LED Drivers for High Power LEDs
ILD2035
350 mA Step Down LED Driver
Data Sheet
Revision 1.0, 2011-08-17
Industrial and Multimarket
Edition 2011-08-17
Published by
Infineon Technologies AG
81726 Munich, Germany
© 2011 Infineon Technologies AG
All Rights Reserved.
Legal Disclaimer
The information given in this document shall in no event be regarded as a guarantee of conditions or
characteristics. With respect to any examples or hints given herein, any typical values stated herein and/or any
information regarding the application of the device, Infineon Technologies hereby disclaims any and all warranties
and liabilities of any kind, including without limitation, warranties of non-infringement of intellectual property rights
of any third party.
Information
For further information on technology, delivery terms and conditions and prices, please contact the nearest
Infineon Technologies Office (www.infineon.com).
Warnings
Due to technical requirements, components may contain dangerous substances. For information on the types in
question, please contact the nearest Infineon Technologies Office.
Infineon Technologies components may be used in life-support devices or systems only with the express written
approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure
of that life-support device or system or to affect the safety or effectiveness of that device or system. Life support
devices or systems are intended to be implanted in the human body or to support and/or maintain and sustain
and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may
be endangered.
ILD2035
350 mA Step Down LED Driver
Revision History
Page or Item
Subjects (major changes since previous revision)
Revision 1.0, 2011-08-17
All
Initial release of data sheet
Trademarks of Infineon Technologies AG
AURIX™, BlueMoon™, C166™, CanPAK™, CIPOS™, CIPURSE™, COMNEON™, EconoPACK™, CoolMOS™,
CoolSET™, CORECONTROL™, CROSSAVE™, DAVE™, EasyPIM™, EconoBRIDGE™, EconoDUAL™,
EconoPIM™, EiceDRIVER™, eupec™, FCOS™, HITFET™, HybridPACK™, I²RF™, ISOFACE™, IsoPACK™,
MIPAQ™, ModSTACK™, my-d™, NovalithIC™, OmniTune™, OptiMOS™, ORIGA™, PRIMARION™,
PrimePACK™, PrimeSTACK™, PRO-SIL™, PROFET™, RASIC™, ReverSave™, SatRIC™, SIEGET™,
SINDRION™, SIPMOS™, SMARTi™, SmartLEWIS™, SOLID FLASH™, TEMPFET™, thinQ!™,
TRENCHSTOP™, TriCore™, X-GOLD™, X-PMU™, XMM™, XPOSYS™.
Other Trademarks
Advance Design System™ (ADS) of Agilent Technologies, AMBA™, ARM™, MULTI-ICE™, KEIL™,
PRIMECELL™, REALVIEW™, THUMB™, µVision™ of ARM Limited, UK. AUTOSAR™ is licensed by AUTOSAR
development partnership. Bluetooth™ of Bluetooth SIG Inc. CAT-iq™ of DECT Forum. COLOSSUS™,
FirstGPS™ of Trimble Navigation Ltd. EMV™ of EMVCo, LLC (Visa Holdings Inc.). EPCOS™ of Epcos AG.
FLEXGO™ of Microsoft Corporation. FlexRay™ is licensed by FlexRay Consortium. HYPERTERMINAL™ of
Hilgraeve Incorporated. IEC™ of Commission Electrotechnique Internationale. IrDA™ of Infrared Data
Association Corporation. ISO™ of INTERNATIONAL ORGANIZATION FOR STANDARDIZATION. MATLAB™ of
MathWorks, Inc. MAXIM™ of Maxim Integrated Products, Inc. MICROTEC™, NUCLEUS™ of Mentor Graphics
Corporation. Mifare™ of NXP. MIPI™ of MIPI Alliance, Inc. MIPS™ of MIPS Technologies, Inc., USA. muRata™
of MURATA MANUFACTURING CO., MICROWAVE OFFICE™ (MWO) of Applied Wave Research Inc.,
OmniVision™ of OmniVision Technologies, Inc. Openwave™ Openwave Systems Inc. RED HAT™ Red Hat, Inc.
RFMD™ RF Micro Devices, Inc. SIRIUS™ of Sirius Satellite Radio Inc. SOLARIS™ of Sun Microsystems, Inc.
SPANSION™ of Spansion LLC Ltd. Symbian™ of Symbian Software Limited. TAIYO YUDEN™ of Taiyo Yuden
Co. TEAKLITE™ of CEVA, Inc. TEKTRONIX™ of Tektronix Inc. TOKO™ of TOKO KABUSHIKI KAISHA TA.
UNIX™ of X/Open Company Limited. VERILOG™, PALLADIUM™ of Cadence Design Systems, Inc. VLYNQ™
of Texas Instruments Incorporated. VXWORKS™, WIND RIVER™ of WIND RIVER SYSTEMS, INC. ZETEX™ of
Diodes Zetex Limited.
Last Trademarks Update 2010-10-26
Data Sheet
3
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Table of Contents
Table of Contents
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2
Product Brief . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3
Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4
Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5
5.1
5.2
5.3
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Switching Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Digital Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
14
15
15
6
6.1
6.1.1
6.2
Basic Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting the average LED current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Temperature Protection Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Switching Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
16
17
17
7
7.1
Application Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Evaluation Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
8
Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Data Sheet
4
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
List of Figures
List of Figures
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Data Sheet
Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Total Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Safe Operating Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Application Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
ILD2035 on Evaluation Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Package Outline SC74 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Recommended PCB Footprint for Reflow Soldering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Tape Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
List of Tables
List of Tables
Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Data Sheet
Pin Definition and Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Thermal Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Switching Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Digital Control Parameter at Pin EN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
10
11
12
14
15
15
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
List of Tables
Data Sheet
7
Revision 1.0, 2011-08-17
350 mA Step Down LED Driver with Internal Switch
ILD2035
1
•
•
•
•
•
•
•
•
•
•
•
Features
Input voltage range 8 V to 22 V
Internal switch for up to 400 mA average LED current
Up to 92 % efficiency
Over current protection
Temperature protection mechanism
Inherent open-circuit LED protection
Soft-start capability
Low shut down current
Typical 3 % output current accuracy
Minimum external components required
Small package: SC74
SC74-3D
Applications
•
•
•
LED replacement lamps, e.g. MR16 halogen replacement
Downlights
Architectural lighting
Product Name
Package
ILD2035
SC74-6-4
Data Sheet
Pin Configuration
1 = VS
2 = GND 3 = EN
8
Marking
4 = Vswitch 5 = GND 6 = Vsense 25
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Product Brief
2
Product Brief
The ILD2035 is a hysteretic step down LED driver IC for general lighting applications, which is capable to drive
high power LEDs with average currents up to 400 mA.
The IC incorporates an input voltage range from 8 to 22 V and an internal power switch. The output current level
can be adjusted with an external sense resistor.
Depending on the value of the switching inductor the switching frequency and the voltage ripple can be set.
The precise internal bandgap stabilizes the circuit and provides stable current conditions over temperature range.
To ensure a long lifetime of the LED system, the ILD2035 incorporates an overcurrent protection.
In addition, the integrated thermal protection will actively control the output current to protect the LEDs and the IC
against thermal stress and hence ensure longer LED lifetimes.
ILD2035
Buck LED Converter
VS
1
Vstab
Vstab
6
Vsense
5
GND
4
Vswitch
I/V
GND
2
TPC
Vref
Vstab
Vstab
Vstab
EN
3
Over Current Protection
ILD2035 _Block diagram.vsd
Figure 1
Data Sheet
Block Diagram
9
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Product Brief
Pin Definition
Table 1
Pin Definition and Function
Pin No.
Name
Pin
Type
Buffer
Type
Function
1
Vs
Input
–
Supply voltage
2
GND
GND
–
IC ground
3
EN
Input
–
Chip enable signal
4
Vswitch
Output
–
Power switch output
5
GND
GND
–
IC ground
6
Vsense
Input
–
LED current sense input
Data Sheet
10
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Maximum Ratings
3
Maximum Ratings
Table 2
Maximum Ratings
Parameter
Symbol
Values
Min.
Typ.
Max.
