Datasheet

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
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Copyright © 2014 Unisonic Technologies Co., Ltd
Package
Packing
SOT-25
Tape Reel
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L4075
Preliminary
„
MARKING
„
PIN CONFIGURATION
„
PIN DESCRIPTION
PIN NO.
1
2
3
4
5
„
PIN NAME
LX
GND
ADJ
ISENSE
VIN
CMOS IC
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
„
Preliminary
CMOS IC
ABSOLUTE MAXIMUM RATING
PARAMETER
RATINGS
UNIT
-0.3~+50
V
VIN>5V
VIN+0.3~VIN-5
V
ISENSE Voltage
VISENSE
VIN<5V
VIN+0.3~ -0.3
V
LX Output Voltage
VLX
-0.3~+50
V
Adjust Pin Input Voltage
VADJ
-0.3~+6
V
Switch Output Current
ILX
400
mA
Power Dissipation
PD
600
mW
Operating Junction Temperature
TJ
150
°C
Operating Temperature Range
TOPR
-40~85
°C
Storage Temperature Range
TSTG
-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.
Input Voltage
„
SYMBOL
VIN
THERMAL CHARACTERISTICS
PARAMETER
Junction to Ambient
SYMBOL
θJA
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MAX
270
UNIT
°C/W
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„
Preliminary
CMOS IC
ELECTRICAL CHARACTERISTICS (VIN=12V, TAMB=25°C unless otherwise stated) (Note 1)
PARAMETER
Input Voltage
Quiescent Supply Current with Output Off
Quiescent Supply Current with Output
Switching
Mean Current Sense Threshold Voltage
Sense Threshold Hysteresis
ISENSE 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 VREF
Continuous LX Switch Current
LX Switch Leakage Current
LX Switch “On” Resistance
Minimum Switch “ON” Time
Minimum Switch “OFF” Time
SYMBOL
TEST CONDITIONS
VIN
IINQOFF ADJ Pin Grounded
IINQON
ADJ Pin Floating
VSENSE
VSENSEHYS
ISENSE
VSENSE=0.1V
Measured on ADJ Pin with
VREF
Pin Floating
VADJ
TYP
60
MAX
40
80
UNIT
V
μA
450
600
μA
10
mV
%
μA
113
±15
8
1.2
0.3
V
1.2
V
VADJOFF
VADJ Falling
0.15
0.2
0.25
V
VADJON
VADJ Rising
0.2
0.25
0.3
V
1
1.5
KΩ
A
μA
Ω
ns
ns
RADJ
ILXmean
ILX(leak)
RLX
TONMIN
TOFFMIN
Brightness Control Range at Low Frequency
PWM Signal
DPWM(LF)
Brightness Control Range at Low Frequency
PWM Signal
DPWM(HF)
Operating Frequency
MIN
6
40
fLX
500
0.35
LX Switch “ON”
LX Switch “OFF”
PWM Frequency=100Hz,
PWM Amplitude=5V,
VIN=15V, Driving 1LED,
L=27μH
PWM Frequency=10KHz,
PWM Amplitude=5V,
VIN=15V, Driving 1LED,
L=27μH
ADJ Pin Floating L=100Μh
(0.82Ω) IOUT=350mA @
VLED=3.4V Driving 1 LED
0.9
200
200
1200:1
13:1
154
KHz
Recommended Maximum Operating
fLXMAX
1
MHz
Frequency
Recommended Duty Cycle Range of Output
DLX
0.3
0.7
0.9
Switch at fLXmax
Internal Comparator Propagation Delay
TPD
50
ns
Thermal Shutdown Temperature
TSD
140
°C
Thermal Shutdown Hysteresis
TSD-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
CMOS IC
TYPICAL APPLICATION CIRCUIT
VIN (DC)= 6V~40V
C1
1µF
D1
5
VIN
LX 1
UTC L4075
4
ISENSE
2
L1
GND
47µH
RS=0.15Ω
„
Preliminary
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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