19-4722; Rev 2; 11/09
TION KIT
EVALUA BLE
AVAILA
Integrated, 4-Channel, High-Brightness LED
Driver with High-Voltage DC-DC Controller
General Description
The MAX16814 high-efficiency, high-brightness LED (HB
LED) driver provides up to four integrated LED current-
sink channels. An integrated current-mode switching
DC-DC controller drives a DC-DC converter that pro-
vides the necessary voltage to multiple strings of HB
LEDs. The MAX16814 accepts a wide 4.75V to 40V input
voltage range and withstands direct automotive load-
dump events. The wide input range allows powering HB
LEDs for small to medium-sized LCD displays in automo-
tive and general lighting applications.
An internal current-mode switching DC-DC controller
supports the boost, coupled-inductor boost-buck, or
SEPIC topologies and operates in an adjustable fre-
quency range between 200kHz and 2MHz. It can also be
used for single-inductor boost-buck topology in conjunc-
tion with the MAX15054 and an additional MOSFET. The
current-mode control with programmable slope com-
pensation provides fast response and simplifies loop
compensation. The MAX16814 also features an adaptive
output-voltage control scheme that minimizes the power
dissipation in the LED current-sink paths.
The MAX16814 consists of four identical linear current
source channels to drive four strings of HB LEDs. The
channel current is adjustable from 20mA to 150mA with
an accuracy of ±3% using an external resistor. The
external resistor sets all 4-channel currents to the same
value. The device allows connecting multiple channels
in parallel to achieve higher current per LED string. The
MAX16814 also features pulsed dimming control, on all
four channels through a logic input (DIM). In addition,the
MAX16814A_ _ and MAX16814U_ _ include a unique
feature that allows a very short minimum pulse width as
low as 1µs.
The MAX16814 includes an output overvoltage, open-
LED detection and protection, programmable shorted
LED detection and protection, and overtemperature pro-
tection. The device operates over the -40NC to +125NC
automotive temperature range. The MAX16814 is avail-
able in the 6.5mm x 4.4mm, 20-pin TSSOP and 4mm x
4mm, 20-pin TQFN packages.
Features
S
4-Channel Linear LED Current Sinks with Internal
MOSFETs
Full-Scale LED Current Adjustable from 20mA
to 150mA
Drives One to Four LED Strings
S
Boost, SEPIC, or Coupled-Inductor Boost-Buck
Current-Mode DC-DC Controller
200kHz to 2MHz Programmable Switching
Frequency
External Switching Frequency Synchronization
S
Adaptive Output-Voltage Optimization to Minimize
Power Dissipation
S
4.75V to 40V Operating Input Voltage Range
S
Less than 40µA Shutdown Current
S
5000:1 PWM Dimming at 200Hz (MAX16814A _ _
and MAX16814U_ _ Only)
S
Open-Drain Fault Indicator Output
S
Open-LED and LED Short Detection and
Protection
S
Overtemperature Protection
S
Thermally Enhanced, 20-Pin TQFN and TSSOP
Packages
MAX16814
Ordering Information
PART
MAX16814ATP+
MAX16814ATP/V+
MAX16814AUP+
MAX16814BUTP+
MAX16814BUUP+
MAX16814UTP+
MAX16814UUP+
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
0°C to +85°C
0°C to +85°C
0°C to +85°C
0°C to +85°C
PIN-PACKAGE
20 TQFN-EP*
20 TQFN-EP*
20 TSSOP-EP*
20 TQFN-EP*
20 TSSOP-EP*
20 TQFN-EP*
20 TSSOP-EP*
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
/V Denotes an automotive qualified part.
Applications
Automotive Displays LED Backlights
Automotive RCL, DRL, Front Position, and Fog
Lights
LCD TV and Desktop Display LED Backlights
Architectural, Industrial, and Ambient Lighting
_______________________________________________________________
Maxim Integrated Products
1
Typical Operating Circuit and Pin Configurations appear at
end of data sheet.
