MC33984CHFK FREESCALE [Freescale Semiconductor, Inc], MC33984CHFK Datasheet - Page 21

• Manufacturer Part Number: MC33984CHFK
• Description: Dual Intelligent High-current Self-protected Silicon High Side Switch (4.0 mOhm)
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

FAULT MODE
driving the
OVER-TEMPERATURE FAULT (NON-LATCHING)
shutdown circuitry in each output structure. Over-
temperature detection is enabled when an output is in the ON
state.
results in the faulted output turning OFF until the temperature
falls below the T
until action is taken by the MCU to shut OFF the output, or
until the offending load is removed.
in the status register and cleared after either a valid SPI read
or a power reset of the device.
OVER-VOLTAGE FAULT (NON-LATCHING)
fault (OVF) condition on the VPWR pin. The output remains
in the OFF state until the over-voltage condition is removed.
When experiencing this fault, the OVF fault bit is set in the bit
OD1 and cleared after either a valid SPI read or a power reset
of the device.
disabled trough the SPI (bit OV_dis).
UNDER-VOLTAGE SHUTDOWN (LATCHING OR
NON-LATCHING)
6.0 V. As long as the V
specified range, the internal logic states within the device will
be sustained.
voltage threshold (VPWRUV) output will turn off, FS will go to
Logic [0], and the fault register UVF bit will be set to 1.
recovers :
SPI (bit UV_dis = 1). In this case, the FS and UVF bits do not
Analog Integrated Circuit Device Data
Freescale Semiconductor
The 33984 indicates the following faults as they occur by
• Over-temperature fault
• Open load fault
• Over-current fault (high and low)
• Over-voltage and under-voltage fault
The 33984 incorporates over-temperature detection and
For the output, an over-temperature fault (OTF) condition
When experiencing this fault, the OTF fault bit will be set
The 33984 shuts down the output during an over-voltage
The over-voltage protection and diagnostic can be
The output(s) will latch off at some battery voltage below
In the case where battery voltage drops below the under-
Two cases need to be considered when the battery level
• If output(s) command is (are) low, FS will go to Logic [1]
• If the output command is ON, then FS will remain at
The under-voltage protection can be disabled through the
but the UVF bit will remain set to 1 until the next read
operation.
Logic [0]. The output must be turned OFF and ON again
to re-enable the state of output and release FS . The
UVF bit will remain set to 1 until the next read operation.
FS
pin to Logic [0]:
SD(HYS)
. This cycle will continue indefinitely
DD
level stays within the normal
PROTECTION AND DIAGNOSIS FEATURES
fault condition is removed, except for over-current and in
some cases under-voltage.
available (and reset) via the SO pin during the first valid SPI
communication (refer to
report any under-voltage fault condition and the output state
will not be changed as long as battery voltage does not drop
any lower than 2.5 V.
OPEN LOAD FAULT (NON-LATCHING)
each output. Output open load fault (OLF) is detected and
reported as a fault condition when that output is disabled
(OFF). The open load fault is detected and latched into the
status register after the internal gate voltage is pulled low
enough to turn OFF the output. The OLF fault bit is set in the
status register. If the open load fault is removed, the status
register will be cleared after reading the register.
OL_dis).
detection circuitry (OL_dis bit sets to logic [1]) in case
of permanent open load fault condition.
OVER-CURRENT FAULT (LATCHING)
detection levels (I
high detection levels (I
The two selectable, simultaneously active over-current
detection levels, defined by I
Figure
(I
current low detect level and the over-current condition
exceeds the programmed over-current time period (t
device will latch the effected output OFF.
then the device will immediately latch the fault and turn OFF
the output, regardless of the selected t
until the device is commanded OFF and then ON again.
REVERSE BATTERY
low as -16 V. Under these conditions, the output’s gates are
enhanced to keep the junction temperature less than 150°C.
The ON resistance of the output is fairly similar to that in the
Normal mode. No additional passive components are
required.
OCL0
The
Fault information is retained in the fault register and is
The 33984 incorporates open load detection circuitry on
The open load protection can be disabled trough SPI (bit
The device has eight programmable over-current low
If the load current level ever reaches the selected over-
If at any time the current reaches the selected I
For both cases, the device output will stay off indefinitely
The output survives the application of reverse voltage as
: I
6. The eight different over-current low detect levels
FS
OCL7
It is recommended to disable the open load
pin will automatically return to Logic [1] when the
) are likewise illustrated in
OCL
PROTECTION AND DIAGNOSIS FEATURES
) and two programmable over-current
OCH
Table
FUNCTIONAL DEVICE OPERATION
) for maximum device protection.
OCH
17).
and I
OCL
OCL
Figure
, are illustrated in
driver.
6.
OCH
OCx
level,
), the
33984
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