Browse Prior Art Database

Notch-Programmed Appliance Coupler for Low/High Utility Voltage Discrimination

IP.com Disclosure Number: IPCOM000044535D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Dobberstein, EA: AUTHOR [+2]

Abstract

This article describes an appliance coupler which provides a simple, effective mechanical means of electrically programming a switching power supply front end for low (100-125 VAC) or high (200-240 VAC) utility voltage applications. A standard IEC appliance connector is used with no internal wiring variations in the connector or cord. Typical off-line switching power supplies employ a rectifier and capacitor-filter combination to establish a DC voltage in the range of 200 to 400 VDC, nominally about 325 V. Switching circuits convert and regulate this voltage into the desired power supply output levels. To derive a common value of bulk voltage from the worldwide menu of AC utility voltages, a bridge rectifier configuration is employed for line voltages of 200-240 VAC and a doubler configuration for 100-125 VAC.

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Notch-Programmed Appliance Coupler for Low/High Utility Voltage Discrimination

This article describes an appliance coupler which provides a simple, effective mechanical means of electrically programming a switching power supply front end for low (100-125 VAC) or high (200-240 VAC) utility voltage applications. A standard IEC appliance connector is used with no internal wiring variations in the connector or cord. Typical off-line switching power supplies employ a rectifier and capacitor-filter combination to establish a DC voltage in the range of 200 to 400 VDC, nominally about 325 V. Switching circuits convert and regulate this voltage into the desired power supply output levels. To derive a common value of bulk voltage from the worldwide menu of AC utility voltages, a bridge rectifier configuration is employed for line voltages of 200-240 VAC and a doubler configuration for 100-125 VAC. Various methods have been devised to select the correct configuration including separate circuit cards for low and high voltage applications, programmed wire sets, such as jumpers or connector plugs, and front-end boost switching regulators that adapt to any line voltage. Another approach has been to include the wire program in the power supply end of the line cord connector. Since various utility voltages each require their own style of connecting cord plug, this latter technique becomes a logical means of achieving the function. Unfortunately, the line cord becomes an electrically non-standard item, and for switching supplies that contain an internal electromagnetic compatability (EMC) filter, inter-contact capacitances in the wire-programmed connector can couple higher frequency noise around the filter since the programming wires must attach to the load side of the filter. Referring to Fig. 1, the appliance coupler receptacle 1 on the power supply is modified to c...