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Integrated, 4-Channel, High-Brightness LED
Driver with High-Voltage DC-DC Controller
MAX16814
ABSOLUTE MAXIMUM RATINGS
IN to SGND............................................................-0.3V to +45V
EN to SGND ...............................................-0.3V to (V
IN
+ 0.3V)
PGND to SGND ....................................................-0.3V to +0.3V
LEDGND to SGND ...............................................-0.3V to +0.3V
OUT_ to LEDGND .................................................-0.3V to +45V
V
CC
to SGND .......... -0.3V to the lower of (V
IN
+ 0.3V) and +6V
DRV,
FLT,
DIM, RSDT, OVP to SGND.....................-0.3V to +6V
CS, RT, COMP, SETI to SGND ................. -0.3V to (V
CC
+ 0.3V)
NDRV to PGND .......................................-0.3V to (V
DRV
+ 0.3V)
NDRV Peak Current (< 100ns) .............................................
Q3A
NDRV Continuous Current ............................................
Q100mA
OUT_ Continuous Current .............................................
Q175mA
V
CC
Short-Circuit Duration ........................................Continuous
Continuous Power Dissipation (T
A
= +70NC) (Note 1)
20-Pin TQFN (derate 25.6mW/NC above +70NC) .......2051mW
Junction-to-Case Thermal Resistance (B
JC
)..................6NC/W
Junction-to-Ambient Thermal Resistance (B
JA
) ...........39NC/W
20-Pin TSSOP (derate 26.5mW/NC above +70NC) .....2122mW
Junction-to-Case Thermal Resistance (B
JC
)...............2.0NC/W
Junction-to-Ambient Thermal Resistance (B
JA
) ........37.7NC/W
Operating Temperature Range
MAX16814A_ _.............................................. -40NC to +125NC
MAX16814U_ _and MAX16814BU_ _ ................0NC to +85NC
Junction Temperature .....................................................+150NC
Storage Temperature Range............................ -65NC to +150NC
Lead Temperature (soldering, 10s) ................................+300NC
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to
http://www.maxim-ic.com/thermal-tutorial.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
IN
= V
EN
= 12V, R
RT
= 12.25kI, R
SETI
= 15kI, C
VCC
= 1FF, V
CC
= V
DRV
, NDRV = COMP = OUT_ = unconnected, V
RSDT
= V
DIM
=
V
CC
, V
OVP
= V
CS
= V
LEDGND
= V
PGND
= V
SGND
= 0V, T
A
= T
J
= -40NC to +125NC for MAX16814A_ _ and T
A
= T
J
= 0NC to +85NC for
MAX16814U_ _ and MAX16814BU_ _, unless otherwise noted. Typical values are at T
A
= +25NC.) (Note 2)
PARAMETER
Operating Voltage Range
Active Supply Current
Standby Supply Current
IN Undervoltage Lockout
IN UVLO Hysteresis
V
CC
REGULATOR
Regulator Output Voltage
Dropout Voltage
Short-Circuit Current Limit
V
CC
Undervoltage Lockout
Threshold
V
CC
UVLO Hysteresis
RT OSCILLATOR
Switching Frequency Range
f
SW
200
2000
kHz
V
CC
6.5V < V
IN
< 10V, 1mA < I
LOAD
< 50mA
10V < V
IN
< 40V, 1mA < I
LOAD
< 10mA
V
IN
- V
CC
, V
IN
= 4.75V, I
LOAD
= 50mA
V
CC
shorted to SGND
V
CC
rising
4.75
5.0
200
100
4
100
5.25
500
V
mV
mA
V
mV
SYMBOL
V
IN
I
IN
MAX16814A_ _ and MAX16814U_ _
MAX16814BU_ _ only
V
EN
= 0V
V
IN
rising
3.975
CONDITIONS
MIN
4.75
2.5
2.75
15
4.3
170
TYP
MAX
40
5
5.5
40
4.625
UNITS
V
mA
µA
V
mV
2
______________________________________________________________________________________
Integrated, 4-Channel, High-Brightness LED
Driver with High-Voltage DC-DC Controller
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
EN
= 12V, R
RT
= 12.25kI, R
SETI
= 15kI, C
VCC
= 1FF, V
CC
= V
DRV
, NDRV = COMP = OUT_ = unconnected, V
RSDT
= V
DIM
=
V
CC
, V
OVP
= V
CS
= V
LEDGND
= V
PGND
= V
SGND
= 0V, T
A
= T
J
= -40NC to +125NC for MAX16814A_ _ and T
A
= T
J
= 0NC to +85NC for
MAX16814U_ _ and MAX16814BU_ _ , unless otherwise noted. Typical values are at T
A
