Fairchild AN-8230 800 v superfetâ® ii mosfet cuts switching loss Datasheet

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AN-8230
800 V SuperFET® II MOSFET Cuts Switching Loss for High
System Efficiency with Reliability
Abstract
Fairchild’s 800 V SuperFET® II MOSFET family using the
latest super junction technology provides extremely low
conduction, switching loss and reliability; thanks to the
lowest RDS(ON), stored energy in output capacitance (EOSS)
and best-in-class robust body diode performance for
lighting, PC power, adapter, audio power, solar inverter,
industrial 3-phase topologies and auxiliary power supplies.
Utilizing an advanced charge balance technology, Fairchild
Semiconductor helps designers to achieve excellent system
efficiency and thermal characteristics with the 800 V
SuperFET® II MOSFET family. Coupled with its best-inclass reliability makes it ideal for a variety of applications,
while its broad range of package options give designers
tremendous flexibility, particularly with size constrained
designs.
The development of LED lighting power supply system
focuses on higher efficiency, dimming control and lower
cost. Furthermore, smart-phones are rapidly developing to
support multiple functions and features. It combines the
functionality of a pocket-sized communication device with
PC-like capabilities. As this happens, it requires more chips
and more processing cycles, which mean higher power
levels. Because of these additional functions, smart-phones
require much higher power than before. The conventional
linear battery charger no longer adequately meets charge
requirements due to its high-power dissipation. Therefore,
the key design challenge for battery charger of portable
devices such as smart-phones or tablet PCs is high power
density and high efficiency to meet energy regulation shown
in Table 2 [1].
Introduction
Table 2. Energy-Efficiency Criteria for AC-AC and
AC-DC External Power Supplies in Active Mode:
Low Voltage Models
With lighting devices consuming around 19% of the world’s
total electrical power, many countries are phasing out the
sale of inefficient incandescent lamps as part of their energy
conservation efforts. According to industry reports, over
8000 billion incandescent lamps were sold in 2012, which
amounts to about 45% of total lighting sales. The United
States, China, Russia, and Brazil started banning sales of
incandescent light bulbs up to 60 W in 2014, putting the
conversion of residential indoor lighting from incandescent
to LED well on track. Meanwhile, advancements in LED
technology and improvements in production costs will most
certainly accelerate the growth of the LED lighting market.
Table 1 highlights the higher efficiency and longer lifetime
benefits of LED lighting over incandescent lamps.
Table 1.
Efficiency and Lifetime Comparison
Important Facts
Incandescent
Lamp
LED
Lighting
Efficiency
6~16 lm/W
80~160 lm/W
Average Lifetime
1,200 hours
50,000 hours
© 2016 Fairchild Semiconductor Corporation
Rev. 1.0 • 8/8/16
Nameplate Output
Power (P )
Minimum Average Efficiency
in Active Mode
0 to ≤ 1 W
≥ 0.497 * P + 0.071
> 1 to ≤ 49 W
≥ [0.075 * Ln (P )] + 0.569
> 49 W
≥ 0.860
no
no
no
Flyback converters are very popular for low power
applications such as LED lighting, battery charger or
adaptor because of its simplicity and low cost [2]. In order
to increase system efficiency, switching losses on the
primary-side have to be reduced. Low stored energy in
output capacitance; EOSS and low RDS(ON) of the MOSFET
are critical factor for flyback converters to maximize system
efficiency. New 800 V, SuperFET® II MOSFET which is
optimized for primary switch, enables lower switching
losses and case temperature without sacrificing EMI
performance due to its optimized design.
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AN-5235
APPLICATION NOTE
800 V SuperFET® II MOSFET
Technology
800 V MOSFETs are widely used in many applications such
as lighting, chargers, adaptors, solar inverters and industrial
3-phase topologies. However, there are silicon limits for a
significant reduction in the on-resistance with the
conventional planar MOSFET. In high voltage MOSFET
technologies, the most remarkable achievement for onresistance reduction is a super-junction technology. It has
deep p-type pillar-like structure in the body in contrast to
well-like structure of conventional planar technology. The
effect of the pillars is to confine the electric field in the
lightly doped epi region. Thanks to this p-type pillar this
super-junction technology broke silicon limit in terms of onresistance and achieved only one sixth specific on-resistance
per unit area compared to planar processes at 800 V
breakdown voltage as shown in Figure 1. With Fairchild’s
advanced super-junction technology, the 800 V SuperFET II
series feature the industry’s best RDS(on) and excellent figure
of merit for increased power density and efficiency in
applications.
