DC1624A - Demo Manual

DEMO MANUAL DC1624A
LTC4225-1/LTC4225-2
Dual Ideal Diode and
Hot Swap Controller
Description
Demonstration circuit 1624A contains two independent rail
circuits each with Hot Swap™ and ideal diode functionality
provided by the LTC4225-1/LTC4225-2 dual ideal diode
and Hot Swap controller.
rail, four LEDs to indicate power good and fault conditions
separately for each channel, and input voltage snubbers.
There are pads for optional RC circuits for each Hot Swap
MOSFET gate in order to adjust output voltage slew rate.
DC1624A facilitates evaluation of LTC4225 performance in
different operation modes such as supply ramp-up, power
supply switchover, steady state, and overcurrent faults.
Power supply switchover mode can be realized as either
an ideal diode functionality or as a prioritizer functionality.
The standard configuration (as DC1624A populated by
default) places the ideal diode MOSFET ahead of the
Hot Swap MOSFET. The board also has pads for an alternative configuration with the Hot Swap MOSFET located
ahead of the ideal diode MOSFET.
Each DC1624A rail circuit is assembled to operate with a
12V supply and 11.5A maximum current load.
Design files for this circuit board are available at
http://www.linear.com/demo
The main components of the board are the LTC4225
controller, two MOSFETs operating as ideal diodes, two
MOSFETs operating as Hot Swap devices, two power sense
resistors, two jumpers for independently enabling each
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
PERFORMANCE SUMMARY
SYMBOL
PARAMETER
VIN
Input Supply Range
VINTVCC(UVL)
Internal VCC Undervoltage Lockout
VINTVCC(HYST)
Internal VCC Undervoltage Lockout
Hysteresis
(TA = 25°C)
CONDITIONS
MIN
TYP
2.9
INTVCC Rising
MAX
UNITS
18
V
2.1
2.2
2.3
V
30
60
90
mV
10
25
40
mV
Ideal Diode Control
ΔVFWD(REG)
Forward Regulation Voltage (VINN - VOUT )
ΔVDGATE
External N-Channel Gate Drive
(VDGATEN - VINN)
ΔVFWD = 0.1V
IN < 7V
IN = 7V to 18V
5
10
7
12
14
14
V
V
ICPO(UP)
CPON Pull-Up Current
CPO = IN = 2.9V
CPO = IN = 18V
–60
–50
–95
–85
–120
–110
µA
µA
IDGATE(FPU)
DGATEN Fast Pull-Up Current
ΔVFWD =0.2V, ΔVDGATE = 0V, CPO = 17V
–1.5
A
IDGATE(FPD)
DGATEN Fast Pull-Down Current
ΔVFWD = –0.2V, ΔVDGATE = 5V
1.5
A
Hot Swap Control
ΔVSENSE(CB)
Circuit Breaker Trip Sense Voltage
(VINN - VISENSEN)
47.5
50
52.5
mV
ΔVSENSE(ACL)
Active Current Limit Sense Voltage
(VINN - VISENSEN)
55
65
75
mV
dc1624af
1
DEMO MANUAL DC1624A
Performance Summary
(TA = 25°C)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
IHGATE(UP)
External N-Channel Gate Pull-Up Current
Gate Drive On, HGATE = 0V
IHGATE(DN)
External N-Channel Gate Pull-Down Current
IHGATE(FPD)
External N-Channel Gate Fast Pull-Down
Current
VON(TH)
ONN On Pin Threshold Voltage
VON(RESET)
ONN Pin Fault Reset Threshold Voltage
VEN(TH)
UNITS
7
10
13
Gate Drive Off, OUT = 12V, HGATE = OUT + 5V
150
300
500
µA
Fast Turn-Off, OUT = 12V, HGATE = OUT + 5V
100
200
300
mA
ON Rising
1.21
1.235
1.26
V
ON Falling
0.55
0.6
0.63
V
ENN Pin Threshold Voltage
EN Rising
1.185
1.235
1.284
V
V TMR(TH)
TMRN Pin Threshold Voltage
TMR Rising
TMR Falling
1.198
0.15
1.235
0.2
1.272
0.25
V
V
ITMR(UP)
TMRN Pin Pull-Up Current
TMR = 1V, In Fault Mode
75
100
125
µA
ITMR(DN)
TMRN Pin Pull-Down Current
TMR = 2V, No Faults
1.4
2
2.6
µA
ITMR(RATIO)
TMRN Current Ratio ITMR(DN)/ ITMR(UP)
1.4
2
2.7
%
µA
Input/Output Pin
quick start procedure
The LTC4225 functions as an ideal diode with inrush current limiting and overcurrent protection by controlling
two external back-to-back N-channel MOSFETs in a power
path. The LTC4225 has two ideal diode and two Hot Swap
controllers. Each ideal diode MOSFET is intended to operate with a defined Hot Swap MOSFET, because they are
tied by common on/off control, and ideal diode controller
sense voltage includes both MOSFETs and sense resistor
voltage drop. Therefore, LTC4225 provides independent
control for the two input supplies.
