MAX16833EAUE/V+T ,High-Voltage HB LED Drivers with Integrated High-Side Current SenseApplicationsIN NDRV● Automotive Exterior Lighting: CSMAX16833 High-Beam/Low-Beam/Signal/Position L ..
MAX16834ATP+ ,High-Power LED Driver with Integrated High-Side LED Current Sense and PWM Dimming MOSFET DriverApplications REFIDIM• Single-String LED LCD BacklightingPGND SENSE+• Automotive Rear and Front Ligh ..
MAX16834ATP+T ,High-Power LED Driver with Integrated High-Side LED Current Sense and PWM Dimming MOSFET DriverFeaturesThe MAX16834 is a current-mode high-brightness LED• Integration Minimizes BOM for High-Brig ..
MAX16834AUP+ ,High-Power LED Driver with Integrated High-Side LED Current Sense and PWM Dimming MOSFET DriverElectrical Characteristics(V = V = 12V, V = 5V, V = V = V , C = 4.7μF, C = 100nF, C = 100nF, R = 0. ..
MAX16834AUP+T ,High-Power LED Driver with Integrated High-Side LED Current Sense and PWM Dimming MOSFET Driverfeatures include external enable/ BOOST LED DRIVERdisable input, an on-chip oscillator, fault indic ..
MAX16835ATE+ ,High-Voltage, 350mA, Adjustable Linear High-Brightness LED DriverFeatures♦ +6.5V to +40V Operating RangeThe MAX16835 current regulator operates from a 6.5Vto 40V in ..
MAX4475AUT#TG16 ,SOT23, Low-Noise, Low-Distortion, Wide-Band, Rail-to-Rail Op AmpsELECTRICAL CHARACTERISTICS(V = +5V, V = 0V, V = 0V, V = V /2, R tied to V /2, SHDN = V , T = -40°C ..
MAX4475AUT+T ,SOT23, Low-Noise, Low-Distortion, Wide-Band, Rail-to-Rail Op AmpsELECTRICAL CHARACTERISTICS(V = +5V, V = 0V, V = 0V, V = V /2, R tied to V /2, SHDN = V , T = -40°C ..
MAX4476ATT+T ,SOT23, Low-Noise, Low-Distortion, Wide-Band, Rail-to-Rail Op Ampsfeatures make the devices an idealchoice for
MAX4476AUT#TG16 ,SOT23, Low-Noise, Low-Distortion, Wide-Band, Rail-to-Rail Op Ampsapplications that require low distortion and/or♦ 10MHz GBW Product, Unity-Gain Stablelow noise. (MA ..
MAX4477ASA ,10 MHz, Low-noise, low-distortion, SOT23, wide-band, rail to rail op amp.MAX4475–MAX4478/MAX4488/MAX448919-2137; Rev 1; 10/02SOT23, Low-Noise, Low-Distortion, Wide-Band,Rai ..
MAX4477ASA+ ,SOT23, Low-Noise, Low-Distortion, Wide-Band, Rail-to-Rail Op AmpsELECTRICAL CHARACTERISTICS (continued)(V = +5V, V = 0V, V = 0V, V = V /2, R tied to V /2, SHDN = V ..
MAX16833CAUE/V+T-MAX16833EAUE/V+T
High-Voltage HB LED Drivers with Integrated High-Side Current Sense
General DescriptionThe MAX16833, MAX16833B, MAX16833C, MAX16833D,
and MAX16833G are peak current-mode-controlled LED
drivers for boost, buck-boost, SEPIC, flyback, and high-
side buck topologies. A dimming driver designed to drive
an external p-channel in series with the LED string pro-
vides wide-range dimming control. This feature provides
extremely fast PWM current switching to the LEDs with
no transient overvoltage or undervoltage conditions.
In addition to PWM dimming, the ICs provide analog
dimming using a DC input at ICTRL. The ICs sense the
LED current at the high side of the LED string.
