensor
(wheels x4)
Wheel speed
sensor (x4)
Lateral
acceleration
sensor
Yaw ・Gyro
Sensor
Interface
ASIC
(PS)
Interface
ASIC
(LAS)
Interface
ASIC
(GS)
Sensor interface
ASIC
LDO
regulator
+- 150 mA
MCU
16 or 32-bit
+
software
Pressure sensor
(master cylinder)
Central
Braking fluid
Motor Driver
(FET)
DC
Motor
Solenoid
valve driver
(FET)
2/2
Valve
Steering
Wheel
Sensor
Interface
ASIC
(SWS)

32. 32
Advanced Braking Systems
• Active Rollover Protection (ARP)
– Extra gyroscopic sensor to monitor roll motion
– AdvanceTrac® with Roll Stability ControlTM (Ford)
• Adaptive Cruise Control (ACC)
– Sensors based on radar or LIDAR (laser) to measure distance
• Brake Assist (BA or BAS)
– Sensors to detect panic braking or that a collision is likely
– Possible actions: warn driver, pre-charge brakes with maximum
pressure, apply full braking automatically
• Brake-by-wire
– Eliminates traditional mechanical and hydraulic control systems
– Uses sensors, electromechanical actuators and human-machine
interfaces, such as pedal and steering feel emulators

33. 33
A brake-by-wire system
Source: Reza Hoseinnezhad

34. 34
Sensors & Sensor
Interface

35. 35
Converting for Signal Processing
Signals to sense
Temperature
Force / Pressure
Torque
Rotation / Position
Level
Speed / Acceleration
Flow
Acoustic
Magnetic field
RF
Light / Radiation
Chemical…
Available electrical signals
Voltage
Current
Charge
Resistance
Capacitance
Inductance
Impedance
Domains for processing
Analog
Digital
Mixed signal

36. 36
Sensing ASICs Requested by our Customers
voltageelectrochemicalO2 concentration
chargeMEMS tuning forkOrientation (gyro)
currentbiochemicalBlood glucose
voltageultrasonicDistance
resistancethermistorUrea concentration
currentultrasonicGas flow
charge
CsI scintillator +
photodetector
X-ray radiation
currentphotodiodeLight
capacitanceMEMS capacitorsAcceleration
inductance, resistancemagneticAngle / position
resistancethermistorAir flow
voltagepiezoresistive bridgePressure
Electrical signalSensorPhysical quantityAutomotive

37. 37
Process depends on Application
I3T50
I3T80
C035
ABX
VoltageVoltage
Gate CountGate Count1K 5K 100K 500K
100 V
80 V
50 V
25 V
5 V
3.3 V
1.8 V
HBIMOS
I2T100
C3,C035U
C07
FeaturesFeatures
(OTP, EEPROM, etc.)(OTP, EEPROM, etc.)
C018
I2T30
I3T25
>1.5 u 0.7 u 0.6 u 0.35 u 0.18 u Geometry
(drawn poly)
D3C5X
I4T

38. 38
Automotive Protections
• Overvoltage and reverse battery (OVRB) protections
• Electrostatic discharge (HBM, MM, CDM…)
• Automotive transients:
– AEC Q100 automotive standards
– ISO 7637 pulses
• Load dump
• Schaffner pulses
– Other local standards
• Output shorted to battery or ground
• Current sensing and limiting
• Over-temperature protection
less common in
sensor interface

39. 39
On-chip Overvoltage Protection
• 5 V supply with on-chip overvoltage / reverse batt protection
– Solution covered by patents
• At least ±18 V protection allowed (process dependent)
Ext. +5V supply Int. ASIC supply
GND
Low voltage drop switch

40. 40
Passive Wheel Speed Sensors
• Wheel speed ➛ sinusoidal voltage
• Both frequency and amplitude are
proportional to wheel speed
• Noise-limited at low wheel speeds
• NCV1124 (dual) and NCV7001
(quad) generate square waveform

