The ISOW14x2 family of devices has multiple protection
features to create a robust system level solution.
- The first feature is an
Enable/Fault protection feature. This EN/FLT pin can be used as either an input
pin to enable or disable the integrated DC-DC power converter or as an output
pin which works as an alert signal if the power converter is not operating
properly. In the /Fault use case, a fault is reported if VDD > 7
V, VDD < 2.5 V, or if the junction temperature >170°C. When a
fault is detected, this pin will go low, disabling the DC-DC converter to
prevent any damage.
- These devices are protected against output overload and short circuit. In cases
of overload or short on power converter output VISOOUT, maximum duty
cycle of power converter is limited. In cases of driver bus short circuit due to
the external power supply cable shorting to the bus cable, or due to bus
contention, short circuit current protection on RS-485 chip restricts the bus
current to ±250 mA maximum.
- Thermal protection is also
integrated to help prevent the device from getting damaged under such scenarios.
An increase in the die temperature is monitored and the device is disabled when
the die temperature becomes 165℃ (typical), thus disabling the short condition.
The device is re-enabled when the junction temperature becomes 155℃ (typical).
If an overload or output short-circuit condition prevails, this protection cycle
is repeated. Care should be taken in the system design to prevent repeated or
prolonged exposure to bus shorts as this exposes the device to high junction
temperatures for extreme amounts of time affecting device reliability.