Linear Technology LT3651EUHE-4.1 Quick setup guide

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dc1362aabfa
DEMO MANUAL DC1362A-A/-B
DESCRIPTION
LT3651EUHE-4.2/-4.1
4A High Voltage Li-Ion
Battery Charger
Demonstrationcircuit1362A-A/1362A-Bisa4Ahighvoltage
Li-Ion battery charger featuring the LT
®
3651EUHE-4.2/
LT3651EUHE-4.1. The LT3651 is a complete, high power
Li-Ion battery charger that can operate over a wide input
voltage range. The charger is aconstant-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
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
signalifthe batterydoesn’t respondtopreconditioning. 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 6.5V to 32V
VOUT 2.9V to 4.24V (–A)/2.7V to 4.14V (–B)
Output Float Voltage (Constant Voltage Mode) 4.2V (–A)/4.1V (–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 (6.5V 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
constantinputcurrentby regulating batterycharge 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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DEMO MANUAL DC1362A-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 1362A-A/1362A-B is easy to set
up to evaluate the performance of the LT3651EUHE-4.2/
LT3651EUHE-4.1.
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. TurnonPS2 and slowlyincreasethe voltage to2.7Vwhile
monitoring the current into the BAT pin. If the current
is less than 5mA, turn on PS1. Increase the voltage on
PS1 to 4V while monitoring the input current. If the
current is less than 5mA, increase PS1 to 12V.
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)
5
EFFICIENCY (%)
POWER LOSS (W)
83
84
85
86
15 25
DC1362ab F01
82
81
80
3.2
3.6
4.0
4.4
2.8
2.4
2.0
10 20 30 32
VBAT = 3.9
EFF
PLOSS

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DEMO MANUAL DC1362A-A/-B
QUICK START PROCEDURE
4. Increase PS2 until VBAT is 3.6V. 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 4.25V. 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 3.9V. 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 3.6V. 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. TurnonLOAD1 andsetto 1A.Verifythe voltageVSYSTEM
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.
DC1362ab F02

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DEMO MANUAL DC1362A-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 3.3µH 20% 8.0A, 9mΩ 7mm × 7mm WURTH, 744314330
9 1 Q1 MOSFET, PCHANNEL, 40V, 25mΩ 1212-8 VISHAY, Si7611DN
10 1 R1 RES, CHIP, 0.015Ω, 1/2W, 1%, 1206 IRC, LRC-LR1206LF-01-R015-F
11 1 R4 RES, CHIP, 0.024Ω, 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, 44.2k, 1/16W, 1%, 0402 VISHAY, CRCW040244K2FKED
14 1 R8 RES, CHIP, 0.05Ω, 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 (-A VERSION)
U1 (-B VERSION)
4A HIGH VOLTAGE Li-ION BATTERY CHARGER LINEAR TECHNOLOGY, LT3651EUHE-4.2
LINEAR TECHNOLOGY, LT3651EUHE-4.1
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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DEMO MANUAL DC1362A-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

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DEMO MANUAL DC1362A-A/-B
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2012
LT 0213 REV A • PRINTED IN USA
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