PREDICTIVE RELIABILITY ASSESSMENT OF A DCDC CONVERTER USING FIDES

HANDBOOK

Sid-Hamed Houalef, Amlie THIONVILLE & Philippe POUGNET (Valeo)

AGENDA

Demonstrator: Reliability target

Mission profile & Hypotheses

Results

Comparison with predictive reliability results based on

RDF 2000 handbook

Conclusion

Demonstrator : DC-DC converter

Converts power (2kW)

from the 24 V network to14V network (buck mode)

From the 14 V network(battery) to the 24 Vnetwork (boost mode)

Converter

Wakeup

Network 24 V

Network 14 V

CAN BusBattery voltage

& currentmeasurements

T carter

IMS

Board

Board FR4

ambiant T

DCDC converter

Reliability target: B10 15 years

DCDC Converter Predictive Reliability

Hypotheses:

Components failure law: exponential

Fabrication process and component fabrication process under control

Thermal conditions

Ambiant under hood temperature defined by the customer

The Carter temperature is measured through testing currents [160,140 A]

The carter temperature is the ambiant temperature of the two boards

Two functions considered: Buck & Boost

Steps:

Mission profile

Components

Applied loads (condensers and resistors)

Component junction temperature (active discrete components)

Audit manufacturing (Automotive Quality)

Audit induit (quality of the assembly design rules-)

DC-DC CONVERTER MISSION PROFILE

Average daily use

Nombres de cycles/jour

Dure en minute Nombre de cycles et dure en hiver

Nombre de cycles et dure en I-S

Nombre de cycles et dure en t

1 46 min 67 51h 168 128h 101 77h 1 25 min 67 28h 168 128h 101 77h 4 13 min 268 55h 670 137h 402 82h

Functioning Thermal Cycles

Temprature Hiver Printemps- automne (Intersaison)

t

T ambiante externe -10C 15C 30C

T ambiante moteur 30C 70C 85C

Tcyclage 25C 25C 25C

T carter=Tmax Cyclage 55C 95C 110C

MISSION PROFILE

Tcarter

T

Tamb cycles

Carter Temperature is the temperature near the electronic

components

Thermal Cycle

Mission profile

DC DC converter

THERMIQUE CYCLAGE THERMIQUE HUMIDITE MECANIQUE CHIMIQUE

PHASE On / Off tannuel-phase Tambiante Tcyclage cy Ncy-annuel Tmax-Cycalge RHstockage-

carte GRMS-phase Pollution saline

Pollution artificielle

Zone d'application

Niveau de protection

garage t Off 2 427 30 - - - - 70 - Faible Zone urbaine Moteur Hermtiquegarage I-S Off 4 045 15 - - - - 70 - Faible Zone urbaine Moteur Hermtiquegarage hiver Off 1 618 - 10 - - - - 70 - Faible Zone urbaine Moteur Hermtiquecycle de nuit t On 77 85 25,00 0,77 101 110 70 0,10 Faible Zone urbaine Moteur Hermtiquecycle de nuit I-S On 128 70 25,00 0,77 168 95 70 0,10 Faible Zone urbaine Moteur Hermtiquecycle de nuit hiver On 51 30 25,00 0,77 67 55 70 0,10 Faible Zone urbaine Moteur Hermtiquecycle matin t On 42 85 25,00 0,42 101 110 70 0,10 Faible Zone urbaine Moteur Hermtiquecycle matin I-S On 70 70 25,00 0,42 168 95 70 0,10 Faible Zone urbaine Moteur Hermtiquecycle matin hiver On 28 30 25,00 0,42 67 55 70 0,10 Faible Zone urbaine Moteur Hermtiquecycle en journe t On 82 85 25,00 0,21 402 110 70 0,10 Faible Zone urbaine Moteur Hermtiquecycle en journe t On 137 70 25,00 0,21 670 95 70 0,10 Faible Zone urbaine Moteur Hermtiquecycle en journe t On 55 30 25,00 0,21 268 55 70 0,10 Faible Zone urbaine Moteur Hermtique

Somme (1an = 8760 h) ===> 8 760

The mission profile is described by i phases parking (off) Driving on a road Traffic jam

Failure rate of a component (FIDES)1. for each component and each phase i of the mission profie Fides calculates a

predictive failure rate

induit

TCyt h r mi q u e

l ec t r i que

mcani que humi di t chi mi que

Temperature

Thermal cycles

Electrical

Humidity

Chemical

vibrations

factor depending on the position of the component on the circuit and on the respect of standard assembly procedures

TCythrmique

lectrique

mcaniquehumiditchimique

iinduitRHRHMcaMBrazjoTCyjoinTCy

TCyBoitierTCyBoitthermiqueth

phases

i

annueli

phases

iphysique

t

+++

+==

)

()8760

(

int

Failure rate of an equipment (FIDES)

+=

composants cartescartescomposantsquipement

processingmanufacturpartphysiquecomponent = _

2. Predictive failure rate for each component (Fides takes in account the processfactor and a quality audit factor)

3. Predicitive failure rate of the equipment

Results

CARTE SMI CARTE FR4

6000

CONVERTISSEUR DC/DC

DEFAILLANCES EN FIT 127 515 685

CONNECTEURS BONDINGS

42

4511 368DEFAILLANCES EN PPM/an 1113

DC DC Converter Failure rate (FIDES)

Critical components of the Power boardPareto taux de dfaillance lev par composant sur la carte SMI

