STGIPL14K60

Smart shutdown function

Doc ID 15589 Rev 3

15/21

4

Smart shutdown function

The STGIPL14K60 integrates a comparator for fault sensing purposes. The comparator

non-inverting input (CIN) can be connected to an external shunt resistor in order to

implement a simple over-current protection function. When the comparator triggers, the

device is set in shutdown state and both its outputs are set to low-level leading the half-

bridge in tri-state. In the common overcurrent protection architectures the comparator output

is usually connected to the shutdown input through a RC network, in order to provide a

mono-stable circuit, which implements a protection time that follows the fault condition.

Our smart shutdown architecture allows to immediately turn-off the output gate driver in

case of overcurrent, the fault signal has a preferential path which directly switches off the

outputs. The time delay between the fault and the outputs turn-off is no more dependent on

the RC values of the external network connected to the shutdown pin. At the same time the

internal logic turns on the open-drain output and holds it on until the shutdown voltage goes

below the logic input lower threshold. Finally the smart shutdown function provides the

possibility to increase the real disable time without increasing the constant time of the

external RC network.

Figure 9.

Smart shutdown timing waveforms

HIN/LIN

HVG/LVG

SD/OD

open drain gate

(internal)

upper

threshold

lower

threshold

comp

Vref

CP+

PROTECTION

Fast shut down:

the driver outputs are set in SD state

immediately after the comparator

triggering even if the SD signal

has not yet reach

the lower input threshold

real disable time

2

1

1

2

SD/OD

FROM/TO

CONTROLLER

SMART

SD

LOGIC

SHUT DOWN CIRCUIT

TIME CONSTANTS