HV301/HV311
Application Information, cont’d.
If a system requires the use of a short connector pin on the
negative supply lead to guarantee that the power pins are fully
mated before the hotswap control circuit is enabled and uses
separate resistor dividers for UV and OV, then a 6.2V to 10V
zenerdiodemustbeconnectedfromtheOVpintotheVEE pinand
only the OV divider should be connected to the short pin
(Application Circuit 10).
Increasing Under Voltage Hysteresis
If the internally fixed under voltage hysteresis is insufficient for a
particular system application, then it may be increased by using
separate resistor dividers for OV and UV and providing a resistor
feedback path from the GATE pin to the UV pin (Application
Circuit 11).
Long
Pin
GND
8
V
DD
PWRGD / PWRGD
1
R1
475kΩ
ENABLE / ENABLE
+5V
Cload
3
2
UV
R2
16.2kΩ
R3
HV301/
HV311
511kΩ
DC/DC
PWM
COM
OV
CONVERTER
R4
10kΩ
RAMP
V
SENSE GATE
EE
7
4
5
6
Short
Pin
-48V
6.2V
C1
10nF
Long
Pin
-48V
R5
12.5mΩ
Q1
IRF530
Note: capacitor may be needed to slow PWRGD dv/dt if
oscillations are observed when VIN is close to OV.
Application Circuit 10
GND
8
V
DD
PWRGD / PWRGD
1
R1
475kΩ
ENABLE / ENABLE
Cload
3
2
+5V
UV
R3
R2
16.2kΩ
HV301/
HV311
511kΩ
DC/DC
PWM
CONVERTER
COM
OV
R4
10kΩ
RAMP
V
4
SENSE GATE
EE
7
5
6
R6
C1
10nF
-48V
R5
12.5mΩ
Q1
IRF530
Note: capacitor may be needed to slow PWRGD dv/dt if
oscillations are observed when VIN is close to OV.
Application Circuit 11
15
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