Operating a DC-DC converter including a coupled inductor formed of a magnetic core and a conductive sheet

• US 9,219,422 B1
• Filed: 08/21/2014
• Issued: 12/22/2015
• Est. Priority Date: 08/21/2014
• Status: Active Grant

• Current Assignee: Lenovo International Limited (Lenovo Group Ltd.)
• Original Assignee: Lenovo Enterprise Solutions (Singapore) Pte., Ltd. (Lenovo Group Ltd.)
• Inventors: Barnette, Jamaica L.
• Primary Examiner(s): Gblende, Jeffrey
• Assistant Examiner(s): AHMED, YUSEF A
• Application Number:
  US14/465,064
• Time in Patent Office: 488 Days
• Field of Search: 336/178, 336/192, 336/200, 336/212, 336/225, 336/229, 336/232
• US Class Current: 1/1
• CPC Class Codes: H01F 27/2847 Sheets; Strips H01F27/2866 takes precedence
• CPC Class Codes: H01F 27/306 Fastening or mounting coils or windings on core, casing or other support
• CPC Class Codes: H01F 3/14 Constrictions; Gaps, e.g. air-gaps in magnetic shunt paths H01F3/12
• CPC Class Codes: H01F 30/16 Toroidal transformers
• CPC Class Codes: H02M 1/143 using compensating arrangements for reducing noise from the supply in transmission systems H04B15/005
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

A DC-DC converter includes power-switching phases which each include a high-side and low-side switch. The high-side switch is coupled to the low-side switch at a connection node. The converter also includes a coupled inductor formed of a magnetic core and a conductive sheet. The sheet is formed of a comb structure having a tab and teeth extending from the tab. The conductive sheet is inserted into a slot defined by the magnetic core and extends through the magnetic core with a portion of the tab protruding from the back and a portion of each tooth protruding from the front of the core. Each tooth is coupled to a connection node of a phase and the tab extending through the core forms a toroidal inductor with a single loop coil for each phase, and for all the phases, a directly coupled inductor.

Claims

1. A method of operating a DC (‘

Direct Current’

)-DC converter, the DC-DC converter comprising;

a plurality a power-switching phases, each phase including a high-side switch and a low-side switch, the high-side switch electrically coupled to the low-side switch at a connection node of the power-switching phase, the high-side switch of each power-switching phase is configured, when activated, to couple a voltage source to the phase'"'"'s single loop coil, the low-side switch of each phase is configured, when activated, to couple the phase'"'"'s single loop coil to a ground voltage;

a coupled inductor comprising;

a magnetic core having a front, back, and bottom side, the bottom side including an air gap, the magnetic core formed to define a slot extending through the magnetic core from the front to the back side; and

a conductive sheet comprising a comb structure having a tab and a plurality of parallel teeth extending from the tab, the conductive sheet inserted into the slot such that the conductive sheet extends through the magnetic core from the back to the front side, a portion of the tab protruding from the back side and a portion of each of the plurality of teeth protruding from the front side, wherein;

each of the teeth is configured to be coupled to a connection node of a power-switching phase;

the tab extending through the magnetic core forms, for each power-switching phase, a toroidal inductor with a single loop coil, and forms, for the plurality of power-switching phases, a directly coupled inductor;

the tab is electrically coupled to a filter and a load; and

the method comprises alternatively activating each switch, wherein no two switches of any phase are activated at the same time.

2. The method of claim 1 wherein:

the tab further comprises an end portion bent around the back side of the magnetic core and under a portion of the bottom side of the magnetic core and each of the plurality of teeth comprises an end portion bent around the front side and under a portion of the bottom side of the magnetic core.

3. The method of claim 1 wherein alternatively activating each switch further comprises:

activating the high-side switch of a first power-switching phase, including coupling the voltage source to the phase'"'"'s single loop coil, energizing the magnetic core around the single loop coil, and providing, via the single loop coil, output current to the filter and load;

activating the low-side switch of the first power-switching phase, including coupling the phase'"'"'s single loop coil to the ground voltage and providing, via a second power-switching phase'"'"'s single loop coil and the energized magnetic core, output current to the filter and load;

activating the high-side switch of the second power-switching phase, including coupling the voltage source to the second power-switching phase'"'"'s single loop coil, re-energizing the magnetic core around the first power-switching phase'"'"'s single coil element, and providing, via the second power-switching phase'"'"'s single coil element, output current to the filter and load; and

activating the low-side switch of the second power-switching phase, including coupling the second power-switching phase'"'"'s single loop coil to the ground voltage and providing, via the first power-switching phase'"'"'s single loop coil and the energized magnetic core, output current to the filter and load.

4. The method of claim 1 wherein alternatively activating each switch further comprises:

activating each high side switch for a period of time according to;

5. The method of claim 1 wherein the number of power-switching phases is inversely proportional to the duty cycle of activating the switches and thereby inversely proportional to the inductance of the directly coupled inductor.

6. The method of claim 1 wherein current ripple experienced by the filter and the load comprises:

7. The method of claim 1 wherein each high-side switch and each low-side switch comprises a Field Effect Transistor implemented in silicon.

