DC1688A - Demo Manual

DEMO MANUAL DC1688A
LT3652HVEDD
17.7V to 34V Input SLA 2A
Battery Charger For Solar Power
DESCRIPTION
Demonstration circuit 1688A is a sealed-lead acid 2A
battery charger for solar power applications featuring the
LT3652HVEDD. The LT3652HV is a complete mid-power
battery charger that can operate over a wide input voltage range. The charger employs a 3.3V battery voltage
feedback reference that allows the voltage for charging to
be adjusted up to 18V. The LT3652HV has an input voltage
regulation loop which reduces charge current if the input
falls below a programmed level, set with a resistor divider.
The circuit provides constant-current/constant-voltage
charging with a maximum charge current of 2A that is
programmed by a current sense resistor. A precondition
feature trickle charges a low voltage battery, and bad
battery detection provides a signal if the battery doesn’t
respond to preconditioning.
The LT3652HVEDD is available in a 12-lead (3mm × 3mm)
DFN surface mount package with an exposed pad.
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
Table 1. Typical Specifications (TA = 25°C)
PARAMETER
CONDITIONS
VALUE
Input Voltage Range
17.7V to 34V
VBAT Charge/VBAT Float
14.3V to 14.5V/13.4V to 13.6V
Output Charge/Float Voltage
Constant Voltage Mode
14.4V/13.5V
Output Current Limit ILIM
VIN_REG Greater Than 2.7V
2A
OPERATING PRINCIPLE
LT3652HV is a complete monolithic mid-power battery
charger, addressing high input voltage applications with
solutions that require a minimum number of external
components. The IC uses a 1MHz constant frequency,
average current mode step-down architecture.
The LT3652HV maximizes efficiency during charging cycles
by using a bootstrapped supply to drive the internal power
switch. Figures 1 and 2 display charger efficiency and input
current for various input voltages and battery voltages. A
precision threshold shutdown pin allows the incorporation
of UVLO functionality using a simple resistor divider. The
IC can also be put into a low-current shutdown mode, in
which the input supply bias is reduced to only 15μA.
The LT3652HV incorporates several degrees of charge current control freedom. The overall maximum charge current
is set using an external inductor current sense resistor. The
LT3652HV employs an input voltage regulation loop which
reduces charge current if the input voltage falls below a
programmed level, set with a voltage divider. This can be
seen in Figure 3. When the LT3652HV is powered by a
solar panel, the input regulation loop is used to maintain
the panel at peak output power.
The LT3652HV automatically enters a battery precondition mode if the sensed battery voltage is very low. In
this mode, the charging current is reduced to 15% of
the programmed maximum, as set by the inductor sense
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DEMO MANUAL DC1688A
OPERATING PRINCIPLE
resistor, RSENSE. Once the battery voltage increases to
the precondition threshold, the IC automatically increases
maximum charging current to the full programmed value.
DC1688A programs the output voltage to be 14.4V during
charging and the 9.5V precondition threshold is internally
set as a fraction of the programmed output voltage.
The LT3652HV can use a charge current based ‘C/10’
termination scheme, which ends a charge cycle when the
battery charge current falls to 1/10th the programmed
maximum charge current. The LT3652HV also contains
an internal charge cycle control timer, for timer-based
termination. When using the internal timer, the IC combines C/10 detection with a programmable time constraint,
during which the charging cycle can continue beyond the
C/10 level. DC1688A programs a lower 13.5V float output
voltage at the time the C/10 condition occurs. Use of the
internal timer allows DC1688A to provide a float voltage
to the battery until the charge cycle terminates because
time elapses. The timer on DC1688A is programmed so the
circuit can provide a float voltage all day, as may be needed
by a solar panel application. When the timer-based scheme
is used, the IC also supports “bad battery” detection, which
2.0
IBAT = 2A
1.8
1.6
INPUT CURRENT
EFFICIENCY
85
80
Once charging is terminated and the LT3652HV is not
actively charging, the IC automatically enters a low current
standby mode where supply bias currents are reduced to
< 100μA. If the battery voltage drops 2.5% from the fullcharge float voltage, the LT3652HV 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.
