Ballast Demonstrator User Guide

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7629A–AVR–04/06

Section 6

Conclusion

The ballast demonstrator shows that the Atmel microcontroller and supporting IXYS

devices can control and regulate one or more fluorescent lamps with precision and effi-

ciency, therefore providing the lamp controller manufacturer with maximum flexibility

with their design. Universal input and power factor control adds to the flexibility of the

design with a minimal addition of more expensive active components.

Additionally, the programmability of the microcontroller offers the lamp manufacturer the

flexibility to add or modify design features to enhance their market position. The ballast

demonstrator, with its many features, does not address all the possibilities available to

the lamp controller designer.

6.1

Appendix 1:

Capacitor

Coupled Low

Voltage Supply

Small currents for the low voltage supply can be obtained from the AC line at low loss by

means of capacitor coupling as shown in the figures below. To estimate the required

size of the coupling capacitor, use the following relationships for current, charge, voltage

and capacitance.

1.dQ/dt = I

DC

Figure 6-1. Negative Line Half Cycle

AC

C1

C2

“Negative” line half -cycle:

Vo

Ich1