1
dc1484aabf
DEMO MANUAL DC1484A-A/-B
DESCRIPTION
LT3651EUHE-8.4/-8.2
4A High Voltage 2-Cell Li-Ion
Battery Charger
Demonstration circuit 1484A-A/-B is a 4A high
voltage 2-Cell Li-Ion battery charger featuring the
LT
®
3651EUHE-8.4/-8.2. The LT3651 is a complete, high
power Li-Ion battery charger that can operate over a wide
input voltage range. The charger is a constant-current,
constant-voltage type with a maximum charge current
of 4A that can be externally set. A precondition feature
trickle charges a low voltage battery and bad battery
detection provides a signal if the battery doesn’t respond
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
to preconditioning. The LT3651EUHE is available in a
36-lead (5mm × 6mm) QFN surface mount package with
two exposed thermal pads.
Design files for this circuit board are available at
http://www.linear.com/demo
Input Voltage Range 12V to 32V
VOUT 5.8V to 8.48V (–A)/5.4V to 8.28V (–B)
Output Float Voltage (Constant Voltage Mode) 8.4V (–A)/8.2V (–B)
Output Current Limit ILIM 4A
Specifications are at TA = 25°C
OPERATING PRINCIPLE
LT3651 is a complete Li-Ion battery charger, addressing
wide input voltage (12V to 32V) and high charge current
(up to 4A). High charging efficiency, as shown in Figure 1,
is produced with a constant frequency, average current
mode synchronous step-down switcher architecture.
The charger includes the necessary circuitry to allow for
programming and control of constant-current, constant-
voltage (CC/CV) charging with both current only and
timer termination. High charging efficiency is achieved
by using a bootstrapped supply for low switch drop on
the high side driver and a MOSFET for the low side (syn-
chronous) switch.
Maximum charge current is set with an external sense
resistor in series with the inductor and is adjusted through
the RNG/SS pin. The total system input current is moni-
tored with an input sense resistor and is used to maintain
constant input current by regulating battery charge current.
It is adjusted through the ILIM pin.
If the battery voltage is low, charge current automatically
reduces to 15% of the programmed current to provide
safe battery preconditioning. Once the battery voltage
climbs above the battery precondition threshold, the IC
automatically increases the maximum charging current
to the full programmed value.
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dc1484aabf
DEMO MANUAL DC1484A-A/-B
OPERATING PRINCIPLE
Charge termination can occur when charge current de-
creases to one-tenth of the programmed maximum charge
current (C/10 termination). Alternately, termination can
be timer based through the use of an internal program-
mable charge cycle control timer. When using the timer
termination, charging continues beyond the C/10 level
to top off a battery. Charging typically terminates three
hours after initiation. When the timer-based scheme is
used, bad battery detection is also supported. A system
fault is triggered if a battery stays in precondition mode
for more than one-eighth of the total charge cycle time.
Once charging is terminated and the LT3651 is not ac-
tively charging, the IC automatically enters a low current
standby mode in which supply bias currents are reduced
to <85µA. If the battery voltage drops below 2.5% from the
full charge float voltage, the LT3651 engages an automatic
charge cycle restart. The IC also automatically restarts a
new charge cycle after a bad battery fault once the failed
battery is removed and replaced with another battery.
After charging is complete, the input bias current lines
connected to the battery are reduced to minimize battery
discharge.
The LT3651 contains provisions for a battery temperature
monitoring circuit. Battery temperature is monitored by
using an NTC thermistor located with the battery. If the Figure 1. Efficiency and Power Loss vs VIN
Demonstration circuit 1484A-A/-B is easy to set up to
evaluate the performance of the LT3651EUHE-8.4/-8.2.
Using short twisted pair leads for any power connections,
with all loads and power supplies off, refer to Figure 2 for
the proper measurement and equipment setup.
Follow the procedure below:
1. Jumper and power supply setting:
JP1 = RUN PS1 = OFF
JP2 = C/10 PS2 = OFF
battery temperature moves outside the safe charging range
of 0°C to 40°C the charging cycle suspends and signals
a fault condition.
The LT3651 contains two digital open-collector outputs,
which provide charger status and signal fault conditions.
These binary coded pins signal battery charging, standby
or shutdown modes, battery temperature faults and bad
battery faults.
A precision undervoltage lockout is possible by using a
resistor divider on the shutdown pin (SHDN). The input
supply current is 17µA when the IC is in shutdown.
QUICK START PROCEDURE
2. Turn on PS2 and slowly increase the voltage to 5.4V while
monitoring the current into the BAT pin. If the current
is less than 5mA, turn on PS1. Increase the voltage on
PS1 to 8V while monitoring the input current. If the
current is less than 5mA, increase PS1 to 24V.
3. Verify that the battery charging current, IBAT is between
400mA and 600mA. The CHRG LED and ACPR LED
should be on and the FAULT LED should be off.
