December 2012

1/16

Rev. 3

AN1971

APPLICATION NOTE

ST7LITE0xxx MICROCONTROLLED BALLAST

Demand for flexibility is increasing in new ballast applications. If a designer can use the same

ballast with different tube lamp wattages and types, savings can be made reducing logistic

costs. The aim of this application note is to show designers how the ST7 microcontroller helps

in the design of such a ballast. In addition, it shows how the use of the ST7LITE0xxx micro-

controller adds some attributes facilitating design-work and improving the ballast functionality.

1 INTRODUCTION

Figure 1 shows a diagram of the whole application.

Figure 1. Block Diagram

Half bridge Driver

L6384

Power

Section

ST7LITE0xxx

Microcontroller

Current

Measurement

Voltage

Measurement

=400V

Lamp

1