L9662 datasheet(34/80 Pages) STMICROELECTRONICS

34 / 80 page

Functional description

L9662

34/80

DocID028325 Rev 1

functions, and results, will be available through the serial interface. This pin must be pulled

high to initiate the FEN latch function (if programmed) and enable firing of the FET drivers.

The FEN function will be considered active when the pin is active (‘1’ or high) for more than

12 microseconds. Tolerance range for the filter to be used will be 12 to 16 μs.

When the FENx input is active, ‘1’, the FEN function will be active. When the FENx input

state transitions from ‘1’ to ‘0’, the programmable latching function will hold the FEN

function active until the timeout of the FEN timer. The programmable latch and hold

function will be capable of delays of 0ms, 128ms, 256ms, and 512ms. There are 4

independent timers with the timer for FEN1 associated with channels 1 & 2, timer for FEN2

associated with channels 3 & 4, timer for FEN3 associated with channels 5 & 6, and the

timer for FEN4 associated with channels 7 & 8. The timer is reset to the programmed

time when the FENx pin transitions from ‘0’ to ‘1’. The programmable counter delay will

be set through a SPI command.

3.4.4

Squib diagnostics

Overview

The ASIC is able to perform the following diagnostics



Short to battery and ground on both SQHx and SQLx pins with or without a squib



Loop to loop diagnostics



Squib resistance measurement



Squib High resistance



High Side Safing FET diagnostics



VRESx voltage status



High and Low side FET diagnostics

Below is a block diagram showing the components involved in the squib diagnostics.

L9662 Datasheet(PDF) 34 Page - STMicroelectronics