UNISONIC TECHNOLOGIES CO., LTD
L4075
Preliminary
CMOS IC
40V LED DRIVER WITH
INTERNAL SWITCH
DESCRIPTION
The UTC
L4075
is a continuous conduction mode inductive
step-down converter, designed for driving single or multiple series
connected LEDs efficiently from a voltage source higher than the
total LEDs chain voltage. The chip operates from an input supply
between 6V and 40V and provides an externally adjustable output
current of up to 750mA (SOT89-5). Depending upon supply voltage
and external components, this can provide up to 30W of output
power.
The UTC
L4075
includes an integrated output switch and a
high-side output current sensing circuit, which uses an external
resistor to set the nominal average output current.
Output current can be adjusted linearly by applying an external
control signal to the ADJ pin. The ADJ pin will accept either a DC
voltage dimming or a wide range of pulsed dimming. This will
provide either a continuous or a gated output current.
Applying a voltage of 0.2V or lower to the ADJ pin can turn the
output off and switch the chip into a low current standby state.
FEATURES
* 6V~40V input voltage range
* Simple low parts count
* Internal 40V power switch
* High efficiency up to 95%
* Typical 5% output current accuracy
* Single pin on/off and brightness control using DC voltage or PWM
* Up to 1MHz switching frequency
* Protection features:
Open-circuit LED Protection
Thermal shutdown Protection
ORDERING INFORMATION
Ordering Number
Lead Free
L4075L-AF5-R
Halogen Free
L4075G-AF5-R
Package
SOT-25
Packing
Tape Reel
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Copyright © 2014 Unisonic Technologies Co., Ltd
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L4075
MARKING
Preliminary
CMOS IC
PIN CONFIGURATION
PIN DESCRIPTION
PIN NO.
1
2
3
4
5
PIN NAME
LX
GND
ADJ
I
SENSE
V
IN
DESCRIPTION
Drain of power switch
Ground (0V)
Multi-function On/Off and brightness control pin
Current sense input
Input voltage
BLOCK DIAGRAM
+
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L4075
ABSOLUTE MAXIMUM RATING
PARAMETER
Preliminary
CMOS IC
RATINGS
UNIT
Input Voltage
-0.3~+50
V
V
IN
>5V
V
IN
+0.3~V
IN
-5
V
I
SENSE
Voltage
V
ISENSE
V
IN
<5V
V
IN
+0.3~ -0.3
V
LX Output Voltage
V
LX
-0.3~+50
V
Adjust Pin Input Voltage
V
ADJ
-0.3~+6
V
Switch Output Current
I
LX
400
mA
Power Dissipation
P
D
600
mW
Operating Junction Temperature
T
J
150
°C
Operating Temperature Range
T
OPR
-40~85
°C
Storage Temperature Range
T
STG
-55~150
°C
Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.
SYMBOL
V
IN
THERMAL CHARACTERISTICS
PARAMETER
Junction to Ambient
SYMBOL
θ
JA
MAX
270
UNIT
°C/W
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L4075
PARAMETER
Input Voltage
Quiescent Supply Current with Output Off
Quiescent Supply Current with Output
Switching
Mean Current Sense Threshold Voltage
Sense Threshold Hysteresis
I
SENSE
Pin Input Current
Internal Reference Voltage
External Control Voltage Range On ADJ Pin
for DC Brightness Control
DC Voltage On ADJ Pin to Switch Chip from
Active (On) State to Quiescent (Off) State
DC Voltage On ADJ Pin to Switch Chip from
Quiescent (Off) State to Active (On) State
Resistance Between ADJ Pin and V
REF
Continuous LX Switch Current
LX Switch Leakage Current
LX Switch “On” Resistance
Minimum Switch “ON” Time
Minimum Switch “OFF” Time
Brightness Control Range at Low Frequency
PWM Signal
Preliminary
CMOS IC
ELECTRICAL CHARACTERISTICS
(V
IN
=12V, T
AMB
=25°C unless otherwise stated) (Note 1)
SYMBOL
TEST CONDITIONS
V
IN
I
INQOFF
ADJ Pin Grounded
I
INQON
V
SENSE
V
SENSEHYS
I
SENSE
V
SENSE
=0.1V
Measured on ADJ Pin with
V
REF
Pin Floating
V
ADJ
V
ADJOFF
V
ADJON
R
ADJ
I
LXmean
I
LX(leak)
R
LX
T
ONMIN
T
OFFMIN
D
PWM(LF)
V
ADJ
Falling
V
ADJ
Rising
0.3
0.15
0.2
0.2
0.25
500
0.35
0.9
200
200
1200:1
1
1.5
ADJ Pin Floating
MIN
6
40
TYP
60
450
113
±15
8
1.2
1.2
0.25
0.3
MAX
40
80
600
UNIT
V
μA
μA
mV
%
μA
V
V
V
V
KΩ
A
μA
Ω
ns
ns
10
Brightness Control Range at Low Frequency
PWM Signal
D
PWM(HF)
Operating Frequency
f
LX
LX Switch “ON”
LX Switch “OFF”
PWM Frequency=100Hz,
PWM Amplitude=5V,
V
IN
=15V, Driving 1LED,
L=27μH
PWM Frequency=10KHz,
PWM Amplitude=5V,
V
IN
=15V, Driving 1LED,
L=27μH
ADJ Pin Floating L=100Μh
(0.82Ω) I
OUT
=350mA @
V
LED
=3.4V Driving 1 LED
13:1
154
KHz
Recommended Maximum Operating
f
LXMAX
1
MHz
Frequency
Recommended Duty Cycle Range of Output
D
LX
0.3
0.7
0.9
Switch at f
LXmax
Internal Comparator Propagation Delay
T
PD
50
ns
Thermal Shutdown Temperature
T
SD
140
°C
Thermal Shutdown Hysteresis
T
SD-HYS
20
°C
Note: Production testing of the chip is performed at 25°C. Functional operation of the chip and parameters specified
are guaranteed by design, characterization and process control in other temperature.
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L4075
V
IN
(DC)= 6V~40V
Preliminary
CMOS IC
TYPICAL APPLICATION CIRCUIT
C1
1µF
D1
5
R
S
=0.15Ω
V
IN
LX 1
47µH
UTC L4075
GND
4
I
SENSE
2
L1
ADJ 3
Up to 10
LEDs
UTC assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or
other parameters) listed in products specifications of any and all UTC products described or contained
herein. UTC products are not designed for use in life support appliances, devices or systems where
malfunction of these products can be reasonably expected to result in personal injury. Reproduction in
whole or in part is prohibited without the prior written consent of the copyright owner. The information
presented in this document does not form part of any quotation or contract, is believed to be accurate
and reliable and may be changed without notice.
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