Most popular advanced LED driver solutions for dif

Ansenmei: advanced LED driver solutions for different applications

nowadays, high brightness LED has been comprehensively improved in light output, energy efficiency and cost. At the same time, it has many advantages such as compact, low-voltage work and environmental protection, and its application range is also constantly expanding. In the future, the growth prospects of LED lighting in general lighting, LCD backlight, automotive lighting and other fields are particularly promising. Ansenmey Semiconductor provides a wide range of LED driver products, which can meet the needs of various LED lighting applications. This article will focus on the application scheme of ansenmey semiconductor in each lighting segment market to help lighting design engineers choose the appropriate scheme and speed up the product launch process

general lighting scheme

under the trend of energy conservation and environmental protection, LED lighting has become the goal of many regulatory agencies. For example, the version 1.1 solid state lighting standard of the "Energy Star" program of the U.S. Department of energy came into effect in February 2009. It is reported that the China Institute of standardization is also preparing to release the Chinese version of LED lighting energy efficiency standard in 2010

take the general lighting market such as replacement of electric bulbs and fluorescent tubes, recessed lights, street lights and parking lights, working lights (table lamps, cabinet lighting), landscape lighting, billboard text, building lighting, etc. as an example, it is estimated that the current LED lighting application proportion is less than 1%, and the market scale is relatively small. However, it is estimated that by 2012, the market scale of LED drivers and related discrete devices will increase from about $688million in 2008 to $1.308 billion, The compound annual growth rate is as high as 17.4%

ansenmey semiconductor has led general lighting schemes suitable for AC-DC power supply of different powers, covering a wide power range

1) 1 w to 8 W scheme

1 w to 8 W low power LED general lighting applications include G13, GU10, par16, PAR20 and recessed lights. The input voltage range of this kind of application is between 90 and 264 V AC. the constant current output current includes 350 Ma and 700 ma. The energy efficiency requirement is 80%. It is also required to provide features such as short circuit and overvoltage protection. For such applications, the ncp1015 self powered monolithic switch control IC of ansenmey semiconductor can be used. The device integrates a fixed frequency (65/100/130 kHz) current mode controller and a 700 V high-voltage MOSFET, and has all the characteristics required to build a strong low-cost power supply, such as soft start, frequency jitter, short-circuit protection, skip cycle, maximum peak current set point and dynamic self power supply function (without auxiliary winding). Ncp1015 can be used for both isolated and non isolated schemes, as shown in Figure 1

Figure 1: 1 w to 8 W isolated (a) and non isolated (b) led lighting schemes based on ncp1015

it is worth mentioning that an important feature of the new solid-state lighting standard of "Energy Star" is that it requires a minimum power factor of 0.7 for a variety of residential lighting products. The power of such LED lighting applications is generally 1 w to 12 W, and the isolated flyback power topology is the most suitable. However, the power factor of the existing standard design technology is usually less than 0.6. To improve the power factor and easily meet the requirements of "Energy Star", we can combine the optimized ncp1014ledgtgevb evaluation board and adopt the reference design of Anson semiconductor's offline 8 W LED driver

Anson semiconductor's ncp1014ledgtgevb evaluation board can drive 1 to 8 high-power and high brightness LEDs. The design is based on a compact fixed frequency pulse width modulation (PWM) converter NCP1014 that integrates a high-voltage power switch with internal current limiting function. Since NCP1014 operates at a fixed frequency, the current cannot rise above a specific point; The limitation of conduction time makes the input current follow the waveform of the input voltage, thus providing a higher power factor. The circuit diagram of the evaluation board is shown in Figure 2

figure 2:ncp1014ledgtgevb circuit diagram

2) 8 w to 25 W scheme (without PFC and with PFC)

in 8 w to 25 W AC-DC LED lighting applications, one scheme does not require power factor correction (PFC), and the other needs to meet the strong PFC requirements specified in the "Energy Star" solid-state lighting (SSL) specification. The main business of Huitian new material is to produce engineering adhesives. The standard is applicable to a series of specific products, such as recessed lamps, cabinet lamps and table lamps. Among them, the power factor of LED drivers for residential applications must be greater than 0.7, and that for commercial applications must be greater than 0.9

typical applications of 8 w to 25 W AC-DC LED lighting without PFC, such as PAR30, PAR38 and recessed lamps. The input voltage requirements for such applications are 85 to 135 VAC or 185 to 264Vac, and the energy efficiency requirements are greater than 80%. It provides characteristics such as short-circuit protection and open circuit protection, and the constant current output current is 350 Ma, 700 Ma and 1 A. For this purpose, NCP1028 or NCP1351 of ansenmey semiconductor can be used. NCP1028 is an enhanced single-chip switch control IC, which provides 800 Ma peak current, as well as features such as over-power protection, built-in slope compensation and input undervoltage protection. It is suitable for providing several watts to 15 W output power in general-purpose wide power input applications

the typical application of 8 w to 25 W AC-DC LED lighting requiring PFC is the same as above, the input voltage specification is 90 to 264 VAC, other indicators are the same as those without PFC, and the power factor is required to be higher than 0.9. This kind of application is suitable for ncl30000 single-stage power factor correction LED driver of ansenmey semiconductor. The single segment topology eliminates the need for a dedicated PFC boost section, reducing the number of components and reducing the total cost of the system. Ncl30000 meets the requirements of IEC class C harmonic content, can directly drive LED, has accurate constant current output control, and has energy efficiency of more than 80% at low output power of 5 w to 15 W, typical energy efficiency of more than 83%, and supports existing dimming schemes such as triac

