EVLB001 Datasheet, PDF (27/35 Pages) ATMEL Corporation – Automatic microcontroller dimmable ballast

Section 7
Conclusion
7.1
Appendix 1:
SWITCH DIM
The ballast demonstrator shows that the AT90PWM2B/216 microcontroller can control
and regulate fluorescent lamps from any of the two (DALI and switch) methods of dim-
ming. It can automatically sense the control method used thereby providing lamp
controller manufacturers with maximum flexibility in their design. One or more lamps can
be controlled with flexibility and precision. 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 more design features than are shown here to enhance their market
position. The ballast demonstrator, although it has many features, does not address all
the possibilities available to the lamp controller designer.
The switch DIM allows dimming control using a simple switch connected to the mains
phase.
Switch DIM operation
The Switch DIM operation is as follows:
With the lamp switched on:
A short push switches the luminary off and stores the current light level.
A long push gradually dims the light level. (Change direction by briefly taking your finger
off the button and pressing down again).
With the lamp switched off:
A short push switches the lamp on to the last light level used. (Optional: Use a soft start
from minimum level to last level used).
A longer push starts on the last light level used and gradually raises the light level to the
required brightness.
The lamps are dimmed for as long as the switch is pressed or until the minimum or max-
imum dimmer setting is reached.
ATAVRFBKIT / EVLB001 User Guide
7-25
7597B–AVR–10/07