The instant application relates to DC-DC converters, and more particularly to optimal placement of discrete power stage components of a DC-DC converter on a circuit board.
DC-DC converters include active and passive components, including discrete power stage components such as discrete high-side and low-side power transistor dies, for regulating the voltage of a load such as a processor. Each pair of discrete high-side and low-side power transistor dies forms an output phase of the DC-DC converter which is coupled to the load by a corresponding output inductor. The components of a DC-DC converter, including the output inductors, are attached to a printed circuit board (PCB) together with the load. The PCB has various electrical pathways for electrically interconnecting the DC-DC converter components, including electrically connecting the discrete power stage transistor dies of the converter to the load. DC-DC converter power stage dies are conventionally attached to a PCB in the same plane as the output inductors, increasing the size of the PCB. Also, conventional layout design practices for PCBs further complicate such an arrangement of the DC-DC converter components.
According to an embodiment of a DC-DC converter, the DC-DC converter comprises a substrate having opposing first and second sides, a first discrete power stage transistor die attached to the first side of the substrate and comprising a high-side power transistor, and a second discrete power stage transistor die attached to the first side of the substrate and comprising a low-side power transistor electrically connected to the high-side power transistor to form an output phase of the DC-DC converter. The DC-DC converter further comprises an inductor attached to the first side of the substrate so as to electrically connect the output phase to a metal output trace on the substrate. The inductor at least partly covers at least one of the first and the second discrete power stage transistor dies.
According to an embodiment of a method of assembling a DC-DC converter, the method comprises: attaching a first discrete power stage transistor die to a first side of a substrate, the first discrete power stage transistor die comprising a high-side power transistor; attaching a second discrete power stage transistor die to the first side of the substrate, the second discrete power stage transistor die comprising a low-side power transistor electrically connected to the high-side power transistor to form an output phase of the DC-DC converter; attaching an inductor to the first side of the substrate so as to electrically connect the output phase to a metal output trace on the substrate, the inductor partly covering at least one of the first and the second discrete power stage transistor dies so that a plurality of pins of each discrete power stage transistor die partly covered by the inductor are uncovered by the inductor; and visually inspecting the plurality of pins uncovered by the inductor.
Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.
The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. The features of the various illustrated embodiments can be combined unless they exclude each other. Embodiments are depicted in the drawings and are detailed in the description which follows.
According to embodiments described herein, a DC-DC converter includes at least one pair of discrete power stage transistor dies. Each discrete power stage transistor die includes a high-side power transistor or a low-side power transistor, but not both transistors. As such, the power transistors which form the power (output) stage of the DC-DC converter are disposed in separate dies. Each discrete high-side transistor die switchably connects the load to an input voltage of the DC-DC converter, and the corresponding discrete low-side transistor die switchably connects the load to ground at different periods. The discrete dies can be bare dies i.e. unpackaged dies and have a thickness of 0.6 mm or less. In another embodiment, the discrete dies are packaged dies such as a molded die package or an open cavity die package each having a thickness of 1.1 mm or less.
In either case, each pair of discrete high-side and low-side power stage transistor dies forms an output phase of the DC-DC converter. Each output phase is coupled to the load by a respective inductor. In the case of a single pair of discrete high-side and low-side power stage transistor dies, the DC-DC converter is a single-phase converter. In the case of two or more pairs of discrete high-side and low-side power stage transistor dies, the DC-DC converter is a multi-phase converter. One or more of the discrete power stage transistor dies is at least partly covered by the inductor electrically coupled to that phase. For each discrete power stage transistor die partly covered by an inductor, a plurality of pins of that discrete die can remain uncovered by the inductor, which allows for easy visual inspection of those pins after the components of the DC-DC converter are attached to a substrate such as a circuit board.
The power stage components of the single-phase or multi-phase DC-DC converter include input capacitors 102, output capacitors 104, discrete high-side and low-side power transistor dies 106, 108 for each phase of the DC-DC converter, and an inductor 110 for coupling each phase to a load regulated by the DC-DC converter. The pair of discrete high-side and low-side transistor dies 106, 108 shown in
The substrate 100 includes various metal traces such as copper traces for electrically connecting the power stage components. The metal traces are separated from one another to prevent shorting. The metal traces include an input trace 112 which is at the input voltage potential (Vin) of the DC-DC converter, an output trace 114 which is at the regulated output voltage potential (Vout) of the DC-DC converter, one or more ground traces 116, 118 connected to ground, and a phase trace 120.
The input capacitors 102 of the power stage are connected between the input trace 112 and one of the ground traces 116. The output capacitors 104 of the power stage are connected between the output trace 114 and one of the ground traces 118. The input side of the discrete high-side transistor die 106 is connected to the input trace 112, so that the high-side transistor Q1 included in the discrete high-side transistor die 106 can switchably connect the load to the input voltage Vin of the DC-DC converter. The input side of the discrete low-side transistor die 108 is connected to one of the ground traces 116, so that the low-side transistor Q2 included in the discrete low-side transistor die 108 can switchably connect the load to ground at different periods than the high-side transistor Q1 is active. The output side of both discrete transistor dies 106, 108 are connected to the phase trace 120. One terminal of the inductor 110 is attached to the phase trace 120 and the other terminal of the inductor 110 is attached to the output trace 114, so that the output sides of the discrete transistor dies 106, 108 are electrically connected to the output trace 114 on the substrate 100 through the inductor 110.
