19-4235; Rev 3; 1/10
IT
TION K
VALUA
E
BLE
AVAILA
High-Power LED Driver with Integrated High-Side LED
Current Sense and PWM Dimming MOSFET Driver
General Description
The MAX16834 is a current-mode high-brightness LED
(HB LED) driver for boost, boost-buck, SEPIC, and high-
side buck topologies. In addition to driving an n-channel
power MOSFET switch controlled by the switching con-
troller, it also drives an n-channel PWM dimming switch to
achieve LED PWM dimming. The MAX16834 integrates
all the building blocks necessary to implement a fixed-fre-
quency HB LED driver with wide-range dimming control.
The MAX16834 features constant-frequency peak cur-
rent-mode control with programmable slope compensa-
tion to control the duty cycle of the PWM controller.
A dimming driver designed to drive an external n-chan-
nel MOSFET in series with the LED string provides
wide-range dimming control up to 20kHz. In addition to
PWM dimming, the MAX16834 provides analog dim-
ming using a DC input at REFI. The programmable
switching frequency (100kHz to 1MHz) allows design
optimization for efficiency and board space reduction.
A single resistor from RT/SYNC to ground sets the
switching frequency from 100kHz to 1MHz while an
external clock signal at RT/SYNC disables the internal
oscillator and allows the MAX16834 to synchronize to
an external clock. The MAX16834’s integrated high-
side current-sense amplifier eliminates the need for a
separate high-side LED current-sense amplifier in
boost-buck applications.
The MAX16834 operates over a wide supply range of
4.75V to 28V and includes a 3A sink/source gate driver
for driving a power MOSFET in high-power LED driver
applications. It can also operate at input voltages
greater than 28V in boost configuration with an external
voltage clamp. The MAX16834 is also suitable for DC-
DC converter applications such as boost or boost-
buck. Additional features include external enable/
disable input, an on-chip oscillator, fault indicator out-
put (FLT) for LED open/short or overtemperature condi-
tions, and an overvoltage protection sense input
(OVP+) for true overvoltage protection.
The MAX16834 is available in a thermally enhanced
4mm x 4mm, 20-pin TQFN-EP package and in a thermal-
ly enhanced 20-pin TSSOP-EP package and is specified
over the automotive -40°C to +125°C temperature range.
Features
o
Wide Input Operating Voltage Range (4.75V to
28V)
o
Works for Input Voltage > 28V with External
Voltage Clamp on V
IN
for Boost Converter
o
3000:1 PWM Dimming/Analog Dimming
o
Integrated PWM Dimming MOSFET Driver
o
Integrated High-Side Current-Sense Amplifier for
LED Current Sense in Boost-Buck Converter
o
100kHz to 1MHz Programmable High-Frequency
Operation
o
External Clock Synchronization Input
o
Programmable UVLO
o
Internal 7V Low-Dropout Regulator
o
Fault Output (FLT) for Overvoltage, Overcurrent,
and Thermal Warning Faults
o
Programmable True Differential Overvoltage
Protection
o
20-Pin TQFN-EP and TSSOP-EP Packages
MAX16834
Ordering Information
PART
MAX16834ATP+
MAX16834ATP/V+
MAX16834AUP+
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
20 TQFN-EP*
20 TQFN-EP*
20 TSSOP-EP*
MAX16834AUP/V+
-40°C to +125°C
20 TSSOP-EP*
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
/V
denotes an automotive qualified part.
Simplified Application Circuit
V
IN
BOOST LED DRIVER
LED+
IN
NDRV
LEDs
ON
OFF
ANALOG
DIM
MAX16834
PWMDIM
REFI
PGND
CS
DIMOUT
SENSE+
LED-
Applications
Single-String LED LCD Backlighting
Automotive Rear and Front Lighting
Projection System RGB LED Light Sources
Architectural and Decorative Lighting (MR16, M111)
Spot and Ambient Lights
DC-DC Boost/Boost-Buck Converters
Pin Configurations appear at end of data sheet.
1
________________________________________________________________
Maxim Integrated Products
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.
