高精度可调限流配电芯片研究与设计
发布时间：2018-07-22 17:28
【摘要】：随着以手机、平板电脑为代表的便携式电子产品的快速发展,以及对绿色能源技术的迫切需求,电源管理系统逐渐向集成化、模块化、智能化发展。限流配电芯片作为电源管理芯片的一员,是实现多元化电源控制的重要组成部分。其主要功能是实现功率控制,对限流精度及配电效率均有较高要求。而受限于大电流检测精度,目前限流配电芯片限流阈值漂移通常在15%以上。本论文通过分析传统配电芯片架构,结合项目需求,开发一款高精度可调限流配电芯片。该芯片通过电荷泵产生高压驱动N型功率管,以提升导电效率。设计高精度电流检测电路,采用高响应速度电路结构,并利用增益自举技术提升电流检测精度。同时结合温度系数补偿技术,以抑制限流阈值随温度及负载的漂移。设计高压误差放大器,构成限流调节环路,实现恒流限流。同时利用误差放大器可控的输出摆率,实现“软启动”功能,防止功率管过快开启产生涌浪电流。利用斩波技术,设计带失调校正功能带隙基准源,有效抑制了由运放失调引起的基准电压偏移。芯片可通过外接电阻设置两个独立限流阈值,并可通过限流阈值选择端ILIM_SEL,在芯片工作过程中对限流阈值进行切换,从而便于处理器对供电模式进行控制。另外,芯片还具有完整的过温保护、欠压锁定、过流保护及异常状态显示功能。采用0.25μm BCD工艺进行芯片设计实现。芯片具有高限流精度,限流阈值随温度及负载漂移仅为8.7%。外接电阻调节限流阈值范围由500 mA到2.5 A。导通2 A电流时芯片导通电阻仅为61.5 mΩ,配电效率达97.1%。通过斩波失调校正,蒙特卡罗仿真下芯片基准电压3σ偏差范围约为±7.5 mV。芯片具有双重过温保护机制:当芯片处于限流模式,过温阈值为135℃,非限流模式下过温阈值为155℃,过温解除迟滞温度20℃。芯片输入电源低于4.05 V时进入欠压锁定状态,锁定解除电压4.15 V。快速过流保护响应时间为1.6μs。
[Abstract]:With the rapid development of portable electronic products represented by mobile phones and tablets, as well as the urgent need for green energy technology, power management systems are gradually becoming integrated, modular and intelligent. As a member of power management chip, current-limiting distribution chip is an important part of multiple power supply control. Its main function is to realize power control, which requires high current limiting precision and distribution efficiency. At present, the current limiting threshold drift of current limiting distribution chip is above 15%, which is limited by high current detection precision. Based on the analysis of traditional distribution chip architecture and project requirements, a high precision adjustable current limiting distribution chip is developed in this paper. The chip generates a high-voltage drive N-type power tube through a charge pump to enhance conductivity. The high precision current detection circuit is designed. The structure of high response speed circuit is adopted, and the gain bootstrap technique is used to improve the accuracy of current detection. At the same time, the temperature coefficient compensation technique is used to restrain the drift of current limiting threshold with temperature and load. A high voltage error amplifier is designed to form a current limiting loop to realize constant current limiting. At the same time, the output swing rate controlled by the error amplifier is used to realize the function of "soft start" and to prevent the surge current generated by the excessive opening of the power transistor. A band gap reference source for band offset correction is designed by using chopper technique, which effectively restrains the reference voltage offset caused by the operational amplifier offset. The chip can set two independent current limiting threshold by external resistor, and can switch the current limiting threshold in the working process of the chip through the current limiting threshold selector ILIMSEL, which is convenient for the processor to control the power supply mode. In addition, the chip also has complete over-temperature protection, under-voltage locking, over-current protection and abnormal state display functions. The chip is designed and implemented by 0.25 渭 m BCD process. The chip has high current limiting precision and current limiting threshold is only 8.7 with temperature and load drift. The current limiting threshold ranges from 500 Ma to 2.5 A. When the current is 2 A, the on-resistance of the chip is only 61.5 m 惟, and the distribution efficiency is 97.1m 惟. By chopping offset correction, the bias range of the reference voltage 3 蟽 is about 卤7.5 MV under Monte Carlo simulation. The chip has a double over-temperature protection mechanism: when the chip is in current limiting mode, the threshold of overtemperature is 135 鈩，
本文编号：2138214
[Abstract]:With the rapid development of portable electronic products represented by mobile phones and tablets, as well as the urgent need for green energy technology, power management systems are gradually becoming integrated, modular and intelligent. As a member of power management chip, current-limiting distribution chip is an important part of multiple power supply control. Its main function is to realize power control, which requires high current limiting precision and distribution efficiency. At present, the current limiting threshold drift of current limiting distribution chip is above 15%, which is limited by high current detection precision. Based on the analysis of traditional distribution chip architecture and project requirements, a high precision adjustable current limiting distribution chip is developed in this paper. The chip generates a high-voltage drive N-type power tube through a charge pump to enhance conductivity. The high precision current detection circuit is designed. The structure of high response speed circuit is adopted, and the gain bootstrap technique is used to improve the accuracy of current detection. At the same time, the temperature coefficient compensation technique is used to restrain the drift of current limiting threshold with temperature and load. A high voltage error amplifier is designed to form a current limiting loop to realize constant current limiting. At the same time, the output swing rate controlled by the error amplifier is used to realize the function of "soft start" and to prevent the surge current generated by the excessive opening of the power transistor. A band gap reference source for band offset correction is designed by using chopper technique, which effectively restrains the reference voltage offset caused by the operational amplifier offset. The chip can set two independent current limiting threshold by external resistor, and can switch the current limiting threshold in the working process of the chip through the current limiting threshold selector ILIMSEL, which is convenient for the processor to control the power supply mode. In addition, the chip also has complete over-temperature protection, under-voltage locking, over-current protection and abnormal state display functions. The chip is designed and implemented by 0.25 渭 m BCD process. The chip has high current limiting precision and current limiting threshold is only 8.7 with temperature and load drift. The current limiting threshold ranges from 500 Ma to 2.5 A. When the current is 2 A, the on-resistance of the chip is only 61.5 m 惟, and the distribution efficiency is 97.1m 惟. By chopping offset correction, the bias range of the reference voltage 3 蟽 is about 卤7.5 MV under Monte Carlo simulation. The chip has a double over-temperature protection mechanism: when the chip is in current limiting mode, the threshold of overtemperature is 135 鈩，
本文编号：2138214
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