With the rapid development of electronic technology and the increasing awareness of environmental protection, the requirements for size, efficiency, reliability, life and comfort of power supply products are getting higher and higher, and traditional switching power supply technology has been difficult to meet these requirements. . In the 70W-500W AC-DC power supply, the switching power supply efficiency using LLC resonant conversion technology is higher than that of the traditional topology switching power supply. Therefore, the LLC resonant conversion technology is more and more widely used in power supply products.

The figure below shows a typical half-bridge LLC resonant converter circuit:

figure 1

Its equivalent voltage transmission relationship is:

figure 2

Fr1 is the resonant frequency of the resonant cavity

x is the normalized value of the switching frequency relative to the resonant frequency

k is the ratio of the magnetizing inductance of the transformer to the resonant inductance

Zr is the characteristic impedance of the cavity

Re is the equivalent load AC impedance

Q is the quality factor

According to the voltage transfer relationship formula, the voltage transmission relationship curve under different variable conditions can be drawn:

image 3

Referring to the voltage transfer ratio curve of the above LLC resonant converter, it can be concluded that the LLC converter has the following characteristics:

1. When the converter design works in the blue region (ZVS-zero voltage switch), the primary converter of the LLC converter realizes zero voltage turn-on in the full load range, and the switching loss of the switch tube is reduced to almost zero. At the same time, the secondary side rectifier diode can achieve zero current switching, and there is almost no reverse recovery problem, thus reducing the loss and the impact on EMI.

2. With the pre-stage PFC circuit, the LLC converter can reliably stabilize the output voltage by adjusting the switching frequency over a wide load range. At the same time, the LLC converter can also rely on its voltage gain adjustment capability to provide longer hold times without increasing the input electrolytic capacitor capacity.

3. Since the LLC resonant converter can realize the soft switching of the switching components, the switching loss is low, and the conditions for increasing the switching frequency and reducing the volume of the magnetic device can be achieved, and the switching power supply can be miniaturized under the premise of maintaining high efficiency. High power density, keeping the components low temperature rise under the fanless heat dissipation design, thus ensuring the life and reliability of the power supply.

Figure 4

The above figure shows TDK-Lambda's new CUS350M series power supply based on LLC resonant conversion technology. The fanless natural cooling, 350W AC-DC medical power supply has a full load efficiency of up to 94.7%, compared with similar power supplies of the traditional topology. , about 5% improvement.

In addition, the CUS350M series achieves a 1U-height flat and compact design with a new technology, achieving a high power density of 8.7 watts/cubic inch under natural cooling conditions, leading the industry in its level of miniaturization. Suitable for more equipment installation requirements, natural cooling can reduce the erosion caused by dust accumulation, fanless noise to create a quiet and comfortable application experience for users.

LED Emergency Driver has been widely used in LED lamps , which can be used not only as an emergency when the power grid is off , but also as an energy saving use . The housing material of LED emergency power supply is divided into aluminum alloy housing , stainless steel housing and ABS housing . The Led Emergency Kit is suitable for LED lights of different powers to be used at AC85-265V wide voltage , and equipped with high quality rechargeable lithium ion battery . It has a wide range of applications such as home , commercial buildings , offices , hospitals , schools etc .

led emergency driver types



Led Emergency Driver

Emergency Devices,Led Emergency Kit,Led Emergency Driver,Emergency Backup Lights, LED Emergency Module

Jiangmen City Pengjiang District Qihui Lighting Electrical Appliances Co., Ltd , https://www.qihuilights.com