Part # Application Notes Lighting Control L6585D EVAL6585D-230V AN2524 datasheet

Part Manufacturer: ST Microelectronics

ST Microelectronics

Part Description: 54 W / T5 ballast driven by the L6585D


Part Details:

AN2524 Application note 54 W / T5 ballast driven by the L6585D Introduction This application note describes a demo board able to drive a 54 W linear T5 fluorescent lamp. The ballast control is done by the L6585D that integrates PFC and half-bridge control circuits, the relevant drivers, and the circuitry able to manage all lamp operating phases (pre-heating, ignition and run mode). Protections against main failures (lamp disconnection, anti-capacitive mode, PFC over-voltage) are guaranteed and obtained with a minimum number of external components After the circuit description, a short overview of the ballast performances is presented. Fluorescent lamps are driven more and more by electronic, rather than electromagnetic ballast primarily because fluorescent lamps can produce around 10% more light for the same input power when driven above 20 KHz instead of 50/60 Hz. Operation at this frequency also eliminates both light flickering (the response time of the discharge is too slow for the lamp to have a chance to extinguish during each cycle) and audible noise. An electronic ballast consumes less power and therefore dissipates less heat than an electromagnetic ballast. The energy saved can be estimated in the range of 20-25% for a certain lamp power. Finally the electronic solution allows better control of the filament current and lamp voltage during pre-heating with the unquestionable benefit of increasing the mean lamp life. Among electronic solutions for ballasts, ST proposes a new IC - the L6585D - that, embedding both the PFC and half-bridge control sections, allows designing a compact and reliable ballast with a minimum number of external components. Figure 1. Evaluation board May 2007 Rev 1 1/11 www.st.com Contents AN2524 Contents 1 Application specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Board performances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3 Protections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.1 3.1 PFC over-voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.2 PFC open loop (feedback disconnection) . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.3 Choke saturation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.4 Ignition voltage increase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.5 Lamp power increase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.6 Lamp disconnection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2/11 AN2524 Application specifications 1 Application specifications This board has been designed in order to drive a T5 54W lamp with the following characteristics: Table 1. T5 ­ 54 W lamp characteristics Input Mains Lamp


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Application Notes Lighting Control L6585D EVAL6585D-230V AN2524.pdf Datasheet