HV301/HV311
Application Information, cont’d.
If separate resistor dividers are used for OV and UV, then only
the positive (VDD) end of the UV resistor divider should be
connected to the short pin (Application Circuit 8).
mated before the hotswap control circuit is enabled and a single
resistor divider string (R1, R2 and R3) is used, then a 6.2V to 10V
zener diode must be connected from the UV pin to the VEE pin,
as seen below in Application Circuit 9.
If a system requires the use of a short connector pin on the
negative supply lead to guarantee that the power pins are fully
Long
Pin
GND
8
Short
Pin
V
DD
PWRGD / PWRGD
1
GND
R1
475K
ENABLE / ENABLE
+5V
Cload
3
2
UV
OV
R3
511K
R2
16.2K
HV311
DC/DC
PWM
COM
CONVERTER
R4
10K
RAMP
7
V
SENSE GATE
EE
4
5
6
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 8
Long
Pin
8
GND
V
DD
PWRGD / PWRGD
1
R1
487kΩ
ENABLE / ENABLE
Cload
+5V
3
2
UV
R2
6.81kΩ
HV311
DC/DC
PWM
COM
OV
CONVERTER
R3
9.76kΩ
RAMP
V
SENSE GATE
EE
7
4
5
6
Short
Pin
6.2V
-48V
C1
10nF
Long
Pin
-48V
R4
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 9
14
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