AN3339 datasheet(22/44 Pages) STMICROELECTRONICS

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Functional check

AN3339

22/44

Doc ID 18449 Rev 2

Figure 37.

Startup at full load and 115 Vac by on/off signal - detail

Output cross regulation has been checked. Resonant feedback signal is obtained by

sensing all three outputs. Therefore, any load change relevant to any output could affect the

other output regulation. The following figures show the effect of load transient on any of the

output loads.

Figure 38 shows output regulation in the case of 12 V load transient from 50 % to maximum

load and vice versa. Because the 12 V output is dedicated to TV panel supply, 50 % of

nominal load is assumed as the minimum load.

Figure 39 shows output regulation in the case of 24 V load transient from minimum to

maximum functional load and vice versa. The 24 V output is dedicated to the audio supply

and load transient is from 0 % to 100 % of nominal load.

Figure 40 shows output regulation in the case of 130 V load transient from minimum to

maximum functional load and vice versa. The 130 V output is dedicated to supplying the

LED backlight. A residual 1 W load is assumed for backlight circuitry driving even at

minimum load.

The maximum measured voltage deviation for 12 V output is 200 mV, for 24 V it is 400 mV

and for 130 V it is 2 V.

CH3: LVG

CH1: HB voltage

CH2: LINE (pin #7)

CH4: Res. current

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