HV301_05 Datasheet, PDF (18/20 Pages) Supertex, Inc – Hot Swap Controller (Negative Supply Rail)

Extending Circuit Breaker Delay
Connecting a resistor in series with the SENSE pin and a
capacitor between the SENSE and V_EE 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
HV301/HV311
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 hot swap controller.
GND
R1
487kΩ
R2
6.81kΩ
R3
9.76kΩ
8
VDD
3 _UV
2 _OV
1
PWRGD / PWRGD
HV301/
HV311
ENABLE/ ENABLE _+5V
Cload
DC/DC
PWM
COM
CONVERTER
RAMP VEE SENSE GATE
7
4
5
6
-48V
C2 R5
R4
12.5mΩ
Q1
IRF530
Note: capacitor may be needed to slow PWRGD dv/dt if gate
oscillations around are
Latched Operation
observed
when
V_IN
is
close
to
OVLO.
For those applications that need to disable the automatic retry
capability, the following circuit disables the auto retry feature.
Application Circuit 15
GND
R1
487kΩ
R2
6.81kΩ
R3
9.76kΩ
8
VDD
PWRGD / PWRGD ₁
3 _UV
2 _OV
HV301 / HV311
VEE SENSE GATE RAMP
4
5
6
7
ENABLE / ENABLE
Cload
DC/DC
PWM
CONVERTER
+5V
COM
2.5MW
-48V
R4
12.5mΩ
Q1
IRF530
Note: capacitor may be needed to slow PWRGD dv/dt if gate
oscillations around are observed when V_IN is close to OVLO.
18
Application Circuit 17
A092605