VIPER26 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

VIPER26

Fixed frequency VIPer™ plus family

STMicroelectronics 

Burst mode

Figure 24. COMP pin voltage versus IDLIM



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, 'OLP

VIPER26

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9&203/

9&203+

9&203

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13 Burst mode

When the voltage VCOMP drops below the threshold, VCOMPL, the power MOSFET is kept in

OFF state and the consumption is reduced to IDD0 current, as reported on Table 7 on

page 6. As reaction at the energy delivery stop, the VCOMP voltage increases and as soon

as it exceeds the threshold VCOMPL + VCOMPL_HYS, the converter starts switching again with

consumption level equal to IDD1 current. This ON-OFF operation mode, referred to as “burst

mode” and reported on Figure 25 on page 16, reduces the average frequency, which can go

down even to a few hundreds hertz, thus minimizing all frequency-related losses and

making it easier to comply with energy saving regulations. During the burst mode, the drain

current limit is reduced to the value IDlim_bm (reported on Table 8 on page 7) in order to

avoid the audible noise issue.

Figure 25. Load-dependent operating modes: timing diagrams

VCOMP

VCOMPL +VCOMPL_HYS

VCOMPL

IDD

IDD1

IDD0

IDRAIN

IDlim_bm

Burst Mode

time

time

time

16/25

Doc ID 17736 Rev 2

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