Patent US4245288A successfully refreshed from Google Patents.
US4245288A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Elimination of current spikes in buck power converters
Assignee: National Aeronautics and Space Administration
•
Filing: 1978-10-31
•
Granted: 1981-01-13
•
Expires: 1998-10-31
Abstract
Abstract Current spikes in a buck power converter due to commutating diode turn-off time is eliminated by using a tapped inductor in the converter with the tap connected to the switching transistor, without the commutating diode in the usual place, and instead connected to conduct current from one end of the tapped inductor remote from the load during the interval in which the transistor is not conducting. In the case of a converter having a center-tapped (primary and secondary) transformer between two switching power transistors operated in a push-pull mode and two rectifying diodes in the secondary circuit, current spikes due to transformer saturation are also eliminated by using a tapped inductor in the converter with the tap connected to the rectifying diodes and a diode connected to conduct current from one end of the tapped inductor remote from the load during the interval in which the transistors are not conducting.
Inventors
- 👤 with respect to an invention of Frosch Robert A. Administrator of the National Aeronautics and Space Administration
- 👤 William T. McLyman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:35
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/02; H02M3/04; H02M3/10; H02M3/145; H02M3/155; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/337; H02M3/3376; H02M3/3378
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
126 words
A buck converter having at least one switching power transistor for coupling a source of DC power to a load through an inductance in series with the load, and having at least one commutating diode for shunting the input of said inductance to the return current path of said load when said switching power transistor is off, the improvement comprising a tapped inductor for said inductor with a coupling from the tap thereof to said transistor and a connection of said commutating diode to one end of said tapped inductor remote from said load, said diode being polarized to conduct return current through said load when said switching power transistor is off, whereby current spikes due to minority-carrier sweepout time in the commutating diode is eliminated.
Claim 2
Dependent Claim
126 words
A buck converter having at least one switching power transistor for coupling a source of DC power to a load through an inductance in series with the load, and having at least one commutating diode for shunting the input of said inductance to the return current path of said load when said switching power transistor is off, the improvement comprising a tapped inductor for said inductor with a coupling from the tap thereof to said transistor and a connection of said commutating diode to one end of said tapped inductor remote from said load, said diode being polarized to conduct return current through said load when said switching power transistor is off, whereby current spikes due to minority-carrier sweepout time in the commutating diode is eliminated.
Claim 3
Dependent Claim
40 words
A buck converter as defined in claim 1 including a transformer for coupling said switching power transistor to said inductor with a rectifying diode in series between the secondary winding of said transformer and said tap of said tapped inductor.
Claim 4
Dependent Claim
96 words
A buck converter as defined in claim 1 including a second switching power transistor and a transformer for coupling said switching power transistors to said inductor, said transformer having a center tapped primary winding with ends thereof connected to said switching power transistors and the center tap thereof connected to a return current path for said source of power and a center tapped secondary winding with ends thereof connected to said tap of said tapped inductor through separate rectifying diodes, and means for alternately turning on said switching power transistors for a push-pull mode of operation.
Claim 5
Dependent Claim
126 words
In apparatus comprising a switching transistor, an inductor, a commutating diode and a filter capacitor for converting DC voltage from a source to DC voltage applied to a load by switching power through said transistor and inductor into said capacitor, said capacitor being connected in parallel with the load, the improvement comprising a tap in said inductor between ends thereof, said tap being connected to said transistor, and one end of said inductor, remote from the other end connected to said load, being connected by said commutating diode to the return current path from said load to said source, said commutating diode being polarized to conduct while said transistor is turned off, whereby current spikes due to minority-carrier sweepout time in the commutating diode is eliminated.
Claim 6
Dependent Claim
126 words
In apparatus comprising a switching transistor, an inductor, a commutating diode and a filter capacitor for converting DC voltage from a source to DC voltage applied to a load by switching power through said transistor and inductor into said capacitor, said capacitor being connected in parallel with the load, the improvement comprising a tap in said inductor between ends thereof, said tap being connected to said transistor, and one end of said inductor, remote from the other end connected to said load, being connected by said commutating diode to the return current path from said load to said source, said commutating diode being polarized to conduct while said transistor is turned off, whereby current spikes due to minority-carrier sweepout time in the commutating diode is eliminated.
