4-to-1 Transimpedance combining amplifier-based static unitary detector for high-resolution of LADAR sensor

Switched 4-to-1 Transimpedance Combining Amplifier for Receiver Front-End Circuit of Static Unitary Detector-Based LADAR System

“…To analyze the effect of the noise introduced by partitioned photosensitive cells and the TCA, the simplified circuit is illustrated in Figure 8 with noise factors [15]. The equivalent total input referred noise of the TCA is approximately given by (2):…”

“…Therefore, the electrical length of the interconnection lines between each photosensitive cell and the corresponding TIA should be designed equal on the test fixture. This limits the number of cells for higher-resolution 3D images over a large ROI due to the interconnection problem between a partitioned photodetector and multiple TIAs [14,15]. To resolve this problem, a 4-to-1 transimpedance combining amplifier (TCA) was proposed in our previous work [14] as the front-end readout integrated circuit (ROIC) for the STUD-based LADAR receiver with a photodetector, which has four photosensitive partitioned cells.…”

High Spatial Resolution Three-Dimensional Imaging Static Unitary Detector-Based Laser Detection and Ranging Sensor

“…A LADAR sensor has difficulty processing all reflected TOF signals for the region of interest (ROI) in every direction when obtaining 3-D imaging information in real-time. To resolve this, many solutions such as the rotational motor (RM)-based method [6], focal-plane-array (FPA) of the photodetectors-based method [7], and the static unitary detector (STUD)-based method [8,9] have been proposed. As both RM-based and FPA-based methods have a structural limitation to increase 3-D resolution, the STUD-based method has been developed to obtain high spatial resolution 3-D images with many advantages.…”

“…However, as the increase in the photodetector area decreases its bandwidth due to an increased parasitic capacitance (CPD), this causes a large timing error (i.e., walk error [10,11]). In order to effectively increase the photodetector area with no harm to its bandwidth, the partitioning photosensitive cell (PPC) method has been proposed in earlier studies [8,9], as shown in Figure 2. In order to independently amplify the received signal, each partitioned cell has its own transimpedance amplifier (TIA), and a signal combiner sums the outputs from all TIAs.…”

“…It has theoretically no limitation in increasing the number of cells, and a high-resolution 3-D image acquisition is possible on a large ROI even with a short laser pulse. However, previous works [9] focused only on implementing the proposed PPC method embedded in a STUD-based LADAR sensor with a fully integrated four-input-combining receiver, which did not consider the high spatial resolution of 3-D imaging. Although a bandwidth limitation caused by a large CPD could be solved by applying the PPC method, the unexpected performance degradation could be caused by the pattern of multiple partitioning and signal combining as the number of partitioning photosensitive cells increases.…”