智能手机屏幕偏置电源芯片设计

发布时间：2018-01-24 11:26

本文关键词： 升压型开关电源峰值电流控 PWM/PSM混合调制模式高效率　出处：《西安电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：本论文设计了一款2.7V至5.5V的输入电压范围,可输出高达36V的电压,具有高效率,高集成度,快速响应的升压型开关电源转换芯片。这款芯片主要用于手持电子设备,给TFT-LCD/OLED屏幕提供偏置电压。论文通过分析升压型开关电源的拓扑结构的工作原理,然后根据芯片的功能要求以及参数指标,开始芯片的设计。介绍几种常见的工作模式、调制模式和控制模式;本论文设计的芯片采用峰值电流控制模式,并根据负载的不同,系统可以在PWM模式和PSM模式之间进行切换从而提高效率。论文中对关键的带隙基准、误差放大器、振荡器、电流采样、电流限制、欠压锁存、过温保护和软启动等模块进行了设计和仿真验证。最后进行了整体的仿真和验证。本论文设计的芯片主要成果有:1、具有1.25MHZ的开关频率,因此有着较小的封装以及更低的成本。高频使得应用的电感和电容的体积也较小,大大提高了市场竞争力。而且固定的频率使得芯片更加容易滤波,大大降低了噪声。通过使用低ESR的陶瓷电容可以使噪声降到毫伏级。2、转换效率高达93%,很好的改善供电效率,延长电池的使用时间。3、设计了一款精简的零温度系数电流的产生电路。零温度系数电流的引用,可以提高芯片的精度以及稳定性。精简的电路设计,使得芯片面积减小。4、电流限制高达1A,能够支持功率更大的负载。因此不仅仅可用于智能手机屏幕,在平板电脑的大屏幕也能够得到广泛应用。5、加入了欠压锁存、过温保护、软启动和误判避免电路等保护电路,提高了芯片的可靠性。6、输出电压的范围广,扩大了应用范围。此款芯片采用CSMC 0.8um BCD工艺,运用Cadence仿真工具进行系统仿真验证。从瞬态仿真,线性调整率,负载调整率,电源转换效率曲线等方面进行仿真验证,结果表明,本论文所设计的芯片完全满足设计指标。
[Abstract]:In this paper, a 2.7V to 5.5V input voltage range is designed, which can output up to 36V voltage, with high efficiency and high integration. Fast response boost switching power supply conversion chip. This chip is mainly used for handheld electronic devices. This paper analyzes the working principle of the topology of the boost switching power supply, and then according to the functional requirements of the chip and parameters. The design of the starting chip. Several common working modes, modulation modes and control modes are introduced. The chip designed in this paper adopts peak current control mode, and according to the different loads, the system can switch between PWM mode and PSM mode to improve efficiency. Error Amplifier, oscillator, current sampling, current limitation, undervoltage latch. The design and simulation of over-temperature protection and soft start are carried out. Finally, the overall simulation and verification are carried out. The main achievements of this paper are: 1: 1, with a switching frequency of 1.25 MHz. As a result, there are smaller packages and lower costs. High frequency makes the size of inductors and capacitors smaller, greatly improving the competitiveness of the market. And the fixed frequency makes the chip easier to filter. By using the ceramic capacitor with low ESR, the noise can be reduced to millivolt level. 2, and the conversion efficiency is as high as 933. The efficiency of power supply is improved, and the service time of battery is prolonged. 3. A simplified zero-temperature coefficient current generation circuit is designed. The use of zero-temperature coefficient current can improve the accuracy and stability of the chip. The current limit is as high as 1A and can support more power loads. So it's not just for smart phone screens, but also for tablet screens that are widely used, with under-voltage latches and over-temperature protection. The protection circuits such as soft start and misjudgment avoid circuits improve the reliability of the chip. 6, the output voltage range is wide, and the application range is expanded. The chip adopts CSMC 0.8um BCD technology. Cadence simulation tool is used to verify the system. The transient simulation, linear adjustment rate, load adjustment rate, power conversion efficiency curve and other aspects of simulation verification, the results show that. The chip designed in this paper completely meets the design specifications.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.53;TN402

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