41. 41
Active Wheel Speed Sensors
• Commonly based on Hall effect
• Only frequency varies with speed
• Can sense speed down to zero
• Delivers a square current waveform
• Sensitive to contamination by rust
or metal fillings
• Other possible technologies:
– Magnetoresistive (MR) and Giant
Magnetoresistive (GMR)
– Based on Eddy current
– Optical sensing
– Wiegand effect
• Sensor interface circuit depends on
the technology

42. 42
Wheel Speed Interface
• Interface for Active and Passive Speed Sensors
• Compact Digital/Analog tracking loop with ~1 MHz sampling
• Programmable Hysteresis levels and filtering to increase noise robustness
• Fast and slow tracking mode (1 DAC + 1 comparator per wheel)
=> Low cost and small size
• Diagnostic for fail safe logic (short to battery or ground, open inputs)
• Proven on silicon
Peak And Valley
Detection
[x] bits
+
D
A
C
+/- [y] lsb
(Fast tracking)
Wheel Speed
Output
Speed Sensor
OutputHysteresis
value
Hysteresis
value
Delay Delay Delay Delay Delay
Analog/Digital interaction
for smallest size
Analog/Digital interaction
for smallest size

43. 43
Steering Angle Sensors
• Different technologies are available
– Optical
– Potentiometric
– Inductive
– Hall-effect
– Magneto resistive
– and others
• Technologies and ICs may be used
in other angle or position applications
– Pedal position
– Throttle control
– Headlamp control
– Height/level regulation
Source: Bosch, Hella

44. 44
A MR Angle Sensor ASIC
• Two magneto-resistive bridges are offset by 45o
• 90o signals (sine/cosine) are divided and arctangent gives the angle

45. 45
Longitudinal or Lateral Accelerometers
• Not strictly required for ABS control
but increasingly present in more
recent ESC systems
• Used as a “sanity check” for wheel
and vehicle speed calculations
• Lateral accelerometer used to
prevent artificially low speed
calculations
• Longitudinal accelerometer used in
4-wheel-drive vehicles where all
wheels can be mechanically coupled
• Capacitive MEMS technology
becoming dominant

46. 46
Sensor Interface for Accelerometer
Analog
GND ref
Temperature
sensor
12b
D/A
PGA
Digital
filters
DSP
for TC
C/V
conv
PGA
C/V
conv
MUX
Digital
filters
Buf
12b
D/A
Buf
ΣΔ
• Single module or IC can accommodate 1, 2, or 3-axis accelerometers
• Each channel is calibrated for accuracy and temperature compensated
• Outputs can be analog or digital

47. 47
Gyroscopic Sensors
• Measures angular speed (rotation)
• Initial automotive gyros derived from
military / aerospace products
• Yaw rate (rotation around vertical axis)
is mandatory in ESC
• Roll rate is a recent addition in some
rollover prevention systems
• Pitch rate has no current automotive
application
• Today MEMS-based solutions allow
compact and inexpensive gyros for
automotive applications
Source: Continental
ESC sensor cluster with gyro
and accelerometers

48. 48
Example: Systron Donner (BEI) GyroChip™
• Quartz Rate Sensor (QRS) proprietary technology
• Coriolis effect: converts momentum of a vibrating object into a force
• Piezoelectric property of the quartz converts the Coriolis force into
electrical charge signals proportional to the angular rate

49. 49
Pressure Sensor Auto Applications
• MAP Manifold Absolute Pressure
• TMAP Temperature Manifold Absolute Pressure
• DMPS Differential Manifold Pressure Sensor
• DPF Diesel Particulate Filter
• DDI Diesel Direct Injection
• GDI Gasoline Direct Injection
• HCCI In-Cylinder Pressure (future)
• ABS Anti-Lock Braking Systems
• ESC Electronic Stability Control

50. 50
Pressure Sensor Interface (Example)
Nonlinear temperature compensation
for gain and offset

