VIPER16

Automatic auto restart after overload or short-circuit

Doc ID 15232 Rev 5

17/25

14

Automatic auto restart after overload or short-circuit

The overload protection is implemented in automatic way using the integrated up-down

counter. Every cycle, it is incremented or decremented depending if the current logic detects

Figure 13 on page 9. After the reset of the counter, if the peak drain current is continuously

be disabled the power MOSFET switch ON. It will be activated again, through the soft start,

values on Table 8 on page 7.

In case of overload or short-circuit event, the power MOSFET switching will be stopped after

protection will occur in the same way until the overload condition is removed, see Figure 25

and Figure 26 on page 17. This protection ensures restart attempts of the converter with low

repetition rate, so that it works safely with extremely low power throughput and avoiding the

IC overheating 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