FDMF5833 datasheet(17/25 Pages) ONSEMI

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The 150°C THDN feature is combined with a 125°C

THWN# flag. If the driver temperature reaches 125°C,

the THWN# pin is pulled LOW. If the driver continues

operation and its temperature increases up to 150°C,

thermal shutdown is activated. The SPS module is shut

down by EN LOW and the THWN# flag is de-asserted,

so the VTHWN# returns HIGH. Figure 38 shows the

relationship among THWN#, EN, and driver temperature.

Figure 38.

VTHWN#, VEN vs. Driver Temperature

Catastrophic Fault

SPS FDMF5833 includes a catastrophic fault feature. If

a HS MOSFET short is detected, the driver internally

pulls the EN / FAULT# pin LOW and shuts down the

SPS driver. The intention is to implement a basic circuit

to test the HS MOSFET short by monitoring LDRV and

the state of SW node.

If a HS short fault is detected, the SPS module clocks

the fault latch shutting down the module. The module

requires a VCC POR event to restart.

PWM

LDRV

(internal)

SW-Fault

(internal)

FAULT

(internal)

EN/FAULT#

Potential noise from

adjacent phases switching

HS FET short during

LS FET turning on

false trigger

Normal switching operation

EN/FAULT#

pulled LOW and

driver IC disabled

Figure 39.

Catastrophic Fault Waveform

FDMF5833 Datasheet(PDF) 17 Page - ON Semiconductor