Switching power supply common output filter

Claim 2

In a switching power supply of the type having a power transformer including a primary winding and a multitap secondary winding, drive means for driving the primary of the transformer with currents of alternate polarity, rectifiers connected to various ones of the taps for providing full wave rectification of at least two different voltages of different voltage magnitudes, and output filters connected to the rectifiers each including a series filter choke and a shunt filter capacitor, the improvement comprising: said filter chokes comprising a single ferromagnetic core with a plurality of choke windings thereon, at least one of said choke windings having a different number of turns with respect to at least one other of said choke windings in the same ratio as the voltage of the output related to that choke winding bears to the voltage of the output related to the other of said choke windings.

Claim 3

A switching power supply comprising: a power transformer having a primary winding and a secondary winding including a plurality of taps to divide said secondary winding into segments; drive means for said transformer including means for providing currents of alternate polarity through said primary winding, thereby to produce at least two different voltages of alternating polarity in said secondary winding; a plurality of rectifierS connected to the taps on said secondary winding in sets so as to provide full wave rectification of current induced in said secondary winding; a plurality of voltage outputs of different voltage magnitudes, each including a shunt filter capacitor; and inductive filter means comprising a single ferromagnetic core and a plurality of choke windings disposed on said single core, each of said windings connected in series from a related set of said rectifiers to a related one of said outputs, each winding having a number of turns related to the number of turns of each other winding in the same ratio as the related output voltage magnitude bears to the output voltage magnitude of each other winding such that all of said choke windings have the same number of volts per turn, whereby said switching power supply comprises a plurality of outputs having different voltage magnitudes, each including a series filter choke wound on said common core.

Claim 4

A switching power supply comprising: a power transformer having a primary winding and a secondary winding including a plurality of taps to divide said secondary winding into segments; drive means for said transformer including means for providing currents of alternate polarity through said primary winding, thereby to produce at least two different voltages of alternating polarity in said secondary winding; a plurality of rectifierS connected to the taps on said secondary winding in sets so as to provide full wave rectification of current induced in said secondary winding; a plurality of voltage outputs of different voltage magnitudes, each including a shunt filter capacitor; and inductive filter means comprising a single ferromagnetic core and a plurality of choke windings disposed on said single core, each of said windings connected in series from a related set of said rectifiers to a related one of said outputs, each winding having a number of turns related to the number of turns of each other winding in the same ratio as the related output voltage magnitude bears to the output voltage magnitude of each other winding such that all of said choke windings have the same number of volts per turn, whereby said switching power supply comprises a plurality of outputs having different voltage magnitudes, each including a series filter choke wound on said common core.

Claim 5

A switching power supply comprising: a power transformer having a primary winding and a secondary winding with a grounded center tap and at least two other taps on either side of the center tap for providing currents of opposite polarity with respect to ground in response to alternate polarity of current in said primary, said taps being arranged in a plurality of pairs so as to permit provision of different voltages; drive means for said transformer including means for providing currents of alternate polarity through said primary winding, thereby to produce at least two different voltages of alternating polarity in said secondary winding; a plurality of voltage outputs, each of said voltage outputs having a shunt filter capacitor; output filter choke means including a single core of ferromagnetic material and a plurality of independent filter choke windings thereon, each of said filter choke windings connected to a corresponding one of said voltage outputs, each of said filter choke winding having a number of turns related to the number of turns of each other choke winding in the same ratio as the voltage of the voltage output corresponding to each choke bears to the voltage corresponding each other choke such that all of said choke windings have the same number of volts per turn; and a plurality of rectifiers, each of said rectifiers connected from one of said taps to one of said choke windings, said rectifiers arranged in sets with corresponding taps of said secondary winding, each set connected to the same one of said choke windings, each of the rectifiers in a set poled to conduct current through the related choke in the same polarity as the other rectifier in the set.

Claim 6

A switching power supply comprising: a power transformer having a primary winding and a secondary winding with a grounded center tap and at least two other taps on either side of the center tap for providing currents of opposite polarity with respect to ground in response to alternate polarity of current in said primary, said taps being arranged in a plurality of pairs so as to permit provision of different voltages; drive means for said transformer including means for providing currents of alternate polarity through said primary winding, thereby to produce at least two different voltages of alternating polarity in said secondary winding; a plurality of voltage outputs, each of said voltage outputs having a shunt filter capacitor; output filter choke means including a single core of ferromagnetic material and a plurality of independent filter choke windings thereon, each of said filter choke windings connected to a corresponding one of said voltage outputs, each of said filter choke winding having a number of turns related to the number of turns of each other choke winding in the same ratio as the voltage of the voltage output corresponding to each choke bears to the voltage corresponding each other choke such that all of said choke windings have the same number of volts per turn; and a plurality of rectifiers, each of said rectifiers connected from one of said taps to one of said choke windings, said rectifiers arranged in sets with corresponding taps of said secondary winding, each set connected to the same one of said choke windings, each of the rectifiers in a set poled to conduct current through the related choke in the same polarity as the other rectifier in the set.

