A Psm Control Flyback Ac / Dc Switching Power Supply Design

Power supply is an indispensable component of electronic equipments. With the rapid development of society, people have more requirements for power management chips, especially in efficiency and cost. Power switches in Switching Power Supply (SPS) only works on two states: on-state and off-state, having low switching losses, which can meet the requirements of low power consumption and high efficiency. Moreover, with high switching frequency, SPS can reduce its volume and cost. All kinds of advantages make SPS widely used in various fields.In this dissertation a self-bais, wide-range input voltage, PSM, isolated flyback AC/DC switching converter is designed. Its input voltage range is 85Vac-265Vac, its oscillator frequency is 132kHz with±8kHz frequency shakes, its output voltage is 5V and its output power is 10W. This converter integrates a 700V high-voltage power LDMOS, a 5.85V voltage regulator, an oscillator with frequency shakes, an current limit controller, an EN/UV circuit, an OVUVcircuit, an OTP circuit, an auto-restart circuit and a LEB circuit in a single chip, which can be widely used in charger or adapter for all kinds of handheld applicationsWith the EDA software Innoveda ePD and Hspice 2007, the whole circuit and three sub-block circuits: oscillator, voltage regulator and OVUV circuit were designed and analysised. With the two-dimensional numerical simulator Tsuprem4 and Medici, the 700V power LDMOS was designed and the relationship between device parameters and breakdown voltage and on-resistance was studied, which indicated that all experimental data could meet the design requirements. Layouts of the circuits and the power device were also designed by means of the software Cadence Virtuoso. Then, the whole chip was taped out on a 1μm 700V BCD process platform. Finally, tested data of the samples was analysised.