Led backlight driver topology

Maximum output current with output voltage figure 5. Choice of led driver topology can improve the power efficiency of led backlight systems in mobiles and other batterypowered systems, writes jan enenkel of austriamicrosystems. In view of many buyers for the led driver board topology do not understand, its working principle does not understand the direct result of the consequences can not be properly used. They are configured as either inductorless charge pump or switching regulatorbased led drivers that support driving white leds in series, parallel or combination. Tps61195 data sheet, product information and support. When the driver must control several leds in series, a boost converter topology is used. Backlight voltage drivers wled display backlighting. Depending on the input voltage and the number of leds used in the led string, the converter can be a buck, boost or buckboost for example when. Led drivers will regulate for constant output current instead of constant output voltage, because leds need to be driven with certain current for specific light output. Our inductive driver ics are extremely useful for portable devices, consumer equipment and ruggedized applications for the automotive, medical, industrial, and white good sectors.

Whether it is for automotive, general illumination, or special led usages selecting the correct driver can be made easier through the use of a multi topology led driver, one that has maximum flexibility to be designed into various input. Design and implementation of 150 w acdc led driver with. Universal led lcd tv backlit constant current module step. Boost buck led driver topology for low input and output ripple for low. Other led strings will have a lower series voltage and thus those drivers have greater headroom. The max20446 is a 6channel backlight driver with boost controller for automotive displays. It must minimize power loss, avoid backlight flicker, and provide uniform brightness. The aat2822 includes a tripleoutput dcdc converter, a led backlight driver, and a vcom buffer in a 4 mm x 4mm tqfn package. The trend in automotive infotainment screens and digital instrument clusters is bigger and. With different combinations of input voltage, topology, pin count or package they can be applied to any led backlight application. In order to properly drive the wide variety of led backlit panels available on the market now, electrical design engineers will need to successfully implement one of the many led driving topologies available.

Most led drivers will also include dimming functions, to be able to control the output current, thereby controlling the led light output. Some guidelines and tips for the led driver application figure 4. In some off line led drivers, linear topology is used. Led solutions for lcd backlighting topology and architecture flexilbility buckboost improved efficiency high side control in boost topology for improved accuracy high frequency 2mhz operation with pwm control chip scale packaging solutions smallest application area lcd backlighting applications. Led backlight driver ic princeton technology corporation. This buck led driver ic has a buck topology with a power factor. Stld41 white led driver for midsize lcd display backlight. I have a question regarding flyback converter control. Universal led lcd tv backlight constant current board. With internal 350khz operating frequency, the size of the external pwm inductor and inputoutput capacitors can be minimized. Led solutions for lcd backlighting topology and architecture flexilbility buckboost. The um1661 pfm stepup dcdc converter drives white leds with a constant current to provide backlight in cell phones, pdas, and other handheld devices. The working principle of the above common led driver board solutions is presented to everyone.

Search for the best device for your system in two different ways. Everything about the laptops backlight, led screen voltages and signals patreon. Stld41 white led driver for midsize lcd display backlight, stld41pur, stmicroelectronics. Contact your local microchip sales representative or distributor for volume and or discount pricing. The integrated current outputs can sink up to ma led current each. It features allowing series connection of the white leds so that the led currents are identical for uniform brightness. This buck led driver ic has a buck topology with a power factor higher than 0. The tps61195evm460 is a fully assembled and tested circuit for evaluating the tps61195 adjustable, 8channel white led driver ic.

Universal led lcd tv backlit constant current module stepup. I hope that you can understand the problems when you use them to complete the work better and more accurately. Filter results by wavelength, equipment type and other parameters to find the led driver ic that is right for you. This provides enough headroom for proper operation of the led driver. Automotive led drivers often require stepupstepdown dcdc converters thatcan. The aat2822aat2825 family of integrated panel power solutions provides the regulated voltages required by an activematrix thinfilm transistor tft liquidcrystal display lcd. Our extensive led driver ic product portfolio, design tools, and technical resources can help you add. The aat2822 includes a tripleoutput dcdc converter, a led backlight driver, and a vcom buffer in a. Lets look at three common ways of driving the led backlight and see how they perform.