A single resistor from RT/SYNC to ground sets the
switching frequency from 100kHz to 1MHz, while an
external clock signal capacitively coupled to RT/SYNC
allows the ICs to synchronize to an external clock. In the
MAX16833/C/G, the switching frequency can be dithered
for spread-spectrum applications. The MAX16833B/D
instead provide a 1.64V reference voltage with a 2%
tolerance.
The ICs operate over a wide 5V to 65V supply range
and include a 3A sink/source gate driver for driving a
power MOSFET in high-power LED driver applications.
Additional features include a fault-indicator output (FLT)
for short or overtemperature conditions and an overvolt-
age-protection sense input (OVP) for overvoltage protec-
tion. High-side current sensing combined with a p-channel
dimming MOSFET allow the positive terminal of the LED
string to be shorted to the positive input terminal or to
the negative input terminal without any damage. This is a
unique feature of the ICs.
Beneits and Features●Integration Minimizes BOM for High-Brightness LED
Driver with a Wide Input Range Saving Space and
Cost+5V to +65V Wide Input Voltage Range with a
Maximum 65V Boost OutputIntegrated High-Side pMOS Dimming MOSFET
Driver (Allows Single-Wire Connection to LEDs)ICTRL Pin for Analog DimmingIntegrated High-Side Current-Sense AmpliierFull-Scale, High-Side, Current-Sense Voltage of
200mV●Simple to Optimize for Efficiency, Board Space, and
Input Operating RangeBoost, SEPIC, and Buck-Boost Single-Channel
LED Drivers2% Accurate 1.64V Reference (MAX16833B/D)Programmable Operating Frequency (100kHz to
1MHz) with Synchronization CapabilityFrequency Dithering for Spread-Spectrum
Applications (MAX16833/C/G)Thermally Enhanced 5mm x 4.4mm, 16-Pin
TSSOP Package with Exposed Pad●Protection Features and Wide Temperature Range
Increase System ReliabilityShort-Circuit, Overvoltage, and Thermal ProtectionFault-Indicator Output -40°C to +125°C Operating Temperature Range
Ordering Information appears at end of data sheet.
Applications●Automotive Exterior Lighting: High-Beam/Low-Beam/Signal/Position Lights Daytime Running Lights (DRLs) Fog Light and Adaptive Front Light Assemblies●Commercial, Industrial, and Architectural Lighting
Simpliied Operating CircuitPWMDIMNDRV
OVP
ISENSE+
ISENSE-
PGND
6V TO 18V
WITH LOAD
DUMP UP
TO 70V
LED+
LED-
PWMDIM
DIMOUT
MAX16833
MAX16833/MAX16833B/C/D/GHigh-Voltage HB LED Drivers with
Integrated High-Side Current Sense
EVALUATION KIT AVAILABLE
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion 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.
IN to PGND ........................................................... -0.3V to +70V
ISENSE+, ISENSE-, DIMOUT to PGND ................ -0.3V to +80V
DIMOUT to ISENSE+ ...............................................-9V to +0.3V
ISENSE- to ISENSE+ ............................................-0.6V to +0.3V
PGND to SGND ....................................................-0.3V to +0.3V
VCC to PGND ..........................................................-0.3V to +9V
NDRV to PGND ........................................-0.3V to (VCC + 0.3V)
OVP, PWMDIM, COMP, LFRAMP, REF, ICTRL,
RT/SYNC, FLT to SGND ...................................-0.3V to +6.0V
CS to PGND .........................................................-0.3V to +6.0V
Continuous Current on IN ................................................100mA
Peak Current on NDRV ........................................................Q3A
Continuous Current on NDRV .......................................Q100mA
Short-Circuit Duration on VCC ...................................Continuous
Continuous Power Dissipation (TA = +70NC)
16-Pin TSSOP (derate 26.1mW/NC above +70NC) .....2089mW
Operating Temperature Range ...................... -40NC to +125NC
Junction Temperature .....................................................+150NC
Storage Temperature Range ............................-65NC to +150NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
Electrical Characteristics(VIN = 12V, RRT = 12.4kI, CIN = CVCC = 1µF, CLFRAMP/CREF = 0.1µF, NDRV = COMP = DIMOUT = PWMDIM = FLT = unconnected,
VOVP = VCS = VPGND = VSGND = 0V, VISENSE+ = VISENSE- = 45V, VICTRL = 1.40V, TA = TJ = -40NC to +125NC, unless otherwise
noted. Typical values are at TA = +25NC.) (Note 2)
Absolute Maximum RatingsNote 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.maximintegrated.com/thermal-tutorial.
