ISL6160 Datasheet, PDF (7/11 Pages) Intersil Corporation – InfiniBand +12V Bulk and +5V Auxiliary Power Controller

ISL6160
enabling the accompanying voltage converter. The DC-DC
converter then provides a well regulated output voltage to
the IM circuitry.
Available from Intersil is the ISL6160EVAL2. The
ISL6160EVAL2 is a complete InfiniBand Class I (non isolated)
power topology evaluation platform consisting of the ISL6160
and the HIP6006 single output PWM controller. See Figure 2
for a simplified block diagram of the ISL6160EVAL2 platform.
This evaluation platform allows the Infiniband Module (IM)
power supply designer to evaluate the concept of this design
and apply it to a specific IM power requirement. The evaluation
platform is configured for 5V Vout and 3A Iout capability and
exhibits a 92% total efficiency. See Figures 19 and 20 for
ISL6160EVAL2 turn-on and turn-off waveforms.
Additional information for the ISL6160EVAL2 can be found in
application note AN9959.
VB_IN
VA_IN
DC-DC_ON
VB_ON
VB CONTROL
ISL6160
VA CONTROL
EN
HI GATE
HIP6006
LO_GATE
Vout
LCL_POWER_EN
VBX_EN_L
VAout
FIGURE 2. SIMPLIFIED ISL6160EVAL2 BLOCK DIAGRAM
Using the ISL6160 beyond IM Applications
-48V, +5V Control Circuit
The ISL6160 can also be used for -48V and +5V telecom power
control. The VB portion of the ISL6160 configured as a low side
switch controller as shown in Figure 3. is capable of controlling
several hundreds of volts, positive or negative and at the same
time provide control and protection for the +5V supply with its
1A integrated current regulating function.
Biased by an external 12V reference in the low side switch
configuration the ISL6160 retains all of its features except for
the DC-DC_EN feature. This is nonfunctional in the low side
configuration as V_ISEN is always near 0V and will not pull high
to indicate that voltage is good.
When controlling a negative voltage the VB_ON control can
be implemented through an optocoupler for on-off control or
left open for an always on hot pluggable adaptor card
application .
-48V
-
-48V
LOAD
0V +
1
14
2
13
3 _ISL6160 12
4
11
5
10
6
9
7
+5V
8+
+5V
LOAD
-
12V
REG
FIGURE 3. -48V/+5V APPLICATION CIRCUIT
Application Considerations
The manufacturers’ MOSFET safe operating area (SOA) data
should be consulted, as during the soft start ramp and current
regulation times, the VGS of the external N-Channel MOSFETs
is reduced driving the N-Channel MOSFET switch into the
(linear region) high rDS(ON) state. Thus avoid extended soft
start and time out periods as the external N-Channel
MOSFETs may be damaged or destroyed due to excessive
internal power dissipation. Refer to the MOSFET
manufacturers’ data sheets for SOA information.
With the high levels of inrush current e.g., highly capacitive
loads and HDD motor start up currents, choosing the ramp up
rate and regulation level of the load current is crucial to provide
both protection and still allow for this inrush current without
latching off. Consider this in addition to the time out delay when
choosing MOSFETs for your design.
Correct physical layout of RSENSE resistor is critical to the
accuracy of sensing the VB current. Ideally trace routing
between the R_SENSE resistors and the ISL6160 is direct and as
short as possible with zero current in the sense lines. (See
Figure 4.)
CORRECT
INCORRECT
TO ISEN AND
R_ISET
CURRENT
SENSE RESISTOR
FIGURE 4. SENSE RESISTOR PCB LAYOUT
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