HV301/HV311
Application Information, cont’d.
Reverse Polarity Protection
The UV and OV pins are protected against reverse polarity input
supplies by internal clamping diodes and the fault currents are
sufficiently limited by the impedance of the external resistor
divider, however, a low current diode with a 100V breakdown
rating must be inserted in series with the VDD pin.
This method (shown in Application Circuit 12) will protect the
hotswap control circuit however, due to the intrinsic diode in the
external MOSFET, the load will not be protected from reverse
polarity voltages.
D1
GND
8
V
DD
PWRGD / PWRGD
1
R1
487kΩ
ENABLE / ENABLE
+5V
Cload
3
2
UV
R2
6.81kΩ
HV311
DC/DC
COM
OV
PWM
CONVERTER
R3
9.76kΩ
RAMP
7
V
4
SENSE GATE
EE
5
6
C1
10nF
-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 12
16
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