Power supply filtering

• US 7,082,041 B2
• Filed: 05/20/2003
• Issued: 07/25/2006
• Est. Priority Date: 01/10/2002
• Status: Expired due to Term

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Coffey, Joseph, Hernandez, Delfino
• Primary Examiner(s): Vu, Bao Q.
• Application Number:
  US10/441,332
• Publication Number:
  US 20030197998A1
• Time in Patent Office: 1,162 Days
• Field of Search: 363/39, 363/55, 363/40, 363/49, 363/901
• US Class Current: 363/39
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: Y10S 323/901 Starting circuits
• CPC Class Codes: Y10S 323/908 Inrush current limiters

Abstract

A power supply is filtered while the amount of in-rush current required by the capacitive charging of the filter is limited. A resistor may be placed in parallel with a relay where the parallel combination is in series with the filtering capacitor. The relay is open upon applying power to the filter and remains open while the capacitor at least partially charges to cause charging current to pass through the resistor and thereby limit in-rush current. The relay is closed thereafter to provide a short circuit around the resistor and thereby unrestrict filtering by the capacitor. Alternatively, a common mode choke is disposed between a capacitor across input nodes and a capacitor across output nodes, whereby the size of the capacitors may be reduced to limit the in-rush current due to the common mode choke. The power supply filter may be included as part of a power distribution panel.

Claims

1. A power supply filter, comprising:

first and second power supply input nodes, wherein a power supply voltage is applied across the first and second power supply input nodes;

first and second power supply output nodes;

a first capacitor connected between the first and second power supply input nodes;

a second capacitor connected between the first and second power supply output nodes; and

a common mode choke electrically disposed between the first and second power supply input nodes and the first and second power supply output nodes such that current flows through the common mode choke in a first direction when passing between the first power supply input node and the first power supply output node and such that current flows through the common mode choke in an opposite direction from the first direction when passing between the second power supply output node and the second power supply input node.

2. The power supply filter of claim 1, wherein the first power supply input node and first power supply output node have a negative potential relative to the second power supply input node and the second power supply output node.

3. The power supply filter of claim 1, wherein the common mode choke is toroidal.

4. A method of filtering a power supply, comprising:

applying a power supply voltage across first and second power supply input nodes to pass current to a first capacitor connected across the first and second power supply input nodes, to pass current in a first direction between the first supply input node and a first power supply output node through a common mode choke and to a second capacitor connected across the first power supply output node and a second power supply output node, and to pass current in a second direction opposite the first direction between the second power supply output node and the second power supply input node through the common mode choke.

5. The method of claim 4, wherein the first power supply input node and the first power supply output node have a potential that is negative relative to the second power supply input node and the second power supply output node.

6. The method of claim 4, wherein the common mode choke is toroidal.

7. A power distribution panel, comprising:

an input voltage connector;

a filtering circuit having a first filtering capacitor connected across first and second input nodes, a second filtering capacitor connected across first and second output nodes, and a common mode choke electrically connected between the input and output nodes such that current flows through the common mode choke in a first direction between the first input node and the first output node and flows through the common mode choke in a second direction opposite the first between the second output node and first output node, the filtering circuit being operable to receive voltage across the input nodes through the input voltage connector;

an output voltage connector; and

an over-current protection device electrically connected between an output node of the filtering circuit and the output voltage connector.

8. The power distribution panel of claim 7, wherein the common mode choke is toroidal.

9. The power distribution panel of claim 7, wherein the over-current protection device includes at least one fuse.

10. The power distribution panel of claim 7, further comprising a faceplate, and wherein the filtering circuit includes a light emitting diode operable to illuminate when the filtering capacitor is at least partially charged, the light emitting diode being disposed on the faceplate.