Analysis And Design Of Temperature Characteristics In AC-DC Power Management Chip And Systems

Pollution problem is getting worse; the majority of cities across the country shrouded in haze; the background of the efficient of using energy proposes new challenges. In the course of the power of technological development, linear regulator is the first appearance of technology. Linear regulator whose fatal weakness is inefficient and it does not meet modern requirements for high energy efficiency, hence the Switching Power Supplies technology is invented. Switching Power Supplies technology has been applied in many fields, such as consumer electronics, industrial control and aerospace. After reading a lot of literature, it summarize the future development trend of Switching Power Supplies technology which is a high efficiency, low power consumption, small size, high frequency, high reliability, digital, low noise and highly suppress EMI. Improving energy efficiency by Modern Switching Power Supplies technology is obvious.In this paper, it designs a switching power supply control chip which has the character of relatively high efficiency in heavy load and light load. This chip has very complex control operating modes. It combined with three modulation modes, PWM, PFM, PSM, which minimize the losses of Power MOSFET, including dynamic and static losses, and improve power efficiency. In order to improve the stability of the circuit and reduce costs,using TSMC analog, digital, VDMOS mixed BCD process, a high voltage about 700 V Power MOSFET integrated in the control chip. Chip also designed a variety of protection circuits, including undervoltage protection, overvoltage protection and temperature protection.The main work of this paper is to analyze the temperature characteristics of the reference voltage source, the reference current source and the chip externally programmable current limit, and to design the specific circuit of module. The reference voltage source and current source provide reference voltage and reference current for all the others modules of the entire chip, so requirements of designing the reference circuit is especially stringent, which require a reference voltage source, a current source that independent on the process parameters and temperature. Therefore, before to design a low temperature coefficient of the reference, firstly it must be analyzed characteristics of processes, devices, and then the circuits can be meet to the design requirements. The function of Programmable current limit module is limiting the current of Power MOSFET, which preventing damage Power MOSFET because of excessive current. Power MOSFET is device which product the major quantity of heat on the entire chip and has relatively large difference of temperature. In the design of programmable current limiting circuit module, especially considering the temperature, and designing a circuit is not sensitive to temperature. After completing the design of circuit, this paper also does some work about layout, which detailedly analysis the problems of layout that need to attention. Finally, verify the chip by a Fly-back Forward Converters Switching Power Supplies circuit which was simulated and tested. By analyzing the test results of the chip, the main function of the chip is implemented, and the basic parameters meet to the design expectations. Summary this chip also has a problem, that is, the chip would be damaged when the line voltage is high, and the problem will be resolved in the next version of the circuit.