Fully integrated multi-phase buck converter with coupled air core inductors

Patent metadata

Field	Value
Publication number	US-2020112254-A1
Application number	US-201916707186-A
Country	US
Kind code	A1
Filing date	Dec 9, 2019
Priority date	Sep 7, 2018
Publication date	Apr 9, 2020
Grant date	—

Abstract

A multi-phase buck switching converter having grouped pairs of phases, each phase using two magnetically coupled air-core inductors. For each group, a first driver circuit controlling switching of a first power transistor switching circuit coupled to a first air-core inductor output for driving an output load at the first phase. A second driver circuit controlling switching of a second power transistor switching circuit coupled to a second air-core inductor output for driving said output load at the second phase. The first and second phases are spaced 180° apart. The coupled air-core inductors per group of such orientation, separation distance and mutual inductance polarity relative to each other such that magnetic coupling between the two or more inductors at each phase results in a net increase in effective inductance per unit volume. Each air-core inductor is a metal slab of defined length, height and thickness formed using back-end-of-line semiconductor manufacturing process.

First claim

1 . A multi-phase switching power supply converter comprising:
grouped pairs of phases, each phase having two magnetically coupled air-core inductors, wherein each group comprises: a first driver circuit controlling switching of a first power transistor switching circuit coupled to a first air-core inductor having an output for driving an output load at a first phase of said switching power supply converter; a second driver circuit controlling switching of a second power transistor switching circuit coupled to a second air-core inductor having an output for driving said output load at the second phase, the first and second phases being spaced 180° apart, the coupled first and second air-core inductors per group of such orientation and mutual inductance polarity relative to each other such that magnetic coupling between the two or more inductors at each phase results in a net increase in effective inductance per unit volume, wherein each said magnetically coupled first air-core inductor and said second air-core inductor is a respective metal slab formed spaced apart in a semiconductor substrate, the metal slabs being coplanar and having a length, a width and a thickness, said metal slabs of said coupled first air-core and said second air-core inductors are in a same physical orientation such that respective lengthwise edges of respective said first air-core inductor and said second air-core inductor are aligned in parallel, and respective widthwise edges of respective said first air-core inductor and said second air-core inductor are co-linear.

2 . The multi-phase switching power supply converter as claimed in claim 1 , wherein each said coupled first air-core inductor and said second air-core inductor comprises:
a pair of metal slabs formed in a semiconductor substrate, a first metal slab of each pair overlying a second metal slab of said pair, the first and second metal slab of each pair having a length, a width and a thickness; and a plurality of conductive vias formed between and having first and second ends contacting said first metal slab and second metal slab of each pair, the conductive vias having a first edge contacting the first metal slab and a second edge contacting the second overlying metal slab.

3 . The multi-phase switching power supply converter as claimed in claim 2 , wherein each overlying first metal slab and second metal slab of each respective pair of metal slabs are in a same physical orientation such that respective lengthwise edges of respective said overlying first and second metal slabs of said first air-core inductor and respective said overlying first and second metal slabs of said second air-core inductor are aligned in parallel, and respective widthwise edges of respective said overlying first and second metal slabs of said first air-core inductor and of respective said overlying first and second metal slabs of said second air-core inductor are substantially co-linear.

4 . The multi-phase switching power supply converter of claim 3 , wherein the paired metal slabs defining first air-core and second air-core inductors are made from one a metal layer selected from a group of: a post fabrication metal layer or a substrate metal layer.

5 . The multi-phase switching power supply converter as in claim 3 , further comprising:
a magnetic shielding structure formed in said substrate for shielding the paired metal slabs defining each first and second air-core inductors from a magnetic coupling due to proximately located current carrying or signal carrying conductors or devices.

6 . An n-phase buck power supply converter comprising:
n/2 driving stages, each driving stage comprising: a first driver circuit receiving a first pulsed signal used for driving an output load at a first phase of said n-phases, the first driver controlling switching of a first power transistor switching circuit coupled to a first air-core inductor for driving said output load at the first phase; a second driver circuit receiving a second pulsed signal used for driving the output load at a second phase of said n-phases, the second driver controlling switching of a second power transistor switching circuit coupled to a second air-core inductor for driving said output load at the second phase, the first and second phases being spaced 180° apart, said first air-core inductor being magnetically coupled with said second air-core inductor such that a polarity of the first driver circuit and second driver circuit driving the respective first air-core and second air-core inductors relative to the magnetic coupling of the inductors results in a net increase in effective inductance per unit volume of each first and second air-core inductor when supplying a current to said load, wherein each said coupled first air-core inductor and said second air-core inductor is a respective metal slab formed spaced apart in a semiconductor substrate, the metal slabs being coplanar having a length, a width and a thickness, the metal slab defining said first air-core inductor connecting the first power transistor switching circuit to said load, and the metal slab defining said second air-core inductor connecting the second power transistor switching circuit to said load.

7 . The n-phase buck power supply converter as claimed in claim 6 , wherein said metal slabs of said coupled first air-core and said second air-core inductors are in a same physical orientation such that respective lengthwise edges of respective said first air-core inductor and said second air-core inductor are aligned in parallel, and respective widthwise edges of respective said first air-core inductor and said second air-core inductor are co-linear.

8 . The n-phase buck power supply converter as in claim 6 , where the first air-core inductor includes a first mutual inductance polarity and the second air-core inductor includes a second mutual inductance polarity, the first and second mutual inductance polarity ensuring the respective net increase in inductance per air-core inductor volume of respective first and second air-core inductors when supplying current phased 180° apart to said load through respective first and second air-core inductors.

9 . The n-phase buck power supply converter as in claim 6 , where the first power transistor switching circuit and the second power transistor switching circuit each includes a connection of a first transistor and a second transistor at a common first terminal, wherein a second terminal of said first transistor connects to a power supply conductor of a power grid and a second terminal of said second connected transistor connects to a ground conductor of the power grid, said metal slab defining said first air-core inductor connecting said common first terminal of the first power transistor switching circuit and said load, and said metal slab defining said second coupled air-core inductor connecting said common first terminal of the second power transistor switching circuit and said load.

10 . The n-phase buck power supply converter as claimed in claim 9 , wherein the first common terminal connection of the first power transistor switching circuit is connected to the metal slab of the first air-core inductor at a first end, the second end of the metal slab connecting to the load; and the first common terminal connection of the second power transistor switching circuit is connected to the metal slab of the second air-core inductor at a first end, the second end of the metal slab connecting to the load, and wherein the first end of the metal slab of the second air-core inductor is an opposite end than the first end of the metal slab of the first air-core inductor.

11 . The n-phase buck power supply converter as in claim 9 ,

Assignees

• IBM

Inventors

• Zhang Xin
• Takken Todd E
• Wang Naigang
• Chang Leland

Classifications

• H02M3/1584 Primary

  with a plurality of power processing stages connected in parallel · CPC title

• H01F2017/0086

  on semiconductor substrate · CPC title

• H02M1/38

  Means for preventing simultaneous conduction of switches · CPC title

• H01F17/0013

  with stacked layers · CPC title

• H01F2017/008

  Electric or magnetic shielding of printed inductances · CPC title