Demonstration board schematic and bill of material

AN2982

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Doc ID 15599 Rev 1

limiting that maintains the frequency constant is not suitable to counter this effect. Actually

the application should be stopped as soon as the saturation effect is detected.

Figure 22.

Ballast anti-choke saturation protection

Asymmetrical ageing of the lamp is detected by the EOL pin. Figure 23 and 24 illustrate the

When the lamp starts ageing, the lamp voltage increases in one direction. The EOL voltage

(lower trace) moves together with the blocking capacitor voltage. Once the difference

and the application is stopped if this situation persists.

Figure 23.

EOL protection (positive deviation)