VIPER06HSTR datasheet(18/28 Pages) STMICROELECTRONICS

18 / 28 page

Burst mode

VIPER06

18/28

Doc ID 022794 Rev 1

Figure 23.

COMP pin voltage versus IDRAIN

Burst mode

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

the OFF state and the consumption is reduced to the IDD0 current, as reported on Table 6 on

page 7. In reaction to the loss of energy, the VCOMP voltage increases and as soon as it

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

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

“burst mode” and shown in Figure 24 on page 18, 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 burst mode, the drain

current limit is reduced to the value IDlim_bm (given inTable 7 on page 8) in order to avoid the

audible noise issue.

Figure 24.

Load-dependent operating modes: timing waveforms

AM01095v1

VCOMPH

VCOMPL

IDlim_bm

IDlim

IDRAIN

VCOMP

time

COMP

COMPL +VCOMPL_HYS

COMPL

DD1

DD0

DRAIN

Dlim_bm

Burst Mode

VIPER06HSTR Datasheet(PDF) 18 Page - STMicroelectronics