FAN7389 Fairchild Semiconductor, FAN7389 Datasheet - Page 14

• Manufacturer Part Number: FAN7389
• Description: The FAN7389 is a monolithic three-phase half-bridge gate-drive IC designed for high-voltage, high-speed driving MOSFETs and IGBTs operating up to +600V
• Manufacturer: Fairchild Semiconductor

© 2010 Fairchild Semiconductor Corporation
FAN7389 • Rev. 1.0.1
2.4 Fault-Out (
FAN7389 provides an integrated fault output (
an adjustable fault-clear timer (t
situations that cause the gate driver to report a fault via
the
low-side gate driver supply voltage (V
second is when the current-sense pin (CS) recognizes a
fault. Once the fault condition occurs, the
internally pulled to COM, the fault-clear timer is
activated, and all outputs (HO1,2,3 and LO1,2,3) of the
gate driver are turned off. The fault output stays LOW
until the fault condition has been removed and the fault-
clear timer expires. Once the fault-clear timer expires,
the voltage on the
The fault-clear time (t
current source (I
RCIN pin, as shown in this equation:
The R
discharge curve with respect to the external capacitor
C
capacitor C
The output of current-sense comparator (CS_COMP)
passes a noise filter, which inhibits an over-current
shutdown caused by parasitic voltage spikes of V
This corresponds to a voltage level at the comparator of
V
where V
comparator (CS_COMP) as shown in Figure 41.
Figure 42 shows the waveform definitions of RCIN, FO
and the low-side driver, which uses a soft turn-off
method when an under-voltage condition of the low-side
gate driver supply voltage (V
(CS) recognizes a fault. Once a fault condition occurs,
the
(HO1,2,3 and LO1,2,3) of the gate driver are turned off.
Low-side outputs decline linearly by the internal sink
current source (I
in Figure 42.
t
CSTH+
RCIN
FLTCLR
FO
FO
. The time constant is defined by the external
ON,RCIN
pin is internally pulled to COM and all outputs
CSHYS
-

pin. The first is an under-voltage condition of
Figure 41. Over-Current Protection
RCIN
C
V
RCIN
=60mV is the hysteresis of the current
CSHYS
FO
and the R
of the MOSFET is a characteristic
RCIN
SOFT
I
RCIN

FO
) and Over-Current Protection
=
V
=5A) and an external C
=40mA) for soft turn-off, as shown
FLTCLR
RCIN
pin returns to pull-up voltage.
500mV
ON,RCIN
,
TH
) is determined by an internal
DD
[
s
) or the current-sense pin
]
of the MOSFET.
FLTCLR
-
60mV
). There are two
DD
) and the
RCIN
FO
=440mV,
FO
CS
pin is
at the
) and
.
(1)
FO
14
3. Noise Filter
3.1 Input Noise Filter
Figure 43 shows the input noise filter method, which has
symmetry duration between the input signal (t
the output signal (t
spikes and short pulses. This input filter is applied to the
HINx, LINx, and EN inputs. The upper pair of waveforms
(Example A) shows an input signal duration (t
much longer than input filter time (t
approximately the same duration between the input
signal time (t
The lower pair of waveforms (Example B) shows an
input signal time (t
time (t
between input signal time (t
time (t
Figure 42. R
OUTx
OUTx
OUTPUT
INx
INx
FLTIN
Figure 43. Input Noise Filter Definition
); it is approximately the same duration
).
CIN
INPUT
and Fault-Clear Waveform Definition
) and the output signal time (t
INPUT
OUTPUT
t
t
FLT,IN
FLT,IN
t
INPUT
) slightly longer than input filter
) and helps to reject noise
t
OUTPUT
t
INPUT
INPUT
t
OUTPUT
) and the output signal
Output duration is
same as input duration
FLTIN
www.fairchildsemi.com
INPUT
); it is
OUTPUT
) and
INPUT
).
)