| With the rapid development of power electronic technology,electronic devices have shown great application potential in more and more fields.Power supply performance is an important factor to determine the quality of electronic equipment.As the core component of power supply,DC-DC converter needs to have the characteristics of wide application range,high efficiency and long service life to make it stand out from the market.Therefore,designing a high stability buck DC-DC of dual output converter has important market value and research significance.Taking BUCK converter as the research object,its topology,working principle and working mode are analyzed in detail,and the overall structure of buck DC-DC converter chip is determined.With two PWM channels integrated inside and power MOS transistor built in,the dual output of chip voltage can be realized by simple peripheral circuit,which expands the application range of the converter.The used peak current control mode improves the transient response speed and conversion efficiency of the converter chip.For the problem of open loop instability when the duty cycle is greater than 50%in the current loop CCM mode,the method of increasing slope compensation is used to improve chip stability.On this basis,the main circuit modules such as the reference voltage source,oscillator,error amplifier and LDO inside the converter chip is designed.At the same time,in order to improve the reliability of the working circuit,a variety of protection modules such as over-temperature protection circuit and under-voltage latch circuit are integrated in the converter chip.The Hspice software was used to simulate and verify each designed module circuit.Based on the Cadence platform,a simulation model of converter chip application circuit is built,and the simulation results show that the chip meets the design index requirements.Finally,Nuvoton’s 0.35μm 80V BCD process is used for chip layout design,and the feasibility of layout design is verified through DRC and LVS. |
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