Figure 2.
The RDS(ON) × QG Figure Of Merit (FOM) is generally
considered as the single most important indicator of
MOSFET technology. Several new device technologies
have been developed lately to improve the RDS(ON) × QG
FOM. Since a MOSFET is a unipolar device, parasitic
capacitances are the only limiting factors during switching
transient. Lower parasitic capacitance is required for lower
switching losses. As the charge balance principle reduces
the chip size for same RDS(ON) as compared to standard
MOSFET technology, 800 V SuperFET® II MOSFET have
much less capacitance. One way to find out how the output
capacitance corresponds to switching losses is by evaluating
an effective value of output capacitance. The stored energy
in the output capacitance of a MOSFET can be calculated
by integrating the product of the output capacitance and
drain-source voltage with respect to the drain-source voltage
from zero to the drain-source voltage just before the turn-on
transient. Figure 3 (a) clearly shows that the channel current
(Ichannel) is significantly lower than the drain current (ID)
during turn-off because drain current is diverted from the
MOSFET channel to charge the output capacitor. At turn-on
transient, The MOSFET channel conducts a current
significantly higher than drain current (ID) because of the
additional current coming from the discharging of the output
capacitor. The energy stored in the output capacitance of the
power MOSFET during turn-off is internally dissipated
through the MOSFET channel in the form of joule heating
during turn-on. This stored energy is dissipated through the
channel of the MOSFET on every turn-on of the switching
cycle. Therefore, the stored energy in output capacitance,
Eoss of the MOSFET, is very critical in hard-switching
applications, such as flyback/forward converters or Power
Factor Correction (PFC), especially at light loads and high
switching frequency, because it is fixed and independent of
load. For low power flyback converters, lower RDS(ON) ×
Eoss, Figure-Of-Merit (FOM) is the most important for
primary-side MOSFETs.
Figure 1.
Specific RDS(ON) comparison between
conventional and Super-junction MOSFETs
The 800 V SuperFET® II series provide industrial lowest
RDS(on) for each packages, the lowest RDS(ON), max. of 800 V
SuperFET® II MOSFET is 60 mΩ(max.), 220 mΩ(max.)
and 850 mΩ(max.) respectively for in the standard TO-247,
TO-220 and TO-251(IPAK) packages. It is well suited for
space-constrained applications that need high power density
by replacing with smaller packages or reducing paralleling
device counts.
© 2015 Fairchild Semiconductor Corporation
Rev. 1.0 • 8/8/16
Comparison of the Lowest RDS(ON) vs.
Competitor’s 800 V SJ MOSFETs
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AN-5235
APPLICATION NOTE
Figure 5 shows body diode ruggedness comparison under
VDD=600 V, ISD=11 A. Figure 5 (b) and (c) show
competitor’s MOSFET failing waveforms during body
diode reverse recovery. With competitor A and B, failure
occurs right after the current level reaches Irrm, peak reverse
recovery current at 334 A/μ and 375 A/μs respectively. This
indicates the peak current triggered parasitic BJT. As shown
VGS
ID
Ichannel
ICOSS
ID
Ichannel
in Figure 5 (a), the 800 V SuperFET® II MOSFET did not
fail at even higher di/dt (1,261 A/μs) conditions. Robust
body diode characteristics are related to the reliability issues
in LLC resonant converters. Rugged intrinsic body diode
performance of 800 V SuperFET® II series can provide
better reliability in applications including resonant
converters.
(a) Decreased MOSFET Channel Current during
Turn-off due to COSS Charging
VGS
ID
Ichannel
Ichannel
ICOSS
ID
(b) Increased MOSFET Channel Current during
Turn-on due to COSS Discharging
Figure 3. MOSFET Channel Current and Drain Current
Waveform during (a) Turn-off and (b) Turn-on
As shown in Figure 4, the 800 V SuperFET® II MOSFET
has respectively 18% and 38% less stored energy in output
capacitance at 400 V, compared to 800 V competitors.
Therefore the 800 V SuperFET® II MOSFETs provide
higher switching efficiency in hard switching applications
by smaller Eoss
Figure 4.
