Power Fortronic Bologna 2012
IGBT Protection and High
Voltage Reliability
Principles and conceptual approach based
on state-of-the-art gate drive solutions
Michael Hornkamp
CT-Concept Technologie AG, Switzerland
© CT-Concept Technologie AG, Switzerland
Content
IGBT Protection and High Voltage Safety




Critical operation of IGBT and failure modes.
Key and advanced requirements to the gate drive
solution.
Reliability aspects of high-voltage insulation and
implication on gate drive unit functionality.
Trade-off between cost, technical performance and
reliability.
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2
Regular Operation of IGBTs
Turn-off
Short-Circuit
Vce
Ic
Vge
Turn-on
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Diode Recovery
3
Critical operation of IGBT and failure modes
How to Destroy an IGBT Module?
VCE over-voltage
VGE over-voltage
High dv/dt
ESD
Over-current
Short-circuit
High di/dt
IGBT Module
Temperature
TJ>150 C
Tcase<-40 C
Thermal cycling
Thermal shock
Power cycling
Vibration
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Critical operation of IGBT and failure modes
IGBT Protection with Gate Driver
VCE over-voltage
VGE over-voltage
High dv/dt
ESD
Over-current
Short-circuit C1;C2
High di/dt
IGBT Module
Temperature
TJ>150 C
Tcase>-40 C
Thermal cycling
Thermal shock
Power cycling
Vibration
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Content
IGBT Protection and High Voltage Safety




Critical operation of IGBT and failure modes.
Key and advanced requirements to the gate drive
solution.
Reliability aspects of high-voltage insulation and
implication on gate drive unit functionality.
Trade-off between cost, technical performance and
reliability.
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6
Short-circuit Case 1 and Case 2
Gate Emitter Voltage
Collector-emitter
voltage
Short-circuit current
Monitored by Vce(sat) protection circuit
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Monitored by Vce(sat) protection circuit
Page 7
IGBT Output Characteristic
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Page 8
IGBT Short-circuit Time and Current
:
Example: Short-circuit time and current are functions of gate-emitter voltage
tsc; Isc= f (VGE)
SC-Time and Current
8
7
SC-current/ rated current
Vge=19V
6
Vge=17V
5
Vge=15V
4
Vge=13V
3
Vge=11V
2
1
0
0
2
4
6
8
10
12
14
16
18
20
max. SC-time (us)
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SCALE-2® Short-circuit Protection

Detection via SCALE-2® ASIC

Reliable against high dv/dt

Adjustable for all available IGBTs
VISO
CO M
Vce
150uA
Vce Monitoring
AC L
+
VCE
-
REF
Cx
0.6...1mA
120k
Vref
VISO
GL
Failure
PWM
Rth
GH
Rvce
BAS316/416
Rg ( on)
Vce sat
t(us)
Rg ( off)
4.7k
CO M
CO M
VE
2SC0435T part of one channel shown
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SCALE-2® IGD (Active Miller clamp)
D riv e r
2 SC 0 4 3 5 T
Channel 2
Logic C ore
S ingle m a sk progra mm able mixed-signa l arra y
V ce M onitoring
A dv a nced
A ctiv e C la mping
V IS O
V DC
V ee C ontrol
V
2.5m A
V olta ge R egula tor
C OM
V
P ow er S upply
M onitoring
< 12.3V
> -6V
V IS O
24
V CE
23
A CL
22
27
V IS O
V ee
C OM
B ootstra p
C ha rge P ump
IN
F ailure
M ana gm ent
a nd T iming
V IS O 2
D5x
GH
28
A na log C ontrol
GL
29
R ds-on control
R ds-on= f(T)
A UX
GH2
Rg(on)
G L2
Rg(off)
T urn-off N -cha nnel M O SF E T
T ransform er
I nterface
P redriv er
25
C OM
C 2x
O UT
V ee
IN
A CL 2
A UX
R ds-on control
R ds-on= f(T)
S CH
F ailure I nput
V CE 2
T urn-on N -cha nnel M O SF E T
P redriv er
F IN
R EF 2
C OM 2
C 1x
26
V E2
O ptiona l
Light I nterface;
S upply a nd Logic
O UT
S CA L E-2 I G D


Combination of voltage regulator “Vee control” and N-Channel MOSFET “Rail to Rail”
provide a true 15V gate clamping.
Benefit: No Gate-Emitter Clamping Diodes. Short circuit energy and current is lower as
with stat of the art gate driver. No IGBT parasitic turn on possible As well by unpowered
SCALE-2.
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SCALE-2® IGD (Active Miller clamp)
+15V gate clamping
CONCEPT SCALE-2 Driver

Standard discreet Gate Diver
CONCEPT SCALE-2® Gate driver control sort circuit current and reduce IGBT SC
energy.
High ruggedness of IGBT in SC condition only with SCALE-2 CONCEPT IGBT gate
Driver
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
(Basic) Active Clamping


