CAT4101 [ONSEMI]
1 A Constant-Current LED Driver with PWM Dimming; 1恒定电流LED驱动器的PWM调光
| 型号： | CAT4101 |
| 厂家： | 
ONSEMI |
| 描述： | 1 A Constant-Current LED Driver with PWM Dimming |
| 文件： | 总10页 (文件大小：149K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
CAT4101
1 A Constant-Current LED
Driver with PWM Dimming
Description
The CAT4101 is a constant−current sink driving a string of
high−brightness LEDs up to 1 A with very low dropout of 0.5 V at full
load. It requires no inductor, provides a low noise operation and
minimizes the number of components. The LED current is set by an
external resistor connected to the RSET pin. The LED pin is
compatible with high voltage up to 25 V, allowing the driving of long
strings of LEDs. The device ensures an accurate and regulated current
in the LEDs independent of supply and LED forward voltage
variation.
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TO−263
TV SUFFIX
CASE 221AE
The PWM/EN input allows the device shutdown and the LED
brightness adjustment by using an external pulse width modulation
(PWM) signal.
The driver features a thermal shutdown protection that becomes
active whenever the die temperature exceeds 150°C.
PIN CONNECTIONS
The device is available in a high−power, 5−lead TO−263 package
offering excellent thermal dissipation characteristics.
1
EN/PWM
VIN
Features
TAB
GND
• Accurate 1 A Current Sink
• Up to 25 V Operation on LED Pin
• Low Dropout 500 mV at 1 A
RSET
LED
(Top View)
• LED Current Set by External Resistor
• High Resolution PWM Dimming via EN/PWM
• “Zero” Current Shutdown Mode
• Thermal Shutdown Protection
MARKING DIAGRAM
• TO−263 5−lead Package
• These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
CAT4101TV
3LYMXXXXA
Compliant
Applications
• High Power LED up to 1 A
• Architectural and General Lighting
• Automotive Lighting
CAT4101TV = Specific Device Code
3 = Lead Finish (Matte−Tin)
L = Assembly Location Code
VCC
3 V to 25 V
LEDs
Y = Production Year (Last Digit)
M = Production Month (1−9, A, B, C)
XXXX = Last Four Digits of Assembly Lot Number
A = Production Revision (Fixed as “A”)
1 A
VIN
VIN
CAT4101
5 V
ON
OFF
EN/PWM LED
ORDERING INFORMATION
RSET
GND
Device
Package
Shipping
549 W
CAT4101TV−T75
TO−263
750/
(Note 1)
(Pb−Free)
Tape & Reel
Figure 1. Typical Application Circuit
1. Lead Finish Matte−Tin
©
Semiconductor Components Industries, LLC, 2010
1
Publication Order Number:
February, 2010 − Rev. 4
CAT4101/D
CAT4101
Table 1. ABSOLUTE MAXIMUM RATINGS
Parameter
Rating
Units
V
VIN, RSET, EN/PWM
6
LED Voltage
25
V
Storage Temperature Range
Junction Temperature Range
Lead Temperature
−65 to +160
−40 to +150
300
_C
_C
_C
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
Table 2. RECOMMENDED OPERATING CONDITIONS
Parameter
Rating
3.0 to 5.5
−40 to +85
Up to 1
Units
V
VIN
Ambient Temperature Range
_C
A
LED Pin Current
NOTE: Typical application circuit with external components is shown on page 1.
Table 3. ELECTRICAL OPERATING CHARACTERISTICS (Min and Max values in bold are over recommended operating
conditions unless specified otherwise. Typical values are at V = 5.0 V, T = 25°C)
IN
AMB
Symbol
Parameter
LED Current Accuracy
Conditions
Min
315
Typ
350
700
1000
500
1.20
0.8
Max
385
Units
I
mA
V
V
V
= 1 V, RSET = 1.47 kW
= 1 V, RSET = 750 W
= 1 V, RSET = 549 W
LED−ACC
LED
LED
LED
V
DOUT
Dropout Voltage
RSET Pin Voltage
Quiescent Current
I
= 1 A
mV
V
LED
V
RSET
1.17
1.23
1
I
Q
No LED, RSET = Floating
mA
No LED, RSET = 549 W
8.0
I
Shutdown Current
V
EN
= 0 V
mA
QSHDN
EN/PWM Pin
R
− Pull−down resistance
− Logic High Level
− Logic Low Level
200
kW
V
V
EN/PWM
V
HI
1.3
V
LO
0.4
T
Thermal Shutdown
150
20
_C
_C
SD
T
Thermal Hysteresis
HYS
I
/I
RSET to LED Current gain ratio
Undervoltage lockout (UVLO) Threshold
100 mA LED current
400
2.0
LED RSET
V
UVLO
V
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CAT4101
Table 4. RECOMMENDED EN/PWM TIMING
(For 3.0 V ≤ VIN ≤ 5.5 V, over full ambient temperature range −40°C to +85°C.)
