At present, most of the adapter applications in the consumer market adopt the topology scheme of SSR architecture (secondary side regulator), while most of the applications using PSR topology architecture (primary side regulator) have a power less than 18W power supply products. The new generation of flyback power products of Tongjia technology are introduced into PSR topology architecture, integrated with high-efficiency MOSFET, combined with Tongjia technology synchronous rectifier chip and integrated with powermos, which greatly simplifies the design and reduces the number of components on PCB board that originally needed SSR topology architecture. PSR topology architecture is adopted and the output power is increased to 24W. With many years of experience in power IC design, Tongjia technology has developed many corresponding products and put forward a low-cost and highly integrated power supply scheme. Figure (I)

Figure 1: design scheme of high integrated adapter power supply

The new generation PSR topology architecture ld9175k of Tongjia technology integrates high-efficiency MOSFET and has excellent mixed mode technology (QR + CCM). Compared with similar PSR power products, the average efficiency can be 1 ~ 2% higher. At the same time, a smaller transformer can be selected for the same power; In addition, with the line compensation function, the output DC line number can be reduced; The low-voltage frequency rise mechanism is adopted. In design, high-voltage capacitors with lower capacitance and lower output capacitance can be used. It still has better performance in output ripple than general PSR products, which has an obvious effect on the bomcost saving of customers. Low standby power consumption; Increased frequency switching range and better EMI performance; Support BNI / BNO function; Complete logic protection and high reliability. Dip-8 package replaces the design of SOT26 + TO-252, so that the design space on the PCB can be greatly reduced, which is conducive to reducing the design product shell, improving the automatic production efficiency, and indirectly reducing the overall cost of the product.

Figure 2: acdcpwmcontrollerdip-8ld9175k

The secondary side synchronous rectifier chip ld8926a82 adopts self powered design, which does not need to add additional auxiliary winding to provide external power supply and save cost. It also supports high / lowside applications. You can select appropriate high / lowside applications to get the best EMI effect. Support CCM and DCM operation modes, low working current (ivcc 200) μ A) , quick shutdown, the whole delay is 30ns. The same sop-8 miniaturization package is adopted.

Figure 3: secondary side synchronous rectifier icsop-8ld8926a82

The 24W consumer adapter adopts one of the integrated MOSFET schemes, the primary side control chip and the secondary side synchronous rectifier chip. In addition, Tongjia technology’s new generation of primary edge control technology and simple design make the number of parts in the whole scheme less than 40 components, simplify PCB design and reduce the production cost of printed parts of PCB. Figure 4 shows its application reference circuit and table 1 application design specifications.

Figure 4: ld9175k + ld8926a82 application reference circuit diagram

Table 1: 12V / 2a24w application specifications

In recent years, the price of passive components fluctuates greatly, the demand for PWM controller and synchronous rectifier IC integrating MOSFET scheme is increasing, and PSR multi-mode PWM controller is also widely used to greatly simplify the design and reduce the components on PCB to achieve the highest cost performance. Tongjia technology has launched a new generation of products, including PWM controller and synchronous rectifier, and a complete set of cost-effective solutions to meet the requirements of the European Union (coctier2) and the U.S. Energy Administration (doelevelvi) for efficiency improvement. The above introduction is expected to help readers, accelerate the development speed of manufacturers who intend to invest in PSR topology architecture of consumer adapters, and obtain advantages in volume and cost.

Editing: hfy

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