Precision worked with International Rectifier to balance the trade-offs to develop the Inductor, Part #019-4120-00, a very high-performance inductor, met all of the 300 Watt circuit requirements of the IR 1150 Demo Board. It is capable of 100 kHz switching frequency, a peak current of 6.2A and a continuous RMS current of 3.8A. The low core loss and SRF were achieved by selecting the right core material and winding configuration.
This design also yields low audible noise and a minimal temperature rise.During the process some options were also considered, including a number of cost and performance variations. One of these includes a bias winding on the PFC choke to supply power for the PFC control circuitry. |
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- Designed for the International Rectifier IR1150 PFC Demo Board
- 100 kHz Switching Frequency / 300 Watt Output
- 6.2A Peak Current / 3.8S Max. RMS
Current
- High Performance Core – Low Loss,
Small and Quiet
- Low SRF
- Lower Cost/Performance and Bias
Winding options available on request
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| Parameters |
Value |
Notes |
| Inductance (μH) |
810 ± 8% |
1-3 @ 100 KHz, 0.1V, 0A |
| Inductance (μH) |
469 Min. |
1-3 @ 100 KHz, 0.1V, 6A |
DCR  |
0.29 Max |
1-3 |
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Precision (and IR) Design
Considerations |
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| Key considerations include:
Inductance, peak current, operating
frequency, ripple current, physical
size, temperature rise, audible noise
and cost. The trade-off’s in design
are driven by the priorities of the
application, this effects proper core
selection, wire and winding
configuration.
Part of Precision’s design approach
begins with listening to the customer
and gaining a thorough
understanding of their unique
application needs. The approach
continues with review of the design
theory and device trade-offs,
samples for design verification and a
review of global manufacturing and
delivery alternatives. The goal is to
respond with solutions on a timely
basis by clearly reviewing and
understanding all key
considerations.
A number of considerations are
examined during Precisions’ design
approach for PFC inductors:
1) Balanced Performance/Cost -
Toroid Design Alternative. A lower
performance core will provide
inductance stability over the
current range and achieve
required inductance in the same
physical package. This will
increase the core loss and
introduce the possibility of audible
noise under high ripple current
conditions.
2) Efficient Cost - Toroid Design
Alternative. This design will
produce low core loss with low
temperature rise and good
magnetostriction characteristics.
Alternative core materials can
yield a lower cost. A larger size
may be needed to achieve the
required inductance.
3) E-core Alternative: The variety of
sizes and materials offer a wide
range of form factors. Bobbin
construction simplifies
manufacturing and mounting to
the PCB.
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Authored By: David Anderson, Chief Engineer – Precision, Inc.
When International Rectifier wanted a high performance power factor correction (PFC) inductor that showed well on their IR1150 reference design, they turned to Precision, Inc. The two companies have successfully collaborated on a number of applications over the years. Precision has proven to be very
responsive in designing andbuilding the ideal magnetics for specific applications on a timely basis and has developed devices for use in many other International Rectifier power conversion designs.
Devices like PFCs are boost circuits that bring current in phase with voltage, to create acceptable power factor front ends for power supplies. The role of the inductor is to store energy, and reduce ripple current.
Design Requirements
International Rectifier wanted to highlight the new controller chip for their IRAC1150-300 watt demo board application. Their requirements for the new PFC inductor included: A high-performance core with low losses to minimize temperature rise, minimize audible noise from magnetostriction, maximize self resonant frequency (SRF) and provide stable inductance over the current range. The single-layer winding and compact size make a very good presentation on the board.
A Family of New Products
Precision has PFC Inductors that
are used with all popular PFC
controllers. They are releasing
products that encompass toroid
and E-core configurations, as well as less expensive options for the IR controller. The new PFC inductor products work with a wide variety of power levels, as
well as other PFC applications.
Precision has PFC inductors that
are used on all popular PFC
controllers. The company
produces many custom PFC
inductor designs for applications
up to 4,000 Watts and beyond.
They can provide a variety of
performance and cost options for
any PFC application, including
lower cost/performance
alternatives.
For more information, contact Lyle Shaw at Precision, Inc. 763-561-6880. |
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