HV301/HV311
PWRGD Output
then the HV311 can be directly connected as shown below
(Application Circuit 1) since the open drain PWRGD output is
in a High-Z state until the external MOSFET is fully turned on and
the potential on the negative input of the converter is essentially
the same as the VEE pin of the HV311.
ItiscriticaltohaveadetailedunderstandingoftheENABLEinput
circuitry of the load (DC/DC PWM Converter) in order to make
the correct choice between the HV301 or HV311.
Many DC/DC PWM Converters reference their ENABLE inputs
tothenegativeinputterminal. IftheENABLEinputisactiveLOW
GND
8
V
DD
PWRGD
1
R1
487kΩ
ENABLE
+5V
3
2
+
UV
Cload
R2
6.81kΩ
HV311
OV
DC/DC
PWM
COM
R3
9.76kΩ
-
CONVERTER
V
RAMP
7
SENSE
GATE
6
EE
4
5
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 1
10
SUPERTEX [ Supertex, Inc ]
