DC1926A - Demo Manual

DEMO MANUAL DC1926A
Dual Ideal Diode Controller
DESCRIPTION
Demonstration circuit 1926A features the LTC4353, a
dual low voltage ideal diode controller, in a typical 12A
application. The LTC4353 creates two near-ideal diodes
using external N-channel MOSFETs thereby replacing high
power Schottky diodes and their associated heat sinks.
Ideal diodes enable low loss power ORing and supply
holdup applications.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
PERFORMANCE SUMMARY
Specifications are at TA = 25°C
SYMBOL
PARAMETER
CONDITIONS
MIN
VIN
VIN1 and VIN2 Input Voltage
Operating Range
With External VCC Supply
2.9
0
VIN1, VIN2 ≤ VCC
2.9
VCC(EXT)
VCC External Supply Operating Range
VCC(REG)
VCC Regulated Voltage
VCC(UVLO)
VCC Undervoltage Lockout Threshold
VCC Rising
VFR
Forward Regulation Voltage (VIN – VOUT)
VIN =1.2V, VCC = 5V
VIN =12V
ΔVGATE
MOSFET Gate Drive (GATE-VIN)
IGATE
TYP
MAX
UNITS
18
VCC
V
6.0
V
4.5
5
5.5
V
2.3
2.55
2.7
V
2
2
12
25
25
50
mV
mV
VFWD = 0.2V; I = 0, –1μA; Highest VIN = 12V
VFWD = 0.2V; I = 0, –1μA; Highest VIN = 2.9V
10
4.5
12
7
14
9
V
V
GATE1, GATE2 Fast Pull-Up Current
GATE1, GATE2 Fast Pull-Down Current
GATE1, GATE2 Off Pull-Down Current
VFWD = 0.4V, ΔVGATE = 0, CPO=17V
VFWD = –0.8V, ΔVGATE = 5V,
Corresponding EN = 1V, ΔVGATE = 2.5V
–0.9
0.9
65
–1.4
1.4
110
–1.9
1.9
160
A
A
μA
VEN(TH)
EN1, EN2 Threshold Voltage
EN Falling
580
600
620
mV
ΔVGATE(ON)
MOSFET On-Detect Threshold (GATE-VIN)
ONST Pulls Low
0.28
0.7
1.1
V
IOUT
Maximum Continuous Load Current for
Si4126DY
Limited by 0.6W power dissipation with
maximum voltage regulation 50mV
12
A
OPERATING PRINCIPLES
The LTC4353 regulates the forward voltage drop across
the external MOSFETs to ensure smooth current transfer
in diode-OR applications. A fast turn-on reduces the load
voltage droop during supply switchover. If the input supply
fails or is shorted, a fast turn-off minimizes reverse current transients. The controller operates with rail voltages
from 2.9V to 18V. Operation with rail voltages below 2.9V
requires an additional supply of 2.9V to 6.0V at the VCC pin.
The LTC4353 indicates the on state of each MOSFET with
the ONST1 and ONST2 pin signals, when the gate voltage
is at least 0.7V higher than VIN. Two enable pins (EN1,
EN2) allow activating or blocking each MOSFET channel
individually.
Green LEDs ON1 and ON2 indicate the state of the associated MOSFET.
dc1926af
1
DEMO MANUAL DC1926A
QUICK START PROCEDURE
Demonstration circuit DC1926A is easy to set up to evaluate
the performance of the LTC4353. Controller performance
can be verified over the full operating range of 2.9V to 18V.
Ideal Diode Test
1. Connect a 12V power supply to VIN1(+) and GND (–) of
the DC1926A. Place a millivoltmeter between the input
(VIN1) and output (OUT1) turrets (refer to the diagram
of Figure 1). This is the controller regulation voltage.
The regulation voltage should be in the range of 2mV
to 50mV.
The installed MOSFETs in the SO-8 package are located on
the top side of the board. Provision is made on the bottom
side for using an additional SO-8 MOSFET in parallel with
the MOSFET on the top side. To extend current capability
the unstuffed PCB footprint (bottom side) also supports
the D2PAK package.
2. LED1 should be illuminated.
3. Repeat the test with the second channel (VIN2, OUT2).
The DC1926A test includes two parts: Ideal Diode Test
and Ideal Diode-ORing test.
4. Record regulation voltage values.
mV
+
POWER
SUPPLY
12V
–
Figure 1. Ideal Diode Regulation Voltage Measurement
dc1926af
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DEMO MANUAL DC1926A
QUICK START PROCEDURE
Ideal Diode-ORing Test
1. Connect two identical power supplies adjusted to +12V
to VIN1 and VIN2 inputs and provide a load to the parallel
connected OUT1 and OUT2 turrets (refer to the diagram
of Figure 2). The output load current should not exceed
12A for continuous operation.
