Data Sheet

15

Rev. 1.0

2016-08-05

TLE8457

LIN Transceiver with integrated Voltage Regulator

Functional Description

4.4

Initialization Watchdog

The TLE8457 features an enhanced Initialization Watchdog timer for detection of local failures and error

handling for minimizing system current consumption. The benefit of this safety function is to prevent a

malfunctioning ECU being stuck in Init Mode with high current consumption and draining the car battery. The

Operation Mode activation.

Figure 12

Initialization Watchdog

VCC Supply Initialization

power up correctly because of short circuits to ground or if components on the board are drawing too high

currents. The timer is started when the linear regulator is switched on after power-up events or after mode

transitions to Init mode triggered by either bus wake-up or the EN input being set “high” in Sleep Mode.

event.

TLE8457_WATCHDOG

NRST

Normal Operation mode Activation

Init mode

Un-powered

EN

Normal Operation mode

Watchdog

1

2

3

4

Timeout

1

Timeout

2

If Timeout → forced transition to Sleep mode

If Timeout → forced transition to Sleep mode

1

Reset timer elapses → Normal Operation mode Activation Watchdog is started

Mode change with the EN input → Mode transition to normal mode

TxD must be „high“ for at least

5

2

3

4

5