Development trend of the hottest DOB high voltage

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The development trend of DOB high-voltage linear drive IC

dob (driver on board) or driverless, that is, what we usually call "de" power supply, is not actually no power supply, but a new drive mode different from the traditional switching power supply, which is a new drive mode derived from the characteristics of LED

dob IC solutions have many pioneers in the industry, mainly Seoul semiconductor, lynklabs in the UK, Texas Instruments and exclara in the United States, and Industrial Technology Research Institute, interlight and other giants in Taiwan. However, China started late because of insufficient R & D reserves and slow response. However, with the rapid development in China, a number of enterprises have followed suit and developed DOB IC. However, the rejection and even suppression of "no power" products by the industry, especially traditional power supply manufacturers, has hindered the development of this innovative new technology to a certain extent

DOB IC scheme is the future road of LED lighting driven development

it is mainly discussed from three aspects:

standardization, scale and automation

there are many traditional power supply devices, which are large in size and complex in processing, which bring inconvenience to standardization, automation and large-scale production. According to incomplete statistics, there are no less than 20000 LED lamp manufacturers in China at present. It is believed that in the coming years, there will be more than a thousand enterprises. In order to survive in this cruel competition, improving production efficiency and accelerating automation will be the only way. If we still rely on traditional power supply, we will face great challenges

because there are many components in the traditional power supply, the bad factor naturally increases. In particular, the life of electrolytic capacitors directly leads to an increase in the probability of LED lamp failure. Although capacitors will be used in valley filling in order to eliminate 100Hz power frequency stroboscopic in DOB IC drive, some capacitors are essentially different from those of traditional power supply in specific applications. On the other hand, capacitor failure in linear valley filling will not lead to dead lights. The capacitor failure in traditional power supply directly leads to dead lamp

intelligent lighting

from the perspective of intelligent lighting, compared with the traditional switching power supply drive, Linear IC drive has its inherent advantages. Traditional power supply can also realize intelligent lighting, but the cost or system integration cost is far more than linear

looking at this table again from the above, DOB Linear IC is a high cost-effective LED driving scheme in terms of stability, safety, performance parameters and high cost

problems existing in DOB IC at present

1) low utilization and efficiency of lamp beads

2) problems such as narrow working voltage range, difficult heat dissipation and pressure flash caused by poor linear adjustment rate

3) 100Hz industrial frequency flash

4) small driving power of single IC, up to 9W

if the above-mentioned core problems cannot be fundamentally solved, it is difficult to say that D adopts the loctite Max polyurethane resin ob IC driving scheme is the future of LED driving

how to solve the problems of DOB IC

(1) improve power efficiency through high-order segmentation. The core of the high-order segment is to realize the 23 order segment drive through the mixed control of NMOS and PMOS. Here, 23 steps and 23 steps refer not to aircraft manufacturing. Another area of concern is the traditional physical LED light string segmentation, but 23 states in logic

here, compare the common voltage waveforms of 4 segments and high-order segments. It can be seen from the figure that the 23 order segment driving voltage waveform is almost sine wave, which improves the power efficiency by more than 90%, so our IC can drive 25W at most

(2) dynamic configuration, in fact, is summarized in a simple sentence: when the voltage is low, each sub series is connected in parallel, and when the voltage is high, each sub series is connected in series. This sentence sounds simple, but it took nearly half a year. We call it "dynamic configuration". Each sub string lamp bead is continuously lit at each voltage segment, so as to improve the light efficiency and lamp bead utilization by 10% - 15%

(3) to solve the 100Hz industrial strobe, we need to use the active valley filling technology: charge the capacitor when the voltage rises, and supply power to the lamp string when the voltage is near the zero crossing point. Completely overcome 100%, 100Hz stroboscopic. On this basis, the utilization rate and luminous efficiency of lamp beads are also increased by 10% - 15%

(4) poor linear adjustment rate and narrow working voltage are important factors that hinder the development of linear drive at present. The power of lamps increases with the increase of voltage, which is a poor user experience. Through the so-called "dynamic configuration" and "active valley filling", the output power remains basically unchanged under different voltage states, and the problem of poor linear adjustment rate is well solved

(5) voltage flicker is the change of light output caused by a wide range of unstable voltage fluctuations. The problem of flashover has not been solved. Line voltage compensation technology is adopted here. When the voltage fluctuates in a large range, if DOB IC will detect the change of peak voltage and automatically compensate the change of light output, the flicker of lamps caused by voltage fluctuation can be suppressed

(6) improve efficiency and heat dissipation technology, and the single driving power is 25W

dob IC scheme's inherent advantages in intelligent lighting

intelligent lighting is indispensable to realize smart home. Without intelligent drive, it is difficult to be called intelligent lighting

dimming can be divided into internal dimming and external dimming

the so-called built-in dimming is that the segmented dimming function has been integrated in the IC to realize fast on-off dimming without increasing any power cost and reducing the power performance index. Through the switch, we can realize the three-level switch dimming of 100%-50%-10% that our team is willing to serve the upgrading of enterprise products. At the same time, we can also realize the function of color matching and temperature

for the so-called external dimming, you can look at this frame diagram: various external sensors such as radar/infrared/voice control module or wifi/Bluetooth/zigbee module transmit instructions to the MCU master chip (which may be included in the wireless communication module), and the MCU sends instructions to the linear constant current drive chip through SDQ single line protocol, so as to realize the dynamic change of the brightness of the lamp. With the lowest system cost and maximum flexibility, it can realize various complex intelligent dimming

the market share of DOB IC scheme is not high. First of all, from the perspective of time and development process, DOB IC scheme has developed rapidly in recent years, which is a new direction and innovation compared with the traditional drive that has been developed for decades. It needs an industrial verification process to replace the traditional switching power supply

the second is more important. Therefore, the core problems of Linear IC drive have not been solved yet, and there is still a certain distance between it and switching power supply in terms of performance. These are the reasons that hinder the development of linear drive and are not widely recognized

if the existing problems cannot be solved, Linear IC drive will always be a trend. It will not be able to replace the traditional power driver, and it will not become the so-called mainstream in the future

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