DC1627A - Demo Manual

DEMO MANUAL DC1627A
LTC4226
Wide Operating Range
Dual Hot Swap Controller
Description
Demonstration circuit 1627A is intended to display the
Hot Swap™ functionality of the LTC®4226 wide operating
range dual Hot Swap controller. The DC1627A has two
independent circuits, each for two rails. The circuit placed
on the upper board area is for a high current load.
The first channel of the upper board circuit operates with
a 10A maximum in the +12V rail while the second channel
operates with a 5A maximum in the +5V rail. Provision is
made for the installation of several MOSFET packages to
test the LTC4226's performance during a short time with
the larger current. Circuit LEDs indicate a presence of the
input rail voltages and fault conditions in each rail. There are
two jumpers: one for the current limit multiplicity selection
and the other one for overvoltage protection configuration.
The circuit located on the lower board area is a special
compact circuit for the Apple FireWire/IEEE 1394 power
distribution.
Performance Summary
SYMBOL
PARAMETER
Both channels of this circuit operate with a 1.25A maximum
current in the 12V rails. It is not recommended to use this
circuit for other operating conditions.
There are two versions of the controller: LTC4226-1 and
LTC4226-2. The LTC4226-1 remains off after a fault while
the LTC4226-2 automatically retries after a 0.5 second
delay.
The DC1627A allows estimating the performance of the
LTC4226 in different operation modes such as ramp-up,
steady-state, and overcurrent fault conditions.
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 and Hot
Swap is a trademark of Linear Technology Corporation. All other trademarks are the property of
their respective owners.
Specifications are at TA = 25°C
CONDITIONS
MIN
TYP
MAX
UNITS
9.79
12
16
V
9.15
9.79
10.53
V
15.4
16
17
Upper Circuit +12V Channel
VCC1
Input Supply Range
VCC1(UV)
Input Supply Undervoltage
VCC Rising; Based on the ON1 Pin Threshold
VCC1(OV)
Input Supply Overvoltage
VCC Rising
S1
Output Voltage Slew Rate
No Current Limit
ICB1
Circuit Breaker Current Limit
12000
8.91
V
V/s
10
11.11
A
tCB1
Timer Period During Circuit Breaker Operation
19
29
48
ILIM1
Current Limit by Current Limit (CL) Amplifier
CLS = 0V (1.5×)
CLS = Open (2×)
CLS = 3V (3×)
13.86
18.42
38.2
17.2
23
34.6
20.80
27.47
41.4
ms
A
A
A
tFTMR1
Fault Timer Period During CL operation
CLS = 0V (1.5×)
CLS = Open (2×)
CLS = 3V (3×)
2
1.12
0.5
2.9
1.6
0.7
4.6
2.6
1.15
ms
ms
ms
4.11
5
7.3
V
Upper Circuit +5V Channel
VCC2
Input Supply Range
VCC2(UV)
Input Supply Undervoltage
VCC Rising; Based on the ON2 Pin Threshold
3.86
4.11
4.37
V
VCC2(OV)
Input Supply Overvoltage
VCC Rising
6.8
7.3
7.7
V
S2
Output Voltage Slew Rate
No Current Limit
12000
V/s
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1
DEMO MANUAL DC1627A
Performance Summary
SYMBOL
PARAMETER
ICB2
Circuit Breaker Current Limit
Specifications are at TA = 25°C
CONDITIONS
MIN
TYP
MAX
UNITS
4.45
5
5.55
A
tCB2
Timer Period During Circuit Breaker Operation
39
50
80
ILIM2
Current Limit by CL Amplifier
CLS = 0V (1.5×)
CLS = Open (2×)
CLS = 3V (3×)
6.9
9.2
13.8
8.6
11.5
17.3
10.4
13.7
20.7
ms
A
A
A
tFTMR2
Fault Timer Period
CLS = 0V (1.5×)
CLS = Open (2×)
CLS = 3V (3×)
3.3
1.9
0.8
5.1
2.8
1.3
8.4
4.7
2.1
ms
ms
ms
16.7
V
V
Compact Circuit for FireWire Power Distribution
VCC
Input Supply Range
Based on the ON Pin Threshold
4.62
VCC(UV)
Input Supply Undervoltage
VCC Rising
4.62
4.96
5.28
ICB
Circuit Breaker Current Limit
1.35
1.51
1.68
A
tCB
Timer Period During Circuit Breaker Operation
6.07
9.2
15.3
ms
ILIM
Current Limit by CL Amplifier
CLS = 0V (1.5×)
CLS = Open (2×)
CLS = 3V (3×)
2.1
2.8
4.2
2.6
3.5
5.3
3.2
4.2
6.3
A
A
A
tFTMR
Fault Timer Period
CLS = 0V (1.5×)
CLS = Open (2×)
CLS = 3V (3×)
0.6
0.35
0.15
0.9
0.5
0.25
1.6
0.9
0.39
ms
ms
ms
Operating Principles
The LTC4226 controls two rails with external N-channel
MOSFETs. Two independent ONn comparators allow ramping rails up and down independently.
active current limiting. By this means, the timer period
during an active current limit is ten times less than it is in
the circuit breaker operation.
During normal operation, the charge pump delivers 9μA to
the gate driver to turn on the external N-channel MOSFET.
The LTC4226-1 latches off after the MOSFET is turned off
under an overcurrent condition. The ON pin status must
be recycled low to high for the gate drive to restart. The
demo board with LTC4226-1 is labeled as DC1627A-A.
Each channel’s circuit breaker (CB) comparator and current limit (CL) amplifier monitor the load current using the
sense resistor voltage between the VCCn and the SENSEn
pins. When the sense resistor voltage exceeds circuit
breaker threshold (VCB), (but lower than VLIMIT) the CB
comparator enables a 2μA current source, and the voltage
at the fault timer (FTMRn) capacitor ramps up. When the
FTMRn comparator voltage reaches 1.23V threshold, the
corresponding MOSFET is turned off.
When the sense resistor voltage exceeds VLIMIT, the CL
amplifier limits the current in the load by reducing the
gate-to-out voltage in an active control loop. The fast
response CL amplifier can quickly adjust the gate-to-out
voltage in the event of an output-to-ground short circuit.
The FTMRn capacitor voltage ramps up with a 20μA (or
36μA, or 80μA) current source instead of the 2μA in the
The LTC4226-2 automatically retries after an overcurrent
condition. It begins with a 0.5 second delay before resetting
the fault timer with a 100µA pull-down, followed by gate
restart if ON pin is high. The demo board with LTC4226-2
is labeled as DC1627A-B.
Both channels share a common current limit select functionality with the current limit select (CLS) pin signal. This
signal can have three input states: low, open and high. The
three input states correspond to the preset current limit
values. VLIMIT becomes 1.5×, or 2.0×, or 3.0× of 1.15× VCB.
Undervoltage protection in the upper circuit is based on the
ONn pin threshold. The resistors of each ONn pin divider
are selected to have a threshold voltage at the LTC4226 ON
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2
DEMO MANUAL DC1627A
Operating Principles
pin, when the input voltage equals the defined minimum.
The Performance Summary table shows their values with
consideration for the voltage tolerance of the comparator
threshold and for 1% resistor tolerance.
on the FTMR capacitor can be found. It lowers the time in
current limit mode. Overvoltage protection levels shown
in the Performance Summary table were obtained by
simulation.
Overvoltage protection in the upper circuit is built with
Zener and Schottky diodes to trigger an artificial overcurrent
mode by charging the FTMR capacitor. Due to the peculiar
current leakage of some devices and their sensitivity to
higher temperature a small initial voltage (0.1V to 0.2V)
Inherent in the LTC4226 is an undervoltage protection
feature that allows the channels to operate only if VCC
is above 3.7V. When VCC rises above the undervoltage
lockout level, there is a delay of 50ms before the gate
starts to ramp.
Quick Start Procedure
The test procedure for each channel of the LTC4226 is
identical and includes verification of the main circuit
parameters:
S1-S2 output voltage slew rate;
n
ICB1-ICB2 circuit breaker level performed by the circuit breaker and fault timer period (FTMR), when an
overcurrent mode is initiated after power up has been
completed;
n
ICL1-ICL2 the current limit level performed by the current limit amplifier and fault timer period (FTMR) with
an initially shorted output and CLS pin grounded.
n
If there is a need to test a channel with rail voltages other
than those used for the DC1627A design (+5V, and +12V),
make changes to the appropriate ON pin signal divider
(R5, R10, R12 for channel 1 or R23, R29, and R31 for
channel 2).
If any LTC4226 channel should operate at other than a
factory assigned current, change the value of the sense
resistor (R2, R22) and select the desired position for the
current limit selection (CLS) jumper. Verify the power
MOSFET current capability in the steady-state and in the
power-up modes. Replace Q1 or Q3 with a suitably packaged MOSFET.
Demonstration circuit DC1627A is easy to set up to evaluate
the performance of the each LTC4226 Hot Swap channel.
Refer to Figure 1 for the proper measurement equipment
setup for one channel and follow the procedure listed next.
UPPER CIRCUIT TEST
Jacks and Joined Turrets
n
n
n
n
n
n
n
n
J1 (VCC1): 12V supply input; do not exceed 35V
J2 (GND): Ground connection for 12V input supply
J3 (OUT1): Output for 12V rail
J4 (GND): Ground connection for 12V output
J5 (VCC2): 5V supply input; do not exceed 35V
J6 (GND): Ground connection for 5V input supply
J7 (OUT2): Output for 5V rail
J8 (GND): Ground connection for 5V output
Turrets Connected to Controller Pins
n
n
n
n
n
n
n
n
E3 (ON1)
E4 (FTMR1)
E5 (CLS)
E6 (FAULT1)
E7 (FAULT2)
E8 (FTMR2)
E11 (ON2)
E26 (DCLA)
Jumpers
JP1 (CLS): Current limit selection: Use 1.5X position to
have 1.725X circuit breaker current limit (CBCL); use
2X position to have 2.3X CBCL; use 3X position to have
3.45X CBCL.
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3
DEMO MANUAL DC1627A
Quick Start Procedure
JP2 (OVBLK): Overvoltage blocking selection: Use SEP
position for individual channel blocking under overvoltage
condition; use BOTH position for both channel blocking
under any channel’s overvoltage condition.
LEDs
n
n
n
n
D3 (green): +12V supply is present
D15 (green): +5V supply is present
D7 (red): +12V channel fault
D9 (red): +5V channel fault
+12V Hot Swap
As the test procedures for all LTC4226 channels are
identical, the following detailed description of the steps
for +12V channel test can be used for the other DC1627's
channels with the only difference being the mentioned
component designators.
1.The jumpers’ shunts should be placed in the following
position:
JP1 (CLS) 1.5×
JP2 (OVBLK) SEP
Connect ON1 and GND turrets with an external wire to
disable the +12V Hot Swap circuit.
2.Connect the +12V supply terminals to the +12V and
GND demo board jacks appropriately and place scope
probes on the OUT1 and FTMR1 turrets and a current
probe to measure the +12V wire current.
Turn on the +12V supply. +12V green LED (D3) will light
indicating the presence of input voltage. Disconnect the
ON1 and GND turrets to provide an ON1 pin signal, and
verify that the output voltage rises in less than 1ms.
3.Keep the scope probes and current probe in the same
place. Initiate +12V channel operation with no load,
gradually increasing the load current with an electronic
or resistive load and verify that the circuit breaker is
in the range of 8.9A to 11.11A and the timer period is
between 19ms and 48ms. Disable the +12V channel by
connecting the ON1 and GND turrets.
4.With the +12V channel disabled, short the output to GND
with an external wire. Monitor the current in the shorting
wire with a current probe. Place the scope probes on
the VCC1 and FTMR1 turrets. Enable the channel with
an ON1 pin signal and verify that current is limited in
the range 13.86A to 20.8A and current limit mode takes
from 2ms to 4.6ms.
The upper circuit provides options for current
limit selection (CLS JP1) and overvoltage protection
(JP OVBLK).
Three positions of the current limit selection (CLS)
jumper (JP1) correspond with the three pair of current limit parameters: current level and timer period.
Estimated values for these parameters are shown in
the Performance Summary table.
Special attention should be given to verification of the
MOSFET’s SOA regarding these parameters.
5.Each channel’s overvoltage protection circuit can block
its own channel if the OVBLK jumper header is installed
in the position SEP, or both channels if the OVBLK is in
the position BOTH. The +12V rail overvoltage protection
is in the 15.4V to 17V range, and +5V rail is in the 6.8V
to 7.7V range.
To test the overvoltage protection level place a scope
probe at the FTMR turret and start to gradually increase
the input voltage. The protection level is estimated
when FTMR voltage reaches threshold and drops low.
It means that an auxiliary overcurrent mode has been
generated.
+5V Hot Swap
6. The jumpers’ shunts should be placed in the following
position:
JP1 (CLS) 1.5×
JP2 (OVBLK) SEP
Connect ON2 and GND turrets with an external wire
to disable the +5V Hot Swap circuit.
dc1627af
4
DEMO MANUAL DC1627A
Quick Start Procedure
7. Connect the +5V supply terminals to the +5V and
GND demo board jacks appropriately and place scope
probes on the OUT2 and FTMR2 turrets and current
probe to measure the +5V wire current.
Turn on the +5V supply. +5V green LED (D15) will light
up indicating the presence of input voltage. Disconnect the ON2 and GND turrets to provide an ON2 pin
signal, and verify that the output voltage rises in less
than 1ms.
8. Keeping the scope probes and current probe in the
same place, initiate +5V channel operation with no
load, gradually increasing the load current with an
electronic or resistive load and verify that the circuit
breaker is in the range of 4.45A to 5.55A and timer
period is from 39ms to 80ms. Disable the +5V channel
by connecting the ON2 and GND turrets.
9. With the +5V channel disabled, short the output to
GND with an external wire. Monitor the current in the
shorting wire with a current probe. Place the scope
probes on the VCC2 and FTMR2 turrets. Enable the
channel with an ON2 pin signal and verify that current
is limited in the range of 6.9A to 10.4A and current
limit mode takes from 3.3ms to 8.4ms.
10.Confirm that each position of the current limit jumper
corresponds to the appropriate current limit level
and timer period. Special attention should be given
to verification of the MOSFET’s SOA regarding these
parameters.
COMPACT CIRCUIT TEST
Turrets
n
n
n
n
E1 and E16: Circuit GND
E13: 1st channel +12V supply input; do not exceed 35V
E14 (OUT1): 1st channel output
E15: 2nd channel +12V supply input; do not exceed 35V
E17 (ON1)
n E18 (FTMR1)
n E19 (CLS)
n E20 (FAULT1)
n E21 (FAULT2)
n E22 (FTMR2)
n E23 (ON2)
n E24 (OUT2)
Connect ON1 and GND turrets with an external wire to
disable the +12V hot swap circuit. Connect CLS and GND
turrets to select the lowest CL level.
n
1.Connect the +12V supply terminals to the +12V and
GND demo board turrets. Place scope probes on the
OUT1 and FTMR1 turrets and a current probe to measure
+12V wire current.
2.Turn on the +12V supply. Disconnect ON1 and GND
turrets to provide an ON1 pin signal, and verify that
the output voltage rises in less than 1ms.
3.Keeping the scope probes and current probe in the same
place, initiate the +12V channel operation with no load,
gradually increasing the load current with an electronic
or resistive load and verify that the circuit breaker is
in the range of 1.35A to 1.68A and timer period 6.1ms
to 15.3ms. Disable the +12V channel by connection of
the ON1 and GND turrets.
4.With the +12V channel disabled, short the output to GND
with an external wire. Monitor the current in the shorting
wire with a current probe. Place the scope probes on
the VCC1 and FTMR1 turrets. Enable the channel with
an ON1 pin signal and verify that current is limited in
the range of 2.1A to 3.2A and current limit mode takes
0.6ms to 1.6ms.
dc1627af
5
DEMO MANUAL DC1627A
Quick Start Procedure
Figure 1. DC1627A Measurement Equipment Setup
dc1627af
6
DEMO MANUAL DC1627A
Parts List
ITEM
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
QTY
4
2
2
2
0
1
1
1
2
4
2
2
1
15
14
1
1
8
2
0
2
0
1
2
0
1
1
4
1
0
2
2
2
3
1
1
1
2
2
2
2
2
2
2
2
REFERENCE
COUT1, C1, COUT2, C8
CT1, CT2
C2, C9
C3, C12
C4, C5, C10, C11
C6
C7
D2
D3, D15
D4, D6, D8, D10
D5, D12
D7, D9
D13
E3-E8, E11, E17-E23, E26
E1, E13-E16, E24, E25, E27-E33
JP1
JP2
J1, J2, J3, J4, J5, J6, J7, J8
Q1, Q3
Q2, Q4
Q5, Q6
R1, R21
R2
R3, R19
R4, R14, R23, R28
R5
R6
R7, R17, R25, R38
R8
R9, R11, R27, R30
R10, R29
R12, R31
R13, R18
R15, R16, R24
R20
R22
R26
R32, R37
R33, R35
R34, R36
Z1, Z2
Z3, Z4
SHUNTS ON JP1&JP2
U1, U2
U1, U2
PART DESCRIPTION
CAP., X7R, 10µF 50V, 10%, 1210
CAP., X7R, 15nF, 50V 10%, 0603
CAP., X7R, 0.1µF 10% 10V, 0603
CAP., X7R, 0.047µF 10% 10V, 0603
CAP., 0603
CAP., X7R, 47nF, 50V 5%, 0603
CAP., X7R, 82nF, 50V 10%, 0603
DIODE ZENER, 1.8V 500mW, 5%, SOD123
LED, GREEN
DIODE, FAST SWITCHING, SOD523
DIODE ZENER, 1.8V 500mW, 5%, SOD123
LED, RED, 0603
DIODE ZENER, 1.8V 500mW, 5%, SOD123
TP, TURRET, 0.064"
TP, TURRET, 0.094"
JMP, 4-PIN, 2mm
JMP, 3-PIN, 2mm
JACK, BANANA
MOSFET, N-CH, POWER56
MOSFET, N-CH, SO8-POWERPAK
MOSFET, N-CH, 40V(D-S), SOT23
RES, 1k, 0805
RES, 0.005Ω, 1% 1/4W, 1206
RES, 30.1k, 5% 1/10W, 0603
RES, 0603
RES, 46.4k, 1% 1/10W, 0603
RES, 5.6k, 5% 1/10W, 0603
RES, 10Ω, 5% 1/10W, 0603
RES, 3.3k, 5% 1/10W, 0603
RES, 10Ω, 0603
RES, 23.2k, 1% 1/10W, 0603
RES, 10k, 5% 1/10W, 0603
RES, 2.4M, 5% 1/10W, 0603
RES., CHIP, 0Ω, 0603
RES, 1.8k, 5% 1/10W, 0603
RES, 0.01Ω, 1% 1/4W, 1206
RES, 1k, 5% 1/10W, 0603
RES, 0.033Ω, 1% 1/4W, 1206
RES,150k, 5% 1/10W, 0603
RES, 49.9k, 5% 1/10W, 0603
DIODE, SMC-DIODE
DIODE, TRANSIENT VOLTAGE SUPPRESSOR, POWEREDi123
SHUNT, 2mm
IC LTC4226CUD-1, DC1627A-A
IC LTC4226CUD-2, DC1627A-B
MANUFACTURER/PART NUMBER
MURATA, GRM32ER71H106KA12L
AVX, 06035C153KAT2A
AVX, 0603ZC104KAT
AVX, 0603ZC473KAT2A
OPT
AVX, 06035C473JAT2A
AVX, 06035C823KAT2A
CENTRAL SEMI., CMHZ4701
PANASONIC, LN1351C-(TR)
DIODES INC., 1N4448HWT
CENTRAL SEMI., CMHZ4683
VISHAY, TLMS1001-GS08
CENTRAL SEMI., CMHZ4690
MILL-MAX, 2308-2-00-80-00-00-07-0
MILL-MAX, 2501-2-00-80-00-00-07-0
SAMTEC, TMM-104-02-L-S
SAMTEC, TMM-103-02-L-S
KEYSTONE, 575-4
FAICHILD SEMI., FDMS86500DC
OPT
VISHAY, Si2318CDS
OPT
VISHAY, WSL12065L000FEA
VISHAY, CRCW060330K1JKEA
OPT
VISHAY, CRCW060346K4FKEA
VISHAY, CRCW06035K60JKEA
VISHAY, CRCW060310R0JNEA
VISHAY, CRCW06033K30JKEA
OPT
VISHAY, CRCW060323K2FKEA
VISHAY, CRCW060310K0JNEA
PANASONIC, ERJ-3GEYJ245V
VISHAY, CRCW06030000Z0EA
VISHAY, CRCW06031K80JKEA
VISHAY, WSL1206R0100FEA
VISHAY, CRCW06031K00JNEA
VISHAY, WSL1206R0330FEA
VISHAY, CRCW0603150KJKEA
VISHAY, CRCW060349K9JKEA
DIODES INC., SMCJ33CA-13-F
DIODES INC., DFLT15A
SAMTEC, 2SN-BK-G
LINEAR TECHNOLOGY CORP
LINEAR TECHNOLOGY CORP
dc1627af
7
DEMO MANUAL DC1627A
Schematic Diagram
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8
DEMO MANUAL DC1627A
Schematic Diagram
dc1627af
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.
9
DEMO MANUAL DC1627A
DEMONSTRATION BOARD IMPORTANT NOTICE
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This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
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measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
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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
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Mailing Address:
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Copyright © 2004, Linear Technology Corporation
dc1627af
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