Unit
Note /
Test Condition
Supply voltage
VS
–
–
24
V
–
Peak output current
ISwitch
–
–
550
mA
Hysteretic peak
current
Total power dissipation, Ts ≤ 85°C
Ptot
–
–
1000
mW
–
Junction temperature
TJ
–
–
150
°C
–
Solder temperature of GND pins
TSGND
–
–
125
°C
–
Storage temperature range
TSTG
-65
–
150
°C
–
ESD capability
at all pins
VESD HBM
kV
–
–
4
HBM acc. to
JESD22-A114
Attention: Stresses above the max. values listed here may cause permanent damage to the device.
Exposure to absolute maximum rating conditions for extended periods may affect device
reliability. Maximum ratings are absolute ratings; exceeding only one of these values may
cause irreversible damage to the integrated circuit.
Data Sheet
11
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Thermal Characteristics
4
Thermal Characteristics
Table 3
Maximum Thermal Resistance
Parameter
Symbol
1)
Junction - soldering point
Values
RthJS
Min.
Typ.
Max.
–
–
65
Unit
Note /
Test Condition
K/W
–
1) For calculation of RthJA please refer to application note AN077 (Thermal Resistance Calculation)
1.2
1
Ptot [W]
0.8
0.6
0.4
0.2
0
Figure 2
0
20
40
60
80
TS [°C]
100
120
140
160
Total Power Dissipation
Equation (1) is gives an estimation for the power dissipation of ILD2035.
Ptot = 1 .1V ⋅ I LED ⋅ duty cycle + f Switch ⋅ 1 µW ⋅ I LED
350 mA
(1)
Data Sheet
12
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Thermal Characteristics
25
VS - VΣfLED [V]
20
47 μH
68 μH
100 μH
15
10
5
0
0.05
Figure 3
0.1
0.15
0.2
0.25
0.3
0.35
Average LED current ILED [A]
0.4
0.45
Safe Operating Area
Figure 2 shows the safe operating area for the respective inductance values. The safe operating area consists of
the minimum and maximum allowed average LED current and the resulting voltage overhead. The voltage
overhead Voverhead is the difference between the supply voltage VS and the sum of the LED forward voltages VΣfLED.
Example calculation
3 LEDs in series, VfLED= 3V, ILED = 350 mA, VS = 12 V
Voverhead = VS - VΣfLED = 12 V - 9 V = 3 V
→ any of the above coil values can be used
Outside the safe operating area the switching frequency, hysteretic peak current and associated power dissipation
Ptot of ILD2035 will increase beyond the maximum ratings.
Data Sheet
13
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Electrical Characteristics
5
Electrical Characteristics
5.1
DC Characteristics
All parameters at TA = 25 °C, unless otherwise specified.
VS = 12 V, 3 LEDs, Rsense = 303 mΩ (ILED = 375 mA), L = 100 μH, VEN = 12 V, VfLED = 3 V
Table 4
DC Characteristics
Parameter
Symbol
Values
Unit
Min.
Typ.
Max.
Note / Test Condition
Supply voltage
VS
8
–
22
V
Overall current consumption open
load
IS open load
–
2.4
–
mA
VS = 12 V
ILED = 0 mA
Overall standby current consumption
IS standby
–
–
1
µA
VEN = 0 V; VS= 12 V
Current of Sense input
Isense
–
20
–
μA
at any LED current
Enable voltage for standby mode
VEN,Off
-0.3
–
0.4
V
Enable voltage for power on
VEN,On
2.5
3
22
V
Min. power on puls duration
tEN,On
10
–
–
µs
Input current of enable pin
IEN
–
310
–
μA
VEN =12 V
Over temperature protection
TS, TSD
–
113
–
°C
TS for 10 % ILED
reduction, defined by TJ
Data Sheet
14
full LED current
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Electrical Characteristics
5.2
Switching Characteristics
All parameters at TA = 25 °C, unless otherwise specified.
VS = 12 V, 3 LEDs, Rsense = 303 mΩ (ILED = 375 mA), L = 100 μH, VEN = 12 V, VfLED = 3 V
Table 5
Switching Characteristics
Parameter
Symbol
Values
Unit
Min.
Typ.
Max.