51. 51
NVM and Nonlinearity Compensation
• All sensing elements have nonlinearities (NL)
– Intrinsic nonlinearity over sensing range
– Offset & sensitivity NL variations over temperature
• Market requirements for sensors with higher
accuracy and extended range
– Trimpots / manual methods not viable for mass production
– Laser trimming: expensive, requires special technologies
– LUT not always can provide enough accuracy
Solution: embedded programmable
compensation with NV memory
Solution: embedded programmable
compensation with NV memory

52. 52
Our Proprietary Solution for NL
• Methods and circuits based on Pade’ Approximants, the ratio
between two power series
• Accuracy and cost advantages when compared to
– Lookup table (LUT)
– Piecewise linear approach
– Polynomial approximation (Taylor expansion series)
• Patents granted and pending worldwide
L
LL xpxpxppxP ++++= L2
210)(
M
MM xqxqxqxQ ++++= L2
211)(
1)(
)(
)(
1
1
+
+
==
cx
bax
xQ
xP
xy
a 1st order Padė Approximanta 1st order Padė Approximant

53. 53
Mapping a NL Function into a Linear one
x2
Vin
Nonlinear input from
sensing element
x1
x
Vout
Calibrated and
compensated output
x
v2
x0
vi1
vi0
vi2
v0
v1
x0
mapping
x2
x1
Vout
Vinc
bVina
=
+⋅
+⋅
1
⎪
⎭
⎪
⎬
⎫
⎪
⎩
⎪
⎨
⎧
=⋅⋅−+⋅
=⋅⋅−+⋅
=⋅⋅−+⋅
2222
1111
0000
vvvicbvia
vvvicbvia
vvvicbvia
By applying Padé to Vin and replacing values at calibration points x0, x1, x2
⇒ a system with 3 linear equations and 3 variables (a, b, c) is generated
By applying Padé to Vin and replacing values at calibration points x0, x1, x2
⇒ a system with 3 linear equations and 3 variables (a, b, c) is generated

54. 54
Two Practical Circuit Implementations
ΣG
D/A
OFFSET
REGISTER
+
+
Vout
D/A
FEEDBACK
REGISTER
D/A
GAIN
REGISTER
Vin
_
voffG
kvf
Input signal
signal
compensated
for nonlinearity
ΣG
D/A
OFFSET
REGISTER
+
+
Vout
D/A
FEEDBACK
REGISTER
D/A
GAIN
REGISTER
Vin
_
G
voff
G
kvf
The following transfer functions are realizedThe following transfer functions are realized
voffVinVoutkvfGVout +⋅⋅−⋅= )1(
Isolating Vout, we verify both functions to be Padé ApproximantsIsolating Vout, we verify both functions to be Padé Approximants
1+⋅⋅
+⋅
=
VinkvfG
voffVinG
Vout
1
)(
+⋅⋅
+⋅
=
VinkvfG
voffVinG
Vout
voffGVinVoutkvfGVout ⋅+⋅⋅−⋅= )1(

55. 55
Application in NL Temperature Compensation
• Temperature compensation is a basic
building block in sensor interface
• A temperature reference is needed
either internal or external to the IC
• Applies temperature dependent
nonlinear offset and gain to the signal
path to cancel out the sensor
temperature dependency
• Many possible implementations can
be realized
OFFSET DAC
REGISTER
OFFSET TC
COEFFIC.
A/D
D/A
T (dig)
a,b,c
TEMP
SENSOR
T
ALU
GAIN TC
COEFFIC.
GAIN DAC
REGISTER
D/A
Σ G
+
+/-
Vin
Vout
a,b,c

56. 56
Methods for Temperature Compensation
• Error plot shows PWL has
greatest error
• Padé and 4th order Taylor
series about the same error
• But when implemented using
integer math (for RTL), the
Padé benefit is evident

57. 57
Communication – Embedded IVN
• Integrate high voltage communication transceiver on chip
– LIN-Spec. 2.1 (SAEJ2602)
– CAN-HS
– CAN-LS
– K-Line (ISO9141)
– SENT Single Edge Nibble Transmission
ON solution: excellent EMI performance, small area (patent pending)
– Other standards (2-wire SENT, PSI5, etc…)
BUS Phys.
Layer ECU
BUS Phys.
Layer
Upper
layer
SPI
Interrupt
ECU
ASICASIC
Flexibility Higher integration