®
(a) 800 V SuperFET II MOSFET Withstanding
Waveforms During Body Diode Reverse Recovery
(b) Competitor A MOSFET Failing Waveforms During
Body Diode Reverse Recovery
Comparisons of Stored Energy in Output
Capacitance, EOSS
© 2015 Fairchild Semiconductor Corporation
Rev. 1.0 • 8/8/16
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3
AN-5235
APPLICATION NOTE
devices. It is not only an issue of efficiency, but also of
thermal management and long term reliability. Power
dissipation in the MOSFETs is highly dependent on onresistances, gate charge and current and voltage rise and fall
times, as well as the switching frequency and operating
temperature. Losses in the power MOSFETs consist of
switching loss, conduction loss and gate driving loss. Figure
7 shows the power loss analysis of the MOSFETs in flyback
converter for laptop adaptor application under VIN=230 VAC
and POUT=45 W condition. As shown in Figure 7, the
switching losses are the most critical. As the MOSFET
switches on and off, it’s intrinsic parasitic capacitance stores
and then dissipates energy during each switching transition.
The losses are proportional to the switching frequency. As
the physical die size of the MOSFET increases, its
capacitance also increases; so, increasing MOSFET die size
also increases switching losses. Therefore, in order to
increase both system efficiency and power density,
switching loss on the primary-side MOSFET have to be
reduced.
(c) Competitor A MOSFET Failing Waveforms during
Body Diode Reverse Recovery
Figure 5.
Body Diode Ruggedness Comparison
under VDD=600 V, ISD=11 A
7.74%
2.22%
Application Evaluation Results
Power Loss Analysis in Flyback Converters
Figure 6 shows typical flyback converter. Due to the high
RMS and peak currents, the MOSFET and output rectifier
diode in the flyback have high switching and conduction
losses, which results in its relatively low efficiency.
Through power loss analysis on 45 W Flyback converters in
Figure 7, critical power loss factors in primary-side
MOSFET are switching losses during switch transient
especially, when a high drain to source voltage, V DS, apply
to the MOSFET.
Pcon[%]
90.04%
Psw[%]
Figure 7.
VIN
The 45 W flyback converter is designed to evaluate the
efficiency of a 800 V SuperFET® II MOSFET. Input voltage
of the rectifier is 230 VAC, and output voltage and current
are set to 15 V and 3 A, respectively. Power losses,
efficiency and case temperature of 800 V, 400 mΩ
SuperFET® II MOSFET is compared with competitor’s
800 V super-junction MOSFETs which has same voltage
rating in TO-220 full package as shown in Table 3, which
shows the key parameter comparison of Fairchild’s 800 V
PWM
controller
Typical Flyback Converter Circuit
400 mΩ SuperFET® II MOSFET, FCPF400N80Z and
competitors. Reduced Stored energy in output capacitance
(EOSS) is one of the advantages of 800 V SuperFET® II
series. The 800 V SuperFET® II MOSFET has respectively
The most popular approach for increased power density is
increasing the switching frequency, which reduces the size
of passive components. The most heat dissipations are
created by transformer, primary power MOSFET and
secondary diode in flyback converters. Especially, power
loss is critical for power MOSFETs since the power
MOSFETs dissipate much more power than any other
© 2015 Fairchild Semiconductor Corporation
Rev. 1.0 • 8/8/16
MOSFET’s Power Loss Analysis under 45 W
Flyback Converter
High-Efficiency and Low-Temperature
Solution
VOUT
Figure 6.
Pdrive[%]
27% and 34% less FOM [RDS(ON) × EOSS at 400VDS ] than
800V competitors. Also 800 V, 400 mΩ SuperFET® II
MOSFET provide better reliability thanks to robust body
diode and ESD capability by integrated Zener diode.
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AN-5235
Table 3.
APPLICATION NOTE
Key Parameter Comparison of 800 V SuperFET® II MOSFET and Competitors
FOM
Peak Diode
Recovery dv/dt
BVDSS
RDS(ON)
Max
EOSS at
400 VDS
Zener
Protection
800 V SuperFET II MOSFET,
FCPF400N80Z
800 V
400 mΩ
4.0 μJ
Yes
1.6 Ω·μJ
20.0 V/ns
800 V Competitor A
800 V
450 mΩ
4.9 μJ
No
2.2 Ω·μJ
4.0 V/ns
800 V Competitor B
800 V
375 mΩ
6.5 μJ
Yes
2.4 Ω·μJ
4.5 V/ns
DUTs
[RDS(ON) Max×
EOSS at 400VDS]
®
SuperFET® II MOSFET and 800 V competitor’s SJ
MOSFETs in 45 W laptop adaptors. The temperature
difference between 800 V SuperFET® II MOSFET and
competitor SJ MOSFETs is 4.8°C and 7.1°C, respectively,
which shows the outstanding thermal performance of 800 V
SuperFET® II MOSFET at full load condition.
