SPAD Array Readout Using Shared Row-Column Lines for Compact LiDAR

The patent merges the readout circuits of multiple SPAD pixels into shared row lines and column lines. Specifically, multiple SPAD pixels connected to the same row line share a common row bias circuit, and multiple SPAD pixels connected to the same column line share a common column bias circuit. This merging approach reduces the total number of independent circuits while maintaining high-resolution pixel arrays, directly resolving the contradiction between measurement precision and device complexity.

The patent implements universal bias circuits that serve multiple functions. The row bias circuit and column bias circuit are designed to simultaneously provide bias signals to multiple SPAD pixels through shared lines. These circuits can operate with different gain modes (first gain mode and second gain mode) to handle different signal conditions, making them multi-functional components that reduce overall device complexity while supporting high-resolution imaging.

The patent incorporates feedback mechanisms in the form of latch circuits that monitor the output signals from SPAD pixels. When a photon detection event occurs, the latch circuit captures and holds the signal state, providing feedback to the readout system. This feedback mechanism ensures that detection events are reliably recorded even with shared circuits, preventing signal loss or ambiguity that could compromise device reliability while maintaining circuit simplicity.

The patent implements prior cushioning through the use of latch circuits that prepare and hold signal states before final readout. The latch circuits are designed to maintain signal integrity during the photon detection process, providing a buffer that protects against potential signal degradation or loss in the shared circuit pathways. This preparatory signal holding mechanism ensures reliable operation even with reduced circuit components.