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新型PD协议芯片BMC解码电路的设计与验证
2021年电子技术应用第11期
张万荣,王飞虎
北京工业大学 信息学部,北京100000
摘要: 提出了一种新型PD协议芯片BMC解码电路。在传统BMC解码电路的基础上,首先,将计数器从解码模块中分离出来并在解码模块内新增状态机,通过改变状态机的跳转条件实现了对单比特周期突变25%的BMC信号的解码;然后,新增的FIR滤波器使得Threshold值随Cnt值线性变化,实现了对周期多次连续变化的BMC信号成功解码;最后,利用Synopsys公司的Verilog Compiled Simulator进行仿真验证,证明了新方案可以对周期相差25%的相邻两位BMC信号解码,可以对周期以6.25%增加的连续十位进行解码。
中图分类号: TN91
文献标识码: A
DOI:10.16157/j.issn.0258-7998.211493
中文引用格式: 张万荣,王飞虎. 新型PD协议芯片BMC解码电路的设计与验证[J].电子技术应用,2021,47(11):29-32,38.
英文引用格式: Zhang Wanrong,Wang Feihu. Design and verification of BMC decoding circuit for new PD protocol chip[J]. Application of Electronic Technique,2021,47(11):29-32,38.
Design and verification of BMC decoding circuit for new PD protocol chip
Zhang Wanrong,Wang Feihu
Faculty of Information Technology,Beijing University of Technology,Beijing 100000,China
Abstract: This paper presents a new type of biphase mark coding(BMC) decoding circuit for PD protocol chip. Based on the traditional BMC decoding circuit, firstly, the counter is separated from the decoding module, and a state machine is added in the decoding module. By changing the jump condition of the state machine, the BMC signal with single bit period mutation of 25% is decoded. Then, a finite impulse response(FIR)filter is added to make the threshold value change linearly with the value of Cnt, so that the BMC signal with multiple continuous cycles can be decoded. Finally, the Verilog Compiled Simulator of Synopsys company is used for simulation verification, which proves that the new scheme can decode two adjacent BMC signals with a period difference of 25%, and decode ten consecutive BMC signals with a period increase of 6.25%.
Key words : BMC decoding;USB PD protocol;FIR;fast charging protocol chip

0 引言

    近年来,随着移动设备快速充电功率的不断提高,USB标准化组织(Universal Serial Bus Implementers Forum,USB-IF)制定了基于BMC编码的USB功率传输(Universal Serial Bus Power Deliver,USB PD)3.0协议,该协议相比于Qualcomm公司的快速充电(Quick Charge,QC)协议、Samsung公司的自适应快速充电(Adaptive Fast Charge,AFC)协议等快充协议具有只占用一根通信线,协议内容可拓展性强等优点,已成为应用最广的快充协议[1-3]BMC解码模块是USB PD 3.0协议芯片的核心模块[4-6]。随着手机快充功率突破120 W,峰值电流可达到6.25 A,电流大范围变化带来的地电位漂移现象愈发严重,地电位漂移导致BMC信号在传输过程中周期多次连续变化使得BMC信号周期累计变化范围可达3.3 μs的±30%[7];随着USB线中数据传输速率提高到20 Gb/s使,USB线包内的电磁环境更加恶劣,从而使得BMC信号在传输过程中受到大量高频噪声干扰而导致周期单次大幅度突变[8]。为解决上述问题,近年来人们提出了一些对BMC解码模块优化的方案,文献[9]提出了一种解码电路能够成功解码周期在3.3 μs±25%范围内变化的BMC信号,但是当BMC信号周期累计变化到±30%时不能成功解码,而是通过错误反馈机制强制USB PD 3.0协议芯片回到初始状态。




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作者信息:

张万荣,王飞虎

(北京工业大学 信息学部,北京100000)




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