High-Power LED Driver with Integrated High-Side LED
Current Sense and PWM Dimming MOSFET Driver
MAX16834
ABSOLUTE MAXIMUM RATINGS
IN, HV, LV to SGND................................................-0.3V to +30V
20-Pin TSSOP (derate 26.5mW/°C above +70°C) ..........2122mW
OVP+, SENSE+, DIMOUT, CLV to SGND ..............-0.3V to +30V
Junction-to-Ambient Thermal Resistance (
θ
JA
) (Note 1)
20-Pin TQFN 4mm x 4mm .................................................39°C/W
SENSE+ to LV........................................................-0.3V to +0.3V
20-Pin TSSOP..................................................................37.7°C/W
HV, IN to LV ............................................................-0.3V to +30V
Junction-to-Case Thermal Resistance (
θ
JC
) (Note 1)
OVP+, CLV, DIMOUT to LV ......................................-0.3V to +6V
20-Pin TQFN 4mm x 4mm ...............................................6°C/W
PGND to SGND .....................................................-0.3V to +0.3V
20-Pin TSSOP..................................................................2°C/W
V
CC
to SGND..........................................................-0.3V to +12V
NDRV to PGND...........................................-0.3V to (V
CC
+ 0.3V)
Operating Temperature Range .........................-40°C to +125°C
All Other Pins to SGND.............................................-0.3V to +6V
Junction Temperature ......................................................+150°C
NDRV Continuous Current................................................±50mA
Storage Temperature Range .............................-65°C to +150°C
DIMOUT Continuous Current..............................................±2mA
Lead Temperature (soldering, 10s) .................................+300°C
V
CC
Short-Circuit Current to SGND Duration ...........................1s
Continuous Power Dissipation (T
A
= +70°C)
*As
per JEDEC51 standard (multilayer board).
20-Pin TQFN (4mm x 4mm)
(derate 25.6mW/°C* above +70°C) ............................2051mW
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
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
HV
= 12V, V
UVEN
= 5V, V
LV
= V
PWMDIM
= V
SGND
, C
VCC
= 4.7µF, C
LCV
= 100nF, C
REF
= 100nF, R
SENSE+
= 0.1Ω,
R
RT
= 10kΩ, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Input Voltage Range
Quiescent Supply Current
Shutdown Supply Current
Output Voltage
Dropout Voltage
Short-Circuit Current
LINEAR REGULATOR (CLV)
Output Voltage
Dropout Voltage
Short-Circuit Current
REFERENCE VOLTAGE (REF)
Output Voltage
REF Short-Circuit Current
UVEN On Threshold Voltage
UVEN Threshold Voltage
Hysteresis
Input Leakage Current
PWMDIM
PWMDIM On Threshold Voltage
PWMDIM Threshold Voltage
Hysteresis
V
PWMDIM
1.395
1.435
200
1.475
V
mV
I
LEAK
V
UVEN
= 0
V
UVEN_THUP
V
REF
0
≤
I
REF
≤
1mA, 4.75V
≤
V
IN
≤
28V
V
REF
= 0
1.395
3.625
3.70
30
1.435
200
I1I
1.475
3.775
V
mA
V
mV
µA
(V
CLV -
V
LV
)
V
DO
0
≤
I
CLV
≤
2mA, 6V
≤
V
HV
≤
28V,
6V
≤
V
(HV-LV)
≤
22V
I
CLV
= 2mA, 0
≤
V
LV
≤
23.3V (Note 3)
V
CLV
= 12V, V
IN
= 12V, V
HV
= 24V
2.2
4.7
5
5.3
0.5
10
V
V
mA
SYMBOL
V
IN
I
Q
I
SHDN
V
CC
V
DO
Excluding I
LED
V
UVEN
= 0
0
≤
I
CC
≤
50mA, 9.5V
≤
V
IN
≤
28V
I
CC
= 35mA (Note 2)
V
CC
= 0, V
IN
= 12V
80
6.3
CONDITIONS
MIN
4.75
6
30
7
0.65
TYP
MAX
28
10
60
7.7
1
300
UNITS
V
mA
µA
V
V
mA
INTERNAL LINEAR REGULATOR (V
CC
)
UNDERVOLTAGE LOCKOUT/ENABLE INPUT (UVEN)
2
_______________________________________________________________________________________
High-Power LED Driver with Integrated High-Side LED
Current Sense and PWM Dimming MOSFET Driver
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
HV