0

0,5

1

1,5

2

2,5

3

capa

p14+

x Fil

tr

2200

F

polar

is

50V

capa

amor

tisse

men

t 820

F

polar

is

50V

induc

tance

Buck

Boos

t 14

H

Induc

tance

p14+

x 40

7nH

induc

tance

p14 4

07nH

capa

non

polar

is

amor

tisse

men

t 680

F

35V

SHUN

T 0.1m

5%

3W

RES.S

HUNT

BVS

0,002

OHM

1%

3W

PLAG

E BRA

SURE

capa

d'am

ortis

sem

ent p

r ch

arge

820

F 50V

TRAN

S.MOS

FET-N

.CM

S 40V

1.5m

OHM

180A

TO26

3-7

TRAN

S.MOS

FET-N

.CM

S 40V

1.5m

OHM

180A

TO26

3-7

RES.1

206 1

60OH

M 1%

250m

W 10

0PPM

TRAN

S.MOS

FET-N

.CM

S 40V

120A

TO26

3

TRAN

S.MOS

FET-N

.CM

S 40

V 120

A TO2

63

CER

4.7uF

10%

50V X

7R

Type composant

L

a

m

b

d

a

e

n

F

I

T

Taux de dfaillance par composant

Critical components of the command boardPareto Taux de dfaillance lev par composant sur la carte FR4

0

2

4

6

8

10

12

14

16

18

LP

CURR

ENT-M

ODE P

WM

CTRL

UCC2

803 S

O8

LIN.CM

P SO1

4 T4 x

4 36V

2901

LIN.CM

P SO8

T4

x2

36V 2

903

RES.2

512 1

OHM

5%

1W

-

200/+

850P

PM

RES 3

0R

1%

500m

W TF

400p

pm

TRAN

SFO

FLYB

ACK 1

04uH

10%

EV15

P=6.8

W

RES.C

ER

0603

T5

13K0

1%

0W

IC DR

V MOS

HBDG

IRS2

110S

SO16

TRAN

N-CH

AN

SMAR

T LOW

-

SIDE

RES.0

805 4

,7KOH

M 5%

125m

W

COND

.06

03

X7R

33NF

10%

16V

COND

.12

06

X7R

100N

F 10%

50V

RES.1

206 1

00OH

M 5%

250m

W

RES.1

206 6

,8KOH

M 5%

250m

W 20

0PPM

COND

.08

05

X7R

150n

F 5%

16V

CAP A

LUM

220u

F 20%

25V

PCB

COMM

ANDE

DCDC

STAR

S+X P

ROTO

RES.C

MS

1210

2,2KO

HM

5%

0,25W

200P

PM

BDE

Type composant

L

a

m

b

d

a

e

n

F

I

T

Taux de dfaillance par composant

Reliability target: B10

Comparison objective / FIDES assessment

ObjectifRf [2]

B10 129648h 15 ans 370000 km 10% 100000PPM 7113PPM 812FIT 6000PPM 685 FIT

Calcul FIDES En FIT

Dfaillance PPM/15ans

Dfaillance en PPM/an

Dfaillance en FIT

Calcul FIDES en PPM/an

Temps calendaire Nombre d'anne

Kilomtrage effectuer

% De dfaillances

A 15% marginFonction Faillure F

0,00

0,01

0,10

1,00

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105Dure de vie du DC-DC en anne calendaire

F

(

l

a

m

b

d

a

)

F(l)B10F(l)FIDES

Effect of thermal cycles amplitude on life time

FIDES MTBF / MTBF target (1.314 106 h) in function of Tcyclageamplitude

MTBF fides / MTBFobjectif

28,10 25,2021,20

16,32

11,35

7,23

4,33,38

2,44

1,73

1,19

0,48

0,25

0,14

0,95

0

1

10

100

-60 -50 -40 -30 -20 -10 0 10 15 20 25 30 40 50 60

Delta T (C)

r

a

t

i

o

d

u

r

e

d

e

v

i

e

M

T

B

F

/

M

T

B

F

(

c

i

b

l

e

)

Comparison FIDES / RDF 2000

SMI Powerboard, FR4 command board and DCDC converter

OBJECTIFS CLIENT

RATIO RATIO RATIO

Carte Carte Carte Carte SMI FR4 DC-DCSMI FR 4 SMI FR 4 RDF/FIDES RDF/FIDES RDF/FIDES

Dfaillances en

FIT/1E-9H 127 515 685 954 1798 2752 812 FIT

Dfaillances 8 3 4En PPM 1113 4511 6000 8357 15750 24108 7113 ppm

DC-DC

CALCUL FIDES CALCUL RDF 2000

DC-DC DC-DC

Conclusion

High failure rate components are identified

Predictive reliability assessment meets the 15years B10 target

Thermal cycles amplitude has an impact on thelifetime A forced convection cooled system is recommended

Comparison FIDES et RDF2000

Assesments are in the same range

Field return data necessary

Feedback on FIDESStrengths:

Takes into account the recent component technological improvements

Component failure rate based on field return experience

Factors for Component Fabrication Process and Quality

Mission profile is precise

Thermal stresses

Mechanical stresses

Humidity

Effect of Chemical environment

Assembly technologies (bonding, )

Easy to use (Excel spreadsheet)

Weaknesses:

Software capacity is limited

Same mission profile for all the components

Power components are not critical

Is it adapted to the automotive sector?

THANK FOR YOUR ATTENTION