FUNCTIONAL DEVICE OPERATION
PROTECTION AND DIAGNOSTIC FEATURES
(OLLED[0:3] bit set to logic [1]). In the cases where load
current drops below the defined current threshold, the OLON
bit is set to logic [1], and the output stays ON and FS will not
be disturbed.
AUTORETRY
The autoretry circuitry is used to reactivate the output(s)
automatically in case of over-current or over-temperature or
under-voltage failure conditions to provide a high availability
of the load.
Open-load Detection In On State For Led
Autoretry feature is available in Fault mode. It is activated
in case of internal retry signal is set to logic [1]:
Open load for LEDs only (OLLED[0:3] set to logic [1]) is
detected periodically each tOLLED (fully-on, D[6:0]=7F). To
detect OLLED in the fully-on state, the output must be ON at
least tOLLED.
retry[x] = OC[x] or OT[x] or UV.
The feature retries to switch-on the output(s) after one
autoretry period (tAUTO) with a limitation in term of number of
occurrence (16 for each output). The counter of retry
occurrences is reset in cases of mode transitions (refer to
NORMAL & Fail Safe MODE TRANSITIONS) and Retry_dis
bit toggling. At each autoretry, the over-current detection will
be set to default values in order to sustain the inrush current.
To delatch the diagnosis, the condition should be removed
and SPI read operation is needed (OL_ON[0:3] bit). The ON
output open-load protection can be disabled through SPI
(OLON_DIS[0:3] bit).
Analog Current Recopy and Temperature Feedbacks
The Figure 12 describes the autoretry state machine.
The CSNS pin is an analog output reporting a current
proportional to the designed output current or a voltage
proportional to the temperature of the GND flag (pin #14).
The routing is SPI programmable (TEMP_en, CSNS_en,
CSNS_s[1,0] and CSNS_ratio_s bits).
DIAGNOSTIC
Output Shorted to VPWR Fault
The 10XS3412 incorporates output shorted to VPWR
detection circuitry in OFF state. Output shorted to VPWR fault
is detected if output voltage is higher than V
In case the current recopy is active, the CSNS output
delivers current only during ON time of the output switch
without overshoot. The maximum current is 2.0 mA typical.
The typical value of external CSNS resistor connected to the
ground is 4.7 kΩ.
and
OSD(THRES)
reported as a fault condition when the output is disabled
(OFF). The output shorted to VPWR fault is latched into the
status register after the internal gate voltage is pulled low
enough to turn OFF the output. The OS[0:3] and
OL_OFF[0:3] fault bits are set in the status register and FS
pin reports in real time the fault. If the output shorted to
VPWR fault is removed, the status register will be cleared
after reading the register.
The current recopy is not active in Fail-safe mode.
Temperature Prewarning Detection
In Normal mode, the 10XS3412 provides a temperature
prewarning reported via SPI in case of the temperature of the
GND flag is higher than TOTWAR. This diagnosis (OTW bit set
to [1]) is latched in the SPI DIAGR0 register. To delatch, a
read SPI command is needed.
The open output shorted to VPWR protection can be
disabled through SPI (OS_DIS[0:3] bit).
Open-Load Faults
ACTIVE CLAMP ON VPWR
The 10XS3412 incorporates three dedicated open-load
detection circuitries on the output to detect in OFF and in ON
state.
The device provides an active gate clamp circuit in order
to limit the maximum transient VPWR voltage at
VPWR(CLAMP). In case of an overload on an output, the
corresponding output is turned off, which leads to a high-
voltage at VPWR with an inductive VPWR line. When VPWR
voltage exceeds VPWR(CLAMP) threshold, the turn-off on the
corresponding output is deactivated and all HS[0:3] outputs
are switched ON automatically to demagnetize the inductive
Battery line.
Open-load Detection In Off State
The OFF output open-load fault is detected when the
output voltage is higher than VOLD(THRES) pulled up with
internal current source (IOLD(OFF)) and reported as a fault
condition when the output is disabled (OFF). The OFF Output
open-load fault is latched into the status register or when the
internal gate voltage is pulled low enough to turn OFF the
output. The OL_OFF[0:3] fault bit is set in the status register.
If the open load fault is removed (FS output pin goes to high),
the status register will be cleared after reading the register.
For a long battery line between the battery and the device
(> 20 meters), the smart high side switch output may exceed
the energy capability in case of a short-circuit. It is
recommended to implement a voltage transient suppressor
to drain the battery line energy.
The OFF output open-load protection can be disabled
through SPI (OLOFF_DIS[0:3] bit).
REVERSE BATTERY ON VPWR
The output survives the application of reverse voltage as
low as -18 V. Under these conditions, the ON resistance of
the output is 2 times higher than typical ohmic value in
Open-load Detection In On State
The ON output open-load current thresholds can be
chosen by SPI to detect a standard bulbs or LEDs
10XS3412
Analog Integrated Circuit Device Data
Freescale Semiconductor
32
FREESCALE [ Freescale ]