Symbol
Name
Conditions
Min
Typ
Max
Units
T
Turn−On time, EN/PWM rising to I
from
I
= 1 A
= 350 mA
1.6
1.1
ms
PS
LED
LED
Shutdown
I
I
I
I
I
LED
T
T
Turn−On time, EN/PWM rising to I
I
= 1 A
= 350 mA
920
620
ns
ns
ns
ns
P1
P2
LED
LED
LED
Turn−Off time, EN/PWM falling to I
LED rise time
I
= 1 A
= 350 mA
440
310
LED
LED
LED
T
I
= 1 A
= 350 mA
840
390
R
LED
LED
T
LED fall time
I
= 1 A
= 350 mA
470
350
F
LED
LED
T
EN/PWM low time
EN/PWM high time
1
5
ms
ms
LO
T
HI
PWRDWN
T
EN/PWM low time to shutdown delay
8
ms
T
T
HI
PWRDWN
T
LO
EN/PWM
SHUTDOWN
SHUTDOWN
T
T
P2
F
T
R
T
T
I
= (1.2 V / R ) x 400
SET
PS
P1
LED
90%
10%
LED CURRENT
50%
50%
0 mA
SHUTDOWN 0 mA
VIN QUIESCENT CURRENT
SHUTDOWN 0 mA
SHUTDOWN
Figure 2. CAT4101 EN/PWM Timing
EN/PWM Operation
The EN/PWM pin has two primary functions. One
function enables and disables the device. The other function
turns the LED channel on and off for PWM dimming
control. The device has a very fast turn−on time (from
EN/PWM rising to LED on) and allows “instant on” when
dimming LED using a PWM signal.
When performing a combination of low frequencies and
small duty cycles, the device may enter shutdown mode.
This has no effect on the dimming accuracy, because the
turn−on time T is very short, in the range of 1 ms.
PS
To ensure that PWM pulses are recognized, pulse width
low time T should be longer than 1 ms. The CAT4101
LO
Accurate linear dimming is compatible with PWM
frequencies from 100 Hz to 5 kHz for PWM duty cycle
down to 1%. PWM frequencies up to 50 kHz can be
supported for duty cycles greater than 10%.
enters a “zero current” shutdown mode after a 5 ms delay
(typical) when EN/PWM is held low.
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CAT4101
TYPICAL PERFORMANCE CHARACTERISTICS
(V = 5 V, V = 5 V, V = 3.5 V, I
= 1 A (1 LED), C = 1 mF, T
= 25°C unless otherwise specified.)
IN
CC
F
LED
IN
AMB
1.2
1.0
0.8
8.0
6.0
4.0
No Load
0.6
0.4
2.0
0
3.0
3.5
4.0
4.5
5.0
5.5
5.5
5.5
0
200
400
600
800
1000
INPUT VOLTAGE (V)
LED CURRENT (mA)
Figure 3. Quiescent Current vs. VIN Voltage
(ILED = 0 mA)
Figure 4. Quiescent Current vs. LED Current
8.5
8.0
7.5
1.2
1.0
0.8
0.6
Full Load
0.4
7.0
6.5
0.2
0
3.0
3.5
4.0
4.5
5.0
0
0.3
0.6
0.9
1.2
1.5
INPUT VOLTAGE (V)
LED PIN VOLTAGE (V)
Figure 5. Quiescent Current vs. VIN Voltage
(Full Load)
Figure 6. LED Current vs. LED Pin Voltage
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.4
0.3
2.0
2.5
3.0
3.5
4.0
4.5
5.0
−40
0
40
80
120
INPUT VOLTAGE (V)
TEMPERATURE (°C)
Figure 7. LED Current Change vs. VIN Voltage
Figure 8. LED Current Change vs.