16 TSSOP
Junction-to-Ambient Thermal Resistance (qJA) .......38.3°C/W
Junction-to-Case Thermal Resistance (qJC) .................3°C/W
Package Thermal Characteristics(Note 1)PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
SYSTEM SPECIFICATIONS
Operational Supply VoltageVIN 565V
Supply CurrentIINQPWMDIM = 0, no switching1.52.5mASwitching2.54
Undervoltage Lockout (UVLO)UVLORINVIN rising4.24.554.85VUVLOFINVIN falling, IVCC = 35mA4.054.34.65
UVLO Hysteresis250mV
Startup DelaytSTART_DELAYDuring power-up410Fs
UVLO Falling DelaytFALL_DELAYDuring power-down3.3Fs
VCC LDO REGULATOR
Regulator Output VoltageVCC0.1mA P IVCC P 50mA, 9V P VIN P 14V6.756.957.15V14V P VIN P 65V, IVCC = 10mA
Dropout VoltageVDOVCCIVCC = 50mA, VIN = 5V0.150.35V
Short-Circuit CurrentIMAXVCCVCC = 0V, VIN = 5V55100150mA
OSCILLATOR (RT/SYNC)
Switching Frequency RangefSW1001000kHz
Bias Voltage at RT/SYNCVRT1V
Maximum Duty CycleDMAX
VCS = 0V; MAX16833/MAX16833B only87.588.589.5VCS = 0V; MAX16833C/MAX16833D/
MAX16833G only939495
MAX16833/MAX16833B/C/D/GHigh-Voltage HB LED Drivers with
Integrated High-Side Current Sense
Electrical Characteristics (continued)(VIN = 12V, RRT = 12.4kI, CIN = CVCC = 1µF, CLFRAMP/CREF = 0.1µF, NDRV = COMP = DIMOUT = PWMDIM = FLT = unconnected,
VOVP = VCS = VPGND = VSGND = 0V, VISENSE+ = VISENSE- = 45V, VICTRL = 1.40V, TA = TJ = -40NC to +125NC, unless otherwise
noted. Typical values are at TA = +25NC.) (Note 2)
Oscillator Frequency Accuracy-5+5%
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
Synchronization Logic-High InputVIH-SYNCVRT rising3.8V
Synchronization Frequency RangefSYNCIN1.1fSW1.7fSW
SLOPE COMPENSATION
Slope Compensation
Current-Ramp HeightISLOPERamp peak current added to CS input
per switching cycle465054FA
DITHERING RAMP GENERATOR (LFRAMP) (MAX16833/MAX16833C/MAX16833G only)
Charging CurrentVLFRAMP = 0V80100120FA
Discharging CurrentVLFRAMP = 2.2V80100120FA
Comparator High Trip Threshold2V
Comparator Low Trip ThresholdVRTV
REFERENCE OUTPUT (REF) (MAX16833B/MAX16833D only)
Reference Output VoltageVREFIREF = 0 to 80FA1.6041.6361.669V
ANALOG DIMMING (ICTRL)
Input-Bias CurrentIBICTRLVICTRL = 0.62V035200nA
LED CURRENT-SENSE AMPLIFIER
ISENSE+ Input-Bias CurrentIBISENSE+VISENSE+ = 65V, VISENSE- = 64.8V200400700FA
ISENSE+ Input-Bias Current with
DIM LowIBISENSE+OFFVISENSE+ = 48V, VISENSE- = 48V,
PWMDIM = 0200FA
ISENSE- Input-Bias CurrentIBISENSE-VISENSE+ = 65V, VISENSE- = 64.8V258FA
Voltage Gain6.15V/V
Current-Sense VoltageVSENSE
VICTRL = 1.4V195199203VICTRL = 0.616V100
VICTRL = 0.2465V38.44041.4
BandwidthBWAVDC - 3dB5MHz
COMP
TransconductanceGMCOMP210035004900FS
Open-Loop DC GainAVOTA75dB
COMP Input LeakageILCOMP-300+300nA
COMP Sink Current ISINK100400700FA
COMP Source CurrentISOURCE100400700FA
PWM COMPARATOR
