US6084790A
Expired / Lapsed
US
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Circuit to ensure equal current sharing and switching losses between parallel power devices
Assignee: Astec International Ltd
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Filing: 1999-01-07
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Granted: 2000-07-04
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Expires: 2019-01-07
Abstract
Abstract A current sharing circuit has a plurality of power devices, such as diode rectifiers, connected in a parallel arrangement. Each leg of the parallel arrangement comprises one power device connected in series to an inductive element. The series resistance of the inductive element in each leg of the parallel circuit moderates the affect of temperature variations on the current drawn by each power device, which enables substantially equal current sharing to occur. As used in switch mode power supplies, such as forward converters and boost converters, the current sharing circuit provides the benefit of substantially equal current sharing between power devices without increasing resistive losses which would reduce the efficiency of the power supply.
Inventors
- 👤 Man Chuen Wong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:30
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/02; H02M3/04; H02M3/10; H02M3/145; H02M3/155; H02M3/156; H02M3/158; H02M3/1584
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
165 words
A current sharing circuit element for use in a power supply, comprising: a first voltage terminal; a second voltage terminal; N inductive elements having first and second terminals, where N is an integer greater than one; the first terminal of each of said N inductive elements connected to said first voltage terminal, each of said N inductive elements having a substantially similar impedance; and a first set of N power devices selected from the group consisting of switches and rectifiers, each of said N power devices coupled between a respective one of said second terminals of a corresponding one of said N inductive elements and said second voltage terminal, each of said first set of N power devices having a conductive mode with substantially similar electrical characteristics; wherein said set of N power devices are operated in phase and wherein the resistance of each said inductive element is greater than the resistance of each said power device in its conductive mode, thereby improving current sharing.
Claim 2
Dependent Claim
165 words
A current sharing circuit element for use in a power supply, comprising: a first voltage terminal; a second voltage terminal; N inductive elements having first and second terminals, where N is an integer greater than one; the first terminal of each of said N inductive elements connected to said first voltage terminal, each of said N inductive elements having a substantially similar impedance; and a first set of N power devices selected from the group consisting of switches and rectifiers, each of said N power devices coupled between a respective one of said second terminals of a corresponding one of said N inductive elements and said second voltage terminal, each of said first set of N power devices having a conductive mode with substantially similar electrical characteristics; wherein said set of N power devices are operated in phase and wherein the resistance of each said inductive element is greater than the resistance of each said power device in its conductive mode, thereby improving current sharing.
Claim 3
Dependent Claim
43 words
The current sharing circuit of claim 1, further comprising a second set of N power devices, each said second power device coupling a respective one of said second terminals of a corresponding one of said N inductive elements to a common electrical ground.
Claim 4
Dependent Claim
30 words
The current sharing circuit of claim 2, wherein each of the power devices of said second set of N power devices has substantially similar electrical characteristics in a conducting mode.
Claim 5
Dependent Claim
256 words
A current sharing circuit comprising: first and second input voltage terminals; first and second output voltage terminals; N inductive elements having first and second terminals, where N is an integer greater than one; the first terminal of each of said N inductive elements connected to said first input voltage terminal, each of said N inductive elements having a substantially similar impedance; a first set of N power devices selected from the group consisting of rectifiers and switches, each device of said first set of N power devices coupled between a respective one of said second terminals of a corresponding one of said N inductive elements and said first output voltage terminal, each of said first set of N power devices having substantially similar electrical characteristics; a second set of N power devices selected from the group consisting of rectifiers and switches, each device of said second set of N power devices coupled between a respective one of said second terminals of a corresponding one of said N inductive elements and said second output voltage terminal, each of said second set of N power devices having substantially similar electrical characteristics; and means for coupling said second input voltage terminal to said second output voltage terminal; wherein said first set of N power devices are operated in phase and said second set of N power devices are operated in phase, and further wherein the resistance of each said inductive element is greater than the resistance of each said power device in its conductive mode, thereby improving current sharing.
Claim 6
Dependent Claim
256 words
A current sharing circuit comprising: first and second input voltage terminals; first and second output voltage terminals; N inductive elements having first and second terminals, where N is an integer greater than one; the first terminal of each of said N inductive elements connected to said first input voltage terminal, each of said N inductive elements having a substantially similar impedance; a first set of N power devices selected from the group consisting of rectifiers and switches, each device of said first set of N power devices coupled between a respective one of said second terminals of a corresponding one of said N inductive elements and said first output voltage terminal, each of said first set of N power devices having substantially similar electrical characteristics; a second set of N power devices selected from the group consisting of rectifiers and switches, each device of said second set of N power devices coupled between a respective one of said second terminals of a corresponding one of said N inductive elements and said second output voltage terminal, each of said second set of N power devices having substantially similar electrical characteristics; and means for coupling said second input voltage terminal to said second output voltage terminal; wherein said first set of N power devices are operated in phase and said second set of N power devices are operated in phase, and further wherein the resistance of each said inductive element is greater than the resistance of each said power device in its conductive mode, thereby improving current sharing.