VIN (V)
10
85
EFFICIENCY (%)
POWER LOSS (W)
86
87
88
89
90
3.5
4.0
4.5
5.0
5.5
6.0
15 20 25 30
dc1484aab F01
EFFICIENCY
POWER LOSS
VBAT = 7.8V
IBAT = 4A
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DEMO MANUAL DC1484A-A/-B
QUICK START PROCEDURE
4. Increase PS2 until VBAT is 7.2V. Verify the input cur-
rent IIN is between 1.4A and 1.7A, the battery current
IBAT is between 3.75A and 4.45A and that the CHRG
LED and ACPR LED are on.
5. Increase PS2 until VBAT is 8.5V. Verify the battery
charging current IBAT is less than 5mA and that the
CHRG LED and ACPR LED are off.
6. Decrease PS2 until VBAT is 7.8V. Verify the battery cur-
rent IBAT is between 3.75A and 4.45A that the CHRG
LED and ACPR LED are on.
7. Decrease PS2 until VBAT is 7.2V. Connect a 10k resistor
from the RNG/SS pin to ground. Verify the charging
current IBAT is between 1.7A and 2.0A. Verify the volt-
age VNTC on the NTC turret is between 1.6V and 1.9V
and the voltage VRNG on the RNG/SS turret is between
450mV and 700mV. Remove the 10k resistor from the
RNG/SS pin to ground
8. Set JP1 to SHDN. Verify the charging current IBAT is
less than 5mA and that the FAULT LED, CHRG LED and
ACPR LED are off.
9. Set JP1 to RUN. Connect a jumper from the NTC pin to
ground. Verify the charging current IBAT is less than
5mA and that the FAULT LED, CHRG LED and ACPR
LED are on.
10. Remove the jumper from NTC to ground. Verify the
charging current IBAT is between 3.75A and 4.45A
and that the FAULT LED is off and the CHRG LED and
ACPR LED are on.
11. Turn on LOAD1 and set to 1A. Verify the voltage VSYSTEM
on the system voltage turret is approximately equal
to VIN.
12. Turn off PS1, PS2 and LOAD1.
Figure 2. Proper Measurement Equipment Setup
NOTE: ALL CONNECTIONS FROM EQUIPMENT SHOULD BE KELVIN CONNECTED DIRECTLY TO THE BOARD PINS WHICH
THEY ARE CONNECTED TO ON THIS DIAGRAM AND ANY INPUT, OR OUTPUT, LEADS SHOULD BE TWISTED PAIR.
.75
25W
+–
AM2
+
–
VM2
+–
AM1
+
–
VM1
+
–
VM3
+–
AM3 +
–
PS2
0V TO 5V SUPPLY
+
–
PS1
0V TO 40V SUPPLY
+
–
LOAD 1
1A
dc1484aab F02
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DEMO MANUAL DC1484A-A/-B
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 C1 CAP., X7R, 1µF, 50V, 10%, 0805 MURATA, GRM21BR71H105KA12L
2 4 C3, C6, C11, C12 CAP., X7S, 10µF, 50V, 20%, 1210 TDK, C3225X7S1H106M
3 1 C4 CAP., X7R, 10µF, 10V, 10%, 0805 MURATA,GRM21BR71A106KE51L
4 3 C5, C7, C13 CAP., X5R, 0.68µF, 10V, 10%, 0402 MURATA, GRM155R61A684KE15D
5 1 C8 CAP., X5R, 100µF, 6.3V, 20%, 1210 TAIYO YUDEN, LMK325BJ107MM-T
6 1 D2 SMD, SCHOTTKY DIODE, SOT-23 CENTRAL SEMI, CMPSH1-4 TR
7 1 D6 DIODE, ZENER, 10V SOD-123 CENTRAL SEMI, CMHZ4697
8 1 L1 POWER INDUCTOR 6.5H, 20%, 6.0A, 21.5m WÜRTH, 744314650
9 1 Q1 MOSFET, PCHANNEL, 40V, 25m, 1212-8 VISHAY, Si7611DN
10 1 R1 RES., CHIP, 0.015, 1/2W, 1%, 1206 IRC, LRC-LR1206LF-01-R015-F
11 1 R4 RES., CHIP, 0.024, 1/2W, 1%, 1206 IRC, LRC-LR1206LF-01-R024-F
12 2 R5, R12 RES., CHIP, 10k, 1/16W, 1%, 0402 VISHAY, CRCW040210K0FKED
13 1 R7 RES., CHIP, 64.9k, 1/16W, 1%, 0402 VISHAY, CRCW040264K9FKED
14 1 R8 RES., CHIP, 0.05, 1/2W, 1%, 1206 IRC, LRC-LR1206LF-01-R050-F