The LT3652HV includes provisions for a battery temperature monitoring circuit. This feature monitors battery
temperature during the charging cycle using a thermistor,
and suspends charging and signals a fault condition if the
battery temperature moves outside a safe charging range
of 0°C to 50°C.
The LT3652HV 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.
2.5
VIN = 12V
VIN = 15V
VIN = 24V
2.0
CHARGE CURRENT (A)
90
triggers a system fault if a battery stays in precondition
mode for more than 1/8th of the total charge cycle time.
1.4
1.2
1.0
0.8
0.6
75
VIN = 12V
VIN = 15V
VIN = 24V
70
3.3 4.5 5.7 6.9 8.1 9.3 10.5 11.7 12.9 14.1
BATTERY VOLTAGE
0.4
1.5
1.0
0.5
0.2
0.0
3.3 4.5 5.7 6.9 8.1 9.3 10.5 11.7 12.9 14.1
BATTERY VOLTAGE
1688A F01
Figure 1. LT3652HV Efficiency
1688A F02
Figure 2. 2A Charge Current
0.0
17.5 17.6 17.7 17.8 17.9 18 18.1 18.2 18.3
INPUT VOLTAGE
1688A F03
Figure 3. Charge Current vs Input Voltage
QUICK START PROCEDURE
Demonstration circuit 1688A is easy to set up to evaluate
the performance of the LT3652HVEDD.
Using short twisted pair leads for any power connections,
with all loads and power supplies off, refer to Figure 4 for
the proper measurement and equipment setup.
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DEMO MANUAL DC1688A
QUICK START PROCEDURE
Follow the procedure below:
1. Jumper and Power Supply Setting:
JP1 = 1
JP4 = 1
JP2 = 0
PS1 = OFF
JP3 = C/10
PS2 = OFF
2. Turn on PS2 and slowly increase the voltage until VBAT
is 7.5V while monitoring the current into the BAT pin.
If the current is less than 5mA, turn on PS1. Increase
PS1 until VIN is 18V while monitoring the input current.
3. Verify the battery charging current is between 250mA
and 350mA. The CHRG LED should be on and the
FAULT LED should be off.
4. Increase PS2 until VBAT is 12.0V. Verify the input current is between 1.3A and 1.7A, the battery current is
between 1.775A and 2.225A and that the CHRG LED
is on.
5. Increase PS2 until VBAT is 14.8V. Verify the battery charging
current is less than 5mA and that the CHRG LED is off.
6. Decrease PS2 until VBAT is 13.8V. Verify the battery charging
current is less than 5mA and that the CHRG LED is off.
7. Decrease PS2 until VBAT is 12.0V. Verify the battery
current is between 1.775A and 2.225A and that the
CHRG LED is on.
8. Set JP1 to 0. Verify the charging current is less than
5mA and that the FAULT LED and the CHRG LED are off.
9. Set JP1 to 1. Connect a jumper from the NTC pin to
ground. Verify the charging current is less than 5mA
and that the FAULT LED and the CHRG LED are on.
10. Remove the jumper from NTC to ground. Verify the
charging current is between 1.775A and 2.225A and
that the FAULT LED is off and the CHRG LED is on.
11. Turn on LOAD1 and set to 1A. Verify the voltage, Vsystem, on the System Load terminal is approximately
equal to VIN. Turn off LOAD1. Decrease PS1 to 14.0V.
12. Verify the battery charging current is less than 5mA
and that the CHRG LED is off.
13. Increase PS1 to 18.5V. Verify the charging current is
between 1.775A and 2.225A and that the CHRG LED
is on. Set JP2 to 1. Decrease PS1 to 17.0V.
