A Computer Atx Half-bridge Switching Power Supply Design And Realization

The purpose of this paper is to analyze and design a desktop PC half-bridge converter.Nowadays, with the fast development of computer technology, the power consumption of computer has increased rapidly. Therefore the high efficiency computer power supply is presented continually.The half-bridge controller chip is a key of entire PC power supply, and the design of efficient controller IC is a major challenge. This controller chip is designed to provide all the functions necessary to monitor and control the output of half-bridge power supply. Remote ON/OFF control power good circuitry, some protections feature against over-voltage, under-voltage and over-power are implemented. An innovated AC signal sampling circuitry provides a function of ant-lockout during line voltage disturbances. Two internal precision shunt regulators TL431 provide stable reference voltage and driver for 3.3V and 5V-standby regulations.In this thesis, the basic theory of desktop PC ATX power supply is introduced firstly. And then the main categories of AC/DC topology, Forward, Flyback, Push-Pull, Half-Bridge, Full-Bridge, are presented and compared. It is shown that the half-bridge topology exhibit higher efficiencies than other topologies at the expense of increased circuit complexity and cost. In chapter three, an application ATX power supply circuitry based on designed controller IC is analyzed in detail.In the main part of this paper, dominating sub-circuits in half-bridge controller IC are designed and simulated. Such sub-circuits include ULVO, voltage reference, current bias, oscillator, soft start, error amplifier, output driver, TL431, UVAC, OPP, ant-lockout. In meantime, the result of simulations of those sub-circuits satisfies the function requirement. At last, the process technology and layout verification are introduced roughly.The half-bridge controller chip is taped out at SINOMOS 1μm BiCMOS process. If the test of taped out chip can meet the function specification, this chip is coming to be commercialized.