= 12V, V
UVEN
= 5V, V
LV
= V
PWMDIM
= V
SGND
, C
VCC
= 4.7µF, C
LCV
= 100nF, C
REF
= 100nF, R
SENSE+
= 0.1Ω,
R
RT
= 10kΩ, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Input Leakage Current
OSCILLATOR
Oscillator Frequency
Oscillator Frequency Range
External Sync Input Clock High
Threshold
External Sync Input Clock Low
Threshold
External Sync Input High Pulse
Width
Maximum External Sync Period
SLOPE COMPENSATION (SC)
SC Pullup Current
SC Discharge Resistance
REFI
REFI Input Bias Current
REFI Input Common-Mode Range
SENSE+
SENSE+ Input Bias Current
Input Offset Voltage
Voltage Gain
3dB Bandwidth
LOW-SIDE LED CURRENT-SENSE AMPLIFIER
Input Offset Voltage
Voltage Gain
3dB Bandwidth
CURRENT ERROR AMPLIFIER (TRANSCONDUCTANCE AMPLIFIER)
Transconductance
Open-Loop DC Gain
Input Offset Voltage
COMP Voltage Range
PWM COMPARATOR
Input Offset Voltage
Propagation Delay
t
PD
50mV overdrive
0.6
0.65
40
0.70
V
ns
V
COMP
(Note 4)
g
m
A
V
-10
0.4
V
COMP
= 2V, V
PWMDIM
= 5V
400
500
60
0
+10
2.5
600
µS
dB
mV
V
A
V
V
LV
< 1V, (V
SENSE+
- V
LV
) = 0V
V
LV
< 1V, (V
SENSE+
- V
LV
) = 0.2V
-2
9.7
0
9.9
600
+2
10.1
mV
V/V
kHz
A
V
(V
SENSE+
- V
LV
) = 100mV
V
LV
> 5V, (V
SENSE+
- V
LV
) = 5mV
V
LV
> 5V, (V
SENSE+
- V
LV
) = 0.2V
(V
SENSE+
- V
LV
) = 0.1V, no load
(V
SENSE+
- V
LV
) = 0.02V, no load
-2.4
9.7
0
9.9
1.8
600
250
+2.4
10.1
µA
mV
V/V
MHz
kHz
HIGH-SIDE LED CURRENT-SENSE AMPLIFIER (V
SENSE+
- V
LV
)
V
REFI
= 1V
(Note 4)
0
I1I
2
µA
V
I
SCPU
R
SCD
V
SC
= 100mV
V
SC
= 100mV
80
100
8
120
µA
Ω
f
OSC
R
RT/SYNC
= 5kΩ
R
RT/SYNC
= 25kΩ
(Note 4)
(Note 4)
(Note 4)
(Note 4)
200
50
0.9
180
100
2
0.4
1
200
1.1
220
1000
MHz
kHz
kHz
V
V
ns
µs
SYMBOL
V
PWMDIM
= 0
CONDITIONS
MIN
TYP
I1I
MAX
UNITS
µA
MAX16834
_______________________________________________________________________________________
3
High-Power LED Driver with Integrated High-Side LED
Current Sense and PWM Dimming MOSFET Driver
MAX16834
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
HV
= 12V, V
UVEN
= 5V, V
LV
= V
PWMDIM
= V
SGND
, C
VCC
= 4.7µF, C
LCV
= 100nF, C
REF
= 100nF, R
SENSE+
= 0.1Ω,
R
RT
= 10kΩ, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Minimum On-Time
Duty Cycle
CURRENT PEAK LIMIT COMPARATOR
Trip Threshold Voltage
Propagation Delay
OVERVOLTAGE PROTECTION INPUT (OVP+)
OVP+ On Threshold Voltage
OVP+ Hysteresis
OVP+ Input Leakage Current
HIGH-SIDE LED SHORT COMPARATOR
Off Threshold
On Threshold
Error Reject Blankout
LOW-SIDE LED SHORT COMPARATOR
Off Threshold
Error Reject Blankout
HICCUP TIMER
Hiccup Time
GATE-DRIVER OUTPUT (NDRV)
NDRV Peak Pullup Current
NDRV Peak Pulldown Current
p-Channel MOSFET R
DSON
n-Channel MOSFET R
DSON
DIMOUT
DIMOUT Peak Pullup Current
DIMOUT Peak Pulldown Current
p-Channel MOSFET R
DSON
n-Channel MOSFET R
DSON
PWMDIM to DIMOUT
Propagation Delay
FAULT FLAG (FLT)
FLT
Pulldown Current
FLT
Leakage Current
Thermal Warning On Threshold
Thermal Warning Threshold
Hysteresis
V
FLT
= 0.2V
V
FLT
= 1.0V
2
5
I1I
+140
20
10
mA
µA
°C
°C
(V
CLV
- V
LV
) = 5V
(V
CLV
- V
LV
) = 5V
(V
CLV
- V
DIMOUT
) = 0.1V
(V
DIMOUT
- V
LV
) = 0.1V
25
25
50
50
31
25
200
mA
mA
Ω
Ω
ns
V
CC
= 7V
V
CC
= 7V
(V
CC
- V
NDRV
) = 0.1V
V
NDRV
= 0.1V
3
3
1.2
0.9
1.9
1.7
A
A
Ω
Ω
f
OSC
= 500kHz
8.2
ms
0.27
0.30
5
0.33
V
µs
V
CLV
- V
LV
V
CLV
- V
LV
f
OSC
= 500kHz
4.0
4.1
4.3
4.4
256
4.6
4.7
V
V
µs
(V
OVP
- V
LV
) = 1.235V
-1
V
OVP_ON
1.375
1.435
200
+1
1.495
V
mV
µA
50mV overdrive with respect to NDRV
0.25
0.3
40
0.35
V
ns
SYMBOL
t
ON(MIN)
(Note 4)
CONDITIONS
On-time includes blanking time
90
MIN
TYP
100
99.5
MAX
UNITS
ns
%
Note 2:
Dropout voltage is defined as V
IN
- V
CC
, when V
CC
is 100mV below the value of V
CC
for V
IN
= 9.5V.
