應用於車用電子之電力線通訊收發器設計

Abstract

近年來車用電子(automotive electronics)越來越受到重視，許多研究或產品多著重在多媒體以及娛樂等的發展。因此，在汽車自動化的程度越來越高以及車內電子控制單元也越來越多的情況下，在接線上也就越來越複雜，所以我們將焦點轉移到車內元件彼此之間的資料傳輸。我們將電力線通信(power line communication)與車用電子結合在一起，每個裝置都會需要一條線連到車上的電源，這個是沒辦法省略的，所以要是我們可以同時在電源線上面供給電源又同時傳輸資料的話，便可使接線簡單化，既可降低複雜度又能省成本。我們利用電源線當作傳輸訊號的通道，為了達到抗拒外界雜訊的干擾，我們利用了直接序列展頻技術(direct sequence spread spectrum)來對資料做編碼，使得訊噪比可以提升。我們也設計了一個應用於此技術的收發器，在資料與時脈恢復器上，將相位選擇與應用在DSSS的傳統架構結合在一起。我們也設計了一個具有封包的32位元的串列解串器，使得我們只需要一條電源線就可達到資料的傳輸。整體系統包含了傳送端、接收端、耦合電路、電源線以及後端的控制電路，控制電路負責的是接收到資料後產生訊號來控制LED、馬達以及降壓電路的亮度、閃爍頻率、閃爍的亮度、轉速以及輸出電壓。我們利用FPGA來實現TX、RX以及後端的控制電路，然後將PowerMOS、LED、馬達、降壓電路、開關等利用印刷電路板來整合，展示了資料傳輸及控制元件的能力，證明了此電路設計是能夠被實現出來且非常實際的，以及將電力線通信用在車用電子上的想法是可行的。

In recent years, the importance and diversity of the automotive electronics has attracted more and more attention. Most of the applications are centered on the multimedia or entertainment. Here we focus on the data communication between the electronic devices on the car. We apply the power line communication to the automotive electronics. DC 12V power line of the car is used as the transmission media. We use direct sequence spread spectrum (DSSS) modulation to the data signal in order to resist the noise interference. We design a clock and data recovery (CDR) circuit which combines the phase picking for clock recovery and byte synchronization for data recovery. We realize a transceiver with DSSS and a 32-bit SERDES. The whole system includes a transmitter, a receiver, a coupling circuit and a control circuit. A delta-sigma digital pulse width modulator (ΔΣ-DPWM) driver is implemented for the power driving. The control circuit adjusts PWM for on-time duty and frequency control of the LEDs, controls the rotation speed of the motors and the output voltage of DC-DC converter. We use FPGA to realize the transmitter and receiver which includes the control circuit. We put PowerMOS, LED, motor, buck converter, switches and coupling circuits on the printed circuit boards. Finally, we demonstrate the data transmission and controlling of the devices. We prove the idea of power line communication for automotive electronics is feasible.