15 1 R9 RES., CHIP, 147k, 1/16W, 1%, 0402 VISHAY, CRCW0402147KFKED
16 1 R13 RES., CHIP, 100k, 1/16W, 1%, 0402 VISHAY, CRCW0402100KFKED
17 1 U1 (DC1484A-A)
U1 (DC1484A-B) 4A HIGH VOLTAGE 8.4V LI-ION BATTERY CHARGER 4A
HIGH VOLTAGE 8.2V LI-ION BATTERY CHARGER LINEAR TECH.,LT3651EUHE-8.4
LINEAR TECH.,LT3651EUHE-8.2
Optional Electrical Components
1 1 C2 CAP, SMT, 22µF, 50V 20% SUNCON, 50CE22BS
2 2 C9, C10 CAP, CHIP, X7R, 0.022µF, ±10%, 16V, 0402 AVX, 0402YC223KAT2A
3 0 D1 SMD, SCHOTTKY, 5A, 40V DIODES INC, PDS540-13
4 1 D3 LED, RED PANASONIC, LNJ208R8ARA
5 2 D4, D5 LED, GREEN LITE-ON, LTST-C190KGKT
6 0 J1 HEADER, 3 PINS HIROSE ELECTRIC, DF3A-3P-2DSA
7 3 R2, R3, R10 RES, CHIP, 5.1k,1/4W, 5%, 1206 VISHAY, CRCW12065K10JNED
8 0 R6, R11 RES, CHIP, 20k, 1/16W, 1%, 0402 VISHAY, CRCW040220K0FKED
Hardware for Demo Circuit
1 8 E1 TO E8 TESTPOINT, TURRET, 0.095" MILL-MAX, 2501-2-00-80-00-00-07-0
2 2 JP1, JP2 2MM SINGLE ROW HEADER, 3 PIN SAMTEC, TMM-103-02-L-S
3 2 JP1, JP2 SHUNT SAMTEC, 2SN-BK-G
4 4 MH1 TO MH4 STAND-OFF, NYLON 0.375" TALL (SNAP ON) KEYSTONE, 8832 (SNAP ON)
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dc1484aabf
DEMO MANUAL DC1484A-A/-B
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
SCHEMATIC DIAGRAM
OPT
*
C/10
LT3651EUHE - 8.4- A
(OPT)
LT3651EUHE - 8.2
*
12V - 32V
8.2V
TIMER
- B
U1
4A
ASSY
OPT
VFLOAT*
VIN
8.4V
RUN
VFLOAT *
SHDN
C3
10uF
50V
1210
C3
10uF
50V
1210
E8 RNG / SS
E8 RNG / SS
+
C2
22uF
50V
20%
+
C2
22uF
50V
20%
L1
6.5uH
WURTH 744314650
L1
6.5uH
WURTH 744314650
1 2
E6 GND
E6 GND
U1U1
NTC
1
ACPR
2
BAT 3
SENSE 4
BOOST 5
GND
6
SW 7
PIN
8
PIN
9
PIN
10
SW 11
SW 12
SW 13
SW 14
SW 15
SW 16
SW 17
SW 18
PIN
19
PIN
20
PIN
21
SW 22
GND
23
TIMER
24
CHRG
26 FAULT
25
SHDN
27
ILIM
28
CLP
29
CLN 30
GND 37
VIN 32
VIN 33
VIN 34
RNG/SS
35
RT
36
GND 31
SW 38
E7 NTC
E7 NTC
D1
PDS540
D1
PDS540
C12
10uF
50V
1210
C12
10uF
50V
1210
R6
20k
R6
20k
E1E1
R3
5.1K
1206
R3
5.1K
1206
C1
1uF
50V
0805
C1
1uF
50V
0805
J1
DF3-3P-2DSA
J1
DF3-3P-2DSA
BAT
1
GND
2
NTC-EXT
3
R2
5.1K
1206
R2
5.1K
1206
R7
64.9k
R7
64.9k
E5 BAT
E5 BAT
D6
CMHZ4697
10V
D6
CMHZ4697
10V
C9
0.022uF
16V
C9
0.022uF
16V
D4
CHRG
GRN
D4
CHRG
GRN
C10
0.022uF
16V
C10
0.022uF
16V
R5
10K
R5
10K
JP1JP1
1
2
3
C5
0.68uF
C5
0.68uF
C11
10uF
50V
1210
C11
10uF
50V
1210
C7
0.68uF
C7
0.68uF
E4 GND
E4 GND
C4
10uF
10V
0805
10%
C4
10uF
10V
0805
10%
D3
FAULT
RED
D3
FAULT
RED
C6
10uF
50V
1210
C6
10uF
50V
1210
R9
147k
R9
147k
R1
0.015
1206
R1
0.015
1206
C13
0.68uF
C13
0.68uF
D5
ACPR
GRN
D5
ACPR
GRN
D2
CMPSH1-4
D2
CMPSH1-4
R11
20k
R11
20k
R8
0.05
1206
R8
0.05
1206
R12
10k
R12
10k
R10
5.1K
1206
R10
5.1K
1206
C8
100uF
10V
1210
20%
C8
100uF
10V
1210
20%
JP2JP2
1
2
3
Q1
Si7611DN
Q1
Si7611DN
R13
100k
R13
100k
E2
GND E2
GND
R4
0.024
1206
R4
0.024
1206
E3 SYSTEM LOAD
E3 SYSTEM LOAD
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dc1484aabf
DEMO MANUAL DC1484A-A/-B
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2013
LT 0113 • PRINTED IN USA
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 applica-
tion engineer.
Mailing Address:
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Copyright © 2004, Linear Technology Corporation
