L9788 datasheet(128/264 Pages) STMICROELECTRONICS

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Pre-drivers - IGNITER IGN[1:6]

L9788

128/264

DS12308 Rev 4

Pre-drivers - IGNITER IGN[1:6]

These 6 Ignition pre-drivers are designed to drive ignition load. They are driven by MSC

command. The push-pull stage is made up of a high-side current generator and a low-side

driver.

When an overcurrent fault is detected the driver switches off with higher slew rate (FAST

SR) to reduce the power dissipation.

There is a bit selection for disabling the LSD in case of external IGBT. It is suggested to

configure the MSC bit (IGN_LSD_DIS CONFIG_REG6 D7) disabling the LSD of igniter

before the msc_driver_enable command.

Figure 51. Ignition pre-drivers block schematic

10.1

Ignition pre_drivers diagnosis

The driver has the following detection diagnosis:



Short To Vbat protection by checking the IGNx pin voltage higher than Vth_STB_IGN,

when the driver is enabled high (high-side on) or low (low-side on);



Open Load when the driver is enabled high (high-side on) (DIAGOL);



Short to Ground when the driver is enabled high (high-side on) (DIAGLV).

GADG0512161455PS

GND1

IGNx

IGN Pre-Driver

OFF state

STB detection

ON state

STB, STG, OL detection

MSC Command

Driver

MSC LS_dis Command

HS current generator

LOAD

VBAT

PGND

L9788 Datasheet(PDF) 128 Page - STMicroelectronics