LTC4223 LINER [Linear Technology], LTC4223 Datasheet - Page 18

• Manufacturer Part Number: LTC4223
• Description: Dual Ideal Diode and Hot Swap Controller
• Manufacturer: LINER [Linear Technology]

LTC4228-1/LTC4228-2
applicaTions inForMaTion
goes high, allowing ON2 to turn on M
INPUT 2 to the output. Diode D1 ensures that ON2 remains
above 0.6V while in the off state so that when ON2 goes
high, M
100ms turn-on delay. When INPUT 1 returns to a viable
voltage, M
MOSFETs M
to the other under any condition.
Additional Applications
In most applications, the two external MOSFETs are con-
figured with the MOSFET on the supply side as the ideal
diode and the MOSFET on the load side as the Hot Swap
control. But for some applications, the arrangement of the
MOSFETs for the ideal diode and the Hot Swap control may
be reversed as shown in Figure 9. The Hot Swap MOSFET
18
PRIMARY
SUPPLY
BACKUP
SUPPLY
5V
49.9k
H2
20k
12V
R2
R1
is turned on immediately without invoking the
H1
+
D1
turns on and M
INPUT 1
INPUT 2
and M
C
0.1µF
F1
D2
R4
41.2k
prevent backfeeding of one input
0.1µF
Z1
SMAJ13A
Z2
SMAJ13A
C1
H2
turns off. The ideal diode
EN1
ON1
INTV
GND
ON2
EN2
CPO1
CPO2
3.92k
H2
R3
CC
C
0.1µF
and connect the
C
0.1µF
CP1
CP2
Figure 8. 2-Channel Power Prioritizer
LS4148
D1
IN2
IN1
SiR466DP
SiR466DP
DGATE2
DGATE1
M
M
D2
D1
SENSE2
SENSE1
LTC4228
is placed on the supply side and the ideal diode MOSFET
on the load side with the source terminals connected to-
gether. If this configuration is operated with 12V supplies,
the gate-to-source breakdown voltage of the MOSFETs
can be exceeded when the input or output is connected
to ground as the LTC4228’s internal 12V clamps only limit
the DGATE-to-IN and HGATE-to-OUT pin voltages. Choose
a MOSFET whose gate-to-source breakdown voltage is
rated for 25V or more as 24V voltage can appear across
the GATE and SOURCE pins of the MOSFET during an
input or output short. As shown in Figure 9, if a MOSFET
with a lower rated gate-to-source breakdown voltage is
chosen, an external Zener diode clamp is required between
the GATE and SOURCE pins of the MOSFET to prevent it
from breaking down.
0.006
0.006
R
R
+
+
S2
S1
SENSE2
SENSE1
–
–
10
R
SiR466DP
SiR466DP
HGATE1
H1
HGATE2
M
M
H1
H2
R
47
HG1
C
33nF
PWRGD2
STATUS1
PWRGD1
STATUS2
HG1
FAULT1
FAULT2
OUT1
OUT2
TMR1
TMR2
+
C
0.1µF
T2
C
470µF
L
C
0.1µF
T1
422812 F08
V
5A
OUT
422812f