AN2640 Datasheet, PDF (9/36 Pages) STMicroelectronics – Intelligent multipower digital ballast for fluorescent lamps

AN2640
Figure 6. 54 W lamp power
Half-bridge design criteria
Figure 7. 80 W lamp power
During the preheating phase in this system the half-bridge works at fixed frequency and the
selected preheating frequency is the best choice according to the selected lamp
specifications.
This working frequency guarantees the right preheating current for all lamps that can be
driven by this system.
After tube recognition the microcontroller sets the right run frequency for the connected
lamp.
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