Note 3:
Dropout is defined as V
HV
- V
CLV
, when V
CLV
is 100mV below the value of V
CLV
for V
HV
= 8V.
Note 4:
Not production tested. Guaranteed by design.
4
_______________________________________________________________________________________
High-Power LED Driver with Integrated High-Side LED
Current Sense and PWM Dimming MOSFET Driver
Typical Operating Characteristics
(V
IN
= V
HV
= 12V, V
UVEN
= 5V, V
LV
= V
PWMDIM
= V
SGND
, C
VCC
= 4.7µF, C
LCV
= 100nF, C
REF
= 100nF, R
SENSE+
= 0.1Ω,
R
RT
= 10kΩ, T
A
= +25°C, unless otherwise noted.)
V
REF
vs. TEMPERATURE
MAX16834 toc01
MAX16834
V
REF
vs. SUPPLY VOLTAGE
MAX16834 toc02
V
REF
vs. I
REF
V
IN
= 12V
3.7015
3.7010
MAX16834 toc03
3.80
3.75
3.70
V
REF
(V)
3.65
3.60
3.7020
3.74
3.72
3.70
V
REF
(V)
3.68
3.66
3.64
3.62
V
IN
= 12V
3.60
V
REF
(V)
4
8
12
16
20
24
28
3.7005
3.7000
3.6995
3.6990
3.55
3.50
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
3.6985
3.6980
0
1
2
3
4
5
6
7
8
9
10
I
REF
(mA)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
18
16
SUPPLY CURRENT (mA)
14
12
10
8
6
4
2
0
4
8
12
16
20
24
28
SUPPLY VOLTAGE (V)
PWMDIM = 0
MAX16834 toc04
SUPPLY CURRENT
vs. TEMPERATURE
MAX16834 toc05
RT vs. SWITCHING FREQUENCY
MAX16834 toc06
20
10
9
8
SUPPLY CURRENT (mA)
7
100
5
4
3
2
1
0
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
V
IN
= 12V
PWMDIM = 0
RT (kΩ)
6
10
1
V
IN
= 12V
100
SWITCHING FREQUENCY (kHz)
1000
SWITCHING FREQUENCY
vs. TEMPERATURE
605
604
603
602
601
600
599
598
597
596
595
594
593
592
591
590
TEMPERATURE (°C)
7.16
7.14
7.12
7.10
7.08
7.06
7.04
7.02
7.00
6.98
6.96
6.94
6.92
6.90
0
MAX16834 toc07
V
CC
vs. I
CC
MAX16834 toc08
V
CC
vs. I
CC
V
IN
= 12V
T
A
= +125°C
7.1
V
CC
(V)
T
A
= +100°C
V
IN
= 12V
MAX16834 toc09
7.2
SWITCHING FREQUENCY (kHz)
V
CC
(V)
7.0
T
A
= +25°C
T
A
= -40°C
6.9
V
IN
= 12V
-40 -25 -10 5 20 35 50 65 80 95 110 125
6.8
10 20 30 40 50 60 70 80 90 100
I
CC
(mA)
0
10 20 30 40 50 60 70 80 90 100
I
CC
(mA)
_______________________________________________________________________________________
5
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