Claim 7

A switching power supply comprising: a power transformer having a primary winding and a secondary winding including a plurality of taps to divide said secondary winding into segments; drive means for said transformer including means for providing currents of alternate polarity through said primary winding, thereby to produce at least two different voltages of alternating polarity in said secondary winding; a plurality of first rectifiers connected to the taps on said secondary winding in sets so as to provide full wave rectification of current induced in said secondary winding; at least one second rectifier connected to the center tap of said secondary winding; a plurality of voltage outputs, each including a shunt filter capacitor; and inductive filter means comprising a single ferromagnetic core and a plurality of choke windings disposed on said single core, each of said windings connected in series from a related set of said first rectifiers or from one of said second rectifiers to a related one of said outputs, each filter choke winding having a number of turns related to the number of turns of each other choke winding in the same ratio as the output voltage of each choke bears to the output voltage of each other choke such that all of said choke windings have the same number of volts per turn, whEreby said switching power supply comprises a plurality of different voltage outputs, each including a series filter choke wound on said common core, less than all driven by said transformer, at least one driven by the filter choke of another.

Claim 8

A switching power supply comprising: a power transformer having a primary winding and a secondary winding including a plurality of taps to divide said secondary winding into segments; drive means for said transformer including means for providing currents of alternate polarity through said primary winding, thereby to produce at least two different voltages of alternating polarity in said secondary winding; a plurality of first rectifiers connected to the taps on said secondary winding in sets so as to provide full wave rectification of current induced in said secondary winding; at least one second rectifier connected to the center tap of said secondary winding; a plurality of voltage outputs, each including a shunt filter capacitor; and inductive filter means comprising a single ferromagnetic core and a plurality of choke windings disposed on said single core, each of said windings connected in series from a related set of said first rectifiers or from one of said second rectifiers to a related one of said outputs, each filter choke winding having a number of turns related to the number of turns of each other choke winding in the same ratio as the output voltage of each choke bears to the output voltage of each other choke such that all of said choke windings have the same number of volts per turn, whEreby said switching power supply comprises a plurality of different voltage outputs, each including a series filter choke wound on said common core, less than all driven by said transformer, at least one driven by the filter choke of another.

Claim 9

A switching power supply comprising: a power transformer having a primary winding and a secondary winding with a grounded center tap and at least two other taps, one on either side of the center tap, for providing currents of opposite polarity with respect to ground in response to alternate polarity of current in said primary; drive means for said transformer including means for providing currents of alternate polarity through said primary winding, thereby to produce at least one voltage of alternating polarity in said secondary winding; a plurality of voltage outputs, each of said voltage outputs having a shunt filter capacitor; output filter choke means including a single core of ferromagnetic material and a plurality of independent filter choke windings thereon, each of said choke windings connected to a corresponding one of said voltage outputs, each filter choke winding have a number of turns related to the number of turns of each other choke winding in the same ratio as the output voltages of each choke winding bears to the output voltage of each other choke winding such that all of said choke windings have the same number of volts per turn; at least one pair of first rectifiers, each rectifier in a pair connected from a different one of said taps to the same one of said choke windings, each choke winding connected to no more than one pair, both rectifiers in a pair poled to conduct current through the related choke winding in the same polarity; and at least one second rectifier connected from ground to at least one other choke winding.

Claim 10

A switching power supply comprising: a power transformer having a primary winding and a secondary winding with a grounded center tap and at least two other taps, one on either side of the center tap, for providing currents of opposite polarity with respect to ground in response to alternate polarity of current in said primary; drive means for said transformer including means for providing currents of alternate polarity through said primary winding, thereby to produce at least one voltage of alternating polarity in said secondary winding; a plurality of voltage outputs, each of said voltage outputs having a shunt filter capacitor; output filter choke means including a single core of ferromagnetic material and a plurality of independent filter choke windings thereon, each of said choke windings connected to a corresponding one of said voltage outputs, each filter choke winding have a number of turns related to the number of turns of each other choke winding in the same ratio as the output voltages of each choke winding bears to the output voltage of each other choke winding such that all of said choke windings have the same number of volts per turn; at least one pair of first rectifiers, each rectifier in a pair connected from a different one of said taps to the same one of said choke windings, each choke winding connected to no more than one pair, both rectifiers in a pair poled to conduct current through the related choke winding in the same polarity; and at least one second rectifier connected from ground to at least one other choke winding.