Smart shutdown function

STGIPN3H60

14/21

Doc ID 018957 Rev 3

4

Smart shutdown function

The STGIPN3H60 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 overcurrent 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 3-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 6.

Smart shutdown timing waveforms

Please refer to

Table 12 for internal propagation delay time details.

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