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Analogue dim interface with advanced switch on/off

IP.com Disclosure Number: IPCOM000010541D
Publication Date: 2002-Dec-13
Document File: 1 page(s) / 10K

Publishing Venue

The IP.com Prior Art Database

Abstract

ID609720

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ID609720

Analogue dim interface with advanced switch on/off

    Ballast circuits for operating a discharge lamp equipped with an analogue dim interface are well known. Usually a dim signal that is a DC voltage between 1 Volt and 10 Volt is used. In such a ballast circuit, 1 Volt corresponds to the lowest light level and 10 Volt corresponds to the highest light level. When the dim voltage drops below 1 Volt the light level is not decreased further. A disadvantage of these ballast circuits is that the light can only be switched off by disconnecting the ballast from the mains. This requires an external switch. Furthermore once the ballast has switched off no further communication via the analogue dim interface is possible since the analogue dim interface is usually supplied from the ballast circuit. These disadvantages can be overcome by making sure that the interface is fed by a separate power supply and providing the ballast with means to switch off when the dim signal is lower than for instance 0.5 Volt and on when the dimsignal is higher than 0.5 Volt. The switching on and off of the ballast circuit can for instance be effected by maintaining one or more high frequency switches of a DC-DC-converter or DC-AC- converter comprised in the ballast circuit in a non-conductive state.

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