an1058

ISL6225EVAL2 Dual Switcher Evaluation Board
Setup Procedure
®
Application Note
May 2003
AN1058.0
General Description
Features
This document describes the setup procedure for the
ISL6225 Evaluation Board dual switcher implementation.
The ISL6225 can control two output voltages adjustable from
0.9V to 5.5V. The ISL6225 combines two synchronous PWM
voltage regulators into a single IC. PWM1 and PWM2 output
voltages are set by a simple feedback voltage divider
connected across the outputs to GND. The feedback voltage
divider outputs are 0.9VDC, which are connected to the
VSEN1 and VSEN2 pins.
• Provides regulated output voltage in the range of 0.9V–
5.5V
- High efficiency over wide load range
- Synchronous buck converter with hysteretic operation at
light load
- Inhibit Hysteretic mode on one, or both channels
Automatic mode selection of constant-frequency synchronous
rectification at heavy load, and hysteretic diode-emulation at
light load, assure high efficiency over a wide range of
conditions. The hysteretic mode of operation can be disabled
separately on each PWM converter if constant-frequency
continuous-conduction operation is desired for all load levels.
Efficiency is further enhanced by using the lower MOSFET
RDS(ON) as the current sense element.
• No current-sense resistor required
- Uses MOSFET RDS(ON)
- Optional current-sense resistor for precision OverCurrent
• Over-Voltage, Under-Voltage and Over-Current protection
on both channels
• Under-voltage lock-out on VCC pin
• Dual input voltage mode operation
- Operates directly from battery 5V to 24V input
- Operates from 3.3V or 5V system rail
- VCC from 5V only
Voltage-feed-forward ramp modulation, current mode control,
and internal feedback compensation provide fast response to
input voltage and output load transients.
• Excellent dynamic response
- Combined voltage feed-forward and average current
mode control
In dual power supply applications the ISL6225 monitors the
output voltage of both CH1 and CH2. An independent
PGOOD (power good) signal is asserted for each channel
after its soft-start sequence has completed, and the output
voltage is within ±10% of the set point.
• Power-good signal for each channel
• 300kHz switching frequency
- 180° channel to channel phase operation
Pinout
GND
LGATE1
PGND1
PHASE1
UGATE1
BOOT1
ISEN1
EN1
VOUT1
VSEN1
OCSET1
SOFT1
DDR
VIN
Built-in over-voltage protection prevents the output from
going above 115% of the set point by holding the lower
MOSFET on and the upper MOSFET off. When the output
voltage decays below the over-voltage threshold, normal
operation automatically resumes. Once the soft-start
sequence has completed, under-voltage protection will latch
the channel off if the output drops below 75% of its set point
value.
Adjustable over-current protection (OCP) monitors the
voltage drop across the RDS(ON) of the lower MOSFET. If
more precise current-sensing is required, an external current
sense resistor may be used.
Ordering Information
PART NUMBER TEMP. (oC)
ISL6225
SSOP-28
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VCC
LGATE2
PGND2
PHASE2
UGATE2
BOOT2
ISEN2
EN2
VOUT2
VSEN2
OCSET2
SOFT2
PG2/REF
PG1
What’s Inside
This Evaluation Board Kit contains the following materials:
• ISL6225EVAL2 Evaluation Board
• ISL6225EVAL2 Board Evaluation Document
What is Needed
PACKAGE
PKG. DWG. #
ISL6225CA
-10 to 85
28 Ld SSOP
ISL6225CA-T
-10 to 85
28 Ld SSOP Tape M28.15
and Reel
1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
M28.15
The following items will be needed to perform a complete
evaluation:
•
•
•
•
•
4 channel oscilloscope with probes
2 electronic loads
2 laboratory power supplies
Precision digital multimeters
Digital pulse generator
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2003. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
JP7 SHUNTED
JP2 SHUNTED
2
JP1 SHUNTED TOWARD VIN>5V
JP3 SHUNTED TOWARD FCCM1
1.
