908E621_07 Datasheet, PDF (40/62 Pages) Freescale Semiconductor, Inc – Integrated Quad Half-Bridge and Triple High-Side with Embedded MCU and LIN for High End Mirror

FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
Table 10. High-Side Configuration Bits
HSxPWM HSxON Mode
0
0
High-side MOSFET off
0
1
High-side MOSFET on, in case of overcurrent
the overcurrent flag (HSxOCF) is set and the
High-side MOSFET is turned off
1
0
In this mode the PWM duty cycle is either
controlled by the PWM input signal or in case
the overcurrent shutdown value is reached by
the part itself.
Without reaching the overcurrent shutdown,
the high-side driver is directly driven from the
PWM input signal. If the Input signal is high the
output is on, if low the output is off (PWM
control).
If the current reaches the overcurrent
shutdown value, the high-side will be
automatically turned off, with the next rising
edge of the PWM input signal the output will
turn on again (current limitation). The HSxOCF
bit will be set, software has to distinguish
between an inrush current and a real short on
the output.
1
1
High-side MOSFET is switched on and the
inrush current limitation is enabled, means the
high side will start automatically with an
current limitation around the overcurrent
shutdown threshold. (PWM signal must be
applied, see Figure 24)
If the high-side enters current limitation the
HSxOCF bit is set, but the output is not
disabled. The software needs to take care
about distinguish between an inrush current
and a real short on the output.
High-Side Overvoltage / Undervoltage Protection
The outputs are protected against under- / overvoltage
conditions. This protection is done by the low and high
voltage interrupt circuitry. If an over- under voltage condition
is detected (LVIF / HVIF) and Bit VIS in the High-Side Status
Register is cleared, the output is disabled.
The over- / undervoltage status flags are cleared (and the
output reenabled) by writing a logic [1] to the LVIF / HVIF
flags in the Interrupt Flag Register or by reset. Clearing this
flag has no effect as long as a high or low voltage condition
is present.
HIGH-SIDE OVERTEMPERATURE PROTECTION
The outputs are protected against over temperature
conditions.
Each power output comprises two different temperature
thresholds.
The first threshold is the high temperature interrupt (HTI),
if the temperature reach this threshold the HTI bit in the
interrupt flag register is set and an interrupt will be generated
if HTIE bit in the interrupt mask register is set. In addition this
interrupt can be used to automatically turn off the power
stages (all high-sides, on Half bridges just the high-side
FET’s). This shutdown can be enabled/disabled by Bit
HTIS0.
The high temperature interrupts flag (HTIE) is cleared (and
the outputs reenabled) by writing a logic [1] to the HTIF flag
in the Interrupt Status Register or by reset. Clearing this flag
has no effect as long as a high temperature condition is
present.
If the HTIS shutdown is disabled, a second threshold
(HTR) will be used to turn off all power stages (HB (all Fet’s),
HS, HVDD, H0) in order to protect the device.
High-Side Overcurrent Protection
The HS outputs are protected against overcurrent. When
the overcurrent limit is reached, the output will be
automatically switched off and the overcurrent flag is set.
Due to the high inrush current of bulbs a special feature
was implemented to avoid a overcurrent shutdown during this
inrush current. If a PWM frequency will be supplied to the
PWM input during the switch on of a bulb, the inrush current
will be limited to the overcurrent shutdown limit. This means,
if the current reaches the overcurrent shutdown, the high-
side will be switched off, but each rising edge on the PWM
input will enable the driver again. The duty cycle supplied by
the MCU has no influence on the switch-on time of the high-
side driver.
In order to distinguish between a shutdown due to an
inrush current or a real shutdown, the software has to check
if the overcurrent status flag (HSxOCF) in the High-Side
Status register is set beyond a certain period of time.
908E621
40
Analog Integrated Circuit Device Data
Freescale Semiconductor