Method and means for combining a transformer and inductor on a single core structure
AssigneeHughes Electronics Corporation
InventorCarl Edward Keuneke
Life of this patent
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Abstract
In a prefer embodiment, an integrated transformer and inductor on a singe core structure to provide an impedance matching function and an inductor in series with the transformer's secondary which includes: a transformer core structure having a primary leg, a secondary leg, and a center leg containing an air gap, said center leg disposed parallel to said primary leg and secondary leg, whereby said air gap provides control of said inductor value; a primary winding on said primary leg; and a secondary winding on said secondary leg.
Claims6
An integrated transformer and inductor on a monolithic core structure to provide an impedance matching function and an inductor in series with a secondary of said transformer which comprises:
- (a) a transformer core structure having a primary leg, a secondary leg, and a center leg containing an air gap, whereby said air gap provides control of an inductor value;
- (b) a primary winding on said primary leg;
- and
- (c) a secondary winding on said secondary leg wherein a secondary-to-primary turns ratio of said primary windings is determined by
- N.sub.s /N.sub.p =V.sub.Rl /V.sub.in
- where N.sub.s =a number of turns of said secondary winding,
- N.sub.p =a number of turns of said primary winding,
- V.sub.Rl =a desired RMS voltage across a load resistance at a resonant frequency, and
- V.sub.in =an RMS voltage of a signal applied to said primary winding at said resonant frequency.
An integrated transformer and inductor on a monolithic core structure to provide an impedance matching function and an inductor in series with a secondary of said transformer which comprises:
- (a) a transformer core structure having a primary leg, a secondary leg, and a center leg containing an air gap, whereby said air gap provides control of an inductor value;
- (b) a primary winding on said primary leg;
- and
- (c) a secondary winding on said secondary leg wherein a core area of said primary leg is determined by
- A.sub.p =(V.sub.p .times.10.sup.8)/(4.0.times.Freq.times.N.sub.p .times.B)
- where A.sub.p =a cross-sectional area of said core's primary leg (in cm.sup.2),
- V.sub.p =an RMS voltage of a square wave applied to said primary winding,
- Freq=a frequency of a square wave applied to said primary winding (in hertz),
- N.sub.p =a number of turns on said primary winding, and
- B=a desired maximum operating flux density (in gausses).
An integrated transformer and inductor on a monolithic core structure to provide an impedance matching function and an inductor in series with a secondary of said transformer which comprises:
- (a) a transformer core structure having a primary leg, a secondary leg, and a center leg containing an air gap, whereby said air gap provides control of an inductor value;
- (b) a primary winding on said primary leg;
- and
- (c) a secondary winding on said secondary leg wherein a core area of said secondary leg is determined by
- A.sub.s =A.sub.p .times.(1+(1/R.sub.l .times.2.times.Pi.times.Freq.times.C.sub.l)).sup.2).sup.1/2
- where A.sub.s =a cross-sectional area of said core's secondary leg (in cm.sup.2),
- A.sub.p =a cross-sectional area of said core's primary leg (in cm.sup.2),
- R.sub.l =a series resistance of a load (in ohms),
- Pi=2.1416,
- Freq=a frequency of a square wave applied to said primary winding (in hertz), and
- C.sub.l =a series capacitance of a load (in farads).
An integrated transformer and inductor on a monolithic core structure to provide an impedance matching function and an inductor in series with a secondary of said transformer which comprises:
- (a) a transformer core structure having a primary leg, a secondary leg, and a center leg containing an air gap, whereby said air gap provides control of an inductor value;
- (b) a primary winding on said primary leg;
- and
- (c) a secondary winding on said secondary leg wherein a core of said center leg is determined by
- A.sub.c =(V.sub.p .times.10.sup.8)/(8.times.Freq.times.N.sub.p .times.B.times.Pi.times.Freq.times.C.sub.l .times.R.sub.l)
- where A.sub.c =a cross-sectional areas of said core's center leg (in cm.sup.2),
- V.sub.p =an RMS voltage of a square wave applied to said primary winding,
- Freq=a frequency of said square wave applied to said primary winding (in hertz),
- N.sub.p =a number of turns on said primary winding,
- B=a desired maximum operating flux density (in gausses),
- Pi=2.1416,
- C.sub.l =a series capacitance of a load (in farads), and
- R.sub.l =a series resistance of said load (in ohms).
