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ISL62391, ISL62392 Triple-Output Evaluation
Board User Guide
Introduction
The ISL62391 and ISL62392 evaluation boards demonstrate
the performance of ISL62391 and ISL62392 triple-output
controllers. The ISL62391 and ISL62392 controllers include
two pulse-width modulation (PWM) controllers featured with
Intersil’s patented R
3
technology, output adjustable from
0.6V to 5.5V, and a linear regulator (LDO3) that generates a
fixed 3.3V output and can deliver up to 100mA.
The evaluation board includes two Enable switches, an LED
Power-Good indicator and various test points. Each
switching channel has an on-board dynamic load generator
for evaluating the transient-load response. There are four
different evaluation boards which provide flexible evaluation
options. Table 1 shows a brief description of the evaluation
boards.
What’s Inside
The Evaluation Board Kit contains the following materials:
• ISL6239xxxEVAL1Z Evaluation Board
• ISL62391, ISL62392 Datasheet
• ISL62391, ISL62392 Evaluation Board User Guide (this
document)
What’s Needed
The following materials will be needed in order to perform
testing:
• Adjustable +25V, 30A Power Supply
• +12V, 100mA Power Supply
• Precision Digital Multimeter
• 3 Electronic Loads
• 4-Channel Oscilloscope
Enable Control
The evaluation board provides flexible control logic to enable
or disable the outputs, and to program the two PWM
channels’ start-up sequence. For start-up timing sequence,
please refer to the ISL62391, ISL62392 datasheet
waveforms. Table 2 is the Enable controller truth table.
.
Resistor Current Sense Configuration
The evaluation board is pre-configured with inductor DCR
current sense. For more precise overcurrent protection, it
also provides the option of resistor current sense. Figure 1
shows the configuration for resistor current sense.
For Channel-1, the ISL62391 and ISL62392 monitor the
OCSET1 pin and the ISEN1 pin voltages. Once the OCSET1
pin voltage is higher than the ISEN1 pin voltage for more than
10µs, the ISL62391 and ISL62392 declare an overcurrent
fault. For a chosen overcurrent set point I
OC
and current
sense resistor R
SENSE
, the value of R
OCSET
is determined
by Equation 1:
Where:
-R
OCSET
(Ω) is the resistor used to program the
overcurrent setpoint
-I
OC
is the output current threshold that will activate the
OCP circuit
-R
SENSE
is current sense resistor (R
3
for Channel-1 and
R
25
for Channel-2)
TABLE 1. EVALUATION BOARD DESCRIPTION
EVALUATION BOARD CHANNEL-1 CHANNEL-2 OCP
ISL62391LOEVAL1Z 3.3V/8A 5V/8A ~10A
ISL62391HIEVAL1Z 1.05V/15A 1.5V/15A ~20A
ISL62392LOEVAL1Z 3.3V/8A 5V/8A ~10A
ISL62392HIEVAL1Z 1.05V/15A 1.5V/15A ~20A
TABLE 2. ENABLE TRUTH TABLE
EN1 EN2 START-UP SEQUENCE
Low Low Both Channel outputs OFF simultaneously
Low Float Both Channel outputs OFF simultaneously
Float Low Both Channel outputs OFF simultaneously
Float Float Both Channel outputs OFF simultaneously
Low High Channel-1 OFF, Channel-2 ON
High Low Channel-1 ON, Channel-2 OFF
High High Both Channel outputs ON simultaneously
Float High Channel-1 enabled after Channel-2 is in regulation
High Float Channel-2 enabled after Channel-1 is in regulation
FIGURE 1. RESISTOR CURRENT SENSE CIRCUIT
PHASEx
C
O
L
V
O
OCSETx
ISENx
R
O
ISL62391
I
L
10µA
+
_
V
RSENSE
+
V
ROCSET
_
R
SENSE
R
OCSET
ISL62392
(EQ. 1)
R
OCSET
I
OC
R
SENSE
•
10μA
-------------------------------------
=
July 31, 2008 AN1397.0Application Note
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774
| Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2008. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
