ON Semiconductor leads LED innovation: the fourth drive technology
From the current LED driving technology, there are mainly three technologies, namely, resistive, linear regulator and switching regulator. Various driving technologies coexist and are applied to different environments, each with advantages and disadvantages.
“The advantages of resistive drive technology are low cost, ease of design, and no EMC issues,†explains Asif Jakwanl, director of market and applications for the Small Signals Division of the ON Semiconductor Standards Group. “But the downside is that the brightness of LEDs depends on the battery voltage. The brightness varies with voltage, and the potential danger is that the LED lamp may burn out. In addition, its shortcomings include the need for proper LED coding, low conversion efficiency, and inventory pressure for customers. However, due to resistance The low cost of the drive and its ease of design are still among the more popular LED drive technologies.
Next, AsifJakwanl explained the advantages and disadvantages of the other two technologies in detail. For linear regulator drive technology, the advantages are also easy to design, no electromagnetic compatibility problems, compared to resistive drive, it also adds steady current and overcurrent protection, with an external current set point. However, its disadvantage is that it is more expensive than the former, there will be power dissipation, and the efficiency is relatively low.
The third type of switching regulator is a popular driving technology in recent years. It has high efficiency, controllable LED brightness, and voltage independence, but its disadvantage is that the cost is much more expensive than the former two, and the design is complicated. The problem is that there is electromagnetic interference. "Some applications are sensitive to electromagnetic interference, such as in cars. For cars, interference from LED drivers can affect the car's audio and video reception, so switching regulators are not necessarily suitable for all applications," he said. However, in some high current applications, due to the high efficiency of the switch drive, it is still the first dizzy
"Considering the advantages and disadvantages of the above three driving technologies, ON Semiconductor has improved the first and second technologies through painstaking research, and proposed a new driving technology - linear constant current regulator (CCR) This drive method is based on ON Semiconductor's patent-pending self-biased transistor technology, which regulates over a wide range to ensure constant brightness over the operating voltage range. The design also features a negative temperature coefficient at extreme voltages and operation. Protect the LED from thermal runaway at temperatures," said AsifJakwanl.
Let's call it the fourth drive technology for now. “The two-terminal and three-terminal linear constant current regulators are simpler and lower cost solutions than linear and switching regulators, and they also greatly improve performance over resistives.†He pointed out, “I am ours. The exclusive patented technology of ON Semiconductor has been patented and is pending. The cost of the CCR solution is between the resistive and linear regulators.
The CCR features constant current and supports a maximum operating voltage of 45V, which is especially suitable for unstable automotive taillight voltages. Advantages of CCR include: constant brightness over a wide voltage range, protection of the LED from overdrive when the input voltage is high, brighter LEDs at lower input voltages, or reduced LED code inventory (because there is no need to match different voltages) LED Light).
Compared with switching regulators, there is no EMI problem due to the absence of switches, making the design simple and easy. CCR is a double-ended drive. LEDs can be placed on top or bottom, which also makes the design simple. In addition, there is no need to surround components, and switching regulators require more peripheral components. “CCR is a low-cost line regulator. At the same time, because it eliminates LED coding and reduces the cost of resistor inventory, the overall system cost is lower,†said AsifJakwan.
In terms of application, AsifJakwan recommends that CCR is the best choice below 50mA. Switching regulators are still the better choice when larger currents are required. In addition to the automotive LED lighting mentioned above, commercial signs and architectural lighting are all very suitable applications for CCR.
Currently, two CCR products are available at both ends, and two other three-terminal CCR devices with dimming are available at the end of the year.
“The advantages of resistive drive technology are low cost, ease of design, and no EMC issues,†explains Asif Jakwanl, director of market and applications for the Small Signals Division of the ON Semiconductor Standards Group. “But the downside is that the brightness of LEDs depends on the battery voltage. The brightness varies with voltage, and the potential danger is that the LED lamp may burn out. In addition, its shortcomings include the need for proper LED coding, low conversion efficiency, and inventory pressure for customers. However, due to resistance The low cost of the drive and its ease of design are still among the more popular LED drive technologies.
Next, AsifJakwanl explained the advantages and disadvantages of the other two technologies in detail. For linear regulator drive technology, the advantages are also easy to design, no electromagnetic compatibility problems, compared to resistive drive, it also adds steady current and overcurrent protection, with an external current set point. However, its disadvantage is that it is more expensive than the former, there will be power dissipation, and the efficiency is relatively low.
The third type of switching regulator is a popular driving technology in recent years. It has high efficiency, controllable LED brightness, and voltage independence, but its disadvantage is that the cost is much more expensive than the former two, and the design is complicated. The problem is that there is electromagnetic interference. "Some applications are sensitive to electromagnetic interference, such as in cars. For cars, interference from LED drivers can affect the car's audio and video reception, so switching regulators are not necessarily suitable for all applications," he said. However, in some high current applications, due to the high efficiency of the switch drive, it is still the first dizzy
"Considering the advantages and disadvantages of the above three driving technologies, ON Semiconductor has improved the first and second technologies through painstaking research, and proposed a new driving technology - linear constant current regulator (CCR) This drive method is based on ON Semiconductor's patent-pending self-biased transistor technology, which regulates over a wide range to ensure constant brightness over the operating voltage range. The design also features a negative temperature coefficient at extreme voltages and operation. Protect the LED from thermal runaway at temperatures," said AsifJakwanl.
Let's call it the fourth drive technology for now. “The two-terminal and three-terminal linear constant current regulators are simpler and lower cost solutions than linear and switching regulators, and they also greatly improve performance over resistives.†He pointed out, “I am ours. The exclusive patented technology of ON Semiconductor has been patented and is pending. The cost of the CCR solution is between the resistive and linear regulators.
The CCR features constant current and supports a maximum operating voltage of 45V, which is especially suitable for unstable automotive taillight voltages. Advantages of CCR include: constant brightness over a wide voltage range, protection of the LED from overdrive when the input voltage is high, brighter LEDs at lower input voltages, or reduced LED code inventory (because there is no need to match different voltages) LED Light).
Compared with switching regulators, there is no EMI problem due to the absence of switches, making the design simple and easy. CCR is a double-ended drive. LEDs can be placed on top or bottom, which also makes the design simple. In addition, there is no need to surround components, and switching regulators require more peripheral components. “CCR is a low-cost line regulator. At the same time, because it eliminates LED coding and reduces the cost of resistor inventory, the overall system cost is lower,†said AsifJakwan.
In terms of application, AsifJakwan recommends that CCR is the best choice below 50mA. Switching regulators are still the better choice when larger currents are required. In addition to the automotive LED lighting mentioned above, commercial signs and architectural lighting are all very suitable applications for CCR.
Currently, two CCR products are available at both ends, and two other three-terminal CCR devices with dimming are available at the end of the year.
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