An integrated transformer and inductor on a monolithic core structure to provide an impedance matching function and an inductor in series with a secondary of said transformer which comprises:
- (a) a transformer core structure having a primary leg, a secondary leg, and a center leg containing an air gap, whereby said air gap provides control of an inductor value;
- (b) a primary winding on said primary leg;
- and
- (c) a secondary winding on said secondary leg wherein a width of said air gap is determined by
- I.sub.g =(0.4.times.Pi.times.10.sup.-9 .times.N.sub.x.sup.2 .times.A.sub.c)/L
- where I.sub.g =said width of said air gap (in cm),
- Pi=2.1416,
- N.sub.s =a number of turns of said secondary winding,
- A.sub.c =a cross-sectional area of said center leg (in cm.sup.2), and
- L=a desired inductance of an equivalent series inductor (in henries).
A method of providing an integrated transformer and inductor on a monolithic core structure to provide an impedance matching function and an inductor in series with a secondary of said transformer which comprises:
- (a) providing a transformer core structure having a primary leg, a secondary leg, and a center leg containing an air gap, whereby said air gap provides control of said inductor value;
- (b) establishing a core area of said primary leg as given by
- A.sub.p =(V.sub.p .times.10.sup.8)/(4.0.times.Freq.times.N.sub.p .times.B)
- where A.sub.p =a cross-sectional area of said primary leg (in cm.sup.2),
- V.sub.p =an RMS voltage of a square wave applied to said primary winding,
- Freq=a frequency of said square wave applied to said primary winding (in hertz),
- N.sub.p =a number of turns on said primary winding, and
- B=a desired maximum operating flux density (in gausses);
- (c) establishing a core area of said secondary leg as given by
- A.sub.s =A.sub.p .times.(1+(1/R.sub.L .times.2.times.Pi.times.Freq.times.C.sub.L)).sup.2).sup.1/2
- where A.sub.s =a cross-sectional area of said secondary leg (in cm.sup.2),
- A.sub.p =a cross-sectional area of said primary leg (in cm.sup.2),
- R.sub.L =a series resistance of a load (in ohms),
- Pi=3.1416 and,
- Freq=a frequency of a square wave applied to said primary winding (in hertz),
- C.sub.L =a series capacitance of said load (in farads);
- (d) establishing a core area of said center leg according as given by
- A.sub.c =(V.sub.p .times.10.sup.8)/(8.times.Freq.times.N.sub.p .times.B.times.Pi'Freq.times.C.sub.L .times.R.sub.L)
- where A.sub.c =a cross-sectional area of said core's center leg (in cm.sup.2),
- V.sub.p =an RMS voltage of a square wave applied to said primary winding,
- Freq=a frequency of said square wave applied to said primary winding (in hertz),
- N.sub.p =a number of turns on said primary winding,
- B=a desired maximum operating flux density (in gausses),
- Pi=3.1416,
- C.sub.L =a series capacitance of a load (in farads), and
- R.sub.L =a series resistance of said load (in ohms),
- (e) establishing a width of said air gap according to the equation
- I.sub.g =(0.4.times.Pi.times.10.sup.-8 .times.N.sub.s.sup.2 .times.A.sub.c)/L
- where I.sub.g =an air gap width of said center leg (in cm),
- Pi=3.1416,
- N.sub.s =a number of turns of said secondary winding,
- A.sub.c =a cross-sectional area of said center leg (in cm.sup.2), and
- L=a desired inductance of an equivalent series inductor (in henries);
- and
- (f) winding a primary winding on said primary leg and a secondary winding on said secondary leg whereby a secondary-to-primary turns ratio of said primary and secondary windings is given by
- N.sub.s N.sub.p =V.sub.RL /V.sub.in
- where N.sub.s =a number of turns of said secondary winding,
- N.sub.p =a number of turns of said primary winding,
- V.sub.RL =a desired RMS voltage across a load resistance at a resonant frequency,
- V.sub.in =an RMS voltage of a signal applied to said primary winding at said resonant frequency (=0.9.times.V.sub.p for V.sub.in =square wave), and
- V.sub.p =an RMS voltage of said square wave applied to said primary winding .
Dependencies are inferred from the claim text.