herunterladen
1
®
ISL62381, ISL62382 Quad-Output Evaluation
Board User Guide
Introduction
The ISL62381 and ISL62382 evaluation boards demonstrate
the performance of ISL62381 and ISL62382 Quad-output
controllers. The ISL62381 and ISL62382 controller include
two pulse-width modulation (PWM) controllers featured with
Intersil’s patented R
3
technology, adjustable from 0.6V to
5.5V, and two linear regulators, LDO5 and LDO3, that
generate a fixed 5V and an adjustable output respectively.
The evaluation board includes two independent Enable
switches, two LED Power-Good indicators and various test
points. Included with each switching channel is 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:
• ISL6238xxxEVAL1Z Evaluation Board
• ISL62381 and ISL62382 Datasheet
• ISL62381 And ISL62382 Evaluation Board User Guide
(this document)
What’s Needed
The following materials will be needed to perform testing:
• Adjustable +25V, 30A Power Supply
• +12V, 100mA Power Supply
• Precision digital multi-meter
• 4 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 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 ISL62381 and ISL62382 monitors 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 ISL62381 and ISL62382 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
ISL62381LOEVAL1Z 3.3V/8A 5V/8A ~10A
ISL62381HIEVAL1Z 1.05V/15A 1.5V/15A ~20A
ISL62382LOEVAL1Z 3.3V/8A 5V/8A ~10A
ISL62382HIEVAL1Z 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
ISL62381
I
L
10µA
+
_
V
RSENSE
+
V
ROCSET
_
R
SENSE
R
OCSET
ISL62382
(EQ. 1)
R
OCSET
I
OC
R
SENSE
•
10μA
-------------------------------------
=
July 31, 2008 AN1396.0Application 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.
