用于车载以太网物理层芯片的降压电路  

Buck Circuit for the Automotive Ethernet Physical Layer Chip

作　　者：赵杰友 李海华[1] Zhao Jieyou;Li Haihua(School of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学电子信息与电气工程学院

出　　处：《半导体技术》2019年第12期921-924,931,共5页Semiconductor Technology

摘　　要：为了给车载以太网物理层芯片内部的数字电路提供稳定的电源,设计了一种3.3 V转换到1.2 V±25 mV的DC-DC降压(Buck)电路。电路采用恒定导通时间控制模式,包括片内集成的软启动电路、定时器、过零检测电路和死区时间控制电路。该Buck电路基于SMIC 0.13μm CMOS工艺实现,并已集成到物理层芯片内部。测试结果表明,电路能够实现3.3 V转换到1.2 V±25 mV的功能;带载电流为100.9 mA,转换效率达到91%;定时器产生的恒定导通时间为410 ns;启动过程中输出电压变化较为平稳,没有过冲,最后稳定在1.194 V±25.25 mV,启动时间为250μs。In order to provide a stable power supply for digital circuits inside automotive Ethernet physical layer chips,a DC-DC Buck circuit which converts a voltage from 3.3 V to 1.2 V±25 mV was designed.The constant on-time control mode was adopted.The circuit includs the on-chip integrated soft-startup circuit,timer,zero-crossing detection circuit and dead-time control circuit.The Buck circuit was realized based on the SMIC 0.13μm CMOS process and was integrated into the physical layer chip.The test results show that the circuit can achieve the function of the voltage conversion from 3.3 V to 1.2 V±25 mV,the load current is 100.9 mA,the conversion efficiency reaches 91%,and the constant on-time generated by the timer is 410 ns.The output voltage changes smoothly without overshoot during the startup process and finally stabilizes at 1.194 V±25.25 mV and the startup time is 250μs.

关 键 词：物理层 开关稳压器 降压(Buck)电路 恒定导通时间控制 软启动电路 

分 类 号：TN432[电子电信—微电子学与固体电子学]