= +25NC.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
f
SW
= 200kHz to 600kHz, MAX16814A_ _
and MAX16814U_ _
Maximum Duty Cycle
f
SW
= 600kHz to 2000kHz, MAX16814A_ _
and MAX16814U_ _
f
SW
= 200kHz to 600kHz, MAX16814BU_
f
SW
= 600kHz to 2000kHz, MAX16814BU_ _
Oscillator Frequency Accuracy
Sync Rising Threshold
Minimum Sync Frequency
PWM COMPARATOR
PWM Comparator Leading-Edge
Blanking Time
PWM to NDRV Propagation Delay
SLOPE COMPENSATION
Peak Slope Compensation
Current Ramp Magnitude
CS LIMIT COMPARATOR
Current-Limit Threshold
CS Limit Comparator to NDRV
Propagation Delay
ERROR AMPLIFIER
OUT_ Regulation Voltage
Transconductance
No-Load Gain
COMP Sink Current
COMP Source Current
MOSFET DRIVER
NDRV On-Resistance
Peak Sink Current
Peak Source Current
Rise Time
Fall Time
I
SINK
= 100mA (nMOS)
I
SOURCE
= 100mA (pMOS)
V
NDRV
= 5V
V
NDRV
= 0V
C
LOAD
= 1nF
C
LOAD
= 1nF
0.9
1.1
2.0
2.0
6
6
ω
A
A
ns
ns
g
M
(Note 4)
V
OUT_
= 5V, V
COMP
= 2.5V
V
OUT_
= 0V, V
COMP
= 2.5V
160
160
340
1
600
75
375
375
800
800
880
V
µS
dB
µA
µA
(Note 3)
10mV overdrive, excluding leading-edge
blanking time
396
416
10
437
mV
ns
Current ramp added to the CS input,
MAX16814A_ _ only
Current ramp added to the CS input,
MAX16814U_ _ and MAX16814BU_ _
44
45
49
50
54
µA x f
SW
55
Including leading-edge blanking time
60
90
ns
ns
f
SW
= 200kHz to 2MHz, MAX16814A_ _ and
MAX16814U_ _
f
SW
= 200kHz to 2MHz, MAX16814BU_ _
MIN
85
82
90
86
-7.5
-7
4
1.1f
SW
TYP
89
86
94
90
MAX
93
90
98
94
+7.5
+7
V
Hz
%
%
UNITS
MAX16814
_______________________________________________________________________________________
3
Integrated, 4-Channel, High-Brightness LED
Driver with High-Voltage DC-DC Controller
MAX16814
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
EN
= 12V, R
RT
= 12.25kI, R
SETI
= 15kI, C
VCC
= 1FF, V
CC
= V
DRV
, NDRV = COMP = OUT_ = unconnected, V
RSDT
= V
DIM
=
V
CC
, V
OVP
= V
CS
= V
LEDGND
= V
PGND
= V
SGND
= 0V, T
A
= T
J
= -40NC to +125NC for MAX16814A_ _ and T
A
= T
J
= 0NC to +85NC for
MAX16814U_ _ and MAX16814BU_ _, unless otherwise noted. Typical values are at T
A
= +25NC.) (Note 2)
PARAMETER
LED CURRENT SOURCES
OUT_ Current-Sink Range
Channel-to-Channel Matching
V
OUT_
= V
REF
I
OUT_
= 100mA
I
OUT_
=
100mA
Output Current Accuracy
T
A
= +125°C, MAX16814A_ _
only
T
A
= -40°C to +125°C,
MAX16814A_ _ only
20
150
±2
±3
mA
±5
±2.75
mA
±4
1
1.125
1.144
1.23
1.23
50
V
EN
= 40V, MAX16814A_ _ only
EN Input Current
DIM Input High Voltage
DIM Input Low Voltage
DIM Hysteresis
DIM Input Current
DIM to LED Turn-On Delay
DIM to LED Turn-Off Delay
I
OUT_
Rise and Fall Times
FLT
Output Low Voltage
FLT
Output Leakage Current
LED Short Detection Threshold
Short Detection Comparator Delay
RSDT Leakage Current
OVP Trip Threshold
OVP Hysteresis
OVP Leakage Current
Thermal-Shutdown Threshold
Thermal-Shutdown Hysteresis
V
OVP
= 1.25V
Temperature rising
165
15
Output rising
1.19
1.228
70
±200
V
IN
= 4.75V and I
SINK
= 5mA
V
FLT
= 5.5V
Gain = 3
1.75
2.0
6.5
±600
1.266
DIM rising edge to 10% rise in I
OUT_
DIM falling edge to 10% fall in I
OUT
_
100
100
200
0.4
1.0
2.25
250
±2
V
EN
= 40V, MAX16814U_ _ and
MAX16814BU_ _
2.1
0.8
±200
±250
nA
V
V
mV
µA
ns
ns
ns
V
µA
V
µs
nA
V
mV
nA
°C
°C
1.335
1.316
V
mV
µA
mA
%
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
OUT_ Leakage Current
LOGIC INPUTS/OUTPUTS
T
A
= +25°C, MAX16814U_ _ and
I
OUT_
=
MAX16814BU_ _
50mA to
150mA T
A
= 0°C to +85°C, MAX16814U_
_ and MAX16814BU_ _
V
DIM
= 0V, V
OUT_
= 40V
V
EN
rising, MAX16814A_ _ only
EN Reference Voltage
EN Hysteresis
V
EN
rising, MAX16814U_ _ and
MAX16814BU_ _
Note 2:
All MAX16814A_ _ are 100% tested at T
A
= +125NC, while alll MAX16814U_ _ and MAX16814BU_ _ are 100% tested at
T
A
= +25°C. All limits overtemperature are guaranteed by design , not production tested.
