PT4119E
50V/1A Step-down High Brightness
LED Driver
GENERAL DESCRIPTION
The PT4119E is a continuous conduction mode
inductive step-down converter, designed for driving
single or multiple series connected LED efficiently
from a voltage source higher than the total LED chain
voltage. The device operates from an input supply
between 6V and 50V and provides an externally
adjustable output current of up to 1A.
The PT4119E includes the power switch and a
high-side output current sensing circuit, which uses an
external resistor to set the nominal average output
current, and a dedicated DIM input accepts either a DC
voltage or a wide range of pulsed dimming. Applying a
voltage of 0.3V or lower to the DIM pin turns the
output off and switches the device into a low current
standby state.
The PT4119E is available in SOT89-5 package.
FEATURES
Simple low parts count
Wide input voltage range: 6V to 50V
High efficiency (up to 97%)
Up to 1A output current
Single pin on/off and brightness control using DC
voltage or PWM
Up to 1MHz switching frequency
Typical 3% output current accuracy
Inherent open-circuit LED protection
Inherent Rcs open protection
High-Side Current Sense
Hysteretic Control: No need compensation
Adjustable Constant LED Current
Thermal shutdown
APPLICATIONS
Low voltage halogen replacement LEDs
Automotive lighting
Low voltage industrial lighting
LED back-up lighting
Illuminated signs
SELV lighting
LCD TV backlighting
ORDERING INFORMATION
PACKAGE
SOT89-5
Note:
xxxxxX
Assembly Factory Code
Lot Number
TEMPERATURE
RANGE
-40
o
C to 85
o
C
ORDERING PART
NUMBER
PT4119EE89E
TRANSPORT
MEDIA
Tape and Reel
1000 units
MARKING
PT4119E
xxxxxX
TYPICAL APPLICATION CIRCUIT
DC6-50V
R
S
LED
L
D
V
IN
C
IN
AC12-24V
VIN
CSN
SW
DIM
PT411 E
GND
CR POWTECH (SHANGHAI) CO., LTD.
PT4119E_DS_Rev EN 1.0
WWW.CRPOWTECH.COM
Page 1
PT4119E
50V/1A Step-down High Brightness
LED Driver
PIN ASSIGNMENT
PIN DESCRIPTIONS
SOT89-5 PIN
No.
1
2
3
4
5
PIN NAMES
SW
GND
DIM
CSN
VIN
Exposed
PAD
DESCRIPTION
Switch Output. SW is the drain of the internal N-Ch MOSFET
switch.
Signal and power ground. Connect directly to ground plane.
Logic level dimming input. Drive DIM low to turn off the current
regulator. Drive DIM high to enable the current regulator.
Current sense input
Input Supply Pin. Must be locally bypassed.
Internally connected to GND. Mount on board for lower thermal
resistance.
ABSOLUTE MAXIMUM RATINGS
(note1)
SYMBOL
V
IN
SW
CSN
DIM
I
SW
P
DMAX
P
TR
T
J
T
STG
ITEMS
Supply Voltage
Drain of the internal power switch
Current sense input (Respect to VIN)
Logic level dimming input
Switch output current
Power Dissipation (Note 2)
Thermal Resistance, SOT89-5
θ
JA
VALUE
-0.3~55
-0.3~55
+0.3~(-6.0)
-0.3~6
1
1.5
45
-40 to 150
-55 to 150
2
o
UNIT
V
V
V
V
A
W
C /W
o
o
Operation Junction Temperature Range
Storage Temperature
ESD Susceptibility (Note 3)
C
C
kV
CR POWTECH (SHANGHAI) CO., LTD.
PT4119E_DS_Rev EN 1.0
WWW.CRPOWTECH.COM
Page 2
PT4119E
50V/1A Step-down High Brightness
LED Driver
RECOMMENDED OPERATING RANGE
SYMBOL
V
IN
T
OPT
ITEMS
V
DD
Supply Voltage
Operating Temperature
VALUE
6 ~ 50
-40 to +85
UNIT
V
o
C
Note 1:
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Recommended
Operating Range indicates conditions for which the device is functional, but do not guarantee specific performance
limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which
guarantee specific performance limits. This assumes that the device is within the Operating Range. Specifications are
not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device
performance.
Note 2:
The maximum power dissipation must be derated at elevated temperatures and is dictated by T
JMAX
, θ
JA
, and
the ambient temperature T
A
. The maximum allowable power dissipation is P
DMAX
= (T
JMAX
- T
A
)/ θ
JA
or the number
given in Absolute Maximum Ratings, whichever is lower.
Note 3:
Human body model, 100pF discharged through a 1.5kΩ resistor.
