IXHQ100 IXYS [IXYS Corporation], IXHQ100 Datasheet - Page 8

• Manufacturer Part Number: IXHQ100
• Description: Negative Voltage Hot Swap Controller with Active Power Filter
• Manufacturer: IXYS [IXYS Corporation]

Vcc, then GSNSin pin can be used to detect
the presence or absence of -Vin. If INV is
connected to AGND, then GSNSin pin can be
used to detect the presence or absence of
Gnd.
COMP2 output goes high whenever an
overcurrent or a short circuit condition is
detected. The inverting input to COMP2 is
connected to the VCL output pin which is
internally set at approximately 120mV. As
shown in Figure 1, one side of R4 is in series
with the source of Q1, the drain output of which
drives the load connected to J8. The return
side of R4 is connected to -Vin through J1. For
R4 = 0.02 , Q1 source currents greater than
6A will turn on COMP2 and will be considered
either an overcurrent or short circuit event.
COMP3 goes high whenever the voltage at
OUTsns with respect to AGND becomes less
than 0.1*VCL(approximately 12mV). This can
only occur if either the current drawn by the driven
load is less than 600mA (12mV/.02) or -V
disconnected. This Auto-Disconnect technique
automatically detects load disconnections
without needing additional sensors.
Thus the SRFF1 will reset when one of the
following events occur:
A valid S input into SRFF1 will immediately
drive its output, Q1, to high and will turn on both
N5 and N4. N5, an open drain output, will result
in RSTout being driven low. A current limiting
resistor, R1, in series with a 4N35 LED
connected to V
generate an isolated reset pulse. Turning on
N4 will discharge C7 and the internal 10pF
capacitor (fig 2). As soon as V
V
through NOR1 and NOR2, and resets SRFF1
DROP
=~0.9V, COMP4 in Figure 2 will turn on
1. Loss of AGND or -Vin.
2. Overcurrent or short circuit.
3. Auto-Disconnection
DD
(fig 1)
can be used to
OFFTM
drops below
IN
is
8
with a high applied to its R input. This act will
then turn off both N5 and N4 and allow OFFTM
pin to initiate its positive ramp as a result of I6
charging the capacitors C7 (Figure 1) and C2
(Figure 2) connected to the OFFTM pin.
Restar
Restar
Restart Operation
The IXHQ100 will automatically attempt to
restart once a disconnection and reconnection
is detected. Either PUR or COMP4 going high
will reset SRFF1 during normal operation of
the IXHQ100 (fig 2). Resetting SRFF1 turns off
N4 and N5, and the OFFTM pin ramps up in
response. During this ramp, as long as V
is less than Vrf=~4.5V, COMP1 will keep N3 on
and C1 (Figure 2) and C8 (Figure 1) discharged.
After T
then goes low, turning off N3. Now the SLOPE
pin is free to ramp up as a result of I5 charging
C1 (Figure 2) and C8 (Figure 1). The two unity-
gain buffers, OA4 and OA5, reflect V
GATE output pin during this positive ramp. As
soon as V
operation is resumed.
F F F F F ault Operation
Shor
Shor
Restar
Restar
When the output load current is such that the
voltage drop across the current sense resistor
between the SOURCE pin and the AGND
exceeds VCL (internally set to ~120 mv), the
GATE output is driven low to turn off the external
Power MOSFET connected between the load
and -V
between OFFTM pin and AGND pin determines
the off time T
on sequence of the external Power MOSFET
with a load voltage slope determined by the
size of the external capacitor that is connected
to the SLOPE pin.
Shor
Short Cir
Shor
When the IXHQ100 detects a short in the load,
a restart is automatically initiated. The GOUT
drops to zero and waits one T
SLOPE ramps up. As before, normal operation
is resumed.
ault Operation
ault Operation
ault Operation
ault Operation
t Cir
t Cir
t Circuit Pre
t Cir
off-delay,
in
t Operation
t Operation
t Operation
t Operation
. An external capacitor connected
GATE
cuit Pre
cuit Pre
cuit Pre
cuit Prevention
off-delay.
V
OFFTM
overcomes the V
IXHQ100 will restart the turn
is at Vrf, COMP1 output
vention
vention
vention
vention
IXHQ 100PI
IXHQ 100SI
off-delay
Q1th
SLOPE
, normal
before
at the
OFFTM