Vol. 51 No. 2
FUJI ELECTRIC REVIEW48
Kiyoshi Sekigawa
Hiroshi Endo
Hiroki Wakimoto
U-series of IGBT-IPMs (600 V)
1. Introduction
Intelligent power modules (IPMs) are intelligent
power devices that incorporate drive circuits, protec-
tion circuits or other functionality into a modular
configuration. IPMs are widely used in motor driving
(general purpose inverter, servo, air conditioning,
elevator, etc.) and power supply (UPS, PV, etc.)
applications.
The equipment that uses these IPMs are required
to have small size, high efficiency, low noise, long
service life and high reliability.
In response to these requirements, in 1997, Fuji
Electric developed the industry’s first internal over-
heat protection function for insulated gate bipolar
transistors (IGBTs) and developed an R-IPM series
that achieved high reliability by employing an all-
silicon construction that enabled a reduction in the
number of components used.
Then in 2002, Fuji Electric changed the structure of
its IGBT chips from the punch through (PT) structure,
which had been in use previously, to a non-punch
through (NPT) structure, for which lifetime control is
unnecessary, in order to realize lower turn-off loss at
high temperature, and also established finer planar gate
and thin wafer processing technology to develop an R-
IPM3 series that realizes low conduction loss.
With the goal of reducing loss even further, Fuji
Electric has developed an IGBT device that employs a
trench NPT structure to realize lower conduction loss
and has developed a new free wheeling diode (FWD)
structure to improve the tradeoff between switching
noise and loss. Both of these technologies are incorpo-
rated into Fuji Electric’s newly developed U-series
IGBT-IPM (U-IPM) which is introduced below.
2. U-IPM Development Concepts and Product
Line-up
The concepts behind the development of the U-IPM
are listed below.
(1) Realization of lower loss
Lower loss can be realized by developing new
power elements and optimizing the drive performance.
Increasing the carrier frequency of the equipment
contributes to improved control performance. Also,
larger output can be obtained from the equipment
during the operation at the same carrier frequency.
(2) Continued use of the same package as prior
products
Table 1 Product line-up, characteristics and internal functions of the U-IPM series
No. of
elements
Inverter part Brake part Internal function
Package
type
Both upper and
lower arms Upper arm Lower arm
V
DC
(V)
V
CES
(V)
4506 in 1
7 in 1
600
450 600
I
C
(A)
P
C
(W)
I
C
(A)
P
C
(W)
Dr: IGBT driving circuit, UV : Under voltage lockout for control circuit, TjOH: Device overheat protection, OC: Over-current protection, ALM: Alarm output,
TcOH: Case temperature over-heat protection
*6MBP20RUA060 uses a shunt resistance-based over-current detection method at the N line.
Model
Dr UV OC ALM OC ALMTjOH TcOH
6MBP 20RUA060 20 84 – – Yes Yes Yes None None None P619Yes Yes
6MBP 50RUA060 50 176 – – Yes Yes Yes Yes None Yes P610Yes Yes
6MBP 80RUA060 80 283 – – Yes Yes Yes Yes None Yes P610Yes Yes
6MBP100RUA060 100 360 – – Yes Yes Yes Yes None Yes P611Yes Yes
6MBP160RUA060 160 431 – – Yes Yes Yes Yes None Yes P611Yes Yes
7MBP 50RUA060 50 176 30 120 Yes Yes Yes Yes None Yes P610Yes Yes
7MBP 80RUA060 80 283 50 176 Yes Yes Yes Yes None Yes P610Yes Yes
7MBP100RUA060 100 360 50 176 Yes Yes Yes Yes None Yes P611Yes Yes
7MBP160RUA060 160 431 50 176 Yes Yes Yes Yes None Yes P611Yes Yes
U-series of IGBT-IPMs (600 V)
49
The continued use of the same package as with
prior products makes it possible to improve equipment
performance by replacing the IPM without having to
modify the design of the equipment.
Table 1 lists the product line-up, characteristics
and internal functions of Fuji Electric’s 600 V U-IPM
series. The U-IPM series maintains internal functions
and a package size that are interchangeable with the
R-IPM series; its rated current is 20 to 160 A for the “6
in 1” pack and 50 to 160 A for the “7 in 1” pack
(containing an internal IGBT for braking use).
Figure 1 shows an external view of the packages.
3. Characteristics of the Power Devices
A fifth-generation U-series IGBT (U-IGBT) is used
as the power device. This U-IGBT combines trench
gate technology with a basic design comprising Fuji
Electric’s floating zone (FZ) wafer technology, thin
wafer processing technology, carrier injection control
technology, and transportation factor improving tech-
nology.