Input Offset VoltageVOS-PWM2V
Leading-Edge Blanking50ns
Propagation Delay to NDRV tON(MIN)Includes leading-edge blanking time with
10mV overdrive5580110ns
CS LIMIT COMPARATOR
Current-Limit ThresholdVCS_LIMIT406418430mV
CS Limit-Comparator10mV overdrive (excluding leading-edge
MAX16833/MAX16833B/C/D/GHigh-Voltage HB LED Drivers with
Integrated High-Side Current Sense
Electrical Characteristics (continued)(VIN = 12V, RRT = 12.4kI, CIN = CVCC = 1µF, CLFRAMP/CREF = 0.1µF, NDRV = COMP = DIMOUT = PWMDIM = FLT = unconnected,
VOVP = VCS = VPGND = VSGND = 0V, VISENSE+ = VISENSE- = 45V, VICTRL = 1.40V, TA = TJ = -40NC to +125NC, unless otherwise
noted. Typical values are at TA = +25NC.) (Note 2)
Leading-Edge Blanking50ns
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
GATE DRIVER (NDRV)
Peak Pullup CurrentINDRVPUVCC = 7V, VNDRV = 0V3A
Peak Pulldown CurrentINDRVPDVCC = 7V, VNDRV = 7V3A
Rise TimetrCNDRV = 10nF30ns
Fall TimetfCNDRV = 10nF30ns
RDSON Pulldown nMOSRNDRVONVCOMP = 0V, ISINK = 100mA0.250.61.1I
PWM DIMMING (PWMDIM)
ON ThresholdVPWMON1.191.2251.26V
HysteresisVPWMHY70mV
Pullup ResistanceRPWMPU1.734.5MI
PWMDIM to LED Turn-Off TimePWMDIM falling edge to rising edge on
DIMOUT, CDIMOUT = 7nF2Fs
PWMDIM to LED Turn-On TimePWMDIM rising edge to falling edge on
DIMOUT, CDIMOUT = 7nF3Fs
pMOS GATE DRIVER (DIMOUT)
Peak Pullup CurrentIDIMOUTPUVPWMDIM = 0V,
VISENSE+ - VDIMOUT = 7V255080mA
Peak Pulldown CurrentIDIMOUTPDVISENSE+ - VDIMOUT = 0V102545mA
DIMOUT Low Voltage with
Respect to VISENSE+-8.7-7.4-6.3V
OVERVOLTAGE PROTECTION (OVP)
ThresholdVOVPOFFVOVP rising1.191.2251.26V
HysteresisVOVPHY70mV
Input LeakageILOVPVOVP = 1.235V-300+300nA
SHORT-CIRCUIT HICCUP MODE (not present in the MAX16833G)
Short-Circuit ThresholdVSHORT-HIC(VISENSE+ - VISENSE-) rising285298310mV
Hiccup TimetHICCUP8192Clock
Cycles
Delay in Short-Circuit Hiccup
Activation1Fs
BUCK-BOOST SHORT-CIRCUIT DETECT
Buck-Boost Short-Circuit
ThresholdVSHORT-BB(VISENSE+ - VIN) falling, VIN = 12V1.151.551.9V
Delay in FLT Assertion from
Buck-Boost Short-Circuit
Condition
tDEL-BB-SHRTCounter increments only when
VPWMDIM > VPWMON8192Clock
Cycles
Delay in FLT Deassertion After
Buck-Boost Short Circuit is
Removed (Consecutive Clock-
Counter increments only when
VPWMDIM > VPWMON8192Clock
Cycles
MAX16833/MAX16833B/C/D/GHigh-Voltage HB LED Drivers with
Integrated High-Side Current Sense
Electrical Characteristics (continued)(VIN = 12V, RRT = 12.4kI, CIN = CVCC = 1µF, CLFRAMP/CREF = 0.1µF, NDRV = COMP = DIMOUT = PWMDIM = FLT = unconnected,
VOVP = VCS = VPGND = VSGND = 0V, VISENSE+ = VISENSE- = 45V, VICTRL = 1.40V, TA = TJ = -40NC to +125NC, unless otherwise
noted. Typical values are at TA = +25NC.) (Note 2)
Note 2: All devices are 100% tested at TA = +25NC. Limits over temperature are guaranteed by design.