58. 58
Released Products
Transceivers
ISO11898-3
CAN LS Transceiver (3.3V)AMIS41683CANN1RGAMIS-41683
Dual CAN HS TransceiverAMIS42700WCGA4RHAMIS-42700
LIN Transceiver with 3.3V VReg.NCV7420D23R2GNCV7420
LIN Transceiver with 5V VReg.NCV7420D25R2G
SW CANSee One PagerNCV7356
CAN LS Transceiver (5V)AMIS41682CANM1RGAMIS-41682
HS LP CAN Transceiver with Error DetectionNCV7341D21R2G
Improved HS LP CAN Transceiver
with Error Detection (>6KV)
NCV7341D20R2GNCV7341
HS LP CAN Transceiver
(Edge WakeUp - Matte Sn)
AMIS42665TJAA6RG
HS LP CAN Transceiver
(Level WakeUp - NiPdAu)
AMIS42665TJAA3RL
ISO11898-5HS LP CAN Transceiver
(Level WakeUp - Matte Sn)
AMIS42665TJAA1RGAMIS-42665
CAN HS Transceiver (3.3V)AMIS30663CANG2RGAMIS-30663
ISO11898-2CAN HS Transceiver (5V)AMIS30660CANH2RGAMIS-30660
Stand-alone LIN TransceiverNCV7321D10R2GNCV7321
LINv1.3/v2.1
J2602
LIN TransceiverAMIS30600LINI1RGAMIS-30600
StandardDescriptionOPN (T&R)WPN

59. 59
Failsafe Logic Functions
1. Between MCU and ASIC
• Checks that MCU and ASIC are not disconnected (watchdog)
• Checks that software inside MCU is following proper sequence and issuing proper flags (no code
jumps)
• Generate references for MCU (clock, voltage etc …)
• Monitor SPI activity from MCU
2. ASIC related
• Undervoltage / Overvoltage
• Start-up check for proper working of failsafe logic
• Monitor of critical functions (solenoid and motor)
• Possibility to only connect supply for solenoid
and motor when MCU and ASIC agree
Failsafe logic: System FMEA
In case something goes wrong then disable ABS functions
but “normal” braking can still be performed by driver.
Micro-
Controller
Reference
Generation
FSFlag
Watchdog
Critical function
monitor
ECU monitor
Under/over
voltage
Disable ABS
functions
ASIC
Failsafe logic
enable

60. 60
Sensor Interface: Partial Redundant System
• Two independent measurement channels on one die
• Synchronicity check performed also inside the ASIC

61. 61
Full Redundant Application
• Safety is guaranteed by redundancy – two ASICs can be
used
• Synchronicity between outputs is checked by ECU
LC
oscillator
Input
Mux
Analog
meas.
path
Digital
processing
Supporting
blocks
Analog
Driver
Failure
detections
Excitation
coil
Receiving
coils
ASIC A
Output A
LC
oscillator
Input
Mux
Analog
meas.
path
Digital
processing
Supporting
blocks
Analog
Driver
Failure
detections
Excitation
coil
Receiving
Rotor
Sensor
coils
ASIC B
Output B
Excitation
driver
Excitation
driver
Sensor
Sensor

62. 62
Opportunities for Cost Reduction
• Advantage of digital communication using SENT protocol
– One driver is sufficient to transmit data from both sensors
– Several checks are performed to validate the received SENT frame
• Use of two external set of sensors with different output
signals
• One measurement path inside the ASIC
• Failure detections / calibrations / self tests

63. 63
Final Diagram
• New proposed architecture uses one measurement path
– Satisfying very high safety requirements
– Highly cost effective

64. 64
For More Information
• View the extensive portfolio of power management products from ON
Semiconductor at www.onsemi.com
• View reference designs, design notes, and other material supporting
automotive applications at www.onsemi.com/automotive