Temperature
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CAT4101
TYPICAL PERFORMANCE CHARACTERISTICS
(V = 5 V, V = 5 V, V = 3.5 V, I
= 1 A (1 LED), C = 1 mF, T
= 25°C unless otherwise specified.)
IN
CC
F
LED
IN
AMB
1.30
1.25
1.20
1.30
1.25
1.20
1.15
1.10
1.15
1.10
3.0
3.5
4.0
4.5
5.0
5.5
−40
0
40
80
120
INPUT VOLTAGE (V)
TEMPERATURE (°C)
Figure 9. RSET Pin Voltage vs. VIN Voltage
Figure 10. RSET Pin Voltage vs. Temperature
1.2
1.0
0.8
0.6
0.4
0.2
0
0
1
2
3
4
5
RSET (kW)
Figure 11. LED Current vs. RSET Resistor
Figure 12. PWM 200 Hz, 1% Duty Cycle
100
10
1.4
1.2
1.0
0.8
−40°C
25°C
85°C
1
100 Hz
1 kHz
0.6
0.4
5 kHz
1
50 kHz
0.1
0.1
10
100
3.0
3.5
4.0
4.5
5.0
5.5
DUTY CYCLE (%)
INPUT VOLTAGE (V)
Figure 13. LED Current vs. PWM Duty Cycle
Figure 14. EN/PWM Threshold vs. VIN
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CAT4101
Table 5. PIN DESCRIPTIONS
Name
EN/PWM
VIN
Pin
Function
1
2
3
4
5
–
Device enable (active high) and PWM control.
Device supply input, connect to battery or supply.
Ground reference.
GND
RSET
LED
A resistor connected between this pin and ground sets the LED current.
Bottom LED cathode terminal.
TAB
Connect TAB to the Ground plane.
Pin Function
VIN is the supply pin for the device. A small 0.1 mF ceramic
bypass capacitor is optional for noisy environments. The
maximum operating voltage is 6.0 V. Whenever the input
supply falls below the under−voltage threshold, the current
sink will automatically be disabled.
high−impedance zero−current state whenever the device is
placed in shutdown mode.
RSET pin is connected to an external resistor to set the LED
current. The ground side of the external resistor should be
star connected to the GND of the PCB. The pin source
current mirrors the current to the LED sink. The voltage at
this pin is regulated to 1.2 V.
EN/PWM is the enable and one wire dimming input for the
LED channel. Guaranteed levels of logic high and logic low
are set at 1.3 V and 0.4 V respectively. When EN/PWM is
initially taken high, the device becomes enabled and the
LED current is set at a gain of 400 times the current in RSET.
To place the device into zero current shutdown mode, the
EN/PWM pin must be held low for 5 ms typical.
GND is the ground reference for the device. The pin must be
connected to the ground plane on the PCB.
TAB is the exposed pad underneath the package. For best
thermal performance, the tab should be soldered to the PCB
and connected to the ground plane.
LED pin is connected to the bottom LED cathode and
provides a regulated current sink. The pin enters a
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CAT4101
Block Diagram
VIN
LED
Undervoltage & Thermal
Lockout
VIN
EN/PWM
Shutdown Delay
Reference Voltage
Current
Regulator
RSET Regulator & Mirror
RSET
GND
Figure 15. CAT4101 Functional Block Diagram
Basic Operation
Table 6. RSET RESISTOR SETTINGS
The CAT4101 has one highly accurate LED current sink
to regulate LED current in a string of LEDs. The LED
current is mirrored from the current flowing from the RSET
pin. Table 6 lists various RSET resistor values for LED
current in 100 mA increments.
The LED channel needs a minimum of 500 mV headroom
to sink constant regulated current. If the input supply falls
below 2 V, the under−voltage lockout circuit disables the
LED channel.
For applications requiring current higher than 1 A, several
CAT4101 devices can be connected in parallel.
The LED channel can withstand and operate at voltages
up to 25 V. This makes the device ideal for driving long
strings of high power LEDs from a high voltage source.
