針對傳統驅動電路一旦做出修改,則需對硬件或程序進行改變的缺點,以型號為TCD1707D的線陣CCD為例,介紹了一種工作模式可調的驅動方法.該方法是利用復雜可編程邏輯器件和控制外端結合,通過分別設置內外觸發來實現的.在外觸發模式下,利用外觸發脈沖,可由用戶控制CCD的曝光和信號輸出時間|內觸發時,可以調節CCD的積分時間和驅動頻率.為提高信號輸出質量,針對EMC問題給出了線陣CCD的外圍驅動電路.實驗結果表明,該方法調試方便、電路結構簡單、集成度較高、輸出信號可靠穩定、受干擾小,可配合多種用戶需要,對高速精確測量及線陣推掃模式具有一定參考價值.
Design of Linear CCD Driving Circuit with Flexible Working Modes Based on the CPLD
?TAN Lu-wen,LI Jing-zhen,LU Xiao-wei,YANG Fan?
?Abstract:
A driving circuit design of TCD1707D was presented.It could overcome the shortcoming of common circuit which is needed to change the hardware or programme in case the condition has been modified.This design shows two flexible working modes,one is internal burst mode,the other is external burst mode.In the external burst mode,the users can control the time of exposure and signal outputs by means of external triggered pulse.Integration time and driving frequency of CCD can be tuned simultaneously in the other mode.The function is carried out by setting internal and external triggered respectively with complex programmable logic device (CPLD) and an external control.CPLD is combined with the control circuit,so external commands can produce corresponding control signals to drive curcuit nomally.And then through the pins of CPLD,the output signals can be transfered to the CCD chip.In addition,in order to solve the EMC problem,the article presents a linear CCD periphery circuit,which is improved the quality of CCD signal outputs.This method has the advantages of convenient debugging,simple circuit and high integration level.It is proved by experiments that the system outputs basically match the simulation,and the signal outputs are more reliable,more stable and less interferential than common system.And the system could fulfill a wide range of users’ needs,especially can be used for accurate high-speed measurement and push-broom.