Smart shutdown function

STGIPS20C60

12/21

DocID024138 Rev 5

4

Smart shutdown function

The STGIPS20C60 integrates a comparator for fault sensing purposes. The comparator has

an internal voltage reference V

ref

connected to the inverting input, while the non-inverting

input, available on pin (C

IN

), 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

halfbridge 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

DMOS connected to the open-drain output (pin SD/OD) is turned on by the internal logic

which holds

it on until the shutdown voltage is lower than the logic input lower threshold

(V

il

). Finally the smart shutdown function provides the possibility to increase the real disable

time without increasing the constant time of the external RC network.