Product News


Application of Reactor Micro Y-free Capacitor Switching Power Supply Scheme in Power Adapters

Publisher:Reactor Microelectronics


Charging Head Network has obtained a power adapter launched by Shenzhen Ruide Electronic Industry Co., Ltd. This adapter supports a wide voltage input of 100-240V and outputs 12V2A, which looks like an adapter for optical modem or router. This adapter adopts a built-in cable design, with an output of 5.5mm DC round head and an output cable length of approximately 1.5 meters. Below is a disassembly of this adapter to take a look at its internal design and materials.

Appearance of Ruide 24W power adapter

The shell of the Ruide power adapter has an upper and lower splicing structure, and the surface is completely treated with frosting technology. The pin layout is parallel to the body to prevent occupying the slot position.

The adapter is equipped with fixed national standard pins and corresponding area shell protrusion design.

The bottom shell is also printed with product specifications.

Power adapter parameter close-up, model RD1202000-C55-154GB, supports 100-240V~50/60Hz 1A input and 12V2A output, produced by Shenzhen Ruide Electronic Industry Co., Ltd., and has passed CCC certification.

The connection between the output cable and the body has been designed with anti bending protection.

Close up of DC terminal, with convex teeth on the outer shell for easy insertion and removal.

The measured length of the Ruide 24W power adapter body is 79.83mm.

The height is 47.31mm.

The width is 35.25mm.

The length of the DC output cable is approximately 151cm.

The size of the power adapter body feels intuitive when held in hand.

Additionally, the total weight of the product was measured to be approximately 118g.

Disassembly of Ruide 24W power adapter

After seeing the exterior display of the Ruide adapter, let's dismantle it and take a look at the internal design and materials used.

Firstly, dismantle the shell along the seam, and connect the AC power supply to the PCBA module through wire welding.

The wire solder joints are reinforced with glue.

The internal PCBA module is fixed through internal buckles on the housing.

Extract the PCBA module from the inside of the housing.

The output wires are connected by welding.

Components such as common mode inductors and transformers are fixed with glue, and the primary power chip is equipped with heat dissipation fins.

The length of the PCBA module measured using a vernier caliper is approximately 73.1mm.

The width of the PCBA module is approximately 40.1mm.

The thickness of the PCBA module is approximately 24.9mm.

Clean up the glue filled between the components, view the front of the PCB module, and weld the input fuse, varistor, NTC thermistor, and safety X2 capacitor in the upper right corner. Weld the common mode inductor and high-voltage filtering capacitor in the lower right corner. Weld the primary control chip above the high-voltage filtering capacitor, weld the transformer on the left side, and output the filtering capacitor and filtering inductor. Welding feedback optocoupler above the transformer.

The back of the PCBA module is welded with a rectifier bridge and a synchronous rectifier chip. The adapter uses a fixed voltage output, and the output voltage is fed back by the optocoupler. Let's start by understanding the information of each device from the input end.

Input terminal soldered fuse, blue varistor, black NTC thermistor, safety X2 capacitor and common mode inductor.

The input fuse comes from Chengrun, with a specification of 3.15A 250V.

The varistor is from Zhimin, model HVR10D561, used for surge overvoltage protection.

The 5D-7 thermistor is used to suppress surge currents when the adapter is powered on.

The safety regulation X2 capacitor comes from Shenzhen Shanrui Electronics, with a specification of 0.22μF.

The common mode inductor is wound with an insulated skeleton.

Side welding transformer, input-output filtering capacitor, and two polyester capacitors.

The rectifier bridge model DB207S has a specification of 2A1000V.

The high-voltage filtering capacitor comes from Tiancheng Source.

Specification 47μF400V.

The power control chip is from Reactor Micro, model RM6515D. It is an offline switching power chip with built-in high-voltage MOSFETs that meet the six level energy efficiency requirements. The chip supports valley detection and has low startup current and working current. The chip supports multiple working modes, with burst mode in idle mode to improve conversion efficiency.

Enter QR working mode under light load, and enter fixed frequency CCM mode under low voltage and heavy load. The chip is equipped with external overvoltage protection, which can be adjusted through resistance and integrates multiple protection functions. RM6515D is equipped with a built-in 1.8 Ω resistive switching transistor, supporting 24W output power, and is packaged in DIP-7.

Information on the RM6515D data of Yacheng Micro.

Side welding of filtering capacitors, transformers, feedback optocouplers, and filtering inductors.

The specification of the filtering capacitor powered by the main control chip is 4.7μF50V.

The transformer is tightly wrapped with tape for insulation.

This power supply scheme reduces EMI interference in the system by optimizing the driver with built-in MOS transistors and special transformer design, enabling the power supply to achieve no Y capacitance. Non Y capacitors can reduce interference with telecommunications equipment such as optical cats and routers, and also eliminate the feeling of electric shock caused by leakage current flowing through the human body.

817C optocoupler is used for output voltage feedback.

The synchronous rectification chip comes from Xinpeng, model PN8308M. The chip integrates a synchronous rectification controller and MOS transistor, supporting CCM, DCM, and QR working modes. The chip is equipped with a 20m Ω 80V voltage resistant synchronous rectifier tube and is packaged in SOP-8.

Solder filter inductance and filter capacitor at the output end.

The output filtering capacitor specification is 1000μF 16V, two in parallel.

The output filtering inductor is wound with two wires and fixed with glue.

Two polyester capacitors are used for the absorption circuit.

Take a complete breakdown and take a family photo.

Summary of dismantling the charging head network

The adapter of Ruide Electronics has a black shell, fixed national standard pins, and comes with a 1.5 meter long output cable. The output specification of the adapter is 12V2A, which meets the needs of optical cats and routers. Through disassembly, it was found that this adapter adopts the Reactor Micro RM6515D highly integrated switch power supply scheme, with integrated switch tubes and multi-mode controllers inside the chip, reducing system EMI interference and achieving a Y-free capacitor design, bringing many benefits to the power supply. The output is synchronous rectification, using Tianchengyuan electrolytic capacitor filtering, combined with filtering inductance to reduce ripple. It is a highly integrated and cost optimized power adapter.