Switching frequency
fSwitch
–
120
–
kHz
Maximum switching frequency
fSwitch max
–
–
500
kHz
–
114
–
mV
Vsensehys
–
±7.5
–
%
Residual voltage at collector of power Vswitch on
transistor
–
1.1
–
V
–
±3
–
%
Mean current sense threshold voltage Vsense
Sense threshold hysteresis
Output current accuracy
5.3
Ioutacc
Note / Test Condition
for any coil value
output switch turned on
Digital Signals
All parameters at TA = 25 °C, unless otherwise specified.
Table 6
Digital Control Parameter at Pin EN
Parameter
Symbol
Values
Min.
Typ.
Max.
Unit
Note / Test Condition
full LED current
Input voltage for power on
VOn
2.5
3
22
V
Input voltage for power off
VOff
-0.3
–
0.4
V
Min. power on puls duration
tOn
10
–
Data Sheet
15
µs
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Basic Application Information
6
Basic Application Information
This section covers the basic information required for calculating the parameters for a certain LED application.
For detailed application information please visit our web site http://www.infineon.com/led.appnotes
6.1
Setting the average LED current
The average output current for the LEDs is set by the external sense resistor Rsense. To calculate the value of this
resistor a first approximation can be calculated using Equation (2).
Vsense is dependent on the supply voltage VS and the number of LEDs in series.
Rsense =
Vsense
I LED
(2)
Example calculation
VS = 12 V, 100 µH, VfLED = 3 V, 3 LEDs in series
→ Vsense = 114 mV
ILED = 375 mA
→ Rsense = 303 mΩ
An easy way to achieve these resistor values is to connect standard resistors in parallel.
Data Sheet
16
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Basic Application Information
6.1.1
Temperature Protection Circuit
ILD2035 incorporates a temperature protection circuit referring to the junction temperature of the IC. The higher
the junction temperature the lower the current of the LEDs. This feature helps to reduce the power dissipation of
ILD2035 and the LEDs. Yet still the product specific maximum ratings for the junction temperature need to be
observed to avoid a permanent damage of the devices.
ILD2035 has been characterized on ILD4035/4001 application board heated from the backside without additional
air flow on the circuit board surface besides natural convection. The size and layout of the circuit board as well as
the air flow around it influence the thermal resistance junction to ambient RthJA of ILD2035 and thus its junction
temperature. Below figures show the LED current versus soldering point temperature TS.
LED current versus TS, VS = 12 V
LED current (relative) versus TS, VS = 12 V
0.4
110
0.35
0.3
100
ILED [%]
ILED [A]
0.25
0.2
0.15
0.1
90
80
0.05
0
40
50
60
303 mΩ, 100 μH
333 mΩ, 100 μH
6.2
70
80
90
TS [°C ]
100
110
120
70
130
600 mΩ, 100 μH
1200 mΩ, 220 μH
40
50
60
303 mΩ, 100 μH
333 mΩ, 100 μH
70
80
90
TS [°C ]
100
110
120
130
600 mΩ, 100 μH
1200 mΩ, 220 μH
Switching Parameters
For all shown parameters ILD2035 has been measured at TA = 25 °C. Used LEDs have a typical VfLED of 3 V.
