Browse Prior Art Database

Microprocessor World-Wide Line Voltage Controller

IP.com Disclosure Number: IPCOM000039818D
Original Publication Date: 1987-Aug-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Clemo, RM: AUTHOR [+3]

Abstract

A technique is described whereby an electrical circuit, using digital codes to represent the range of an AC voltage, provides the controls necessary to enable a single power supply to function in accordance with all world-wide line voltage specifications. The circuit also eliminates the need to insert or remove jumpers, or engage a mechanical switch, as was required in the prior art. As a result, utilizing this circuit enables a computer system, or similar units, to install only one power supply type, regardless of the voltage ranges seen by that system. The electrical circuit to provide the voltage control is shown in the figure and, for simplification, components such as clamping diodes, decoupling capacitors, pull-ups and rectifier filter are not shown.

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Microprocessor World-Wide Line Voltage Controller

A technique is described whereby an electrical circuit, using digital codes to represent the range of an AC voltage, provides the controls necessary to enable a single power supply to function in accordance with all world-wide line voltage specifications. The circuit also eliminates the need to insert or remove jumpers, or engage a mechanical switch, as was required in the prior art. As a result, utilizing this circuit enables a computer system, or similar units, to install only one power supply type, regardless of the voltage ranges seen by that system. The electrical circuit to provide the voltage control is shown in the figure and, for simplification, components such as clamping diodes, decoupling capacitors, pull- ups and rectifier filter are not shown. The internal voltage VI is derived from a bulk voltage, and the bulk voltage is proportional to the AC input voltage. The bulk voltage is encoded through hysteresis comparators 10 and 11 to provide a two-bit code to microprocessor 12. The thresholds of comparators 10 and 11 are based on the normal AC line voltage tolerances and the minimum and maximum voltages allowed for the power supply circuits. The hysteresis enables operation to continue during power line disturbances. Power is supplied to the circuit at VI, which derives its power from the AC line, and is present before any switching occurs within the circuit. The portion of the circuit shown within the d...