14. Set JP4 to 0. Setting JP4 to 0 turns off the charge
current when VIN is less than 17.7V. Verify the battery
charging current is less than 5mA and that the CHRG
LED is off.
15. Increase PS1 to 19.0V. Verify the charging current is
between 1.775A and 2.225A and that the CHRG LED
is on. Set JP4 to 1. Set JP2 to 0.
16. Turn off PS1 and PS2.
1688a F04
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.
Figure 4. Proper Measurement Equipment Setup for DC1688A
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DEMO MANUAL DC1688A
PARTS LIST
ITEM
QTY
REFERENCEDESCRIPTION
DESCRIPTION
MANUFACTURER’S PART NUMBER
MURATA, GRM32ER71H106KA88L
Required Circuit Components:
1
1
C2
CAP., X7R, 10μF, 50V, 10%, 1210
2
1
C3
CAP., X7R, 1μF, 50V, 10%, 0805
MURATA, GRM21BR71H105KA12B
3
1
C5
CAP., SMT, 100μF, 20V, 20%
SANYO, 20SVP100M
4
1
C6
CAP., X7R, 10μF, 25V, 10%, 1206
MURATA, GRM31CR71E106KA12L
5
1
C9
CAP., X5R, 4.7μF, 4V, 20%, 0402
MURATA, GRM155R60G475M
6
2
D1, D2
SMD, SCHOTTKY BARRIER RECTIFIER
CENTRAL SEMI, CMSH3-40MA
7
1
D5
SMD, SCHOTTKY DIODE, SOT-23F
CENTRAL SEMI, CMPSH1-4
8
1
D6
SMD, ZENER DIODE, 6.2V, SOT-23
CENTRAL SEMI, CMHZ4691TR
9
1
D8
SMD, SWITCHING DIODE, SOD323
VISHAY, 1N4148WS-V-GS08
10
1
L1
POWER INDUCTOR, 15μH, 20%, 3.5A
COILCRAFT, MSS1038-153ML
11
1
R1
RES., CHIP, 1.33MEG, 1/16W, 1%, 0402
VISHAY, CRCW04021M33FKED
12
1
R4
RES., CHIP, 562K, 1/16W, 1%, 0402
VISHAY, CRCW0402562KFKED
13
2
R5, R6
RES., CHIP, 100K, 1/16W, 1%, 0402
VISHAY, CRCW0402100KFKED
14
1
R7
RES., CHIP, 0.05 OHM, 1/2W, 1%, 1206
SUSUMU, RL1632R-R050-F
15
1
R9
RES., CHIP, 174K, 1/16W, 1%, 0402
VISHAY, CRCW0402174KFKED
16
1
R10
RES., CHIP, 309K, 1/16W, 0.1%, 0603
SUSUMU, RG1608P-3093-B-T5
17
1
R11
RES., CHIP, 100K, 1/16W, 0.1%, 0603
SUSUMU, RG1608P-104-B-T5
18
1
R12
RES., CHIP, 1.00MEG, 1/16W, 1%, 0402
VISHAY, CRCW04021M00FKED
19
1
U1
SLA 2A BATTERY CHARGER FOR SOLAR POWER
LINEAR TECHNOLOGY, LT3652HVEDD
C1
CAP., SMT, 390μF, 50V, 20
SANYO, 50CE390BS
Additional Demo Board Circuit Components:
1
1
2
2
C7, C8
CAP., CHIP, X7R, 0.022μF, ±10%, 16V, 0402
AVX, 0402YC223KAT2A
3
1
D3
LED, RED
PANASONIC, LN208R8ARA
4
1
D4
LED, GREEN
LITE-ON, LTST-C190KGKT
5
2
R2, R3
RES., CHIP, 5.1K,1/4W, 1%, 1206
VISHAY, CRCW12065K10FKEA
6
1
R8
RES., CHIP, 20,1/16W, 5%, 0402
VISHAY, CRCW040220R0JNED
Optional Demo Board Circuit Components:
1
0
C4(OPT)
CAP,. OPT, 0402
CUSTOMER SELECTABLE
2
0
D7(OPT)
SMD, SCHOTTKY BARRIER RECTIFIER
CENTRAL SEMI, CMSH3-40MA
3
0
D9(OPT)
SMD, ZENER DIODE, 10V, SOT-23
