HV301 SUTEX [Supertex, Inc], HV301 Datasheet - Page 6

• Manufacturer Part Number: HV301
• Description: Hotswap, Controllers with Circuit Breaker
• Manufacturer: SUTEX [Supertex, Inc]

Method 1: Inrush independent of I
Programming Inrush and I
V
Design Information, cont’d.
From the calculated resistor values the OV and UV start up
threshold voltages can be calculated as follows:
Where | V
Up Threshold points relative to V
Then
Therefore, the circuit will start when the input supply voltage is
in the range of 38.29V to 59.85V.
UV
OV
And
SENSE
V
V
V
V
EEUV on
EEUV on
EEOV on
EEOV on
Transistor
ON
ON
Pass
=
(
(
(
(
=
V
IN
V
V
OV
UV
)
)
)
)
OV
UV
UVH
GND
OVL
EEUV(on)
10V
OFF
OFF
OFF
=
=
=
=
ON
ON
ON
Undervoltage/Overvoltage Operation
2.5µA
5k
1 26
1 26
1 16
1 16
7.5µA
10µA
.
.
.
.
=
=
1 16
1 26
| and | V
.
.
×
×
×
×
10n
0µA
R
487
R
487
0µA
=
1
1
=
RAMP
R
+
+
k
k
V
V
2
6 81
Ω
Ω
7.5µA
dv
df
EEOV on
R
R
EEUV on
EEOV(on)
R
.
+
2
2
on Cramp constant
during limiting so no
current flowing into cap
3
+
+
+ K –
R
+
+
k
6 81
6 81
3
9 76
Ω
(
(
R
.
R
.
.
GATE
| are Under & Over Voltage Start
3
3
Vgs
+
)
)
–
k
k
k
C 2
9 76
×
Ω
Ω
+
–
×
Ω
EE
.
+
R
R
+
+
.
1
Cgs
1
CB
CB
k
9 76
9 76
R
+
Ω
+
.
.
Cgd
2
R
R
R
(Circuit Breaker)
+
2
k
k
3
2
Ω
Ω
R
+
+
Rsense=12.5mΩ
gm(Vgs-Vt)
3
R
=
= = 59 85
R
3
3
inrush
38 29
.
. V
V
+
–
Vin
(DRAIN)
Cdb
V
Cload=100µF
SENSE
6
1.
2
3. Calculate Isink
4. Calculate C discharge limit
4a. Adjust for Auto - retry disable, if used
5. Note: i = C
.
V SENSE
Rsense =
In this example we assume Auto
In this example we assume Auto - retry is enabled so
ignore 1.6 A,
Note V is fixed and V
Inrush =
Note that RAMP is protected by AC divider and Gate
is clamped internally.
Choose circuit breaker trip point eg. 8A as follows
Choose inrush level, for example Inrush = 1A
= 10 A -Isink = 7.5 A (typical) = iC
≅
⇒
⇒
common node and their other terminals are fixed during inrush)
by conservation of charge on RAMP Node iC = 7.5 A
=
iC
C
2
7 5
2
R
.
e.g. iC = 10 A -Isink -1.6 A
Vt
dv
dt
=
disable
µ ×
µ
max
A
Inrush
IN
C
across C
1
10V
load
7 5
A
100
.
5k
2
µ
Isink
10µA
10µA
µ ×
100
dv
2
e.g.
dt
A C
nF
I
C C
⇒
CB
∴
mV
2
=
µ
load
= 750pF = 0.75nF
2.5M
Inrush *Rsense
iC = 10 A -Isink = 7.5 A
iC = C
10n=Cramp
Inrush =
load
4V
=
µ
RAMP
terminal
2
2
=
100
Ω
⇒
dv
RAMP
dt
5
8
k
mV
C =
Ω
2
= 1.6 A
across C (as they share a
µ
iC
2
×
dv
is constant during limiting
2
=
dt
µ
×
1 : 2
12 5
C
7 5
µ
.
Internal Circuitry
C
2
.
µ ×
load
=
Inrush
m
A C
Inrush = C
2
2
1
mirror
Ω
A
→
×
C 2
load
5
0.75nF
12 5
k
Max Vt of a typical
power FET
µ
Ω
.
m
load
Ω
2
HV301/HV311
Termial
GATE
=
×
2.5 A
dv
dt
Rsense
µ
µ
48V
Vsense
Cload