Typical Operating Characteristics(VIN = +12V, CVIN = CVCC = 1FF, CLFRAMP/CREF = 0.1FF, TA = +25NC, unless otherwise noted.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
OPEN-DRAIN FAULT (FLT)
Output Voltage LowVOL-FLTVIN = 4.75V, VOVP = 2V, and ISINK = 5mA40200mV
Output Leakage CurrentVFLT = 5V1FA
THERMAL SHUTDOWN
Thermal-Shutdown TemperatureTemperature rising+160NC
Thermal-Shutdown Hysteresis10NC
IN RISING/FALLING UVLO THRESHOLD
vs. TEMPERATURE
MAX16833 toc01
TEMPERATURE (°C)
IN RISING/FALLING UVLO THRESHOLD (V)
VIN RISING
VIN FALLING
QUIESCENT CURRENT
vs. TEMPERATURE
MAX16833 toc02
TEMPERATURE (°C)
QUIESCENT CURRENT (mA)
VPWMDIM = 0V
QUIESCENT CURRENT vs. VIN
MAX16833 toc03
VIN (V)
QUIESCENT CURRENT (mA)
VIN ~ 4.6V
VPWMDIM = 0V
VCC vs. IVCC
MAX16833 toc04
(V)403530252015105
VCC vs. TEMPERATURE
MAX16833 toc05
(V)
MAX16833 toc06
DIMOUT (WITH RESPECT TO ISENSE+)
vs. TEMPERATURE
DIMOUT (WITH RESPECT TO ISENSE+) (V)
MAX16833/MAX16833B/C/D/GHigh-Voltage HB LED Drivers with
Integrated High-Side Current Sense
Typical Operating Characteristics (continued)(VIN = +12V, CVIN = CVCC = 1FF, CLFRAMP/CREF = 0.1FF, TA = +25NC, unless otherwise noted.)
MAX16833 toc07
TEMPERATURE (°C)
DIMOUT RISE TIME (µs)
DIMOUT RISE TIME vs. TEMPERATURE
CDIMOUT = 6.8nF
MAX16833 toc08
TEMPERATURE (°C)
DIMOUT FALL TIME vs. TEMPERATURE
DIMOUT FALL TIME (µs)
CDIMOUT = 6.8nF
VSENSE vs. TEMPERATURE
MAX16833 toc09
TEMPERATURE (°C)
SENSE
(mV)
VSENSE vs. VICTRL
MAX16833 toc10
VICTRL (V)
SENSE
(mV)
OSCILLATOR FREQUENCY
vs. 1/RRT CONDUCTANCE
(MAX16833/MAX16833B ONLY)
MAX16833 toc12
OSCILLATOR FREQUENCY (kHz)
OSCILLATOR FREQUENCY vs. TEMPERATURE
(MAX16833/MAX16833B ONLY)
MAX16833 toc11
OSCILLATOR FREQUENCY (kHz)
RRT = 24.9kI
MAX16833/MAX16833B/C/D/GHigh-Voltage HB LED Drivers with
Integrated High-Side Current Sense
Typical Operating Characteristics (continued)(VIN = +12V, CVIN = CVCC = 1FF, CLFRAMP/CREF = 0.1FF, TA = +25NC, unless otherwise noted.)