CENTRAL SEMI, CMHZ4697
4
0
J1(OPT)
HEADER, 3 PINS
HIROSE ELECTRIC, DF3A-3P-2DSA
5
0
R13(OPT)
RES., CHIP, 10K, 1/16W, 1%, 0402
VISHAY, CRCW040210K0FKED
6
0
R14(OPT)
RES., CHIP, 100K, 1/16W, 1%, 0402
VISHAY, CRCW0402100KFKED
7
0
Q1(OPT)
SMD, P-CHANNEL MOSFET, 40V, 82mΩ
VISHAY, SI2319DS
Hardware For Demo Board Only:
1
7
E1-E7
TESTPOINT, TURRET, .095"
MILL-MAX, 2501-2-00-80-00-00-07-0
2
1
J1
HEADER, 3 PINS
HIROSE ELECTRIC, DF3A-3P-2DSA
3
4
JP1-JP4
2mm SINGLE ROW HEADER, 3 PIN
SAMTEC, TMM-103-02-L-S
4
4
JP1-JP4
SHUNT
SAMTEC, 2SN-BK-G
5
4
STAND-OFF, NYLON, 0.625" TALL (SNAP ON)
KEYSTONE, 8834 (SNAP ON)
dc1688afa
4
GND
E2
E1
3
1
R13
10k
OPT
2
R14
100k
OPT
1
JP2
0
1
UVLO
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.
X
0
SHDN
C1
390uF
50V
20%
D9
CMHZ4697
10V
OPT
+
0
1
JP1
2
R1
1.33Meg
D3
FAULT
RED
LED-LN
R2
5.1K
1206
0
1
D4
CHRG
GRN
LED-LN
TIMER
C/10
JP2
2
R3
5.1K
1206
0
1
JP3
C9
4.7uF
4V
20%
2
R6
100K
R5
100K
2
JP4
6
3
5
4
2
1
1.00Meg
R12
TIMER
SHDN
FAULT
CHRG
VIN
VIN_REG
R4
562K
D8
NTC
VFB
BAT
SENSE
BOOST
1N4148WS-V
13
GND
SW
12
8
7
9
10
11
U1
LT3652HVEDD
D5
R9
174k
L1 15uH
2
R11
100K
0603
0.1%
R10
309K
0603
0.1%
TP2
D6
R7
0.05
1206
1/4W
6.2V
CMSH3-40MA
D2
+
MSS1038-153ML
1
CMHZ4691
1
R8
20
TP1
OPT
C4
CMPSH1-4
3
C3
1uF
50V
0805
C2
10uF
50V
1210
2
C5
100uF
20V
20%
C6
10uF
25V
1206
10%
C7
0.022uF
25V
C8
0.022uF
25V
CMSH3-40MA
OPT
D7
CUSTOMER NOTICE: LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR
RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
Unless noted:
Resistors: Ohms
0402
1%
1/16W
Capacitors:
0402
10%
10V
1
JP1
RUN
JP1 - JP2 SETTINGS
Q1
Si2319DS
OPT
1
3
CMSH3-40MA
1
3
1
3
VIN
17.7V - 34V
1
3
D1
1
2
3
GND
SYSTEM LOAD
GND
J1
(OPT)
E7
NTC
DF3-3P-2DSA
BAT
GND
NTC
E6
BAT
14.4V / 13.5V
2A
E5
E4
E3
DEMO MANUAL DC1688A
SCHEMATIC DIAGRAM
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DEMO MANUAL DC1688A
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
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ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
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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,
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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:
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1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
dc1688afa
6
Linear Technology Corporation
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●
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