Magnetic energy-transmitting element and power supply for cancelling out electrical noise

Abstract

A magnetic energy-transfer element including: a core of the magnetic energy-transfer element; an input winding wound around the core of the magnetic energy-transfer element, a first terminal of the input winding being connected to a first terminal of the input filter capacitor, a second terminal of the input winding being connected to a first terminal of the switching element; an output winding wound around the core of the magnetic energy-transfer element to take out energy; and a cancellation winding wound around the core of the magnetic energy-transfer element.

What is claimed is: 
     
         1 . A magnetic energy-transfer element used for a power supply, the power supply comprising at least one of a first input voltage terminal, a second input voltage terminal, an input filter capacitor, a switching element, an output rectifier, and a magnetic energy-transfer element, the magnetic energy-transfer element comprising:
 a core of the magnetic energy-transfer element;   an input winding wound around the core of the magnetic energy-transfer element, a first terminal of the input winding being connected to a first terminal of the input filter capacitor, a second terminal of the input winding being connected to a first terminal of the switching element;   an output winding wound around the core of the magnetic energy-transfer element to take out energy, wherein a polarity of the potential variation of a terminal connected to the output rectifier is opposite to that of the potential variation at a connecting point between the second terminal of the input winding and the first terminal of the switching element; and   a cancellation winding wound around the core of the magnetic energy-transfer element, the cancellation winding being wound to substantially fill a winding layer between the input winding and the output winding to reduce a capacitive coupling between the input winding and the output winding, the cancellation winding being capacitively coupled to the output winding so as to cancel out and reduce the sum of capacitive couplings generated from windings other than the output winding and the core of the magnetic energy-transfer element to the output winding,   wherein the number of turns of the cancellation winding wound per unit area of one winding layer for reducing the sum of capacitive couplings generated to the output winding is greater than that of the output winding wound per unit area of one winding layer.   
     
     
         2 . The magnetic energy-transfer element of  claim 1 , wherein the number of turns of the cancellation winding is adjusted to take out auxiliary power. 
     
     
         3 . The magnetic energy-transfer element of  claim 1 , wherein the number of turns of a winding layer formed farthest apart from the output winding among the winding layers of the input winding is set differently from a number of turns corresponding to the other winding layers of the input winding. 
     
     
         4 . The magnetic energy-transfer element of  claim 1 , wherein the winding layer having the lowest potential variation width among the winding layers of the input winding is located farthest apart from the output winding. 
     
     
         5 . The magnetic energy-transfer element of  claim 1 , wherein a winding layer having the highest potential variation width among the winding layers of the input winding is located farthest apart from the output winding. 
     
     
         6 . The magnetic energy-transfer element of  claim 1 , wherein a winding layer having the highest potential variation width among the winding layers of the input winding is wound between a winding layer having the lowest potential variation width among the winding layers of the input winding and the remaining winding layer of the input winding. 
     
     
         7 . The magnetic energy-transfer element of  claim 1 , further comprising:
 a core bias winding wound between a winding layer located farthest from the output winding among the winding layers of the input winding and the core of the magnetic energy-transfer element, the core bias winding having the same polarity of potential variation as that of potential variation at a connecting point between the second terminal of the input winding and the first terminal of the switching element.   
     
     
         8 . The magnetic energy-transfer element of  claim 1 , further comprising:
 a core bias winding wound between a winding layer located farthest apart from the output winding among the winding layers of the input winding and the core of the magnetic energy-transfer element, wherein one side terminal with the same polarity of potential variation as that of potential variation at a connecting point between the second terminal of the input winding and the first terminal of the switching element is connected to the core of the magnetic energy-transfer element.   
     
     
         9 . The magnetic energy-transfer element of  claim 1 , wherein the magnetic energy-transfer element is used for a flyback converter type power supply. 
     
     
         10 . The magnetic energy-transfer element of  claim 1 , wherein the magnetic energy-transfer element is used for a forward converter type power supply. 
     
     
         11 . A magnetic energy-transfer element used for a power supply, the power supply comprising at least one of a first input voltage terminal, a second input voltage terminal, an input filter capacitor, a switching element, an output rectifier, and a magnetic energy-transfer element, the magnetic energy-transfer element comprising:
 a core of the magnetic energy-transfer element;   an input winding wound around the core of the magnetic energy-transfer element, a first terminal of the input winding being connected to a first terminal of the input filter capacitor, a second terminal of the input winding being connected to a first terminal of the switching element;   an output winding wound around the core of the magnetic energy-transfer element to take out energy, wherein a polarity of the potential variation of a terminal connected to the output rectifier is opposite to that of the potential variation at a connecting point between the second terminal of the input winding and the first terminal of the switching element; and   a cancellation winding wound around the core of the magnetic energy-transfer element, the cancellation winding being wound to substantially fill a winding layer between the input winding and the output winding to reduce a capacitive coupling between the input winding and the output winding, the cancellation winding being capacitively coupled to the output winding so as to cancel out and reduce the sum of capacitive couplings generated from windings other than the output winding and the core of the magnetic energy-transfer element to the output winding.   
     
     
         12 . The magnetic energy-transfer element of  claim 11 , wherein the magnetic energy-transfer element is used for a flyback converter type power supply. 
     
     
         13 . The magnetic energy-transfer element of  claim 11 , wherein the magnetic energy-transfer element is used for a forward converter type power supply. 
     
     
         14 . A manufactured article, comprising:
 a magnetic energy-transfer element of  claim 1 .   
     
     
         15 . A manufactured article, comprising:
 a magnetic energy-transfer element of  claim 11 .