AN2654 Datasheet, PDF (5/26 Pages) STMicroelectronics – CCFL backlight half-bridge topology based on L6574 and STD7NS20

AN2654
Figure 4. PCB bottom-side view
Board description
1.2
Schematic
This CCFL backlighting solution is designed for 17" LCD monitors. This development design
board is able to drive 4 tubes of CCFL. During normal conditions, the L6574 provides a
current loop that is controlled by varying the switching frequency. The input DC bus voltage
has been lifted to 110 V. This reference design provides an open lamp protection,
overvoltage protection, soft-start time setting, and analog and digital dimming functions.
Figure 5 shows the application schematic and Table 2 gives the bill of materials.
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