Pin ConigurationNDRV RISE/FALL TIME
vs. TEMPERATURE
MAX16833 toc13
TEMPERATURE (°C)
NDRV RISE/FALL TIME (ns)
NDRV RISE TIME
CNDRV = 10nF
NDRV FALL TIME
600Hz DIMMING OPERATION
MAX16833 toc14
ILED
500mA/div
0mA
VCOMP
2V/div
VNDRV
10V/div
400µs/div
VDIMOUT
50V/div
PWMDIM = 600Hz
VCC
NDRV
PGNDICTRL
SGND
RT/SYNC
LFRAMP (REF)
TOP VIEW
MAX16833
MAX16833B
MAX16833C
MAX16833D
MAX16833GCS
ISENSE+
ISENSE-PWMDIM8OVP*EP
*EP = EXPOSED PAD.
( ) FOR MAX16833B/MAX16833D ONLY.
COMP
TSSOPFLT
DIMOUT
MAX16833/MAX16833B/C/D/GHigh-Voltage HB LED Drivers with
Integrated High-Side Current Sense
Pin DescriptionPINNAMEFUNCTION
LFRAMP
(MAX16833/
MAX16833C/
MAX16833G)
Low-Frequency Ramp Output. Connect a capacitor from LFRAMP to ground to program the ramp
frequency, or connect to SGND if not used. A resistor can be connected between LFRAMP and
RT/SYNC to dither the PWM switching frequency to achieve spread spectrum.
REF
(MAX16833B/
MAX16833D)
1.64V Reference Output. Connect a 1FF ceramic capacitor from REF to SGND to provide a stable
reference voltage. Connect a resistive divider from REF to ICTRL for analog dimming.RT/SYNC
PWM Switching Frequency Programming Input. Connect a resistor (RRT) from RT/SYNC to SGND to
set the internal clock frequency. Frequency = (7.350 x 109)/RRT for the MAX16833/B. Frequency =
(6.929 x109)/RRT for the MAX16833C/D/G. An external pulse can be applied to RT/SYNC through a
coupling capacitor to synchronize the internal clock to the external pulse frequency. The parasitic
capacitance on RT/SYNC should be minimized.SGNDSignal GroundICTRLAnalog Dimming-Control Input. The voltage at ICTRL sets the LED current level when VICTRL < 1.2V.
For VICTRL > 1.4V, the internal reference sets the LED current.COMPCompensation Network Connection. For proper compensation, connect a suitable RC network from
COMP to ground.FLTActive-Low, Open-Drain Fault Indicator Output. See the Fault Indicator (FLT) section.PWMDIMPWM Dimming Input. When PWMDIM is pulled low, DIMOUT is pulled high and PWM switching is
disabled. PWMDIM has an internal pullup resistor, defaulting to a high state when left unconnected.OVP
LED String Overvoltage-Protection Input. Connect a resistive divider between ISENSE+, OVP, and
SGND. When the voltage on OVP exceeds 1.23V, a fast-acting comparator immediately stops PWM
switching. This comparator has a hysteresis of 70mV.DIMOUTActive-Low External Dimming p-Channel MOSFET Gate DriverISENSE-
Negative LED Current-Sense Input. A 100I resistor is recommended to be connected between
ISENSE- and the negative terminal of the LED current-sense resistor. This preserves the absolute
maximum rating of the ISENSE- pin during LED short circuit.ISENSE+Positive LED Current-Sense Input. The voltage between ISENSE+ and ISENSE- is proportionally
regulated to the lesser of VICTRL or 1.23V.CSSwitching Regulator Current-Sense Input. Add a resistor from CS to switching MOSFET current-
sense resistor terminal for programming slope compensation.PGNDPower GroundNDRVExternal n-channel MOSFET Gate-Driver OutputVCC7V Low-Dropout Voltage Regulator Output. Bypass VCC to PGND with a 1FF (min) ceramic capacitor.INPositive Power-Supply Input. Bypass IN to PGND with at least a 1FF ceramic capacitor.EPExposed Pad. Connect EP to the ground plane for heat sinking. Do not use EP as the only electrical
connection to ground.
