AN2640

Half-bridge design criteria

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Figure 6.

54 W lamp power

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.