An active current limit amplifier servos the gate of the
MOSFET to 65mV across the current sense resistor. Inrush current can be further reduced, if desired, by adding
a capacitor from HGATE to GND. When the MOSFET’s
gate overdrive (HGATE to OUT voltage) exceeds 4.2V, the
PWRGD pin pulls low.
The LTC4225 gate drive amplifiers (DGATEN,) monitor
the voltage between the INN and OUTN pins and drive the
DGATEN pins. The amplifier quickly pulls up the DGATE
pin, turning on the MOSFET (Q1 or Q3), for ideal diode
control when it senses a large forward voltage drop.
When both MOSFETs (Q1 and Q2 or Q3 and Q4) are turned
on, the gate drive amplifier controls DGATE to servo the
forward voltage drop (VIN - VOUT) across the sense resistor
and the back-to-back MOSFETs to 25mV. If the load current
causes more than 25mV of voltage drop, the gate voltage
rises to enhance the MOSFET used for ideal diode control.
For large output currents the MOSFET’s gate is driven
fully on and the voltage drop is equal to the sum of the
ILOAD • RDS(ON) of the two MOSFETs in series.
Pulling the ON pin high and EN pins low initiates a 100ms
debounce timing cycle. After 100ms, a 10µA current source
from the charge pump ramps up the HGATEN pin. When
the Hot Swap MOSFET (Q2 or Q4) turns on, the inrush
current is limited to a set level set by an external sense
resistor placed between IN and SENSE pins.
In the case of an input supply short circuit when the
MOSFETs are conducting, a large reverse current starts
flowing from the load towards the input. The gate drive
amplifier detects this failure condition as soon as it appears and turns off the ideal diode MOSFET by pulling
down the DGATE pin.
dc1624af
2
DEMO MANUAL DC1624A
quick start procedure
Demonstration circuit DC1624A can be easily to set up to
evaluate the performance of the LTC4225-1/LTC4225-2.
Refer to the Figure 1 for proper measurement equipment
setup and follow the procedure below.
position to the ON position. Observe the transient. The
output voltage rise time should be in the range of 12ms
to 29ms. PWRGD1 (PWRGD2) green LED should be lit.
Turn off the rail using the ON1_SEL (ON2_SEL) jumper.
The DC1624A test includes independent tests of the
LTC4225 Hot Swap functionality, ideal diode functionality and two power rails prioritizer functionality with the
channel 1 highest priority.
Second Step
HOT SWAP FUNCTIONALITY TEST
This test is identical for each 12V rail and is performed
in the three steps by the measuring of the transient’s
parameters in the different operation modes.
The first step is a power-up without any additional load.
The second step is the current limit operation after successful power-up transient. The third step is a power-up
with a shorted output.
Initially install the jumper heads in the following positions:
ON1_SEL and ON2_SEL in position OFF;
EN1_SEL and EN2_SEL in position LOW.
First Step
Connect a 12V power supply to the board input turrets
IN1 (IN2) and GND. Do not load the output. Place current
probe on the 12V supply and voltage probes on the OUT1
(OUT2) turret.
Provide ON1 (ON2) signal at the ON1 (ON2) pin by moving the ON1_SEL (ON2_SEL) jumper header from OFF
Initially adjust an electronic resistive load to 10Ω to 12Ω
and connect it to the OUT1 (OUT2) turret and GND. Turn
on the rail and slowly increase load current up to the circuit
breaker threshold level. The current limit range should be
from 11.5A to 13.3A. Turn off the rail using the ON1_SEL
(ON2_SEL) jumper.
Third Step
Short the output to ground with a wire. Place the current
probe on this wire. Turn on the rail and record the current
shape. The maximum current should be in the (13.6A to
18.9A) range. The LTC4225-1 latches off after overcurrent
condition, but the LTC4225-2 automatically retries after
200ms to 450ms.
IDEAL DIODE FUNCTIONALITY TEST
Use an individual 12V power supply for each rail; connect
the two outputs together at a common load. Adjust each
input voltage to 12V with maximum possible accuracy.
