VIPER06

Automatic auto-restart after overload or short-circuit

Doc ID 022794 Rev 1

19/28

14

Automatic auto-restart after overload or short-circuit

The overload protection is implemented automatically using the integrated up-down counter.

Every cycle, it is incremented or decremented depending upon the current logic detection of

page 11. After the reset of the counter, if the peak drain current is continuously equal to the

MOSFET switch ON will be disabled. It will be activated again through the soft-start after the

Table 7 on page 8.

For overload or short-circuit events, the power MOSFET switching will be stopped after a

sequence continues until the overload condition is removed, see Figure 25 and Figure 26.

This protection ensures a low repetition rate of restart attempts of the converter, so that it

works safely with extremely low power throughput and avoids overheating the IC in case of

repeated overload events. If the overload is removed before the protection tripping, the

counter will be decremented cycle-by-cycle down to zero and the IC will not be stopped.

Figure 25.

Timing diagram: OLP sequence (IC externally biased)

Figure 26.

Timing diagram: OLP sequence (IC internally biased)

time

time

V

DD

V

DDon

V

DDCSon

I

DRAIN

I

Dlim_bm

t

1

*

* The time t

t

RESTART

t

SS

t

OVL

t

RESTART

t

SS

t

OVL

t

RESTART

t

SS

SHORT CIRCUIT

OCCURS HERE

SHORT CIRCUIT

REMOVED HERE

time

time

V

DD

V

DDon

V

DDCSon

I

DRAIN

I

Dlim_bm

t

1

*

* The time t

t

RESTART

t

SS

t

OVL

t

RESTART

t

SS

t

OVL

t

RESTART

t

SS

SHORT CIRCUIT

OCCURS HERE

SHORT CIRCUIT

REMOVED HERE