L99PM72PXP datasheet(25/128 Pages) STMICROELECTRONICS

Part #	L99PM72PXP

Description	Advanced power management system IC with embedded LIN and high speed CAN transceiver supporting CAN Partial Networking

PDF	128 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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25 / 128 page

L99PM72PXP

Detailed description

Doc ID 023553 Rev 3

25/128

serve the watchdog by alternating the watchdog trigger bit within the safe trigger area (refer

to Figure 32).

A correct watchdog trigger signal immediately starts the next cycle.

After 8 watchdog failures in sequence, the V1 regulator is switched off for 200 ms. If

subsequently, 7 additional watchdog failures occur, the V1 regulator is completely turned off

and the device goes into VBat_standby mode until a wakeup occurs.

In case of a Watchdog failure, the outputs (RELx, OUTx, V2) are switched off and the device

enters Fail_safe mode (i. e. all control registers are set to default values except the 'OUT3

control bit').

The following diagrams illustrate the Watchdog behavior of the L99PM72PXP. The diagrams

are split into 3 parts. First diagram shows the functional behavior of the watchdog without

any error. The second diagram covers the behavior covering all the error conditions, which

can affect the watchdog behavior. Third diagram shows the transition in and out of FLASH

mode. All 3 diagrams can be overlapped to get all the possible state transitions under all

circumstances. For a better readability, they were split in normal operating, operating with

errors and flash mode.

Figure 10.

Watchdog in normal operating mode (no errors)

L99PM72PXP Datasheet(PDF) 25 Page - STMicroelectronics