Figure 2 compares the structures of the convention-
al planar IGBT and the trench IGBT. The adoption of
Fig.1 External view of U-IPM packages
a trench gate structure results in a smaller voltage
drop at the channel (R-ch) due to increased surface cell
density and results in a lower saturation voltage due to
the smaller voltage drop resulting from the elimination
of the planar device’s characteristic JFET region (R-
JFET). Moreover, short circuit immunity capability is
realized through optimization of the design of the
surface structure. Figure 3 illustrates the changes that
have occurred in the cross-sectional IGBT structure in
the transition from the conventional IGBT to the U-
IGBT, and Table 2 compares their applied technologies.
The FWD, in accordance with the U-IGBT, incorpo-
rates a new design featuring optimized wafer specifica-
tion, control of anode-side injection and optimal life-
time control technology to realize the characteristics of
low peak current during reverse recovery operation,
low generated loss, and soft recovery.
4. U-IPM Loss
4.1 Comparison of total loss
The marketplace requires that new IPM products
achieve lower levels of loss. (1) Increased carrier
frequency to enhance controllability and (2) larger
output current at the same carrier frequency are
necessary for the achievement of the goal. The loss
Table 2 Changes in IGBT technology
Fig.2 Comparison of planar IGBT and trench IGBT chip cross
sections
Fig.3 Change in cross-sectional structure of 600 V IGBT chip
P619
P610
P611
n+
source
p
-
channel
Emitter
electrode
(a) Planar IGBT (b) Trench IGBT
Insulation
layer
Gate electrode
Gate oxide
layer
n
-
silicon
substrate
n+
source
p
-
channel
R-ch
R-acc
R-JFETR-drift
R-drift R-acc
R-ch
V-pn
V-pn
p+ layer
Collector
electrode
IGBT technology R-IPM R-IPM3 U-IPM
N-IGBT T-IGBT U-IGBT
EpitaxialWafer FZ
350 µmWafer thickness 100 µm
PTStructure NPT
PlanarGate structure Trench
YesLifetime control None
HighCarrier injection Low
LowTransportation factor High
n+ buffer
n
-
p
n
+
n
+
p+ substrate
n
-
n
-
pp
U-IPM
Trench NPT
structure
R-IPM3
Planar NPT
structure
thinner surface
R-IPM
Planar PT structure
C
GE
GEGE
C
C
Vol. 51 No. 2
FUJI ELECTRIC REVIEW50
Fig.4 Comparison of total loss (at same current) for the U-IPM, R-IPM3 and R-IPM series
Fig.5 Current vs. total loss (at same frequency) for U-IPM, R-
IPM3 and R-IPM
generated by existing models and by the U-IPM is
described below.
Figure 4 compares the loss of the U-IPM and the
existing R-IPM and R-IPM3 devices in the case of
operation at carrier frequencies of 4, 8 and 16 kHz, and
a current of 50 Arms (1 /3 of the rated current). As can
be seen in the figure, the newly developed U-IPM
realizes a total loss that is approximately 22 to 28 %
lower than that of the R-IPM and approximately 11 to
12 % lower than that of the R-IPM3. In particular, it
can be seen that the loss generated when using the U-
IPM at a carrier frequency of 8 kHz is less than the
loss generated by a R-IPM operating at a carrier
frequency of 4 kHz, and therefore, the carrier frequen-
cy can be increased from 4 kHz to 8 kHz by replacing a
R-IPM with a U-IPM of the same size package.
Moreover, according to Fig. 5 which shows the relation-
ship between current and total loss at fc=4kHz, to
generate the same amount of loss (50 W) as the R-IPM,
the output current of the U-IPM can be increased by
24.5 % compared to that of the R-IPM, or increased by
13.7 % compared to that of the R-IPM3.