Claim 7
Dependent Claim
180 words
In apparatus comprising two switching transistors, means for alternately switching said transistors on, an inductor and filter capacitor, an isolating transformer having a center tapped primary winding and a center tapped secondary winding, with rectifying diodes coupling the ends of said secondary winding to said inductor in series with a load, said load being connected in parallel with said capacitor between said inductor and the center tap of said secondary winding, for converting DC voltage from a source to DC voltage applied to said load by switching power through said transistor and isolating transformer in a push-pull mode, the improvement comprising a tap in said inductor between ends thereof, and a commutating diode, said tap being connected to said rectifying diodes, and one end of said inductor, remote from the other end connected to said load, being connected by said commutating diode to the center tap of said secondary winding of said isolating transformer, said diode being polarized to conduct while said transistors are turned off, whereby current spikes due to minority-carrier sweepout time in the commutating diode is eliminated.
Claim 8
Dependent Claim
180 words
In apparatus comprising two switching transistors, means for alternately switching said transistors on, an inductor and filter capacitor, an isolating transformer having a center tapped primary winding and a center tapped secondary winding, with rectifying diodes coupling the ends of said secondary winding to said inductor in series with a load, said load being connected in parallel with said capacitor between said inductor and the center tap of said secondary winding, for converting DC voltage from a source to DC voltage applied to said load by switching power through said transistor and isolating transformer in a push-pull mode, the improvement comprising a tap in said inductor between ends thereof, and a commutating diode, said tap being connected to said rectifying diodes, and one end of said inductor, remote from the other end connected to said load, being connected by said commutating diode to the center tap of said secondary winding of said isolating transformer, said diode being polarized to conduct while said transistors are turned off, whereby current spikes due to minority-carrier sweepout time in the commutating diode is eliminated.
Claim 9
Dependent Claim
94 words
In a buck power converter for converting DC voltage from a source to DC voltage applied to a load, said converter having a switching transistor and a commutating diode to alternately connect said source of DC voltage and circuit ground to an inductor in series with said load, the improvement comprising a tap in said inductor and a connection from said transistor instead of to one end of said inductor remote from said load where said commutating diode is connected, whereby current spikes due to minority-carrier sweepout time in the commutating diode is eliminated.
Claim 10
Dependent Claim
94 words
In a buck power converter for converting DC voltage from a source to DC voltage applied to a load, said converter having a switching transistor and a commutating diode to alternately connect said source of DC voltage and circuit ground to an inductor in series with said load, the improvement comprising a tap in said inductor and a connection from said transistor instead of to one end of said inductor remote from said load where said commutating diode is connected, whereby current spikes due to minority-carrier sweepout time in the commutating diode is eliminated.
Claim 11
Dependent Claim
194 words
In a push-pull buck power converter for converting DC voltage from a source to DC voltage applied to a load, said converter having an isolating transformer with a center tapped primary winding and a center tapped secondary winding, two switching transistors, one transistor for connecting said source between the center tap of said primary winding and one end terminal thereof, the other transistor for connecting said source between the center tap of said primary winding and the other end terminal thereof, and means for alternately switching said transistor on for pulse width modulated intervals, two rectifying diodes connecting the ends of said secondary winding to an inductor in series with said load connected to the center tap of said secondary winding, the improvement comprising a tap in said inductor and a connection from said rectifying diodes to said tap in said inductor instead of to an end thereof remote from the load, and a commutating diode connected between the end of said tapped inductor remote from said load and the center tap of said secondary winding of said isolating transformer, whereby current spikes due to minority-carrier sweepout time in the commutating diode is eliminated.
Claim 12
Dependent Claim
194 words
In a push-pull buck power converter for converting DC voltage from a source to DC voltage applied to a load, said converter having an isolating transformer with a center tapped primary winding and a center tapped secondary winding, two switching transistors, one transistor for connecting said source between the center tap of said primary winding and one end terminal thereof, the other transistor for connecting said source between the center tap of said primary winding and the other end terminal thereof, and means for alternately switching said transistor on for pulse width modulated intervals, two rectifying diodes connecting the ends of said secondary winding to an inductor in series with said load connected to the center tap of said secondary winding, the improvement comprising a tap in said inductor and a connection from said rectifying diodes to said tap in said inductor instead of to an end thereof remote from the load, and a commutating diode connected between the end of said tapped inductor remote from said load and the center tap of said secondary winding of said isolating transformer, whereby current spikes due to minority-carrier sweepout time in the commutating diode is eliminated.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-13 | 1984-07-14 | 1985-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-13 | 1988-07-14 | 1989-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-13 | 1992-07-14 | 1993-01-13 | $7700.00 | Window Closed / Lapsed |