3) 50 W to 200 W scheme

AC-DC LEDs with power higher than 50 W are widely used in street lighting and high-power area lighting. The input voltage specification is 90 to 264 VAC, the power factor is higher than 0.9, and the energy efficiency is greater than 85%. It provides short-circuit and overvoltage protection, and the constant current output is 350 Ma, 700 Ma and 1 A. Such applications can use single-stage PFC LED driver ncl3001, CRM pfc+ QR PWM driver ncp1607+ncp1377, and CRM pfc+ to provide integrated solutions for Products LLC PWM driver ncp1607+ncp1397 or ncp1392/3 to meet different needs

portable device backlight or Flash scheme

portable applications require extended battery life and reduced board area and height. The LED driver scheme for backlight application of many low-voltage portable products of ansenmey semiconductor can be used in different topologies such as linear, inductive and charge pump. Among them, the inductive scheme has the best overall energy efficiency, the charge pump scheme has the smallest board area and height, and the linear driver is suitable for simple backlight applications

on semiconductor's cat3200, ncp5602, ncp5612, ncp5623, cat3606, cat3616, cat3626, cat3603, cat3604, cat3614, ncp5603 and other different dimming products that support charge pump solutions, such as single-mode, dual-mode, the third mock examination or four mode solutions. Taking ncp5623 as an example, this is a high-energy LED Driver with I2C interface and built-in progressive dimming function, which is especially suitable for RGB LED decorative light and enhanced LCD backlight of portable products such as drivers. It can achieve 94% peak energy efficiency and a standby current less than 1 μ a, which will prolong the working time of portable device battery to the maximum as the requirements increase in the future. The package of the device is very small, only four passive components are required, and it has the function of short circuit and overvoltage protection

digital cameras that want to take high-resolution photos in weak light need high brightness flash. Although white LED can provide this level of light energy, it needs nearly 400% more energy than the battery. Take the ncp5680 of Anson semiconductor as an example. It works with battery management and super capacitor to drive the led to flash to full brightness, providing a high peak current of 10 A. The integrated driver of ncp5680 can also manage super capacitors and handle other peak power functions, such as zoom, auto focus, audio, video, wireless transmission, GPS data reading and radio frequency (RF) amplification. It can prolong the battery life and take into account the thin design, saving development time, circuit board space and component costs, as shown in Figure 3

figure 3:ncp5680 full function typical application

LCD TV LED backlight scheme

a hot spot in the LCD TV market is energy saving, and using advanced technology can perform the same function with less power. Other hot spots include the trend towards a larger screen and lower thickness, which brings challenges to its power design and promotes the transition of backlight technology from traditional cold cathode fluorescent lamp (CCFL) backlight to LED backlight

the ncp1397 primary end controller of ansenmey semiconductor, together with 6-channel linear LED driver cat4026 and other devices with forward voltage monitoring function, supports the design of low height led backlit LCD TV, so that the height on the circuit board is less than 8 mm, and the total height is less than 12.5 mm. It can also deal with a wide range of dimming, heat dissipation, fault protection and other problems, so that the challenges of power design can be solved. The 46 inch LCD TV backlight scheme using ncp1397 and cat4026 is composed of LED backlight converter (ncp1397 and other devices) and LED controller (cat4026 and other devices)

cat4026 is a cost-effective scheme of multi-channel linear LED driver applied to large-scale side light LED backlight LCD TV. It can form a single IC Branch 4. The molding temperature of polyphenylene oxide is 280 ℃ (3) 30 ℃, holding 6 channels, and it is easy to grade up to 12 or 18 channels (2 or 3 controllers are used accordingly). The target energy efficiency is higher than 90%, and the typical energy efficiency is 94%. In addition, the driver also provides forward voltage monitoring function, which can limit the overall power consumption; It can also provide protection for different LED string faults such as LED open circuit and too many led short circuits

led car headlamp scheme

at present, most cars still use halogen headlamp scheme to provide high beam and low beam functions. For mid-range vehicles, the trend is to use xenon lights and LED lights. The application of LED in automobile headlamps has gone beyond the scope of high beam and low beam lamps, such as fog lamps, steering assist lamps, steering indicators, daytime running lamps, clearance lamps, etc. It is expected that these non high beam/low beam applications will rise rapidly, and 30% of vehicles will be equipped with a variety of LED headlamp functions within five years

Anson semiconductor will release a new LED driver in the fourth quarter of 2010, which is specially used for the control function of all headlamps. It will integrate switch mode boost converter and step-down converter, which can be used for two channels, and provide diagnostic function, which will help to significantly reduce the fuel consumption of vehicles caused by headlamp power consumption, which is worthy of users' expectation

interior LED lighting scheme

convenient lighting for passengers to get on and off has become a standard function of modern cars. This kind of lighting system and light path configuration are relatively simple

using the nud4001 low-cost integrated current source of ansenmey semiconductor can replace the discrete solution of automotive interior lighting, and drive LEDs in low and high AC or DC voltage applications (6 to 120V), so that separate components are no longer required, significantly reducing the system cost and circuit board area

the device uses AC or DC input to provide stable DC current for LED arrays, which can drive LED arrays in series or in parallel, with low voltage overhead (1.4V), and is suitable for low-voltage applications. Its current stability principle is to generate a constant voltage drop (0.7V) on an external low-power detection resistor (rext), which sets a current independent of the input voltage, making it very simple to use nud4001 to design LED circuit

nud4001 provides a low-cost solution for automotive applications. Compared with linear or switching regulator, its design is simpler, and it can form a simpler and lower cost circuit, as shown in Figure 4

Figure 4: cabin ceiling light circuit using nud4001 device to drive a 200mA led

summary of this paper

LED lighting Fangxing