2. The steady state operation of the Ideal Diode ORing
circuit is defined by the following parameters:
–VDS(ON) is the voltage drop of the MOSFET RDS(ON)
under maximum load current. This is measured by using
only the power supply of the channel under test with
the load connected and the measurement between VIN
and OUTPUT. Record VDS(ON);
–ΔVREG is the absolute value of the differences in voltage recorded in step 4 above;
–ΔSUPPLIES is the difference of the power supply output
voltages.
3. Adjust the voltage of the power supply connected to
[ΔSUPPLIES-ΔVREG] > VDS(ON) > 0. The power supply
will provide all of the current to the load. The LED associated with this channel will be illuminated
4. Adjust the voltage of the power supply to VDS(ON) >
[ΔSUPPLIES-ΔVREG] > 0. The supply with the higher
voltage will supply most of the current to the load,
while the supply with the lower voltage will supply less
current. Both LEDs diodes will be illuminated because
both channels are providing current to the load.
+
POWER
SUPPLY 1
12V
–
REGULATED
LOAD
–
POWER
SUPPLY 2
12V +
Figure 2. Ideal Diode ORing Operation
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DEMO MANUAL DC1926A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
1
1
CVCC
Cap., X7R, 0.1μF 50V 10%, 0805
AVX, 08055C104KAT2A
2
2
C1, C2
Cap., X7R, 0.056μF 50V 10%, 0805
AVX, 08055C563KAT2A
3
2
D1, D2
LED, GREEN
Panasonic, LN1351C-TR
4
2
D3, D4
Diode, Current Limiting, 3.2V, SOD-80
Central Semi. Corp., CMJ3500-TR
5
9
E1-E9
Turret, 0.064"
Mill Max, 2308-2-00-80-00-00-07-0
6
6
J1, J2, J3, J4, J5, J6
Connector, Banana Jack
Keystone, 575-4
7
2
M1, M2
MOSFET, N-Channel, 30V, SO8-POWERPAK
Vishay, Si4126DY
8
2
R3, R5
Resistor, Chip 10k 0.1W 5%,0805
Vishay, CRCW080510K0JNEA
9
0
R4, R6
Resistor, 0805
TBD
10
1
U1
I.C., Dual Ideal Diode, DFN16DE-4 × 3
Linear Technology, LTC4353IDE
dc1926af
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Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
D
C
B
A
GND
VIN2
18V MAX
EN2
EN1
VCC
VIN1
18V MAX
1
E8
J5
E7
J4
E5
E2
E3
E1
J1
1
R5
10K
R3
10K
R4
OPT
R6
OPT
VIN2
1
2 EN2
3 NC
NC
15
17 GND
EP
VCC
EN1
4
6
50V
C2
0.056uF
VIN2
CPO2
VIN1
CPO1
CUSTOMER NOTICE
CVCC
0.1uF
14
16
13
0.056uF
50V
C1
11
U1
LTC4353IDE
VIN1
M2
Si4126DY
GATE2
5
GATE2
OUT2
ONST2
ONST1
OUT1
GATE1
12
GATE1
M1
Si4126DY
3
2
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
D4
CCLM3500
ONST2
ONST1
1
REV
D3
CCLM3500
__
ECO
4
2
2
(GREEN)
ON2
D2
LN1351C-TR
1
(GREEN)
ON1
D1
LN1351C-TR
1
1ST PROTOTYPE
DESCRIPTION
SCALE = NONE
DATE:
N/A
SIZE
DATE
OUT2
GND
OUT1
12-09-11
DEMO CIRCUIT 1926A
LTC4353IDE
4
12/09/2011, 09:36 AM
IC NO.
5
SHEET 1
1
REV.
OF 1
DUAL IDEAL DIODE CONTROLLER
TITLE: SCHEMATIC
TECHNOLOGY
E9
J6
E6
J3
E4
J2
VLADIMIR O.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
1. ALL RESISTORS AND CAPACITORS ARE 0805.
5
APPROVED
REVISION HISTORY
NOTE: UNLESS OTHERWISE SPECIFIED
OUT2
APPROVALS
7
8
9
10
OUT1
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.
KIM T.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APP ENG. VLADIMIR O.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
2
D
C
B
A
DEMO MANUAL DC1926A
SCHEMATIC DIAGRAM
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DEMO MANUAL DC1926A
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
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Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
dc1926af
6
Linear Technology Corporation
LT 0812 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
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