Low Cost Compact Ac-dc Energy-saving Power Spring Control Ic Design

The usage of small power off-line AC-DC power supplies for adapter, battery charger and standby power source have been increased dramatically due to the growth in both cell phones and computers. There is a need to continuously develop a lower cost and more efficient small-power AC-DC power supply to benefit consumers and to reduce energy waste. In this paper, a very low cost, compact and energy saving control IC for small power off-line AC-DC power supply is presented. Over the years many highly integrated power semiconductor IC's with or without internal high-voltage transistor have been developed for low-power AC-DC supply by several power semiconductor companies such as Power Integration, ST, Fairchild, TI and ON Semiconductors to meet the energy saving requirement. These IC's also reduce component counts significantly due to their high integration of control function in a single IC chip. Even though most of these products have met the energy saving requirement, their cost is still much more expensive than the linear power supply or Ringing Choke Converter (RCC) especially in the output power less than 5W. In this article, a Very Low-Cost and Compact Control IC for Energy Saving AC-DC Standby Power Supply based on the EMITTER SWITCHING technology is designed., And discusses the architecture and the ways to realize it, and the results of TopSPICE simulation. Main circuit of chip is designed ,like BandGap voltage reference, UVLO (Under Voltage Lock Out),Current Bias, Driver, Oscillator, Error Comparator, PWM Current Mode Control and Logic cells. The layout of chip is done by other colleagues, This controller IC is taped out at CSMC 0.6um CMOS process and success at first time. To verify this controller IC, a related Li-ion battery charger low-power AC-DC supply is designed, which results prove that it fully meets the customer's requirements using this controller IC with EMITTER SWITCHING. This 3 pins PFWM IC discussed by this article is the unique analog chip for this architecture, driving external low cost high voltage NPN transistor, which can realize the AC/DC power supply. This IC and its architecture is special and new direction for the development of power supply, which is a new area and methods, and gets many big customer's recognition, verification and usage , which enters into mass production by the end of last year. The end user is like NEC, BIRD and HUAWEI.