Data Sheet
17
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Basic Application Information
Rsense = 303 mΩ, L= 47 µH
ILED versus VS and Number of LEDs
fSwitch versus VS and Number of LEDs
0.5
500
400
fSwitch [kHz]
ILED [A]
0.45
0.4
0.35
0.3
300
200
100
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
0
25
Efficiency versus VS and Number of LEDs
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
25
Duty Cycle versus VS and Number of LEDs
100
100
95
80
85
Duty Cycle [%]
Efficiency [%]
90
80
75
70
40
20
1 LED
2 LEDs
3 LEDs
65
60
60
5
Data Sheet
10
15
VS [V]
20
0
25
18
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
25
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Basic Application Information
Rsense = 303 mΩ, L= 68 µH
ILED versus VS and Number of LEDs
fSwitch versus VS and Number of LEDs
0.5
500
400
fSwitch [kHz]
ILED [A]
0.45
0.4
0.35
0.3
300
200
100
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
0
25
Efficiency versus VS and Number of LEDs
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
25
Duty Cycle versus VS and Number of LEDs
100
100
95
80
85
Duty Cycle [%]
Efficiency [%]
90
80
75
70
40
20
1 LED
2 LEDs
3 LEDs
65
60
60
5
Data Sheet
10
15
VS [V]
20
0
25
19
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
25
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Basic Application Information
Rsense = 303 mΩ, L= 100 µH
ILED versus VS and Number of LEDs
fSwitch versus VS and Number of LEDs
0.5
500
400
fSwitch [kHz]
ILED [A]
0.45
0.4
0.35
0.3
300
200
100
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
0
25
Efficiency versus VS and Number of LEDs
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
25
Duty Cycle versus VS and Number of LEDs
100
100
95
80
85
Duty Cycle [%]
Efficiency [%]
90
80
75
70
40
20
1 LED
2 LEDs
3 LEDs
65
60
60
5
Data Sheet
10
15
VS [V]
20
0
25
20
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
25
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Basic Application Information
Rsense = 367 mΩ, L= 47 µH
ILED versus VS and Number of LEDs
fSwitch versus VS and Number of LEDs
0.45
500
400
fSwitch [kHz]
ILED [A]
0.4
0.35
0.3
0.25
300
200
100
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
0
25
Efficiency versus VS and Number of LEDs
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
25
Duty Cycle versus VS and Number of LEDs
100
100
95
80
85
Duty Cycle [%]
Efficiency [%]
90
80
75
70
40
20
1 LED
2 LEDs
3 LEDs
65
60
60
5
Data Sheet
10
15
VS [V]
20
0
25
21
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
25
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Basic Application Information
Rsense = 367 mΩ, L= 68 µH
ILED versus VS and Number of LEDs
fSwitch versus VS and Number of LEDs
0.45
500
400
fSwitch [kHz]
ILED [A]
0.4
0.35
0.3
0.25
300
200
100
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
0
25
Efficiency versus VS and Number of LEDs
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
25
Duty Cycle versus VS and Number of LEDs
100
100
95
80
85
Duty Cycle [%]
Efficiency [%]
90
80
75
70
40
20
1 LED
2 LEDs
3 LEDs
65
60
60
5
Data Sheet
10
15
VS [V]
20
0
25
22
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
25
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Basic Application Information
Rsense = 367 mΩ, L= 100 µH
ILED versus VS and Number of LEDs
fSwitch versus VS and Number of LEDs
0.45
500
400
fSwitch [kHz]
ILED [A]
0.4
0.35
0.3
0.25
300
200
100
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
0
25
Efficiency versus VS and Number of LEDs
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
25
Duty Cycle versus VS and Number of LEDs
100
100
95
80
85
Duty Cycle [%]
Efficiency [%]
90
80
75
70
40
20
1 LED
2 LEDs
3 LEDs
65
60
60
5
Data Sheet
10
15
VS [V]
20
0
25
23
1 LED
2 LEDs
3 LEDs
5
10
15
VS [V]
20
25
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Application Circuit
7
Application Circuit
Rsense
VS
1
Vstab
Vref
6
I/V
TPC
2
Vref
Vstab
5
Vstab
Vstab
EN
3
Figure 4
Application Circuit
7.1
Evaluation Board
Figure 5
ILD2035 on Evaluation Board
Data Sheet
4
ILD2035
24
Revision 1.0, 2011-08-17
ILD2035
350 mA Step Down LED Driver
Package Information
Package Information
2.9 ±0.2
(2.25)
B
1.1 MAX.
0.15 +0.1
-0.06
5
4
1
2
3
0.35 +0.1
-0.05
Pin 1
marking
0.2
1.6 ±0.1
6
2.5 ±0.1
(0.35)
0.25 ±0.1
8
A
B 6x
M
0.1 MAX.
0.95
0.2
1.9
M
A
SC74-PO V04
Figure 6
Package Outline SC74
2.9
1.9
0.5
0.95
SC74-FPR V04
Figure 7
Recommended PCB Footprint for Reflow Soldering
0.2
2.7
8
4
Pin 1
marking
Figure 8
Data Sheet
3.15
1.15
SC74-TP
Tape Loading
25
Revision 1.0, 2011-08-17
w w w . i n f i n e o n . c o m
Published by Infineon Technologies AG