8. A coupled inductor comprising:

a magnetic core having a front, back, and bottom side, the bottom side including an air gap, the magnetic core formed to define a slot extending through the magnetic core from the front to the back side; and

a conductive sheet comprising a comb structure, the comb structure comprising a tab and a plurality of parallel teeth extending from the tab, the conductive sheet inserted into the slot such that the conductive sheet extends through the magnetic core from the back to the front side, a portion of the tab protruding from the back side and a portion of each of the plurality of teeth protruding from the front side, wherein;

each of the teeth is configured to be coupled to a connection node of a power-switching phase that includes a high-side switch and a low-side switch, the high-side switch electrically coupled to the low-side switch at the connection node of the power-switching phase;

the tab extending through the magnetic core forms, for each power-switching phase, a toroidal inductor with a single loop coil, and forms, for the plurality of power-switching phases, a directly coupled inductor;

the tab is configured to be electrically coupled to a filter and a load;

the high-side switch of each power-switching phase is configured, when activated, to couple a voltage source to the phase'"'"'s single loop coil;

the low-side switch of each phase is configured, when activated, to couple the phase'"'"'s single loop coil to a ground voltage; and

each switch is configured to be alternatively activated and no two switches of any phase are activated at the same time.

9. The coupled inductor of claim 8 wherein:

the tab further comprises an end portion bent around the back side of the magnetic core and under a portion of the bottom side of the magnetic core and each of the plurality of teeth comprises an end portion bent around the front side and under a portion of the bottom side of the magnetic core.

10. The coupled inductor of claim 8 wherein each switch is configured to be alternatively activated and no two switches of any phase are activated at the same time by:

activating the high-side switch of a first power-switching phase, including coupling the voltage source to the phase'"'"'s single loop coil, energizing the magnetic core around the single loop coil, and providing, via the single loop coil, output current to the filter and load;

activating the low-side switch of the first power-switching phase, including coupling the phase'"'"'s single loop coil to the ground voltage and providing, via a second power-switching phase'"'"'s single loop coil and the energized magnetic core, output current to the filter and load;

activating the high-side switch of the second power-switching phase, including coupling the voltage source to the second power-switching phase'"'"'s single loop coil, re-energizing the magnetic core around the first power-switching phase'"'"'s single coil element, and providing, via the second power-switching phase'"'"'s single coil element, output current to the filter and load; and

activating the low-side switch of the second power-switching phase, including coupling the second power-switching phase'"'"'s single loop coil to the ground voltage and providing, via the first power-switching phase'"'"'s single loop coil and the energized magnetic core, output current to the filter and load.

11. The coupled inductor of claim 8 wherein each switch is configured to be alternatively activated by:

activating each high side switch for a period of time according to;

12. The coupled inductor of claim 8 wherein the number of power-switching phases is inversely proportional to the duty cycle of activating the switches and thereby inversely proportional to the inductance of the directly coupled inductor.

13. The coupled inductor of claim 8 wherein current ripple experienced by the filter and the load comprises:

14. The coupled inductor of claim 8 wherein each high-side switch and each low-side switch comprises a Field Effect Transistor implemented in silicon.

15. A DC (‘

Direct Current’

)-DC converter comprising;

a plurality a power-switching phases, each phase including a high-side switch and a low-side switch, the high-side switch electrically coupled to the low-side switch at a connection node of the power-switching phase, the high-side switch of each power-switching phase is configured, when activated, to couple a voltage source to the phase'"'"'s single loop coil, the low-side switch of each phase is configured, when activated, to couple the phase'"'"'s single loop coil to a ground voltage; and

a coupled inductor comprising;

a magnetic core having a front, back, and bottom side, the bottom side including an air gap, the magnetic core formed to define a slot extending through the magnetic core from the front to the back side; and

a conductive sheet comprises a comb structure having a tab and a plurality of parallel teeth extending from the tab, the conductive sheet inserted into the slot such that the conductive sheet extends through the magnetic core from the back to the front side, a portion of the tab protruding from the back side and a portion of each of the plurality of teeth protruding from the front side, wherein;

each of the teeth is configured to be coupled to a connection node of a power-switching phase;

the tab extending through the magnetic core forms, for each power-switching phase, a toroidal inductor with a single loop coil, and forms, for the plurality of power-switching phases, a directly coupled inductor;

the tab is electrically coupled to a filter and a load; and

each switch is alternatively activated and no two switches of any phase are activated at the same time.

16. The DC-DC converter of claim 15 wherein:

the tab further comprises an end portion bent around the back side of the magnetic core and under a portion of the bottom side of the magnetic core and each of the plurality of teeth comprises an end portion bent around the front side and under a portion of the bottom side of the magnetic core.

17. The DC-DC converter of claim 15 wherein each switch is configured to be alternatively activated and no two switches of any phase are activated at the same time by:

activating the high-side switch of a first power-switching phase, including coupling the voltage source to the phase'"'"'s single loop coil, energizing the magnetic core around the single loop coil, and providing, via the single loop coil, output current to the filter and load;

activating the low-side switch of the first power-switching phase, including coupling the phase'"'"'s single loop coil to the ground voltage and providing, via a second power-switching phase'"'"'s single loop coil and the energized magnetic core, output current to the filter and load;

activating the high-side switch of the second power-switching phase, including coupling the voltage source to the second power-switching phase'"'"'s single loop coil, re-energizing the magnetic core around the first power-switching phase'"'"'s single coil element, and providing, via the second power-switching phase'"'"'s single coil element, output current to the filter and load; and

activating the low-side switch of the second power-switching phase, including coupling the second power-switching phase'"'"'s single loop coil to the ground voltage and providing, via the first power-switching phase'"'"'s single loop coil and the energized magnetic core, output current to the filter and load.

18. The DC-DC converter of claim 15 wherein each switch is configured to be alternatively activated by:

activating each high side switch for a period of time according to;

19. The DC-DC converter of claim 15 wherein the number of power-switching phases is inversely proportional to the duty cycle of activating the switches and thereby inversely proportional to the inductance of the directly coupled inductor.

20. The DC-DC converter of claim 15 wherein current ripple experienced by the filter and the load comprises: