HV301/HV311
Application Information, cont’d.
Redundant Supplies
controllers. The HV311 is ideally suited for such applications
since two or more active low PWRGD signals can be connected
to a single active low ENABLE pin, thus enabling the load as long
as at least one primary power source is available. By adding low
current 100V diodes in series with the VDD pins, full reverse
polarity protection on either power source is also provided
(Application Circuit 13).
Many systems use redundant primary power supplies or battery
backup. WhenredundantACpoweredsourcesareusedtheyare
generally diode OR’ed to the load on the hot terminal.
For these systems, the use of independent hotswap controllers
isrecommendedwiththediodeOR’ingprovidedafterthehotswap
D2
GND
8
V
DD
PWRGD
1
R1
487kΩ
3
2
UV
R2
6.81kΩ
HV301/
HV311
PS1
OV
R3
9.76kΩ
RAMP
7
V
4
SENSE GATE
EE
5
6
C1
10nF
-48V
GND
D1
R4
60mΩ
Q1
IRF530
D2
8
V
DD
PWRGD
1
R1
487kΩ
ENABLE / ENABLE
Cload
+5V
3
2
UV
R2
HV301/
HV311
PS2
6.81kΩ
DC/DC
PWM
CONVERTER
COM
OV
R3
9.76kΩ
RAMP
V
SENSE GATE
EE
7
4
5
6
C1
10nF
-48V
D1
Q1
IRF530
R4
60mΩ
Note: capacitor may be needed to slow PWRGD dv/dt if
oscillations are observed when VIN is close to OV.
Application Circuit 13
17
SUPERTEX [ Supertex, Inc ]
