Abstract: A time delay integration circuit in which a number of unit cell inputs (101, 103, 105, 107) along with their respective switches (170, 171, 172, 173) are input to a bi-directional BBD circuit (110). The BBD circuit performs an SCA TDI with reduced ROIC circuitry and compatibility with standard LSI processing. The bi-directional BBD circuit has numerous pairs of MOSFETs (111, 112; 113, 114; 115, 116; 117, 118; 119, 120; 121, 122; 123, 124; 125, 126; 127, 128; 129, 130; 131, 132; 133, 134; 135, 136; 137, 138; 139, 140; 141, 142) connected in series and numerous storage capacitors (151, 152,153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166) having one of their terminals respectively connected between each of the MOSFET pairs and the other of their terminals alternately connected to clock phases Ø1 and Ø2.