Total power loss [W]
1.700
1.500
1.300
1.100
SuperFET II
0.900
Competitor A
Vin=230Vac, Pout=45W
Competitor B
0.700
64.0
62.2
0.500
62.0
Figure 8.
50%
75%
100%
Case Temperatur [ ⁰C]
25%
Power Loss in 45 W laptop adaptor
91.00%
90.00%
58.0
56.0
55.1
54.0
52.0
89.00%
Efficiency [%]
59.9
60.0
50.0
SuperFET II
Competitor A
Competitor B
88.00%
Figure 10.
87.00%
SuperFET II
Case Temperature Comparison in 45 W
Laptop Adaptor
86.00%
Competitor A
Competitor B
85.00%
Conclusion
84.00%
25%
50%
75%
100%
800 V SuperFET® II MOSFET is Fairchild’s high
performance MOSFET family offering 800 V breakdown
Output Power [%]
Figure 9.
Efficiency vs. Output Power in 45 W Laptop
Adaptor
voltage. This new family of 800 V SuperFET® II MOSFET
enables to make more efficient, compact, cooler and more
robust applications for switching application designers
because of its remarkable performance.
As shown in Figure 8, power loss of FCPF400N80Z is 5%
and 13% less compared to competitors SJ MOSFETs at full
load condition due to its low switching losses. The summary
of the efficiency measurements is shown Figure 9.
Efficiency increases about 0.15% and 0.9% at light load and
0.19% and 1.52% at heavy load respectively compared to
competitor A and B SJ MOSFETs. The major reason for
higher efficiency of FCPF400N80Z is the reduced switching
losses because of its lower Eoss. Figure 10 shows the
relative temperature performance comparison of 800 V
© 2015 Fairchild Semiconductor Corporation
Rev. 1.0 • 8/8/16
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AN-5235
APPLICATION NOTE
Table 4.
®
800 V SuperFET II MOSFET Lineup
PKG
DPAK
IPAK
D2PAK
TO-220
TO-220F
TO-247
RDS(ON) / Qg
60 mΩ / 270 nC
FCH060N80_F155
85 mΩ / 196 nC
FCH085N80_F155
220 mΩ / 78 nC
FCP220N80
FCPF220N80
FCP290N80
FCPF290N80
400 mΩ / 43 nC
FCP400N80Z
FCPF400N80Z
FCPF400N80ZL1
650 mΩ / 27 nC
FCP650N80Z
FCPF650N80Z
FCP850N80Z
FCPF850N80Z
290 mΩ / 58 nC
850 mΩ / 22 nC
FCB290N80
FCD850N80Z
FCU850N80Z
1300 mΩ / 16.2 nC FCD1300N80Z
FCPF1300N80Z
2250 mΩ / 11 nC
FCD2250N80Z
FCU2250N80Z
3400 mΩ / 7.4 nC
FCD3400N80Z
FCU3400N80Z
4300 mΩ / 6.8 nC
FCPF2250N80Z
FCU4300N80Z
FCPF4300N80Z
References
ENERGY STAR® Program Requirements for Single Voltage External Ac-Dc and Ac-Ac Power Supplies (version 2.0)
S.-K. Chung, “Transient characteristics of high-voltage flyback transformer operating,” Applied IEE Proceedings
Electric Power Applications, Vol. 151,No. 5, pp.628-634, Sep. 2004
[3] Wonsuk Choi and Dongkook Son “New Generation Super-Junction MOSFETs, SuperFET® II and SuperFET® II Easy
Drive MOSFETs for High Efficiency and Lower Switching Noise”, Fairchild Application note, AN-5232, Sept., 2013
[1]
[2]
Author
Wonsuk Choi and Dongkook Son, Application Engineer
PSS Team / Fairchild Semiconductor
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS
HEREIN TO IMPROVE RELIABILITY, FUNCTION, OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE
APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS
PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS
WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION.
As used herein:
1.
Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body, or
(b) support or sustain life, or (c) whose failure to perform
when properly used in accordance with instructions for use
provided in the labeling, can be reasonably expected to
result in significant injury to the user.
© 2015 Fairchild Semiconductor Corporation
Rev. 1.0 • 8/8/16
2.
A critical component is any component of a life support
device or system whose failure to perform can be reasonably
expected to cause the failure of the life support device or
system, or to affect its safety or effectiveness
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