The substrate 300 includes various metal traces such as copper traces for electrically connecting the power stage components. The metal traces are separated from one another to prevent shorting. The metal traces include an input trace 312 which is at the input voltage potential (Vin) of the DC-DC converter, an output trace 314 which is at the regulated output voltage potential (Vout) of the DC-DC converter, one or more ground traces 316, 318 connected to ground, and a phase trace 320 also as previously described herein.
The input capacitors 302 of the power stage are connected between the input trace 312 and one of the ground traces 316. The output capacitors 304 of the power stage are connected between the output trace 314 and one of the ground traces 318. The discrete high-side transistor die 306 is electrically connected between the input trace 312 and the phase trace 320. The discrete low-side transistor die 308 is electrically connected between one of the ground traces 316 and the phase trace 320. One terminal 322 of the inductor 310 is attached to the phase trace 320 and the other terminal 324 is attached to the output trace 314, so that the outputs of the discrete transistor dies 306, 308 are electrically connected to the output trace 314 on the substrate 300 through the inductor 310.
In
In
In
The transistor die orientations shown in
The transistor die orientations and metal trace layouts shown in
Various types of inductors can be used as the output phase inductor of a DC-DC converter and which partly covers at least one of the discrete transistor dies that form that phase. For example in
Spatially relative terms such as “under”, “below”, “lower”, “over”, “upper” and the like, are used for ease of description to explain the positioning of one element relative to a second element. These terms are intended to encompass different orientations of the device in addition to different orientations than those depicted in the figures. Further, terms such as “first”, “second”, and the like, are also used to describe various elements, regions, sections, etc. and are also not intended to be limiting. Like terms refer to like elements throughout the description.
As used herein, the terms “having”, “containing”, “including”, “comprising” and the like are open-ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.
With the above range of variations and applications in mind, it should be understood that the present invention is not limited by the foregoing description, nor is it limited by the accompanying drawings. Instead, the present invention is limited only by the following claims and their legal equivalents.
Number | Name | Date | Kind |
---|---|---|---|
8004070 | Chen | Aug 2011 | B1 |
8471664 | Huang et al. | Jun 2013 | B1 |
9190383 | Cho et al. | Nov 2015 | B2 |
9281739 | Ikriannikov | Mar 2016 | B2 |
9729059 | Parto | Aug 2017 | B1 |
9742304 | Kato et al. | Aug 2017 | B2 |
20030031339 | Marshall et al. | Feb 2003 | A1 |
20040140877 | Nakao et al. | Jul 2004 | A1 |
20050052888 | Takeshima et al. | Mar 2005 | A1 |
20060279267 | Burton et al. | Dec 2006 | A1 |
20090147541 | Shimada | Jun 2009 | A1 |
20090207574 | Chen et al. | Aug 2009 | A1 |
20090212391 | Carobolante et al. | Aug 2009 | A1 |
20100085139 | Yan et al. | Apr 2010 | A1 |
20100133670 | Liu | Jun 2010 | A1 |
20110134613 | Moussaoui | Jun 2011 | A1 |
20110205008 | Brennan | Aug 2011 | A1 |
20110228507 | Yin | Sep 2011 | A1 |
20110242775 | Schaible et al. | Oct 2011 | A1 |
20120069529 | Chen et al. | Mar 2012 | A1 |
20130099886 | Yan et al. | Apr 2013 | A1 |
20140062246 | Langford et al. | Mar 2014 | A1 |
20140062446 | Ikriannikov | Mar 2014 | A1 |
20140159054 | Otake | Jun 2014 | A1 |
20140167900 | Murtagian et al. | Jun 2014 | A1 |
20140239472 | Jones | Aug 2014 | A1 |
20140292459 | Andres et al. | Oct 2014 | A1 |
20150162297 | Cho et al. | Jun 2015 | A1 |
20150194374 | Ananiev | Jul 2015 | A1 |
20150311655 | Han | Oct 2015 | A1 |
20160005528 | Yan et al. | Jan 2016 | A1 |
20160163631 | Truax | Jun 2016 | A1 |
20160164417 | Ishii | Jun 2016 | A1 |
Number | Date | Country |
---|---|---|
102088241 | Jun 2011 | CN |
103081325 | May 2013 | CN |
103227172 | Jul 2013 | CN |
103325783 | Sep 2013 | CN |
103367361 | Oct 2013 | CN |
2005102485 | Apr 2005 | JP |
2005522173 | Jul 2005 | JP |
2008092653 | Apr 2008 | JP |
2008112941 | May 2008 | JP |
3147172 | Nov 2008 | JP |
2011019083 | Jan 2011 | JP |
2012109518 | Jun 2012 | JP |
03085476 | Oct 2003 | WO |
Entry |
---|
“60A Power Block Non-Isolated DC-DC Converter”, Murata Power Solutions, Okami OKLP-X/60-W12A-C. |
“Programmable Output 12-Amp iLGA SMT PoL DC-DC Converter Series”, Murata Power Solutions, Okami OKL2-T/12-W12 Series. |
“Programmable Output 3-Amp iLGA SMT PoLs”, Murata Power Solutions, Okami OKL-T/3-W5 Series. |
Number | Date | Country | |
---|---|---|---|
20160352226 A1 | Dec 2016 | US |