JP4 SHUNTED TOWARD FCCM2
FIGURE 1. INITIAL SHUNT PLACEMENT FOR ISL6225EVAL2
Application Note 1058
JP6 - NO SHUNT
JP5 - NO SHUNT
S
CONNECT THE
NEGATIVE TERMINAL
(-) OF THE 24VDC
POWER SUPPLY AND
THE NEGATIVE
TERMINAL (-) OF THE
DVM TO THE GND
TERMINAL J1
CONNECT THE
POSITIVE TERMINAL
(+) OF THE
ADJUSTABLE 24VDC
POWER SUPPLY TO
THE VIN TERMINALS
J2 AND J3
CONNECT THE
POSITIVE TERMINAL
(+) OF THE DVM TO
ONE OF THE VIN
TERMINALS J2 OR
J3
CONNECT THE
POSITIVE
TERMINAL (+) OF
THE 5VDC POWER
SUPPLY AND THE
POSITIVE
TERMINAL (+) OF
THE DVM TO J4
VCC
CONNECT THE
NEGATIVE TERMINAL
(-) OF THE 5VDC
POWER SUPPLY AND
NEGATIVE TERMINAL
(-) OF THE DVM TO
THE GND TERMINAL
J14
3
OSCILLOSCOPE TIP
MEASUREMENT
POINT FOR PHASE1
OSCILLOSCOPE TIP
MEASUREMENT
POINT FOR PHASE2
CONNECT THE
POSITIVE TERMINAL
(+) OF THE
ELECTRONIC LOAD
AND THE DVM TO
THE VOUT1
TERMINAL J5
CONNECT THE
POSITIVE TERMINAL
(+) OF THE
ELECTRONIC LOAD
AND THE DVM TO
THE VOUT2
TERMINAL J6
CONNECT THE
NEGATIVE
TERMINAL (-) OF
THE ELECTRONIC
LOAD AND THE DVM
TO THE GND
TERMINAL J8
CONNECT THE
NEGATIVE
TERMINAL (-) OF
THE ELECTRONIC
LOAD AND THE DVM
TO THE GND
TERMINAL J7
OSCILLOSCOPE TIP MEASUREMENT POINT FOR VOUT1
OSCILLOSCOPE TIP MEASUREMENT POINT FOR VOUT2
FIGURE 2. WIRING CONNECTIONS FOR ISL6225EVAL2
Application Note 1058
CR2 — CHANNEL 2
POWER GOOD
INDICATOR LED
CR1 — CHANNEL 1
POWER GOOD
INDICATOR LED
Application Note 1058
Step 2:
Connect the positive terminal (+) of a DVM to the
VCC terminal J4. Connect the negative terminal (-)
of the DVM to the GND terminal J14.
Step 3:
Set the adjustable 24VDC output voltage to zero
volts. Connect the positive terminal (+) of the
power supply to the VIN terminals J2 and J3.
Connect the negative terminal (-) of the 24VDC
power supply to the GND terminal J1.
TABLE 1. DETAILED DESCRIPTION OF THE JUMPER
SETTINGS
JUMPER
JP1
POSITION
*VIN>5V
*Input Voltage greater than 5V
VIN=5V
Input Voltage 3.3V to 5V operation
*Shunted
*An AmpMeter may be connected across
these pins to measure IC and GATE Drive
Current only
JP2
JP3
JP4
JP5
JP6
JP7
FUNCTION
*FCCM1
*PWM1 Fixed Continuous Conduction
Mode
Away from
FCCM1
PWM1 Hysteretic Operation
enabled
*FCCM2
*PWM2 Fixed Continuous Conduction
Mode
Away from
FCCM2
PWM2 Hysteretic Operation enabled
Shunted
CH1 enabled
* Removed
* CH1 disabled
Shunted
CH2 enabled
*Removed
* CH2 disabled
*Shunted
* One VIN supply for both CH1 and CH2
Removed
Separate VIN supplies for CH1 and CH2
NOTE: * = Initial Setting
.
Do not apply power yet
Step 4:
Connect the positive terminal (+) of a DVM to one
of the VIN terminals J2 or J3. Connect the negative
terminal (-) of the DVM to the GND terminal J1.
Step 5:
Connect the positive terminal (+) of the electronic
load and the DVM to the VOUT1 terminal J5.
Connect the negative terminal (-) of the electronic
load and the DVM to the GND terminal J8.
Step 6:
Connect the positive terminal (+) of the electronic
load and the DVM to the VOUT2 terminal J6.
Connect the negative terminal (-) of the electronic
load and the DVM to the GND terminal J7.
Step 7:
Take the adjustable 24VDC power supply that is
connected to the VIN terminals J2 and J3 and
make sure the output voltage is set to zero VOLTS.
Step 8:
Turn on the 24VDC power supply.
Step 9:
While reading the DVM, increase the output
voltage of the 24VDC power supply to 5.0 VDC.
Step 10:
Turn on the 5VDC power supply.
