Transcript TSCP 8

Reliability/Safety Analysis
Dong-Han Ryu
Yukeun Sim
Shiv Biddanda
Po-Cheng (Robert) Wang
Criticality Levels

High



Medium



Failure of one block and related subsystem
Damage to PCB
Damage to single block
Does not affect working operation of other blocks
Low


No damage to components
Wiring, Software Design
Power Supply / Battery Charger
Schematic
FMECA - Power Supply/Charging
Fail
ure
No.
Failure Mod
e
1
Battery
Charger
IC Failu
re
2
Voltage
regulato
r IC Fail
ure
Possible Causes
Failure Effects
Method of
Detection
Criticality
Remarks
•
Supply voltage
too high/low
•
No charging
• Bad chargin
g rates
LED
High
Affects operatio
n of entire PCB.
Over/underc
harge
• Charging rate
too high
•
Damage to
battery
• Leakage
• Explosion
Obser
vation
High
Battery very se
nsitive to charg
ing characterist
ics and may ex
plode if mis-ha
ndled
•
MCU Block
FMECA – MCU Block
Fail
ure
No.
1
Failure Mode
Dead
pic18f4550 –
unresponsive
Possible Causes
Failure of power system
• Short on bypass capacitors
• Failure of crystal
•
Failure
Effects
Non-progr
ammable
• Failure of
system
•
Method of Det
ection
Criticality
Obser
vation
High
•
Accelerometer Schematic
FMECA - Accelerometer
Failure
No.
Failure Mode
1
No
output
on
port
Pins
2
Noisy
output
Possible Causes
Failure Effects
Method of Detectio
n
Criticality
•
Bypass caps C1-C3
shorted
• Open line
between glove and
main PCB
• IC Damaged due to e
xtremely quick move
ment, dropping IC
No ATD input
Observation
Medi
um
Failure of op-amps
• Failure of passive co
mponents
Incorrect cursor
movements on
PC
Observation
Low
•
Bluetooth Schematic
FMECA - Bluetooth Module
Failure N
o.
Failure Mode
Possible Causes
Failure Effects
Method of
Detection
Criticality
1
Incorrect data on
host PC
•
Retransmission of
data
• Error in packet const
ruction
Unpredic
table
cursor m
ovements
Obser
vation
Low
2
No data
•
UART Tx error
• No Bluetooth hands
hake between host PC
and radio
No
cursor m
ovement
Obser
vation
Low