FUJI ELECTRIC JOURNAL 2001 Vol.74-No.2

Power Semiconductors


Present Status and Trends of Power Semiconductors
Yasukazu Seki
This paper reviews Fuji Electric's recent development of power semiconductor devices. The circumstances of our development of transistors and IGBTs as power semiconductor devices are outlined, citing the graphs of changes in the design rule and the device capacity. Also with regard to power MOSFETs, IGBTs, and the assembly technology standing in the forefront of power device development, the paper gives a brief description of Super FAP-G series, EconoPACK- Plus, and the reliability of power modules due to the new Sn-Ag-base solder respectively.


Integrated Power Modules with Thyristor
Taku Sato, Yasuyuki Kobayashi
With the rapid growth in power electronics in recent years, the power module used in inverters has been required to be compact-packaged and more reliable. In addition to the existing devices such as input diode bridge, output IGBT bridge, dynamic braking IGBT, and thermistor for overheating protection, the newly developed integrated power module incorporates a thyristor for suppressing surge current on charging the DC bus capacitor. This compact-package module simplifies the design of inverter systems.


Large Capacity 6 in 1 IGBT Module "EconoPACK-Plus"
Shin-ichi Yoshiwatari, Nobuhiko Betsuda
There has been a growing demand for high-current inverters in the 40 kW to 1 MW class. Requirement of power devices used in them are small size, high reliability, high current rating, high efficiency, and easy handling. Fuji Electric is developing the high-current 6 in 1 IGBT module "EconoPACK-Plus" to meet these requirements. Compared with conventional modules, the new module will realize about 20% loss reduction, more accurate temperature sensing with the built-in thermistor, about 50% base area reduction, IGBT/FWD characteristics optimized and package design for easy parallel connection.


Power MOSFET "Super FAP-G Series" for Low-Loss, High-Speed Switching
Tadanori Yamada, Atsushi Kurosaki, Hitoshi Abe
As energy-saving measures for electric and electronic equipment have been developed, also the switched mode power supply are required to improve power consumption, efficiency, and energy consumption on standby. To meet these requirements, Fuji Electric optimized the stripe cell design using high-precision processing technology and improved characteristics through tradeoff between on-resistance and turnoff dissipation; thus the new power MOSFET that realized low-dissipation, high-speed switching was developed and marketed.


High-Side Intelligent Power MOSFET
Hiroshi Tobisaka, Takatoshi Ooe, Takeshi Ichimura
Electronic control equipment for automobiles increases every year and car-electrics manufacturers desire reduction in size and cost as well as high performance. Fuji Electric has been developing the highside intelligent power MOSFET F5045P with drive, control and protection circuits, and a power device integrated on a chip. Its outstanding features are (1) Ratings and package : 50 V, 1 A ; SOP-8 (2) Built-in detective functions against overcurrent and over temperature (3) Minimum operation voltage : 3 V (4) Standby current: 100microA (5) Two input terminals provided to keep ON state.


Multichip Power Device M-POWER for Power Supply
Hiroyuki Ota, Noriho Terasawa
Environmental considerations, such as reduction in energy dissipation, input current distortion and noise, are necessary for switching power supply. Fuji Electric has developed power supply that can meet these requirements with one converter and put it on the market as application specific multichip power device M-POWER. The outstanding features are (1) High efficiency by regenerating snubber energy (2) Standby input power less than 3W, conforming to Energy 2000; subpower supply not required (3) Harmonic regulation in accordance with IEC class D; no active filter circuit required (5) Protective function using latched shutdown.


Super Thin Power Surface Mounted Devices
Hidetoshi Umemoto, Tatsuya Furushima
With rapid progress in the information-oriented society by the internet, etc. further improvements in size and weight, energy consumption, and efficiency are required in the field of portable electronic appliances and communication equipment. To meet these market requirements, Fuji Electric has developed and put on the market the new large-current, super thin power SMD (surface mounted device) "SD series" and "TFP series". These series use a flat lead construction with enough radiation characteristics and the device height is about 60% in thickness compared with the conventional power SMD.


High-Voltage Diode for Microwave Ovens
Takahiro Kuboyama, Taketo Watashima
The technical trend of recent microwave ovens is an increase in high-frequency output and an increase in drive frequency for high-frequency driven microwave ovens. The improvement of the effective capacity ratio of a cooker unit gives only a smaller space for the power supply, and its high-voltage diode is required to perform lower dissipation drive. On the other hand, high surge-proof capacity caused by abnormal magnetron discharge must be ensured. Under these circumstances, Fuji Electric has developed a high-voltage diode for microwave ovens using a newly designed chip that realizes low dissipation and high surge-proof capacity.


New 4.5 kV High-Power Flat-Packaged IGBTs
Takeshi Fujii, Koh Yoshikawa, Kunio Matsubara
To meet the requirement of IGBTs for high voltage and large capacity, Fuji Electric developed flat-packaged IGBTs of 4.5 kV, 2,000 A and 1,200 A. The improvement of package construction and the optimization of built-in IGBTs and diode chip design realize high reliability for a long period as well as high durability against element destruction. The IGBTs have high durability against rupture and facilitate application to equipment by series connection making good use of the flat construction. Now further improvement in element characteristics and application to systems are under development.


New 600 V Super LLD
Shoji Kitamura, Toshiyuki Matsui
With the recent movement for the regulation against harmonic noise, switching power supply is required more severely to use a power-factor-improved circuit. The keys to reduce switching loss and noise in the power-factor-improved circuit are reduction in diode reverse recovery current and soft recovery. Fuji Electric made good use of diode behavior simulation technology to optimize the diode construction and developed a 600 V low-loss fast-recovery diode (600 V Super LLD). This has about a half of reverse recovery current compared with the conventional level and moreover soft recovery.


Reliability Design Technology for Power Semiconductor Modules
Akira Morozumi, Katsumi Yamada, Tadashi Miyasaka
With regard to power cycling reliability, which is regarded as most important among the reliability of power semiconductor modules, this paper describes a design technology to lengthen the span of life. On a level of actual working junction temperature, the power cycling life of IGBT modules using lead-base solder to join silicon chips depends on the life of soldered parts. To improve the life of soldered parts, Sn/Ag-base lead-free solder material of high strength and superior wettability was newly developed. This new solder improved the power cycling life, and in addition, the failure mechanism was clarified.


Analysis of Diode Reverse Recovery Behavior at a Transient On-State Condition
Fumio Nagaune, Saburo Tagami, Fumiaki Kirihata
The critical reverse recovery phenomenon of a free wheeling diode (FWD) occurring after an on-pulse current flow shorter than 1micros is experimentally produced with a 1,800 V/800 A IGBT module. In this case, extremely high dv/dt, spike voltage and voltage-current oscillation are observed. This phenomenon is originated from smaller carrier injection into the n-base layer within a short on-pulse period. The oscillation is due to LC resonance between the completely depleted FWD chips and the inductance of external circuit. Thus the generation of high spike voltage over the voltage ratings signifies the destruction of a semiconductor device like a wedge-shaped damage on the guard ring region of the FWD chip edge.

Back

Page Top