ISL6115 Intersil Corporation, ISL6115 Datasheet - Page 5

• Manufacturer Part Number: ISL6115
• Description: Power Distribution Controllers
• Manufacturer: Intersil Corporation

and as short as possible with zero current in the sense lines.
(See Figure 1.)
TO ISEN AND
Using the ISL6116 as a -48V Low Side Hot
Swap Power Controller
To supply the required V
chip supply 10 to 16V above the -48V bus. This may be
accomplished with a suitable regulator between the voltage
rail and pin 5 (VDD). By using a regulator, the designer may
ignore the bus voltage variations. However, a low-cost
alternative is to use a Zener diode (See Figure 2 for typical
5A load control) this option is detailed below.
Note that in this configuration the PGOOD feature (pin 7) is
not operational as the I
threshold.
See Figures 17 to 20 for waveforms relevant to -48V and
other high voltage application.
CORRECT
1.58kΩ
DD1
R
1W
CL
R
ISET
FIGURE 1. SENSE RESISTOR PCB LAYOUT
12V
LOAD
V
BUS
0.001µF
SENSE RESISTOR
SEN
0.01µF
-48V
CURRENT
DD
FIGURE 2.
, it is necessary to maintain the
pin voltage is always < UV
INCORRECT
5
2kΩ
0.047µF
ISL6115, ISL6116, ISL6117, ISL6120
ISL6116
NC
0.005
1.47kΩ
1%
PWRON
1%
Biasing the ISL6116
Table 3 gives typical component values for biasing the
ISL6116 in a ±48V application. The formulas and
calculations deriving these values are also shown below.
When using the ISL6116 to control -48V, a Zener diode may
be used to provide the +12V bias to the chip. If a Zener is
used then a current limit resistor should also be used.
Several items must be taken into account when choosing
values for the current limit resistor (R
(DD1):
• The variation of the V
• The chip supply current needs for all functional conditions
• The power rating of R
• The current rating of DD1
Formulas
Example
A typical -48V supply may vary from -36 to -72V. Therefore,
V
V
I
Sizing R
Power Rating of R
DD1 Current Rating:
CHIP
1. Sizing R
2. Power Rating of R
3. DD1 Current Rating:
R
R
R
P
P
P
I
I
I
current]
BUS,MAX
BUS,MIN
DD1
DD1
DD1
TABLE 3. TYPICAL VALUES FOR A -48V HOT SWAP
RCL
RCL
RCL
CL
CL
CL
R
P
I
SYMBOL
DD1
CL
RCL
= (V
= (36 - 12)/0.015
= 15mA (max)
= 1.6kΩ [Typical Value = 1.58kΩ]
= (
= (72 - 12)/1.58kΩ
= 38mA [Typical Value = 12V rating, 50mA reverse
DD1
R
= I
= (0.015)(72 - 12)
= 0.9W [Typical Value = 1W]
CL
CL
= (V
= (V
VBUS,MAX
C
= I
BUS,MIN
= -36V
:
= -72V
(V
APPLICATION
CL
C
BUS,MIN
BUS,MAX
BUS,MAX
(V
:
BUS,MAX
1.58kΩ, 1W
12V Zener Diode, 50mA Reverse Current
CL
- 12)/I
- 12)/R
:
- 12)/I
CL
- 12)/R
- 12)
BUS
CL
:
C
- 12)
.
CL
CHIP
(in this case, -48V nominal)
CL
PARAMETER
CL
) and Zener Diode