Topologies include boost regulator led drivers, buck regulator led drivers, buckboost led drivers, and more. Because of this, the unique floating led driver topologies such as boost buck and. It provides a single channel of dimmable currentregulated output intended for 3s led strings operating between 7v to 9. Led drivers can be designed to offer a combination of. Direct ac led driver solution accurate led cc regulation. Boards and tools leds driver with boost converter for lcd panels backlight white led controller in boost topology 6row, 30 ma led driver with boost. American bright optoelectronics corporation ams analog devices inc. These princeton integrated circuits are the ideal solutions for driving led backlights. They are configured as either inductorless white led drivers for leds in parallel, or inductorbased white led drivers for leds in series. The electrical configuration of these leds is also critical because some configurations can lead to impractical, expensive, or inefficient driver designs. Analog devices stepup boost led drivers provide current control of multiple leds and support for high brightness led lighting, large format led backlighting, cameraenabled smart devices, and a range of related applications. The led backlight driver is a key part of this lcd panel system, and some engineers may. Um1661 led backlight boost driver switching regulators.

The ncp5007 is high efficiency boost converter operating in current control loop, based on a pfm mode, to drive white leds. Contents led solutions for lcd backlighting led array driver featuresbenefits. Jim christensen, strategic applications engineer jun 30, 2009 abstract. Mps offers a full range of wled backlight drivers that can power screens from small to large, with accurate current matching and flexible dimming modes. I hereby secretary of the current popular topology program brief. The presented led driver circuit topology, which is designed to drive a. Vin v topology fosc khz dimming output channel output current protection. May 10, 2019 many lighting applications require led backlight driver solutions with the following features. Max20446 automotive 6channel backlight driver with boost. The current mode regulation allows a uniform brightness of the leds. The demoboard uses supertexs hv9911 ic in a boost topology. For more information on led lighting and led drivers including a full selection of the latest products to ensure your success go to mouser lighting applications. Our extensive led driver ic product portfolio, design tools, and technical resources can help you add innovative lighting features to your design. Dcdc converter for smart lighting applications power.

For a typical boost topology with an integrated fet, it is easy to use the previously discussed method to estimate the maximum output current with detailed application specifications, and the trend of maximum output current with output voltage or input. Boostbuck led driver topology for automotive leds operates with. An illuminating look at led driving electronic design. Each led driver topology is designed for optimal high efficiency in the smallest footprint with accurate current regulation, low noise and a wide dimming range. The chip has been optimized for small ceramic capacitors and is capable of supplying up to 1. Some guidelines and tips for the led driver application. Our dcdc led backlight drivers also use dialogs proprietary digital control techniques, including broadled technology to enable the use of loosely binned, lowcost led arrays, as well as a digital control engine that generates the pwm wave form and manages all fault conditions, eliminating the need for expensive microcontrollers. Introduction to led backlight driving techniques for liquid. Microsemis led driver family is among the richest in the industry, with controllers and drivers that can power strings of leds in general illumination applications, as well as backlight with one or more strings for tvs monitors, mobile devices and computers. Product index integrated circuits ics pmic led drivers. Real world example whenever there are leds there are needs for led drivers. Power management led lighting driver product details holtek. Analog devices has a very broad line of led drivers for backlighting applications.

In other word, ub series led strip cannot be mounting on these panels. How to design an led backlight driving system using the max20446. The prices are representative and do not reflect final pricing. Microsemis controllers employ flyback, boost or buck switching regulation, or the innovative llc control toplogy for best in industry. Choosing the right topology for led driver design endicott. If leds are not available for connection to the evaluation module, the wledevm260 board can be ordered. They are configured as either inductorless charge pump or switching regulatorbased led drivers that support driving white leds in. This is a reference design for a sepiclinear led display backlight driver for eight parallel strings of 8 wleds white leds at 70mastring. Many lighting applications require led backlight driver solutions with the following features. The driver topologies are available in three main categories. Backlight led drivers products microchip technology inc. Support cascode topology for applications higher than 70v. The adaptive mode when the pwm signal is high will diodeor the outputs so that the lowest driver voltage largest series led string voltage is regulated to about 700mv. Led backlight boost driver switching regulatorspower.