MAX16833/MAX16833B/C/D/GHigh-Voltage HB LED Drivers with
Integrated High-Side Current Sense
MAX16833/MAX16833C Functional DiagramMAX16833
MAX16833C
REF
ICTRL
ISENSE+
ISENSE-
PWMDIM
OVP
RT/
SYNC
VCC
VCC
NDRV
PGND
RESET
DOMINANT
PWM
COMP
MAX
DUTY CYCLE
UVLO
UVLO
RT OSCILLATOR
SLOPE
COMPENSATION
1.64V (80µA)
REFERENCE
CS/PWM
BLANKING
0.42V
6.15 x 0.3V
1µs DELAY
8192 x tOSC
HICCUP TIMER
VISENSE+ - 7V
ISENSE+SYNC
BUCK-BOOST
SHORT DETECTION
TSHDN
SGND
FLT
DIMOUT
COMP
VBG
3.3V
VBG
3MI
VBG
LPF
MIN
OUT
THERMAL
SHUTDOWN
LVSH
TSHDN
5.7V5VVBG
5V REGBG7V LDO
200kI
MAX16833/MAX16833B/C/D/GHigh-Voltage HB LED Drivers with
Integrated High-Side Current Sense
MAX16833B/MAX16833D Functional DiagramMAX16833B
MAX16833D
REF
ICTRL
ISENSE+
ISENSE-
PWMDIM
OVP
RT/
SYNC
VCC
VCC
NDRV
PGND
RESETDOMINANT
PWMCOMP
MAXDUTY CYCLE
UVLO
UVLO
RT OSCILLATOR
SLOPE
COMPENSATION
1.64V (80µA)
REFERENCE
CS/PWM
BLANKING
0.42V
6.15 x 0.3V
1µs DELAY
8192 x tOSC
HICCUP TIMER
VISENSE+ - 7V
ISENSE+SYNC
BUCK-BOOST
SHORT DETECTION
TSHDN
SGND
FLT
DIMOUT
COMP
VBG
3.3V
VBG
3MI
VBG
LPF
MIN
OUT
THERMAL
SHUTDOWN
LVSH
TSHDN
5.7V5VVBG
5V REGBG7V LDO
200kI
MAX16833/MAX16833B/C/D/GHigh-Voltage HB LED Drivers with
Integrated High-Side Current Sense
MAX16833G Functional DiagramMAX16833G
LFRAMP
ICTRL
ISENSE+
ISENSE-
PWMDIM
OVP
RT/
SYNC
VCC
VCC
NDRV
PGND
RESETDOMINANT
PWMCOMP
MAXDUTY CYCLE
UVLO
UVLO
RT OSCILLATOR
SLOPE
COMPENSATION
RAMP
GENERATION
CS/PWM
BLANKING
0.42V
VISENSE+ - 7V
ISENSE+SYNC
BUCK-BOOST
SHORT DETECTION
SGND
FLT
DIMOUT
COMP
VBG
3.3V
VBG
3MI
VBG
LPF
MIN
OUT
THERMAL
SHUTDOWN
LVSH
TSHDN
5.7V5VVBG
5V REGBG7V LDO
200kI
TSHDN
MAX16833/MAX16833B/C/D/GHigh-Voltage HB LED Drivers with
Integrated High-Side Current Sense
Detailed DescriptionThe MAX16833, MAX16833B, MAX16833C, MAX16833D,
and MAX16833G are peak current-mode-controlled LED
drivers for boost, buck-boost, SEPIC, flyback, and high-
side buck topologies. A low-side gate driver capable of
sinking and sourcing 3A can drive a power MOSFET
in the 100kHz to 1MHz frequency range. Constant-
frequency peak current-mode control is used to control
the duty cycle of the PWM controller that drives the power
MOSFET. Externally programmable slope compensation
prevents subharmonic oscillations for duty cycles exceed-
ing 50% when the inductor is operating in continuous con-
duction mode. Most of the power for the internal control
circuitry inside the ICs is provided from an internal 5V reg-
ulator. The gate drive for the low-side switching MOSFET
is provided by a separate VCC regulator. A dimming driver
designed to drive an external p-channel in series with the
LED string provides wide-range dimming control. This
dimming driver is powered by a separate unconnected
reference -7V regulator. This feature provides extremely
fast PWM current switching to the LEDs with no transient
overvoltage or undervoltage conditions. In addition to
PWM dimming, the ICs provide analog dimming using a
DC input at the ICTRL input.
