This part is a kind of semiconductor called RM6203.

Function of this product has High Performance Current Mode PWM Switching Power Supply Controller.

Manufacturers : Reactor

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Some of the text within the PDF file :

RM6203 High Performance Current Mode PWM Switching Power Supply controller DESCRIPTION The RM6203 is a current mode PWM switching power supply controller that specifically designed for AC/DC converter with high performance versus cost ratio. It provides continuous output power up to 12W in the broad voltage range of 85V – 265V.Its optimized and highly reasonable circuit design has made it possible to minimize the total cost of the product. This power supply controller could be used in typical flyback circuit topology to constitute simple AC/DC converter. The internal initiating circuit of RM6203 has been designed with a unique means of current sink to complete the startup using the amplifying function of the power switching tube. This will significantly reduce the p [ ... ]

RM6203 PDF Datasheet Download