Magnetics Business & Technology - November/December 2022 - 23

PRODUCT NEWS
current transients the voltage regulators used must increase their
bandwidth to improve on response time. This is usually done
by either increasing the number of phases and/or reducing the
inductance value of each phase. These solutions, however, can
create complications in the converter design.
Increasing the phase count necessitates less space per phase
which means less width for the power stages and inductors. For
the inductor, this space constraint creates skinny but tall components
that can become mechanically unstable which limits
the ability to shrink the inductor width. Reducing the inductance
value used per power stage (which is already sub 100nH) drives
higher ripple currents per phase resulting in higher AC losses as
well as complicating the converter control. It is important to note
that transient response time of the entire converter is somewhat
limited by the fact that each phase will respond to the step by
increasing or decreasing its duty cycle in a round-robin fashion,
one at a time.
In order to mitigate these issues and further drive performance
improvements, a " Trans-Inductor " based voltage regulator was
developed in the technical disclosure commons domain. The
trans-inductor is very similar to a traditional one turn VR inductor
but has the addition of a second tightly coupled winding.
The main low DCR 'primary' is used in the same fashion as in a
traditional VR inductor, having a PWM input with several phases
feeding the single output. Each single turn 'secondary' is tied in
a series loop referenced to the local ground. When a load step
occurs on a given phase, the resultant increase or decrease in
duty cycle is reflected to its secondary winding and because the
secondaries of each phase are in a series loop they all 'see' this
change immediately. Through the magnetic coupling this sensed
change is reflected to each inductors primary winding. In effect,
this allows all phases to respond simultaneously to a load transient
greatly reducing the time needed for the converter to adjust.
Additionally, a compensation
inductor has been introduced into
the converter circuit. It is typical
for this inductor to be similar in
construction to a traditional VR
inductor. The compensation inductor
exists to give design engineers
the ability to adjust the total
inductance in the secondary loop,
allowing for freedom to adjust for
converter stability. Due to the AC
coupled nature of the secondary circuit, the compensation inductor
sees almost no DC current which minimizes the impact of
DCR. However, the inductor is subject to a superposition of each
phases ripple current. In practice, this means that for a 4 phase
converter switching at 1MHz, the compensation inductor will
see a reflected ripple current with a frequency of 4MHz. At such
frequencies care must be taken to minimize AC winding loss as
well as ensuring a proper high frequency, low loss core material
is chosen.
As an initial offering, Pulse is releasing the PGL6215.XXXHLT
trans-inductor and PGL6312.XXXHLT compensation inductor
with plans to release an additional five families of trans-inductors
and footprint compatible traditional inductors in various sizes.
See www.pulseelectronics.com.
Global market leader for precision magnetometers
HALLINSIGHT® 32x32
HALL MAGNETIC FIELD CAMERA
MAKING THE INVISIBLE VISIBLE
- 32x32 true three-axis Hall sensor array*
- DC & AC magnetic field maps
- 2.5 mm sensor spacing
- 4 µT resolution
www.metrolab.com
HallinSight® is a technology developed by Fraunhofer IIS
*16x16 & 32x2 also available
www.MagneticsMag.com
November/December 2022 * Magnetics Business & Technology 23
©Fraunhofer IIS / P. Beran
http://www.pulseelectronics.com http://www.metrolab.com http://www.MagneticsMag.com
Magnetics Business & Technology - November/December 2022

Table of Contents for the Digital Edition of Magnetics Business & Technology - November/December 2022
