AN809

AN809 Digitally Addressable DALI Dimming Ballast Authors: Ross Fosler Microchip Technology Incorporated Cecilia Contenti International Rectifier Tom Ribarich International Rectifier INTRODUCTION This reference design is a high efficiency, high power factor and digital dimming electronic ballast designed to drive rapid start fluorescent lamp types. The design contains an active power factor correction circuit for universal voltage input as well as a ballast control circuit using the IR2159. The design also includes a PIC16F628 microcontroller and an isolation circuit for connecting to a Digitally Addressable Lighting Interface (DALI). Other features include EMI filtering, transient protection and lamp FAULT protection. International Rectifier (IR) and Microchip Technology Inc. worked together to design a DALI type ballast. An application note is provided here, and the corresponding reference design is available from IR (see page 10 for ordering information). This document describes many of the details within the design of the ballast and some of the basics to DALI. However, this document does not describe all the details contained within the DALI specification. The reader should be familiar with DALI and international standard EN60929. FIGURE 1: DALI DIMMING BALLAST Features Lamp Type: 1X 36W T8 Lamp (IRPLDIM2E) 1X 32W T8 Lamp (IRPLDIM2U) Line Input: 185-265 VAC/50Hz (IRPLDIM2E) 90-140 VAC/60Hz (IRPLDIM2U) Interface DALI (2 wires) High Power Factor/Low THD Hi...