Led drivers integrated circuits power circuits, lcd, led. When trying to understand these topologies, we first need to understand the most important portion of any. One method to power the led backlight is with a voltage regulated dc to dc source. In the latest generation of smartphones, which feature large displays suitable for showing web pages and video, the led backlight system is one of the biggest power loads in the device. Everything about the laptop backlight, led screen voltages. The hv9911db2 is an led driver capable of driving up to twenty 100ma leds in series from an input of 9 16v dc. Power management led lighting driver product details. Introduction the max20446 is a peak currentmodecontrolled led driver, capable of driving up to six led strings in several different configurations. Dc to dc power for driving ledbacklit lcds by michael keene, design engineer. Led solutions for lcd backlighting mouser electronics. Owing to improvement in long operative life, wider operation temperature range, and the simplicity of driver circuit work with low and safe voltages, light emitting diode led has gradually substituted the ccfl as backlight 69. Xb series led backlight kit for a single lamp industrial lcd panel this led backlight kit is designed for smaller industrial lcd panels where space is limited by its original ccfl backlight assembly. Led driver led driver fpga host mcu video 10 leds per string, 16 led strings, total 160 leds i 80ma 20 monitor screen usb dvi high speed differential interface spi edgelit type led backlighting local dimming block diagram led backlighting types and dimming modes, contd.

This application note focuses on the boost converter topology, and the same design process can be extended to other led driver products. Ca 288 universal 26 to 55 inch led lcd tv backlight driver. The sepic power supply operates at a frequency of 200khz, which is fast enough for small power components and yet slow enough to prevent overheating the switching mosfet. Members of this portfolio include i2ccompatible programming interfaces, with compact, high efficiency features suited to. Topology fosc khz dimming output channel output current protection pin count package data sheet. This is a preferred topology because of the input and output voltage variations that occur with leds in automotive environments. This display backlight driver has been designed specifically for. With the use of medium to highpower leds, the driver electronics are more simplified. Choice of led driver topology can improve the power efficiency of led backlight systems in mobiles and other batterypowered systems, writes jan enenkel of austriamicrosystems in the latest generation of smartphones, which feature large displays suitable for showing web pages and video, the led backlight system is one of the biggest power loads. Key parameters for selecting led drivers are input voltage, led string voltage and led string current, singlemultistring leds and dimming. Apr 18, 2018 the led backlight driver should perform three key functions to properly drive the leds. Boostbuck led driver topology for low input and output ripple for.

Universal 1065 led tv backlight constant current driver. In some cases, a buckboost topology provides the capability to address a variety of application requirements including the ability to handle voltage extremes. Most high brightness leds have a forward voltage between 3 3. Leds driver with boost converter for lcd panels backlight white led controller in boost topology 6row, 30 ma led driver with boost. The trend in automotive infotainment screens and digital instrument clusters is bigger and brighter. Many automotive led driver circuits require constantcurrent dcdc. All of lcd lighting drivers operate from 85v ac to 265v ac 2. I am currently trying to create a led ballast using flyback converter topology, however, i am unable to produce the voltage 10v and current 1a that i would like to get. Dcdc led backlight drivers products dialog semiconductor. Led driver ic analog devices has a very broad line of led driver ics for automotive, display backlighting, handheld, and general highpower lighting applications. I suspect that the problem is with the control system that i have designed but i cannot figure out what went wrong. This chapter will introduce some led backlight driving techniques for lcd panels. An enable input can be pulsed repeatedly to adjust leds brightness.