Step 11:
While reading the DVM, increase the output
voltage of the 5VDC power supply to 5VDC.
Step 12:
Install the EN1 shunt jumper JP5.
Step 13:
Install the EN2 shunt jumper JP6.
TABLE 2. LED CONDITION INDICATORS
LED CONDITION
CONDITION
Green
CR1
CR2
RESULT
VOUT1 Within PGOOD
Range
Red
VOUT1 Outside PGOOD
Range
Green
VOUT2 Within PGOOD
Range
Red
VOUT1 Outside PGOOD
Range
Quick Setup
• The VIN Power Supply must always be the first supply
on and the last supply off.
• The 5V VCC Power Supply must be between 5V ± 5%.
• Make sure the power is off before moving any jumpers,
except EN1 and EN2.
Step 1:
Set the output voltage of the 5V adjustable power
supply to zero volts. Connect the positive terminal
(+) of the power supply to the VCC terminal J4.
Connect the negative terminal (-) of the 5VDC
power supply to the GND terminal J14.
NOTE: Terminals J1 (EN1) and J12 (EN2) may be connected to a
Pulse generator for controlled on/off operation and may be observed
with an oscilloscope.
Step 14:
Read the DVM connected to the VOUT1
terminal J5.
Step 15:
Read the DVM connected to the VOUT2
terminal J6.
The 24V VIN Power Supply may be adjusted between 5-24
VDC.
If Hysteretic operation is desired move jumper J3 for PWM1
or JP4 for PWM2, to the position opposite the silk screen
“FCCM”.
The Electronic Load can be connected to VOUT1 and
VOUT2 for load regulator measurement.
Make sure the power is off before moving the jumpers.
Terminals J1 (EN1) and J12 (EN2) may be connected to a
Pulse generator for controlled on/off operation and may be
observed with an oscilloscope.
Make sure the enable voltage is less than 5V VCC.
Do not apply power yet
4
5
4
3
2
J2
1
VIN>5V
C1
NI
JP1
VIN2
J3
VIN1=VIN2
3
2
+
C2
10u
25V
X5R
GND
J1
1
JP7
VIN1
VIN=5V
C3
10u
25V
X5R
R1
100k
GND
J14
VIN'
D
VCC
VCC
J4
JP2
D
VCC'
CURR-MEAS
PHAS E 1
PHAS E 2
VCC'
C5
4.7u
10V
R2
VOUT1
R3
U1
0
GND
2
LGATE1
FDS6912A
C7
1.0u
10V
C8
0.15u
25V
C
GND
R8
17.8K
PGND2
26
PHASE1
PHASE2
25
1
8
7
2
5
UGATE1
UGATE2
24
2
7
6
BOOT1
BOOT2
23
JP3
6
3
5
4
2.00K
7
ISEN1
ISEN2
22
EN2
21
20
8
EN1
9
VOUT1
VOUT2
VSEN1
VSEN2
10
R7
NI
2
3
FCCM1
220u
4V
PGND1
4
C9
0.15u
25V
11
C
R5
2.00K
3
6
4
5
OCSET1
12
SOFT1
U2
C17
NI
C23
4.7u
10V
13
DDR
14
VIN
OCSET2
SOFT2
17
PG2/REF
16
PG1
15
ISL6225
VIN'
U3
J6
GND
R9
10.0K
R6
NI
C16
NI
2
J7
C11
10n
50V
VOUT2
JP4
FCCM2
C20 +
220u
4V
PG1
B
1.80V
Sumida CDRH1 24-100MC
19
18
C6
1.0u
10V
L2
10.0u
1
C10
10n
50V
VOUT1
+ C22
3
1
J8
FDS6912A
1
R4
Sumida CDRH12 4-100MC
27
C21
4.7u
10V
B
PG2
VCC
R12
10.0k
R10
100k
R13
10.0K
R11
100k
C18
10n
50V
JP5
JP6
EN1
EN2
C19
10n
50V
VCC
VCC
R18
680
2.50V
VOUT1
+ C12
+ C13
NI
NI
R15
680
R19
680
1.80V
VOUT2
R14
680
R16
680
J11
CR1
LXA3025IGC-TR
R20
10.0K
R21
10.0K
J12
RED
RED
PG1
J10
GND
J9
PGOOD1
J13
Q2
BSS123LT1
PG2
Title
ISL6225 EVALUATION BOARD (DUAL SWITCHER)
PGOOD2
Date:
4
3
FIGURE 3. ISL6225EVAL2 SCHEMATIC
NI
Building 2A, Suite 105
4020 Stirrup Creek Drive
Durham, NC 277 03
Phone: (919) 405 3650
Fax: (919) 405 3651
INTERSIL
Size
B
5
+ C15
NI
GREEN
A
Q1
BSS123LT1
+ C14
CR2
LXA3025IGC-TR
EN2
EN1
G REEN
R17
680
2
Document Number
ISL6225EVAL2 _DUALSWITCHER
Rev
A
Sheet
1
1
of
1
A
Application Note 1058
2.50V
LGATE2
8
L1
10.0u
J5
VCC
28
TP1
VOUT2
0
1
3
TP2
D2
BAT54WT1
TP3
3
TP4
3
5
D1
BAT54WT1
1
C4
68u
16V
1
+
Application Note 1058
TABLE 3. BILL OF MATERIALS (BOM)
QTY
REFERENCE
DESCRIPTION
VENDOR
PART NO.
