MAX16834数据手册.pdf

General DescriptionThe MAX16834 is a current-mode high-brightness LED(HB LED) driver for boost, buck-boost, SEPIC, and high-side buck topologies. In addition to driving an n-channelpower MOSFET switch controlled by the switching con-troller, it also drives an n-channel PWM dimming switch toachieve LED PWM dimming. The MAX16834 integratesall 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 provideswide-range dimming control up to 20kHz. In addition toPWM dimming, the MAX16834 provides analog dim-ming using a DC input at REFI. The programmableswitching frequency (100kHz to 1MHz) allows designoptimization for efficiency and board space reduction.A single resistor from RT/SYNC to ground sets theswitching frequency from 100kHz to 1MHz while anexternal clock signal at RT/SYNC disables the internaloscillator and allows the MAX16834 to synchronize toan external clock. The MAX16834’s integrated high-side current-sense amplifier eliminates the need for aseparate high-side LED current-sense amplifier inbuck-boost applications.The MAX16834 operates over a wide supply range of4.75V to 28V and includes a 3A sink/source gate driverfor driving a power MOSFET in high-power LED driverapplications. The MAX16834 is also suitable for DC-DCconverter applications such as boost or buck-boost.Additional features include external enable/disableinput, an on-chip oscillator, fault indicator output (FLT)for LED open/short or overtemperature conditions, andan overvoltage protection sense input (OVP+) for trueovervoltage protection.The MAX16834 is available in a thermally enhanced4mm x 4mm, 20-pin TQFN-EP package and is specifiedover the automotive -40°C to +125°C temperature range.ApplicationsSingle-String LED LCD BacklightingAutomotive Rear and Front LightingProjection System RGB LED Light SourcesArchitectural and Decorative Lighting (MR16, M111)Spot and Ambient LightsDC-DC Boost/Buck-Boost ConvertersFeaturesa111 Wide Input Operating Voltage Range (4.75V to28V)a111 3000:1 PWM Dimminga111 Analog Dimminga111 Integrated PWM Dimming MOSFET Drivera111 Integrated High-Side Current-Sense Amplifier forLED Current Sense in Buck-Boost Convertera111 100kHz to 1MHz Programmable High-FrequencyOperationa111 External Clock Synchronization Inputa111 Programmable UVLOa111 Internal 7V Low-Dropout Regulatora111 Fault Output (FLT) for Overvoltage, Overcurrent,and Thermal Warning Faultsa111 Programmable True Differential OvervoltageProtectiona111 20-Pin TQFN-EP PackageMAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver________________________________________________________________ Maxim Integrated Products 1VINBOOST LED DRIVERINONNDRVCSANALOGDIMOFFDIMOUTSENSE+PWMDIMPGNDLED+LEDsLED-MAX16834REFISimplified Application CircuitOrdering Information19-4235; Rev 0; 8/08For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,or visit Maxim’s website at www.maxim-.EVALUATION KITAVAILABLE+Denotes a lead-free/RoHS-compliant package.*EP = Exposed pad.PART TEMP RANGE PIN-PACKAGEMAX16834ATP+ -40°C to +125°C 20 TQFN-EP*Pin Configuration appears at end of data sheet.MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver2 _______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGSELECTRICAL CHARACTERISTICS(VIN= VHV= 12V, VUVEN= 5V, VLV= VPWMDIM= SGND, CVCC= 4.7µF, CLCV= 100nF, CREF= 100nF, RSENSE+= 0.1Ω, RRT= 10kΩ, TA= TJ= -40°C to +125°C, unless otherwise noted. Typical values are at TA= +25°C.)Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.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- HV, LV to SGND................................................-0.3V to +30VOVP+, SENSE+, DIMOUT, CLV to SGND ..............-0.3V to +30VSENSE+ to LV........................................................-0.3V to +0.3VHV, IN to LV............................................................-0.3V to +30VOVP+, CLV, DIMOUT to LV......................................-0.3V to +6VPGND to SGND .....................................................-0.3V to +0.3VVCC to S。