Note 3:
CS threshold includes slope compensation ramp magnitude.
Note 4:
Gain = δV
COMP
/δV
CS
, 0.05V < V
CS
< 0.15V.
4
______________________________________________________________________________________
Integrated, 4-Channel, High-Brightness LED Driver
with High-Voltage Boost and SEPIC Controller
Typical Operating Characteristics
(V
IN
= V
EN
= 12V, f
SW
= 300kHz, R
SETI
= 15kI, C
VCC
= 1FF, V
CC
= V
DRV
, NDRV = COMP = OUT_ = unconnected, V
OVP
= V
CS
=
V
LEDGND
= V
DIM
= V
PGND
= V
SGND
= 0V, load = four strings of seven white LEDs, T
A
= +25NC, unless otherwise noted.)
SWITCHING WAVEFORM AT 5kHz
(50% DUTY CYCLE) DIMMING
MAX16814 toc01
MAX16814
SUPPLY CURRENT vs. SUPPLY VOLTAGE
C
NDRV
= 13pF
3.6
3.4
I
IN
(mA)
3.2
3.0
2.8
2.6
2.4
5
10
15
20
25
V
IN
(V)
30
35
40
45
T
A
= -40NC
T
A
= +25NC
T
A
= +125NC
MAX16814 toc02
3.8
V
LX
10V/div
0V
I
OUT1
100mA/div
0A
V
OUT
10V/div
FIGURE 2
40Fs/div
0V
SUPPLY CURRENT
vs. SWITCHING FREQUENCY
C
NDRV
= 13pF
4.2
4.0
I
IN
(mA)
3.8
3.6
3.4
3.2
3.0
200 400 600 800 1000 1200 1400 1600 1800 2000
f
SW
(kHz)
MAX16814 toc03
SWITCHING FREQUENCY
vs. TEMPERATURE
308
SWITCHING FREQUENCY (kHz)
306
304
300
298
296
294
292
290
-50
-25
0
25
50
75
100
125
TEMPERATURE (NC)
V
SETI
(V)
302
MAX16814 toc04
V
SETI
vs. TEMPERATURE
MAX16814 toc05
4.4
310
1.240
1.236
1.232
1.228
1.224
1.220
-50
-25
0
25
50
75
100
125
TEMPERATURE (NC)
V
SETI
vs. PROGRAMMED CURRENT
MAX16814 toc06
EN THRESHOLD VOLTAGE
vs. TEMPERATURE
MAX16814 toc07
EN LEAKAGE CURRENT
vs. TEMPERATURE
V
EN
= 2.5V
EN LEAKAGE CURRENT (nA)
MAX16814 toc08
1.234
1.233
1.232
V
SETI
(V)
1.231
1.230
1.229
1.228
20
46
72
98
124
1.30
150
120
90
60
30
0
EN THRESHOLD VOLTAGE (V)
1.25
V
EN
RISING
1.20
V
EN
FALLING
1.15
150
1.10
-50
-25
0
25
50
75
100
125
TEMPERATURE (NC)
-50
-25
0
25
50
75
100
125
LED STRING CURRENT (mA)
TEMPERATURE (NC)
_______________________________________________________________________________________
5
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