3D point cloud processing plays an important role in many emerging applications such as autonomous driving, visual navigation, and virtual reality. It calls for hardware acceleration of multiple key operations, including 3D Submanifold SCONV, 3D non-Submanifold SCONV, and 2D SCONV. This work presents a 2D/3D unified sparse convolution accelerator for large-scale voxel-based point cloud networks. The chip is fabricated in TSMC 28nm CMOS technology to achieve 3.3-16.9 FPS running from 60-400MHz when computing the SECOND network on KITTI dataset. This work has been included by ISSCC2023 [1]. A demonstration is given to show the real-time 3D processing with a lidar sensor.