LED Current [mA]
RSET [W]
4990
2490
1690
1270
1050
866
100
200
300
400
500
600
700
800
900
1000
768
680
604
549
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CAT4101
Application Information
Single 12 V Supply
For a given package style and board layout, the operating
junction temperature T is a function of the power
The circuit shown in Figure 16 shows how to power three
LEDs in series from a single 12 V supply using the
CAT4101. The CAT4101 can not be driven directly from
12 V, three components are needed to create a lower voltage
for the VIN pin (below 5.5 V). Resistor R2 and zener diode
D provide a regulated voltage while the quiescent current
runs through the N−Channel transistor M. Suitable parts for
this circuit are the ON Semiconductor MM3Z6V2 zener
diode and the 2N7002L N−channel transistor (SOT23
package).
J
dissipation P , and the ambient temperature, resulting in the
D
following equation:
TJ + TAMB ) PD(qJC ) qCA) + TAMB ) PD qJA
The CAT4101 TO−263 5−lead package provides a
thermal resistance when the ground tab is soldered down to
the PCB. When mounted on a double−sided printed circuit
board with two square inches of copper allocated for “heat
spreading”, the resulting q is about 30°C/W.
JA
For example, at 60°C ambient temperature, the maximum
power dissipation is calculated as follow:
12 V
C2
1 mF
R2
5 kW
T
Jmax * TAMB
150 * 60
PDmax
+
+
+ 3 W
qJA
30
M
D
6.2 V
Recommended Layout
VIN
LED
The board layout should provide good thermal dissipation
through the PCB. Multiple via can be used to connect the tab
of the CAT4101 to a large ground plane underneath the
package.
Input capacitor C1 should be placed as close to the driver
IC as possible. The RSET resistor should have a Kelvin
connection to the GND pin of the CAT4101.
C1
0.1 mF
CAT4101
EN/PWM
RSET
GND
R1
Figure 16. Single Supply Driving Three LEDs
Power Dissipation
The power dissipation (P ) of the CAT4101 can be
D
calculated as follows:
P
D + (VIN IIN) ) (VLED ILED)
where V
is the voltage at the LED pin. Combinations of
LED
high V
voltage or high ambient temperature can cause
LED
the CAT4101 to enter thermal shutdown. In applications
where V is high, a resistor can be inserted in series with
LED
the LED string to lower P .
D
Thermal dissipation of the junction heat consists
primarily of two paths in series. The first path is the junction
to the case (q ) thermal resistance which is defined by the
JC
package style, and the second path is the case to ambient
(q ) thermal resistance, which is dependent on board
CA
layout. The overall junction to ambient (q ) thermal
JA
resistance is equal to:
q
JA + qJC ) qCA
Figure 17. CAT4101 Recommended Layout
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CAT4101
PACKAGE DIMENSIONS
TO−263, 5 Lead
CASE 221AE−01
ISSUE O
E
A
c2
L1
D1
D
H
A1
PIN#1 ID
c
L
θ
e
b
TOP VIEW
END VIEW
BOTTOM VIEW
SYMBOL
MIN
NOM
MAX
A
A1
b
c
c2
D
D1
E
4.20
0.00
0.60
0.33
1.15
8.40
6.86
9.80
4.80
0.25
0.88
0.50
1.60
9.60
10.67
e
1.70 BSC
H
L
L1
q
14.61
1.78
15.87
2.79
1.67
8º
Notes:
(1) ꢀAll dimensions are in millimeters. Angles in degrees.
(2) ꢀComplies with JEDEC standard TO-263.
0º
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CAT4101
Example of Ordering Information (Note 4)
Prefix
Device #
Suffix
CAT
4101
TV−
T75
Company ID
(Optional)
Product Number
Package
TV: TO−263
Tape & Reel (Note 6)
T: Tape & Reel
4101
75: 750 / Reel
2. All packages are RoHS−compliant (Lead−free, Halogen−free).
3. The standard plated finish is Matte−Tin.
4. The device used in the above example is a CAT4101TV−T75 (TO−263, Tape & Reel, 750/Reel).
5. For additional temperature options, please contact your nearest ON Semiconductor Sales office.
6. For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should
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and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal
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CAT4101/D
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