he dynamic range of camera is refered to the relative ratio between the brightest signal and darkest  signal the camera is able to present.In normal situation,we can use the following formula for calculating:dynamic range = 20 log (MAX singal/MIN singal) ,and there is a derivative fomula:dynamic range = 20 log (Well depth/Read noise) ,in this formula,well depth represents full well electron,which is the max power value a single pixel of CCD can recieve,reading noise represents reading noise(signified with electron number)which it's equal to the minimum efficient power value of a single CCD pixel. For the same rank CCD,the smaller noise reading,the bigger dynamic range.In normal case,to improve the dynamic range of CCD,we can change the eletronic circuit designing and decrease the CCD temperature to reduce the reading noise and therefore improve the dynamic range of the camera.
Please note:The noise will be produced in every CCD reading process and the smaller noise the better.However,it's a misunderstanding that the smaller reading noise the more sensitive of the CCD is,the reading noise have no direct connection with the sensitivity and have nothing to do with the bit of the camera.

For example:Well depth = 65,000 electron, read noise = 7 electon
Dynamic range = 20 log (685,000/7), or79dB.