4
C10, C11, C18, C19
Capacitor, SMD, 0805, .01μF,50V, 10%,X7R
Kemet
C0805C103K5RAC
2
C2, C3
Capacitor, SMD,1812, 10μF, 25V,20%, X5R
Taiyo Yuden
TMK432BJ106MM-T
2
C20, C22
Pos Cap, Low ESR, SMD, D3, 220μF, 4V, 20%
Sanyo
4TPB220M
1
C4
Capacitor, TANT, Low ESR, SMD, D, 68μF, 16V, 10%
Kemet
T494D686K016AS
3
C5, C21, C23
Capacitor, SMD,1206, 4.7μF, 10V, 10%, X7R
Venkel
C1206X7R100475KNE
2
C6, C7
Capacitor, SMD, 1206, 1μF, 10V, 10%, X7R
Kemet
C1206C105K8RAC
2
C8, C9
Capacitor, SMD, 0805, 0.15μF, 25V, 10%, X7R
2
CR1, CR2
Led, SMD, 4P, Polarized, Red/Grn
2
D1, D2
Diode, Schottky, SMD, SOT323, 3P, 30V, 0.2A
14
J1-J14
Terminal Post, TH, 0.09
Keystone
1502-2
3
JP1, JP3, JP4
Header, 1x3, Breakaway, 1X36, 2.54mm, ST
Berg/FCI
68000-236-1X3
7
JP1-JP7
Jumper, 2PIN, Shunt
4
JP2, JP5-JP7
Header, 1x2, Retentive, 2.54mm, ST
2
L1, L2
Inductor, SMD, 5.7mm, 4.6μH
2
Q1, Q2
MOSFET, N-Channel, 3P, SOT23, 100V, 0.17A
3
R1, R10, R11
Resistor, SMD, 0805, 100K, 1/10W, 1%, TF
Panasonic
ERJ-6ENF1003V
6
R14-R19
Resistor, SMD, 0805, 680Ω, 1/10W, 5%, TF
Panasonic
ERJ-6GEYJ681V
2
R2, R3
Resistor, SMD, 0805, 0Ω, 1/10W, TF
Panasonic
ERJ-6GEY0R00V
2
R4, R5
Resistor, SMD, 0805, 2K, 1/10W, 1%, TF
Panasonic
ERJ-6ENF2001V
1
R8
Resistor, SMD, 0805, 17.8K, 1/10W, 1%, TF
Panasonic
ERJ-6ENF1782V
5
R9, R12, R13, R20, R21 Resistor, SMD, 0805, 10K, 1/10W, 1%, TF
Panasonic
ERJ-6ENF1002V
4
TP1-TP4
Test Point, Scope Probe, 0.135" DIA
Tektronix
131-5031-00
1
U1
IC, Dual Switcher, 24V, 28Pin, SSOP
Intersil
ISL6225CA
2
U2, U3
MOSFET, Dual, N-Channel, Logic, 8P, SOIC, 30V, 6A
Fairchild
FDS6912A
6
Panasonic
ECJ-2YB1E154K
Lumex
SSL-LXA3025IGC
ON-Semiconductor
Sullens
Berg/FCI
Panasonic
ON-Semiconductor
BAT54WT1-T
SPC02SYAN
69190-202
ETQ-P6F4R6HFA
BSS123LT1-T
Application Note 1058
7
Application Note 1058
8
Application Note 1058
9
Application Note 1058
All Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at website www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time without notice.
Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use.
No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see web site www.intersil.com
10
Similar pages