CR POWTECH (SHANGHAI) CO., LTD.
PT4119E_DS_Rev EN 1.0
WWW.CRPOWTECH.COM
Page 3
PT4119E
50V/1A Step-down High Brightness
LED Driver
ELECTRICAL CHARACTERISTICS
(Note 4, 5)
The following specifications apply for V
IN
=24V, T
A
=25
o
C, unless specified otherwise.
SYMBOL
V
IN
V
UVLO
V
UVLO_HYS
F
SW
Current Sense
V
CSN
V
CSN_hys
I
CSN
I
SD
I
OFF
DIM Input
V
DIM
V
DIM_H
V
DIM_HYS
V
DIM_DC
F
DIM_MIN
F
DIM_MAX
R
DIM
I
DIM_H
I
DIM_L
Output Switch
R
SW
I
SWmean
I
LEAK
T
SD
T
SD_HYS
SW On Resistance
Continuous SW Current
SW Leakage Current
Thermal
Threshold
Thermal
hysteresis
Note 4:
Note 5:
Typical parameters are measured at 25˚C and represent the parametric norm.
Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.
ITEMS
Input Voltage
Under voltage lock out
UVLO hysterisis
Max. Switching Frequency
Mean current sense
threshold voltage
Sense threshold hysteresis
CSN Pin Input Current
Shutdown supply current
Quiescent
supply
current
with output off
Internal supply voltage
DIM input voltage High
DIM input voltage hysterisis
DC brightness control
Min. DIM Frequency
Max. DIM Frequency
DIM pull up resistor to
Internal supply voltage
DIM input leakage high
DIM input leakage low
CONDITIONS
V
IN
rising
V
IN
falling
Min.
6
Typ.
4.5
0.3
Max.
50
UNIT
V
V
V
1
MHz
V
IN
-V
CSN
194
200
±
15
206
mV
%
µA
V
IN
-V
CSN
=50mV
8
60
100
0.3
Operating Current
µA
mA
No Switching
0.16
DIM floating
20
0.5
4.2
0.3
50
0.1
20
200
0.35
80
2.5
V
V
mV
V
kHz
kHz
KΩ
µA
µA
Ω
1
A
µA
℃
℃
5
V
DIM
= 5.0V
V
DIM
= 0
VIN=6V½50V
2.8
22
0.6
0.5
155
20
Thermal Shutdown
Shutdown
Shutdown
CR POWTECH (SHANGHAI) CO., LTD.
PT4119E_DS_Rev EN 1.0
WWW.CRPOWTECH.COM
Page 4
PT4119E
50V/1A Step-down High Brightness
LED Driver
SIMPLIFIED BLOCK DIAGRAM
OPERATION DESCRIPTION
The PT4119E in conjunction with current sense
resistor (R
CS
),the inductor (L1), and MOSFET
forms a self oscillating continuous-mode buck
converter.
When input voltage VIN is first applied, the initial
current in L1 and R
CS
is zero and there is no output
from the current sense circuit. Under this condition,
the output of CS comparator is high. This turns on
switch, causing current to flow from V
IN
to ground,
via R
CS
, the LED(s),L1 and internal MOSFET. The
current rises at a rate determined by V
IN
and L1 to
produce a voltage ramp (VCSN) across R
CS
. When
(VIN-VCSN)
>
230mV,
the
output
of
CS
comparator switches low and the switch turns off.
The current flowing on the R
CS
decreases at
another rate. When (VIN-VCSN) < 170mV, the
switch turns on again and the mean current on the
LED is determined by 200mV/R
CS
.
The high-side current-sensing scheme and
on-board current-setting circuitry minimize the
number of external components while delivering
LED current with ±3% accuracy, using a 1% sense
resistor. The PT4119E allows dimming with a PWM
signal at the DIM input. A logic level below 0.3V at
DIM forces PT4119E to turn off the LED and the
logic level at DIM must be at least 2.5V to turn on
the full LED current. The frequency of PWM
dimming ranges from 100Hz to 20 kHz.
The DIM pin can be driven by an external DC
voltage (V
DIM
) to adjust the output current to a value
below the nominal average value defined by R
CS
.
The DC voltage is valid from 0.5V to 2.5V. When
the DC voltage is higher than 2.5V, the output
current keeps constant.
Additionally, to ensure the reliability, the
PT4119E is built with a thermal shutdown (TSD)
protection. The TSD protests the IC from over
temperature (155℃).
CR POWTECH (SHANGHAI) CO., LTD.
PT4119E_DS_Rev EN 1.0
WWW.CRPOWTECH.COM
Page 5
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