Claim 7
Dependent Claim
23 words
The current sharing circuit of claim 4, further comprising a magnetic core, wherein said N inductive elements are wound around said magnetic core.
Claim 8
Dependent Claim
22 words
The current sharing circuit of claim 4, wherein said first set of N power devices comprises a first set of N rectifiers.
Claim 9
Dependent Claim
22 words
The current sharing circuit of claim 4, wherein said second set of N power devices comprises a second set of N rectifiers.
Claim 10
Dependent Claim
19 words
The current sharing circuit of claim 4, wherein said second set of N power devices comprises N power switches.
Claim 11
Dependent Claim
211 words
A boost voltage converter, comprising: first and second input voltage terminals; first and second output voltage terminals; N inductive elements having first and second terminals, where N is an integer greater than one; the first terminal of each of said N inductive elements connected to said first input voltage terminal, each of said N inductive elements having a substantially similar impedance; a set of N power rectifiers each coupled between a respective one of said second terminals of a corresponding one of said N inductive elements and said first output voltage terminal, each of said set of N power rectifiers having substantially similar electrical characteristics; a set of N power field effect transistor switches each coupled between a respective one of said second terminals of a corresponding one of said N inductive elements and said second output voltage terminal, each of said set of N field effect transistor switches having substantially similar electrical characteristics; and means for coupling said second input voltage terminal to said second output voltage terminal; wherein said set of N power field effect transistor switches are operated substantially in phase and wherein the resistance of each said inductive element is greater than the resistance of each said power rectifier in its conductive mode, thereby improving current sharing.
Claim 12
Dependent Claim
211 words
A boost voltage converter, comprising: first and second input voltage terminals; first and second output voltage terminals; N inductive elements having first and second terminals, where N is an integer greater than one; the first terminal of each of said N inductive elements connected to said first input voltage terminal, each of said N inductive elements having a substantially similar impedance; a set of N power rectifiers each coupled between a respective one of said second terminals of a corresponding one of said N inductive elements and said first output voltage terminal, each of said set of N power rectifiers having substantially similar electrical characteristics; a set of N power field effect transistor switches each coupled between a respective one of said second terminals of a corresponding one of said N inductive elements and said second output voltage terminal, each of said set of N field effect transistor switches having substantially similar electrical characteristics; and means for coupling said second input voltage terminal to said second output voltage terminal; wherein said set of N power field effect transistor switches are operated substantially in phase and wherein the resistance of each said inductive element is greater than the resistance of each said power rectifier in its conductive mode, thereby improving current sharing.
Claim 13
Dependent Claim
8 words
The boost converter of claim 9, wherein N=2.
Claim 14
Dependent Claim
56 words
The boost converter of claim 10, wherein said inductive elements are magnetically coupled and the sum of the uncoupled inductances of said inductive elements is substantially greater than the phase delay time interval in the response of said first switch and said second switch multiplied by the peak load voltage divided by the peak load current.
Claim 15
Dependent Claim
198 words
A forward converter comprising: a transformer, said transformer including a primary winding and a secondary winding, said secondary winding having a first and second secondary winding terminals; first and second output voltage terminals; N inductive elements having first and second terminals, where N is an integer greater than one; wherein said second terminal of each said inductive element is coupled to said first output terminal; a first set of N power rectifiers each coupled between a respective one of said first terminals of a corresponding one of said N inductive elements and said first secondary winding terminal, each of said first set of N power rectifiers having substantially similar electrical characteristics; a second set of N free-wheeling diodes each coupled between a respective one of said first terminals of a corresponding one of said N inductive elements and said second output voltage terminal, each of said second set of N free-wheeling diodes having substantially similar electrical characteristics; and means for coupling said second secondary winding terminal to said second output voltage terminal; wherein the resistance of each said inductive element is greater than the resistance of each said power rectifier in its conductive mode, thereby improving current sharing.
Claim 16
Dependent Claim
198 words
A forward converter comprising: a transformer, said transformer including a primary winding and a secondary winding, said secondary winding having a first and second secondary winding terminals; first and second output voltage terminals; N inductive elements having first and second terminals, where N is an integer greater than one; wherein said second terminal of each said inductive element is coupled to said first output terminal; a first set of N power rectifiers each coupled between a respective one of said first terminals of a corresponding one of said N inductive elements and said first secondary winding terminal, each of said first set of N power rectifiers having substantially similar electrical characteristics; a second set of N free-wheeling diodes each coupled between a respective one of said first terminals of a corresponding one of said N inductive elements and said second output voltage terminal, each of said second set of N free-wheeling diodes having substantially similar electrical characteristics; and means for coupling said second secondary winding terminal to said second output voltage terminal; wherein the resistance of each said inductive element is greater than the resistance of each said power rectifier in its conductive mode, thereby improving current sharing.
Claim 17
Dependent Claim
8 words
The forward converter of claim 12, wherein N=2.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-07-04 | 2004-01-03 | 2004-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-07-04 | 2008-01-03 | 2008-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-07-04 | 2012-01-03 | 2012-07-04 | $7700.00 | Window Closed / Lapsed |