Large capacity memory systems are constructed using stacked memory integrated circuits or chips. The stacked memory chips are constructed in such a way that eliminates problems such as signal integrity while still meeting current and future memory standards.

Methods and apparatus of stacking DRAMs

A memory module includes a plurality of memory devices and a circuit. Each memory device has a corresponding load. The circuit is electrically coupled to the plurality of memory devices and is configured to be electrically coupled to a memory controller of a computer system. The circuit selectively isolates one or more of the loads of the memory devices from the computer system. The circuit comprises logic which translates between a system memory domain of the computer system and a physical memory domain of the memory module.

Memory module with a circuit providing load isolation and memory domain translation

A memory circuit system and method are provided in the context of various embodiments. In one embodiment, an interface circuit remains in communication with a plurality of memory circuits and a system. The interface circuit is operable to interface the memory circuits and the system for performing various functionality (e.g. power management, simulation/emulation, etc.).

Configurable memory circuit system and method

A memory circuit system and method are provided. In one embodiment, an interface circuit is capable of communication with a plurality of memory circuits and a system. In use, the interface circuit is operable to interface the memory circuits and the system for reducing command scheduling constraints of the memory circuits. In another embodiment, an interface circuit is capable of communication with a plurality of memory circuits and a system. In use, the interface circuit is operable to translate an address associated with a command communicated between the system and the memory circuits. In yet another embodiment, at least one memory stack comprises a plurality of DRAM integrated circuits. Further, a buffer circuit, coupled to a host system, is utilized for interfacing the memory stack to the host system for transforming one or more physical parameters between the DRAM integrated circuits and the host system. In still yet another embodiment, at least one memory stack comprises a plurality of DRAM integrated circuits. Further, an interface circuit, coupled to a host system, is utilized for interfacing the memory stack to the host system so to operate the memory stack as a single DRAM integrated circuit.

Memory circuit system and method

A memory module, which includes at least one memory stack, comprises a plurality of DRAM integrated circuits and an interface circuit. The interface circuit interfaces the memory stack to a host system so as to operate the memory stack as a single DRAM integrated circuit. In other embodiments, a memory module includes at least one memory stack and a buffer integrated circuit. The buffer integrated circuit, coupled to a host system, interfaces the memory stack to the host system so to operate the memory stack as at least two DRAM integrated circuits. In yet other embodiments, the buffer circuit interfaces the memory stack to the host system for transforming one or more physical parameters between the DRAM integrated circuits and the host system.

Memory module with memory stack and interface with enhanced capabilities

A memory system has a plurality of interleaved memory ranks that use SDRAMs requiring a periodic refresh, and an arbiter which controls access to the memory ranks and restricts access to a memory rank being refreshed. The memory ranks are interleaved on a memory module. Counting refresh registers on each memory module are associated with the module's memory ranks. The arbiter has its own counting refresh register. At regular intervals, the arbiter broadcasts a refresh signal along with a refresh address to the modules via a transaction bus. The refresh address provided by the arbiter is latched by the refresh registers which then begin counting at a pre-programmed interval. A refresh to a particular memory rank is triggered when a refresh register associated with the memory rank matches a unique identifier assigned to that rank. The arbiter uses its refresh register to identify the memory rank being refreshed, allowing the arbiter to restrict access to that memory rank. As a result, the memory ranks are refreshed sequentially without ongoing control by the arbiter.

Memory refresh control system

Data coherency in a multiprocessor system is improved and data latency minimized through the use of data mapping "fill" requests from any one of the multiprocessor CPUs such that the information requested is acquired through the crossbar switch from the same memory module to which the "victim" data in that CPUs cache must be rewritten. With such an arrangement rewrite latency periods for victim data within the crossbar switch is minimized and the `ships crossing in the night` problem is avoided.

Stephen Van Doren

Papers

Memory refresh control system

Cache memory exchange optimized memory organization for a computer system