Intersil ISL62381 User Manual

®
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
3
Intersil's patented R 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.
TABLE 1. EVALUATION BOARD DESCRIPTION
EVALUATION BOARD CHANNEL-1
ISL62381LOEVAL1Z 3.3V/8A
ISL62381HIEVAL1Z 1.05V/15A
ISL62382LOEVAL1Z 3.3V/8A
ISL62382HIEVAL1Z 1.05V/15A
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.
ISL62381, ISL62382 Quad-Output Evaluation
Application Note
CHANNEL-2 OCP
5V/8A ~10A
1.5V/15A ~20A
5V/8A ~10A
1.5V/15A ~20A
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774
Board User Guide
July 31, 2008
.
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
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.
L
PHASEx
ISL62381
ISL62382
10µA
R
OCSET
OCSETx
_
+
V
ROCSET
ISENx
FIGURE 1. RESISTOR CURRENT SENSE CIRCUIT
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
sense resistor R , the value of R
SENSE
by Equation 1
I R
•
OC SENSE
R = ------------------------------------ -
OCSET
10μA
Where:
- R (Ω) is the resistor used to program the
OCSET
overcurrent setpoint
- I is the output current threshold that will activate the
OC
OCP circuit
- R is current sense resistor (R
SENSE
R for Channel-2)
25
|
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.
AN1396.0
R
SENSE I
V
L
O
_
+
V
RSENSE
C
O
R
O
and current
OC
is determined
OCSET
(EQ. 1)
for Channel-1 and
3