DS12748 Rev 2

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HVLED001B

Application information

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7.1.1

Start-up mode

This state is entered to begin the switching activity (during application's turn-on or exiting

from the low consumption state). The HVSU is involved in the mechanism of VCC charging;

all other peripherals, except the UVLO and logic supply, are turned off to minimize the start-

up time.

Start-up mode ends when the OPTO and FB pins are within respective range of operations

and VCC is higher than VCC,on threshold.

When the device is turned on for the first time or, in other words, when VCC crosses

upwards of the VCC,shd threshold, start-up mode invokes ramp-up mode.

When start-up mode is entered after a low consumption mode, start-up mode invokes active

mode.

Figure 19. Initial start-up phase