LED power supplies into GaN era!

As LED lighting power increases, the big traditional LED drivers can no longer ensure slim design. In addition, temperature rise in a small space is also a serious constraint for traditional inefficient drivers. Therefore, the application of high-frequency and high-efficiency GaN technology in LED driver power supplies to reduce size and heat has become a preferred choice for high-end lighting.

Chongdiantou.com has got a 200W drive power supply design. This power supply is an ultra-thin design, with three built-in GaN transistors on an APFC+LLC architecture, which is efficient and thin, and meet stringent requirements of small spaces.

The input end of the Innoscience LED driver uses a two-stage common-mode inductor with a bridge rectifier welded to a small vertical board. The PFC booster inductor is a flat design with a filter capacitor in the middle. It has an input voltage of 180-264V, an output voltage of 48V, a output current of 4.2A, a power of 200W.

The output end adopts filters with multiple parallel electrolytic capacitors. The LLC transformer uses a planar transformer, which is equipped with a primary induction coil filter.

The PFC boost inductor, resonant inductor and transformer are placed in PCB via holes, which reduces product thickness. Power devices are welded, which ensures high space utilization.

The front of the PCB contains filter capacitors, transformers, and other components, with a complete input filter circuit structure.

The length of the PCB is about 196mm when measured with a vernier caliper.

The width is about 35.2mm.

The thickness is about 11.7mm, a very slim design for a power supply. The calculated power density is about 2.5W/CC.

The thickness of this LED power supply is only half the diameter of a 1 RMB coin.

Thickness comparison with iPhone 12 Pro Max.

Let's start with the input end. The PFC boost controller is ON Semiconductor NCL2801, a current-mode boost power factor controller with critical conduction mode that supports 200W of power. The valley count frequency foldback is used to obtain high energy efficiency and low standby power consumption.

Detailed information of the ON Semiconductor NCL2801.

The PFC transistor is the Innoscience INN650D01, a GaN transistor with 650V of withstand voltage, 750V of transient withstand voltage, and 130mΩ of conduction resistance. The use of GaN transistor in PFC can reduce switching losses and minimizes conduction losses.

Detailed information of the Innoscience INN650D01.

The PFC boost rectifier is on the front side of the board and uses the Repower BYV25FD-600, an enhanced ultra-fast power diode with 600V of withstand voltage and 5A of rated current.

The LLC controller is ON Semiconductor’s NCP13992, a high-performance current-mode controller for half-bridge resonant converters. This controller has a built-in 600V gate driver, which simplifies the layout and reduces the number of external components. In applications requiring a PFC pre-amplifier, the NCP13992 can output a drive signal to control the PFC controller.

Detailed information of the ON Semiconductor NCP13992.

Two Innoscience INN650D02s form a half bridge for LLC soft resonant switching. The INN650D02 is a GaN transistor with 650V of withstand voltage, 750V of transient withstand voltage, and 200mΩ of conduction resistance. The use of GaN transistors can further reduce the switching losses of the LLC topology.

Detailed information of the Innoscience INN650D02.

Due to the high-frequency LLC and the high energy efficiency requirements, this power supply uses the output uses synchronous rectifiers instead of Schottky diodes to improve efficiency and reduce heat generation. The synchronous rectifier controller is the NCP4306 for LLC synchronous rectification control.

Detailed information of the ON Semiconductor NCP4306.

The synchronous rectifier uses Infineon’s BSC093N15NS with 150V of withstanding voltage, 9.3mΩ of conduction resistance, and 15mΩ of output current sample resistance on the right.

Detailed information of the Infineon BSC093N15NS.  

Another Infineon BSC093N15NS synchronous rectifier.

The output voltage is fed back to the NCP13992 pre-amp LLC controller via an optocoupler.

One of the Y capacitors in the power supply uses the TRX chip Y capacitor, which has an obvious height advantage over the traditional plug-in Y capacitors. 

There are two more TRX chip Y capacitors at the input end of the power supply.

The output constant current control uses the ON Semiconductor NCP4328B for constant voltage and constant current control to provide constant current output for the LED power supply.

Detailed information of the ON Semiconductor NCP4328B.

It is worth mentioning that both the pre-amp filter capacitors and output filter capacitors of this LED driver power supply use the Ymin electrolytic capacitors. The small-sized KCX series fast charging capacitors, which are frequently used in GaN chargers, are used as the pre-amp high-voltage capacitors in this power supply since small size can ensure a high-density design.

The output filter capacitor is Ymin’s LKM series capacitor with long life, high frequency, and low impedance, and has 105℃ 7000-10000 hours guarantee. Ymin capacitors have a proven record in the market. The product quality is stable, which is perfect for LED power supplies requiring high reliability.

Summary

At present, as LED lighting is becoming increasingly popular, the disadvantages of the traditional power supply are looming large. The large size and temperature rise now fail to respond to the higher requirements of high-end lighting designs. Considering the limitations of the existing LED driver power supply, Innoscience has launched a new high-power and small-size GaN LED driver power supply by using GaN devices.

The power supply adopts high-voltage GaN transistors for PFC and LLC switching power supply. The small size and ultra-thin package effectively reduce the thickness of the power supply and facilitate cooling, which ensures a high-density and high-efficiency LED driver design. Innoscience’s GaN transistors are easy to drive and can work with various controllers for different application scenarios.

The use of GaN in a large number of LED drivers has brought the GaN technology’s advantages of small size and high efficiency to LED lighting. The use of GaN in high-power LED power supplies can reduce power loss and the need for cooling, making the already energy-efficient LED lighting greener.

The link: https://www.chongdiantou.com/archives/89971.html