33480 datasheet(26/39 Pages) FREESCALE

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Analog Integrated Circuit Device Data

Freescale Semiconductor

33480

PROTECTION AND DIAGNOSIS FEATURES

The current recopy feature for OUT1:5 is disabled during

high overcurrent shutdown phase (t2) and is only enabled

during low overcurrent shutdown threshold. The current

recopy output delivers current only during ON time of the

output switch without overshoot (aperiodic settling).

The current recopy is not active in Fail Mode.

TEMPERATURE PREWARNING

The 33480 provides a temperature prewarning reported

via SPI (OTW bit) in Normal Mode. The information is

latched. To delatch, a read SPI command is needed. In case

of Power on Reset, the fault will be reset.

EXTERNAL TERMINAL STATUS

The 33480 provides the status of the FLASHER, IGN, and

CLOCK terminals via SPI in real time and in Normal Mode.

FAILURE HANDLING STRATEGY

A highly sophisticated failure handling strategy enables

light functionality even in case of failures inside the

component or the light module. Components are protected

against:

• Reverse Polarity

• Loss of Supply Lines

• Fatal Mistreatment of Logic I/O Terminals

REVERSE POLARITY PROTECTION ON VBAT

In case of permanently reverse polarity operation, the

output transistors are turned ON (Rsd) to prevent thermal

overload and no protections are available.

External diode on Vcc is necessary in order to not destroy

the 33480 in case of reverse polarity.

In case of negative transients on the VBAT line (per

ISO 7637), the VCC line is still operating, while the VBAT line

is negative. Therefore, the device is protected against latch-

up.

LOSS OF SUPPLY LINES

The 33480 is protected against loss of any supply line. The

detection of the supply line failure is provided inside the

device itself.

LOSS OF VBAT

During undervoltage of VBAT (VBATPOR<VBAT<VBATUV)

and with active device (wake=1), the outputs [1-5] are

switched off and the external MOSFET remains in the

previous state. No current path from Vbat to Vcc. The

external MOSFET (OUT6) can be controlled by SPI if Vcc

remains and is above to VCCUV. The fault is reported to UVF

bit (OD13). To delatch the fault, the undervoltage condition

should be removed and:

• The bit D7 must be rewritten to logic [1] in Normal Mode.

Application of OCHI window depends on toggling or not

toggling D7 bit. When the fault is delatched, the 33480

returns in the configuration it was just before the failure.

• If the device was in Fail mode, the fault will be delatched

by the Autorestart feature periodically.

In case of VBAT<VBATPOR (Power OFF state), all latched

faults are reset if VCC < VBAT. In case of VBAT is missing, all

outputs (out[1:6]) are OFF and no current is conducted from

Vcc to VBAT.

LOSS OF VCC (DIGITAL LOGIC SUPPLY LINE)

During loss of VCC (VCC < VCCUV) and with wake=1, the

33480 is switched automatically into Fail mode (no deglich

time). The external SMART MOSFET is OFF. All SPI

registers are reset and must be reprogrammed when Vcc

goes above VCCUV.

LOSS OF GROUND (GND)

During loss of ground, the 33480 cannot operate the loads

(the outputs (1:5) are switched OFF) but is not destroyed by

the operating condition. Current limit resistors in the digital

input lines protect the digital supply against excessive current

(1kohm typical). The state of the external smart power switch

controlled by FETout is not guaranteed and the state of

external smart MOS is defined with external termination

resistor.

FATAL MISTREATMENT OF LOGIC I/O

TERMINALS

The digital I/Os are protected against fatal mistreatment

by signal plausibility check according to Table 6.

In case of LIMP input is set to logic [1] for a delay longer

than 10ms typical, the 33480 is switched into Fail mode. In

case of (PWM) Clock failure, no PWM feature is provided and

Table 6. Logic I/O Plausibility Check

Input/Output

Signal Check Strategy

LIMP

Debounce for 10 ms

(PWM) CLOCK

Frequency range

(bandpass filter)

SPI (MOSI, SCLK, CS)

WD, D10 bit internal toggle

33480 Datasheet(PDF) 26 Page - Freescale Semiconductor, Inc

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