COSEL CO., LTD.
Comparing and Examining the Variability of Regulated DC Power Supplies
via Simulation
Masahiro Shima
Group Leader
OS Design Dept.
Cosel Co., Ltd.
Cosel Co., Ltd. is one of the leading market shareholders of high quality/miniaturized
switching power source devices (regulated DC power sources), DC-DC converters,
and noise filters for EMC. Cosel often manufactures their own specialized
transformers vital to power supply modules by optimizing the geometry of
cores and the structure of windings.
Masahiro Shima, Group Leader of the OS Design Dept. in charge of comparing
and examining the variability of design specifications for DC-DC converters
using magnetic field analysis simulations discusses why he decided to implement
JMAG and how they are using it.
Satisfying the Demands for Small DC-DC Converters with a Higher Power Density
- What kind of products do you develop at Cosel?
Mr. Shima We handle regulated DC power supplies. The power produced by electric
generation plants is distributed through utility poles to switchboards
for residents and factories as an AC power source. A stabilized DC power
supply is a device required to create voltage by converting the alternating
power source to a direct current to use in electric circuits. Regulated
DC power supplies can be separated into two large categories: unit type
power supplies and on-board type power supplies. A unit type power supply
is a type of power supply that can be added directly onto our customers
products, such as industrial robots or vending machines. An on-board type
power supply is a small power source that can be attached to our customers
printed circuit boards, similar to other components. We also handle noise
filters. Problems steaming from noise produced by devices or around devices
is becoming more apparent as products get smaller and smaller. Noise filters
are now an indispensable part of electric devices because of the malfunctions
and reduction in communication speed cause by the noise.
- What is important to meet the needs of your customers?
Mr. Shima Our customers require low-noise switching power sources with a high power
density. However, heat becomes a problem as products are miniaturized.
The losses inside of our products needs to be reduced to deal with the
heat that is generated.
Increasing the reliability of our products with our technological strengths
to reduce the heat generated internally as well as increasing the temperature
range is vital to satisfying the needs of our customers.
- What type of responsibilities do you have at Consel?
Mr. Shima In the OS Design Dept. were I work, we develop standard on-board type
power supplies, examine new types of circuits, and create designs for smaller
transformers. The on-board power supplies we are currently developing is
a DC-DC converter. The Output power is 10 to 30 W. Designs are assigned
to one of the engineers in each section. My responsibility as a group leader
is to unify our engineers proceeding with the total development of the
product while discussing the development with the design engineer in charge.
The requirements for miniaturization and a high power density are requested
by our customers. However, these products cannot be miniaturized without
constantly worrying about costs unless the development is undertaken as
a whole. My group is also responsible for developing transformers. We are
especially focused on the miniaturization of transformers because transformers
have the largest exterior dimensions of the products we handle. Transformers
are one of the main sources of heat in DC-DC converters. The switching
components also generate a large amount of heat requiring us to examine
how to arrange the heat sources in a miniaturized product. Designs have
to balance the power loss and heat dissipation because the losses will
increase if the arrangement of the heat sources is too far apart to account
for the dissipation of heat. Therefore, we optimize the arrangement of
the heat sources by running a circuit and thermal simulation.
