HV301/HV311
Application Information cont’d.
Extending Circuit Breaker Delay
delay circuit will also effect the current control feedback loop and
will result in a current overshoot during the external pass device
turn on transition to current limit. If the time delay required for the
Circuit Breaker causes excessive current overshoot during the
turn on transition then the following circuit may be used, where
the RC filter is switched on after the completion of the current
limit control function of the hotswap controller.
Connecting a resistor in series with the SENSE pin and a
capacitor between the SENSE and VEE pins as shown in the
following diagram may be used to extend the Circuit Breaker
delay time beyond the 5µs internally set delay time (Application
Circuit 15).
The time delay achievable by this method is limited since this
8
GND
V
DD
1
PWRGD / PWRGD
R1
487kΩ
ENABLE/ ENABLE
Cload
3
2
+5V
UV
R2
6.81kΩ
HV301/
HV311
DC/DC
PWM
CONVERTER
COM
OV
R3
9.76kΩ
RAMP
V
4
SENSE GATE
EE
7
5
6
R5
C2
R4
-48V
Q1
IRF530
12.5mΩ
Note: capacitor may be needed to slow PWRGD dv/dt if
oscillations are observed when VIN is close to OV.
Application Circuit 15
19
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