Buffer Circuit with Data Bit Inversion for DRAM Signal Integrity

The patent introduces buffer circuits as intermediary components between the DIMMs and the memory channel. These buffers act as mediators that isolate the electrical loading effects of multiple DIMMs from the shared memory channel, allowing multiple modules to be installed without significant signal integrity degradation. The buffers present a controlled impedance interface that maintains signal quality while supporting increased capacity.

The buffer circuit is designed to perform multiple functions within a single integrated component: it provides load reduction for signal integrity, enables Data Bit Inversion (DBI) for power saving, and maintains compatibility with both ×4 and ×8 DRAM configurations. By combining these functions into one universal buffer module, the patent avoids the need for separate circuits for each function, thereby limiting the increase in device complexity while achieving multiple objectives.

The patent merges the DBI encoder and decoder functionality directly into the existing buffer circuit structure. Rather than adding separate DBI handling circuits, the encoder and decoder are integrated with the buffer's signal processing paths, allowing DBI to be implemented with minimal additional complexity. This merging approach enables power saving through DBI while keeping the overall circuit structure relatively simple.

The patent utilizes parameter changes in the buffer circuit's impedance characteristics and signal conditioning to achieve both load reduction and DBI functionality. By dynamically adjusting the buffer's electrical parameters based on the DRAM configuration (×4 or ×8) and operational mode, the circuit maintains efficient signal transmission while minimizing energy loss. The impedance matching and signal amplification functions are optimized to reduce power dissipation even as memory capacity increases.