A single resistor from RT/SYNC to ground sets the
switching frequency from 100kHz to 1MHz, while an
external clock signal capacitively coupled to RT/SYNC
allows the ICs to synchronize to an external clock. The
switching frequency can be dithered for spread-spectrum
applications by connecting the LFRAMP output to RT/
SYNC through an external resistor in the MAX16833/C/G.
In the MAX16833B/D, the LFRAMP output is replaced by a
REF output, which provides a regulated 1.64V, 2% accu-
rate reference that can be used with a resistive divider
from REF to ICTRL to set the LED current. The maximum
current from the REF output cannot exceed 80FA.
Additional features include a fault-indicator output (FLT)
for short, overvoltage, or overtemperature conditions and
an overvoltage-protection (OVP) sense input for overvolt-
age protection. In case of LED string short, for a buck-
boost configuration, the short-circuit current is equal
to the programmed LED current. In the case of boost
configuration, the ICs enter hiccup mode with automatic
recovery from short circuit. In the MAX16833G, the hiccup
mode is disabled. The MAX16833G should not be used in
boost applications.
UVLOThe ICs feature undervoltage lockout (UVLO) using the
positive power-supply input (IN). The ICs are enabled
when VIN exceeds the 4.6V (typ) threshold and are dis-
abled when VIN drops below the 4.35V (typ) threshold.
The UVLO is internally fixed and cannot be adjusted.
There is a startup delay of 300µs (typ) + 64 switching
clock cycles on power-up after the UVLO threshold is
crossed. There is a 3.3Fs delay on power-down on the
falling edge of the UVLO.
Dimming MOSFET Driver (DIMOUT)The ICs require an external p-channel MOSFET for PWM
dimming. For normal operation, connect the gate of the
MOSFET to the output of the dimming driver (DIMOUT).
The dimming driver can sink up to 25mA or source up to
50mA of peak current for fast charging and discharging
of the p-MOSFET gate. When the PWMDIM signal is
high, this driver pulls the p-MOSFET gate to 7V below
the ISENSE+ pin to completely turn on the p-channel
dimming MOSFET.
n-Channel MOSFET Switch Driver (NDRV)The ICs drive an external n-channel switching MOSFET.
NDRV swings between VCC and PGND. NDRV can sink/
source 3A of peak current, allowing the ICs to switch
MOSFETs in high-power applications. The average cur-
rent demanded from the supply to drive the external
MOSFET depends on the total gate charge (QG) and the
operating frequency of the converter, fSW. Use the follow-
ing equation to calculate the driver supply current INDRV
required for the switching MOSFET:
INDRV = QG x fSW
Pulse-Dimming Input (PWMDIM)The ICs offer a dimming input (PWMDIM) for pulse-width
modulating the output current. PWM dimming can be
achieved by driving PWMDIM with a pulsating voltage
source. When the voltage at PWMDIM is greater than
1.23V, the PWM dimming p-channel MOSFET turns on
and the gate drive to the n-channel switching MOSFET is
also enabled. When the voltage on PWMDIM drops 70mV
below 1.23V, the PWM dimming MOSFET turns off and
the n-channel switching MOSFET is also turned off. The
COMP capacitor is also disconnected from the internal
transconductance amplifier when PWMDIM is low. When
left unconnected, a weak internal pullup resistor sets this
input to logic-high.
MAX16833/MAX16833B/C/D/GHigh-Voltage HB LED Drivers with
Integrated High-Side Current Sense