In this test, both rails are active and small variations in
the input voltage will force one channel off and the other
channel on.
dc1624af
3
DEMO MANUAL DC1624A
quick start procedure
Place a voltmeter between IN1 and IN2 turrets to measure
the difference between two input voltages. Activate both
rails and keep a load around 1A to 3A. Adjust with the input
voltage levels and verify that when the difference between
input voltages exceeds 40mV only one rail is active.
THE PRIORITIZER FUNCTIONALITY TEST
The DC1624A is assembled with components to implement a two power rails prioritizer with channel 1 having
the higher priority.
Install R17 with 470 and R18 with 41.2k.
Place JP5 PPR_SEL (power priority select) jumper in position ON2 and JP4 ON2_SEL (ON2 select) in position OFF.
Apply independent supply voltages (12V) to both inputs.
Channel 1 will be connected to load. Reduce channel 1
input voltage until it reaches an undervoltage condition
and D5 (PWRGD2) lights. At the same time channel 2
power supply will deliver power to the load.
dc1624af
4
DEMO MANUAL DC1624A
quick start procedure
RL1
CL1
POWER
SUPPLY 1
SW1
RL2
SW2
CL2
POWER
SUPPLY 2
SW3
SW4
DC1624A F01
Figure 1. Measurement Equipment Setup for Hot Swap Functionality Test
dc1624af
5
DEMO MANUAL DC1624A
parts list
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
7
C1, C2, C3, C8, C9, C11, C14 CAP, X7R, 0.1µF, 50V, 0603
AVX, 06035C104KAT
2
2
C4, C5
CAP, X7R, 47nF, 50V, 0603
AVX, 06035C473KAT
3
2
C6, C7
CAP, X7R, 15nF, 50V, 0603
AVX, 06035C153KAT
4
0
C10, C13
OPT
5
2
C12, C15
CAP, AL, El, S/M 100µF, 50V
SANYO, 50CE100BS
6
2
D1, D2
DIODE, VOLTAGE SUPP 13V 5% SMA
VISHAY, SMAJ17A-E3
7
2
D3, D5
LED, SMT GREEN
PANASONIC, LN1351C
8
2
D4, D6
LED, SMT RED
PANASONIC, LN1251CTR
9
0
D7, D8, D10, D11
OPT
10
1
D9
DIODE, SWITCHING, SOD80
VISHAY, LS4148
11
8
E10 to E16, E18
TURRET, TESTPOINT, 2308
MILL-MAX, 2308-2-00-80-00-00-07-0
12
10
E1 to E9, E17
TURRET, TESTPOINT, 2501
MILL-MAX, 2501-2-00-80-00-00-07-0
13
8
J1 to J8
JACK BANANA
KEYSTONE, 575-4
14
5
JP1, JP2, JP3, JP4, JP5
HEADERS, 3 PINS 2mm CTRS
SAMTEC TMM-103-02-L-S
15
5
XJP1, XJP2, XJP3, XJP4,
XJP5
SHUNT, 2mm CTRS
SAMTEC 2SN-BK-G
16
4
Q1, Q2, Q3, Q4,
N-CHANNEL 30-V MOSFET, PPSO-8
VISHAY, Si7336ADP
17
0
Q5, Q6, Q7, Q8
OPT
18
2
RS1, RS2
RES, CHIP, 0.004, 1/2W, 1%, 2010
19
0
RS3, RS4
OPT
VISHAY, WSL20104L000FEA
20
4
R1, R3, R13, R14
RES, CHIP, 10, 1%, 0603
VISHAY, CRCW060310R0FKEA
21
2
R2, R4
RES, CHIP, 47, 1%, 0603
VISHAY, CRCW060347R0FKEA
22
4
R5, R6, R7, R8
RES, CHIP, 3k, 1%, 0805
VISHAY, CRCW08053K00FKEA
23
2
R9, R11
RES, CHIP, 20k, 1%, 0603
VISHAY, CRCW0060320K0FKEA
24
2
R10, R12
RES, CHIP, 137k, 1%, 0603
VISHAY, CRCW0603137KFKEA
25
0
R15, R16, R17, R18
OPT
26
4
MTGS AT 4 CORNERS
STANDOFF, NYLON, 0.25, 1/4"
KEYSTONE, 8832 (SNAP ON)
dc1624af
6
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.