Active Clamping implements a feedback from the collector to the gate of the
IGBT module: the IGBT is kept in the linear operation mode thus limiting the
di/dt and therefore the Vce overvoltage
(Basic) Active Clamping: single feedback from the collector of the IGBT module
to its gate
VISO
Power Supply
Monitoring
Vce Monitoring
Advanced
Active Clamping
CO M
IN
Transformer
Interface
VCE
AC L
VISO
Predri ver
Bootstrap
Charge Pump
AUX
GH
GL
Vee Control
Predri ver
AUX
Turn-on Driver
Rg ( on)
Rg ( off)
Turn-off Driver
CO M
Vee
SCALE-2 IGD
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SCALE-2® Advanced Active Clamping

Controlled via SCALE-2 ASIC

Fast and effective

Adjustable for all available IGBTs

Not available for 2SC0108T
VISO
Power Supply
Monitoring
Vce Monitoring
Advanced
Active Clamping
CO M
IN
VCE
AC L
VISO
Transformer
Interface
Pre dri ve r
Bootstrap
Charge Pump
AUX
GH
GL
Vee Control
Pre dri ve r
AUX
Turn-on Driver
Rg ( on)
Rg ( off)
Turn-off Driver
CO M
Vee
SCALE-2 IGD
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SCALE-2® Advanced Active Clamping
Sort-circuit turn-off 25 C
4000A
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Turn-off 2xIn 25 C
1800A
Page 15
Dynamic Advanced Active Clamping (DA2C)


Dynamic Advanced Active Clamping (DA2C) implemented on 1SP0635/1SP0335
allows to further increase the max. DC-link voltage to higher values in IGBT off
state
The function is realized with additional transient voltage suppressors that are
short circuited during IGBT on state and during the IGBT turn-off process
VISO
Power Supply
Monitoring
Vce Monitoring
Advanced
Active Clamping
CO M
IN
Transformer
Interface
VCE
AC L
VISO
Predri ver
Bootstrap
Charge Pump
AUX
GH
GL
Vee Control
Predri ver
AUX
Turn-on Driver
Rg ( on)
DA2C Control
Circuit
Rg ( off)
Turn-off Driver
CO M
Vee
SCALE-2 IGD
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Page 16
Content
IGBT Protection and High Voltage Safety




Critical operation of IGBT and failure modes.
Key and advanced requirements to the gate drive
solution.
Reliability aspects of high-voltage insulation and
implication on gate drive unit functionality.
Trade-off between cost, technical performance and
reliability.
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17
High Voltage Insulation
1. SCALE ASICs
Primary Side IC LDI

Signal conditioning

Error management

Bidirectional signal
transmission

DC/DC controller
Command
Secondary Side IC IGD

Bidirectional signal
transmission

IGBT monitoring

High-power gate driver
ASIC Design
Knowledge of the overall inverter
system functionality and in-depth
understanding of power semiconductor
technology is a key success factor
and major differentiator to competition
Power
Status
2. Galvanic Isolation
Ring Core
Planar
Galvanic Isolation
Coreless

Flexible form factor

High power

Low power

Rugged

Low profile

Ultra-flat

Encapsulation

Low stray inductance

Low cost
Handling the galvanic isolation topic in
a cost effective way - while ensuring
high-performance signal and power
transmission as well as taking care of
security aspects – is the second core
competence
Providing the optimum technology platform for IGBT gate driver voltage classes 1.2 to 6.5kV
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Example: Requirements on 3.3kV SCALE-2 Driver
Core


Electrical pulse transmission and DC/DC
converter on Board
Cleepage and clearances according to
IEC60077-1 and IEC60664-1

Partial Discharge free <4125V

Insulation test voltage 9100V

Couple capacity 19pF
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CONCEPT Modular HV Transformer Platform (Ring
Core)
Challenge to develop long-life time reliable components in high volume mass
production
Wire Insulation
Potting Material
Potting Style
Winding Style
Housing
Preparation / Curing
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Life Time Reliability of HV Transformer
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Up to 10W output Power at 85 C
Standards for Insulation
IEC60077-1 and IEC60664-1
UL compliant Material; wire
insulation, plastic case,
compound, cores
-55 C…+85 C
Construction and materials are
the key elements for Safe
insulation and life time reliability
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Page 21
Content
IGBT Protection and High Voltage Safety




Critical operation of IGBT and failure modes.
Key and advanced requirements to the gate drive
solution.
Reliability aspects of high-voltage insulation and
implication on gate drive unit functionality.
Trade-off between cost, technical performance and
reliability.
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22
Trade-off between cost, technical performance and
reliability
Development

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
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
2-5 Years for GDU
Need for experienced
engineers
Comparable high
development risk
Long Time to Market
Continuous design
support over lifetime
Performance
EMI ruggedness
Advanced protection
function
Best-in-class
compactness
Flexible and scalable
system approach
Fitting all IGBT’s




6-24 Month
Low development risk

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
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Supply Chain




Sourcing hundred of
components
High component price
levels
Overhead to manage
production
Hard to follow up on
guarantee or liability
Discrete Solution
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Large PCB area
EMI susceptible
Slow, large tolerances
Reliabiltiy





Only 1 supplier
Guaranteed for
functionality
Low Price
Application support



Minimize component
count
Minimum solder joints
Meeting regulatory
requirements
CONCEPT

Large number of
components and PCB
solder joints
Degradation
23
Discrete Solution
“With
Safety the Best Solution”
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24