Back to results
US 12,322,535 B2Granted
Planar multilayer transformer with minimum noise injection in between primary and secondary winding
AssigneeRompower Technology Holdings, LLC
InventorsIonel Jitaru, Mihai Bogdan Jitariu
Life of this patent
Estimating the term…
Abstract
A planar multilayer transformer in a power converter wherein winding arrangements and placement of shields reduces common mode noise to a level wherein the common mode inductor in an input EMI filter can be reduced and even eliminated decreasing the power dissipation and increasing the power density. The methods presented herein can reduce the number of layers in the multilayer PCB by eliminating the layers used for the shields and still be in full compliance with EMI requirements.
Claims14
A system for reducing common-mode noise, the system comprising:
- a switch mode power supply including primary and secondary sides, primary and secondary grounds, an input voltage source, a primary switch, a transformer core having at least two magnetic legs, a planar multilayer transformer having primary windings and primary auxiliary windings which report to the primary and surrounds the magnetic legs and secondary windings and secondary auxiliary windings which report to the secondary and surrounds the magnetic legs, and a power output, wherein the primary windings and the secondary windings have primary and secondary quiet terminations, respectively, wherein the voltage does not change with respect to the primary and with respect to the secondary side ground;
- wherein the primary windings and the secondary windings have primary and secondary noisy terminations, respectively, wherein the voltage changes most with respect to the primary and with respect to the secondary side ground;
- a first shield, using fractional turns, placed on a first shield layer having a center tap which is connected to the primary ground, and two terminations on left and right sides of the center tap, wherein each termination has a maximum of one turn with respect to the center tap, wherein the voltage induced in each termination with respect to center tap has opposite polarities;
- and
- a second shield on a second shield layer, wherein the second shield contains a plurality of turns.
2 more elements
A system for reducing common-mode noise, the system comprising:
- a switch mode power supply including primary and secondary sides, primary and secondary grounds, an input voltage source, two primary switches placed in series across the input voltage source, a transformer core having at least two magnetic legs, a planar multilayer transformer having primary windings and primary auxiliary windings which report to the primary and surrounds the magnetic legs and secondary windings and secondary auxiliary windings which report to the secondary and surrounds the magnetic legs, said transformer primary windings placed in series to a capacitor connected to an input ground and a power output, wherein the primary windings and the secondary windings have primary and secondary quiet terminations, respectively, wherein the voltage does not change with respect to the primary and with respect to the secondary side ground;
- wherein the primary windings and the secondary windings have primary and secondary noisy terminations, respectively, wherein the voltage changes most with respect to the primary and with respect to the secondary side ground;
- and
- a first shield, using fractional turns, placed on a first shield layer having a center tap which is connected to the primary ground, and two terminations on left and right sides of the center tap, wherein each termination has a maximum of one turn with respect to the center tap, wherein the voltage induced in each termination with respect to the center tap has opposite polarities;
- a second shield on a second shield layer, wherein the second shield contains a plurality of turns.
2 more elements
Dependencies are inferred from the claim text.