ISL62381LOEVAL1Z Просмотр технического описания (PDF) - Intersil
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ISL62381LOEVAL1Z Datasheet PDF : 13 Pages
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ISL62381, ISL62382 Quad-Output Evaluation
®
Board User Guide
Application Note
July 31, 2008
AN1396.0
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 R3 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 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
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.
.
EN1
Low
Low
Float
Float
Low
High
High
Float
High
TABLE 2. ENABLE TRUTH TABLE
EN2
START-UP SEQUENCE
Low Both Channel outputs OFF simultaneously
Float Both Channel outputs OFF simultaneously
Low Both Channel outputs OFF simultaneously
Float Both Channel outputs OFF simultaneously
High Channel-1 OFF, Channel-2 ON
Low Channel-1 ON, Channel-2 OFF
High Both Channel outputs ON simultaneously
High Channel-1 enabled after Channel-2 is in regulation
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.
PHASEx
L
RSENSE IL
VO
+
_
VRSENSE
ISL62381
CO
ISL62382
10µA
ROCSET
OCSETx
_
+
VROCSET
RO
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 IOC and current
sense resistor RSENSE, the value of ROCSET is determined
by Equation 1
ROCSET
=
I--O-----C-----•--R-----S----E----N----S----E--
10 μ A
(EQ. 1)
Where:
- ROCSET (Ω) is the resistor used to program the
overcurrent setpoint
- IOC is the output current threshold that will activate the
OCP circuit
- RSENSE is current sense resistor (R3 for Channel-1 and
R25 for Channel-2)
1
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.
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