These techniques for reducing loss were focused on
reducing the conduction loss, which accounts for more
than 50 % of the total loss, and on reducing the turn-on
Fig.6
I
C-
V
CE characteristics for U-IPM, R-IPM3 and R-IPM
Total loss (W)
20
0
40
60
80
100
R-IPM : 6MBP150RA060
R-IPM3 : 6MBP150RTB060
U-IPM : 6MBP160RUA060
Tj = 125°C, Ed = 300 V
VCC = 15 V, Io = 50 Arms
Power factor = 0.85, =1
λ
Prr
Pf
Poff
Pon
Psat
R-IPM
45.50
26.9
6.13
7.01
4.12
1.34
R-IPM3
fc = 4 kHz
40.55
26.3
5.76
3.03
3.90
1.59
U-IPM
22.2
4.21
3.85
3.89
1.22
R-IPM
59.80
26.7
12.3
14.0
4.12
2.68
R-IPM3
fc = 8 kHz
50.90
26.2
11.6
6.04
3.90
3.18
U-IPM
44.57
22.1
8.46
7.68
3.89
2.44
R-IPM
88.79
26.7
24.7
27.9
4.12
5.37
R-IPM3
fc = 16 kHz
71.67
26.1
23.2
12.1
3.89
6.38
U-IPM
63.08
22.0
17.0
15.3
3.89
4.89
35.37
100
150
50
0
Total loss (W)
120100806040200
R-IPM
R-IPM3
U-IPM
53 A
58 A
66 A
I
o
(Arms)
R-IPM : 6MBP150RA060
R-IPM3 : 6MBP150RTB060
U-IPM : 6MBP160RUA060
T
j
= 125°C, E
d
= 300 V
f
c
= 4 kHz, V
cc
= 15 V
Power factor = 0.85, =1
λ
V
CE
(sat)
(V)
I
c
(A)
1.5 2 2.5 3 3.510.50
50
0
100
150
R-IPM3
R-IPM
U-IPM
T
j
= 125°C,
V
CC
= 15 V
V
CE
(sat)
at IPM pin
U-series of IGBT-IPMs (600 V)
51
the emission noise.
(1) Application of the new soft recovery FWD sup-
presses dv/dt.
(2) The capacitance between the gate and emitter is
optimized in order to reduce di/dt, which in-
creased as a result of the lower gate resistance,
without reducing dv/dt
Through application of the above techniques, even
if currents of all sizes are controlled with the same
gate resistance, emission noise will be maintained at
the same level as that of the R-IPM3 as shown in
Fig. 8, and lower loss can be realized. Accordingly, the
total loss generated in all these products is linearly
proportional to the current, and the total loss and
temperature rise that occur during actual use can
easily be estimated.
5. Conclusion
Fuji Electric’s 600 V U-IPM that uses a U-series
IGBT chip having a trench NPT structure has been
described above. This U-IPM provides suitable perfor-
mance to satisfy the marketplace in which lower loss is
required. In the future, Fuji Electric intends to
continue to develop new IPMs that will satisfy market
requirements.
Fig.7 Characteristics of turn-on waveform and emission noise
Table 3 Characteristics of gate resistance and turn-on
waveform
Fig.8 Emission noise
loss, which accounts for a large percentage of the
switching loss of the R-IPM3. Each type of loss
reduction is described below.
4.2 Reduction of conduction loss
Figure 6 shows IC-VCE(sat) characteristics for U-
IPM, R-IPM3 and R-IPM devices. It can be seen that
when IC=150 A, the VCE(sat) of the U-IPM is 0.45 V
less than that of the R-IPM and 0.55 V less than that
of the I-RPM3. This is the VCE(sat) reduction effect due
to the trench IGBT described in chapter 3.
4.3 Turn-on loss and emission noise
Figure 7 shows a schematic drawing of the current
(IC) and voltage (VCE) at the time when the device is
turned on. As can be seen in the figure, typically, loss
can be reduced by making dv/dt larger and emission
noise can be reduced by making di/dt smaller. Howev-
er, in the case where turn-on operation is controlled by
the typical method of gate resistance only, there is a
tradeoff relation as shown in Table 3, and it is difficult
to establish both high dv/dt and low di/dt simulta-
neously.
In the newly developed U-IPM, the following two
techniques suppress the emission noise that usually
increases when gate resistance is decreased and di/dt
is increased, thereby enabling di/dt to be increased and
turn-on loss to be decreased without any increase in
Low noise
Low loss
V
GE
V
CE
I
C
t
1
t
2
t
1
: Time from I
C
= 0 until I
C
= I
CP
t
2
: Time from I
C
= I
CP
until V
CE
= 0
di/dt is small and t
1
is long low emission noise
dv/dt is large and t
2
is short low loss
Gate
resistance RG
High Low Low Increases Decreases
Low High High Decreases Increases
Turn-on
di/dt
Turn-on
dv/dt Loss Emission
noise
Measurement conditions: Distance between servo amplifier and
antenna is 2 m, vertical direction, standby state
Emission noise level (dBµV/m)
Frequency (MHz)
(a) R
-
IPM3 (150RTB)
(b) U
-
IPM (160RUA)
Frequency (MHz)
8030
50
100
Emission noise level (dBµV/m)
80
130
13030
50
100