A
B
C
D
J7
E7
E10
E17
E9
E18
E6
J6
J5
E5
GND
GND
5
E8
J8
2.9V TO 18V
IN2
IN2
ON2
GND
PROBE GND
ON1
GND
GND
2.9V TO 18V
IN1
IN1
ON2
IN2
OFF
ON2
SMAJ17A
D1
+
3
1
3
R13
10
20K
1%
R11
R9
20K
1%
LTC4225CUFD-1
LTC4225CUFD-2
-B
C14
0.1uF
50V
R14
10
C3
0.1uF
50V
C9
0.1uF
50V
C8
0.1uF
50V
C2
0.1uF
50V
ASSY
-A
2
1
U1
1%
C11
0.1uF
50V
R10
137K
2
1
R12
137K 1%
D2
SMAJ17A
JP4
2
ON2_SEL
JP3
2
ON1_SEL
1
+
4
1. ALL RESISTORS ARE IN OHMS, 0603.
ALL CAPACITORS ARE IN MICROFARADS, 0603.
NOTE: UNLESS OTHERWISE SPECIFIED
*
C13
100uF
50V
OPT
IN2
OFF
ON1
IN1
C10
100uF
50V
OPT
IN1
RS4
0.004
0.5W
RS2
0.004
0.5W
R16
OPT
1
2
3
6
5
8
7
U1
6
5
8
7
Q7 OPT
Si7336ADP
1
2
3
7
8
5
6
*
2
1
D10
CMHZ4706
OPT
Q3
Si7336ADP
ON2
GND
EP
ON1
3
2
1
Q1
Si7336ADP
INTVCC
HG1
1
3
2
1 2
D7
CMHZ4706
OPT
Q5 OPT
Si7336ADP
7
8
5
6
R15
OPT
HG2
5
4
25
18
3
INTVCC
C1
0.1uF 50V
2010
RS1
0.004
0.5W
2010
RS3
0.004
0.5W
DG1
24
4
23
CPO1
4
D8
CMHZ4706
3
2
1
7
8
5
6
1 OPT
2
R1
10
3
2
1
1
2
3
6
5
8
7
R3
10
C7
15nF
50V
R4 47
TMR2
PWRGD2
FAULT2
EN2
EN1
FAULT1
PWRGD1
TMR1
C6
15nF
50V
D11
CMHZ4706
OPT
6
5
8
7
C5
47nF
16V
X7R
C4
47nF
16V
D3
GREEN
R5
3K
0805
IN1
R7
3K
0805
OUT2
R8
3K
0805
D6
RED
D9
LS4148
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
2
SCALE = NONE
+
3
DATE:
N/A
SIZE
2
EXT
JP2
3 LOW
1
EXT
JP1
3 LOW
1
EN2_SEL
2
ON2
JP5
3 OFF
EN1_SEL
2
PPR_SEL
1
E1
1
APPROVED
GND
GND
OUT2
11.5A
OUT2
PWRGD2
FAULT2
EN2
EN1
FAULT1
PWRGD1
GND
GND
11.5A
OUT1
OUT1
VLADIMIR O.
DATE
11-09-10
1
SHEET 1
LTC4225CUFD-1/-2
DEMO CIRCUIT 1624A
Tuesday, December 07, 2010
IC NO.
3
REV.
OF 1
DUAL IDEAL DIODE AND HOT SWAP CONTROLLER
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
E4
J4
J3
E3
E11
E12
E13
E14
E15
E16
ON2
E2
J2
J1
PRODUCTION
DESCRIPTION
REVISION HISTORY
TECHNOLOGY
REV
TITLE: SCHEMATIC
C15
100uF
50V
R17
OPT
+
__
ECO
R18
OPT
C12
100uF
50V
INTVCC
OUT1
APPROVALS
IN2
D5
GREEN
D4
RED
R6
3K
0805
2
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.
AK
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.
CUSTOMER NOTICE
Q8 OPT
Si7336ADP
3
2
1
DG2
Q4
Si7336ADP
1
2
3
15
12
13
14
17
19
20
16
4
R2 47
7
8
5
6
DG1
Q6 OPT
Si7336ADP
Q2
Si7336ADP
3
1
2
4
6
CPO2
9
2
IN1
IN2
1
2
4
7
4
DGATE1
1
SENSE1
SENSE2
22
10
HG2
DGATE2
8
DG2
HGATE1
HGATE2
21
OUT1
OUT2
11
HG1
4
2
1
4
4
2
1
5
A
B
C
D
DEMO MANUAL DC1624A
Schematic Diagram
dc1624af
7
DEMO MANUAL DC1624A
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
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
dc1624af
8
Linear Technology Corporation
LT 0611 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2011
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