Memory module and memory system
In a memory module including a plurality of DRAM chips which transmit/receive a system data signal with a predetermined data width and at a transfer rate and which transmit/receive an internal data signal having a larger data width and a lower transfer rate as compared with the system data signal, the transfer rate of the system data signal is restricted. Current consumption in DRAMs constituting the memory module is large, hindering speed increases. For this memory module, a plurality of DRAM chips are stacked on an IO chip. Each DRAM chip is connected to the IO chip by a through electrode, and includes a constitution for mutually converting the system data signal and the internal data signal in each DRAM chip by the IO chip. Therefore, wiring between the DRAM chips can be shortened, and DLL having a large current consumption may be disposed only on the IO chip.
1. A memory system comprising:
a board;
a first device mounted on the board, wherein the first device provides a first plurality of system address signals, a second plurality of system address signals, and a plurality of system command signals; and
a second device mounted on the board, wherein the second device comprises a plurality of stacked memory chips interconnected by through electrodes;
wherein the second device comprises a first stacked chip receiving the first plurality of system address signals, the second plurality of system address signals, and the plurality of system command signals, decoding the first plurality of system address signals to provide a plurality of chip selection signals, and providing the plurality of chip selection signals, a second plurality of internal address signals, and a plurality of internal command signals to the through electrodes; and
wherein a first memory chip among the plurality of stacked memory chips is selected by the chip selection signals.
2. The memory system as claimed in claim 1 wherein the first device provides a third plurality of system write data signals to the first stacked chip and receives a third plurality of system read data signals from the first stacked chip, and the first stacked chip provides a fourth plurality of internal write data signals to the plurality of stacked memory chips and receives a fourth plurality of internal read data signals from the plurality of stacked memory chips via the through electrodes.
3. The memory system as claimed in claim 2 wherein the fourth plurality is greater than the third plurality.
4. The memory system as claimed in claim 1 wherein each of the plurality of stacked memory chips comprises a chip selection circuit receiving the plurality of chip selection signals.
5. The memory system as claimed in claim 4 wherein the chip selection circuit comprises a counter circuit.
6. The memory system as claimed in claim 4 wherein the chip selection circuit comprises a fuse circuit.
7. The memory system as claimed in claim 1 further comprising:
a third device mounted on the board, wherein the third device comprises an additional plurality of stacked memory chips interconnected by additional through electrodes;
wherein the third device comprises an additional first stacked chip receiving the first plurality of system address signals, the second plurality of system address signals, and the plurality of system command signals, decoding the first plurality of system address signals to provide an additional plurality of chip selection signals, and providing the additional plurality of chip selection signals, a second plurality of additional internal address signals, and a plurality of additional internal command signals to the additional through electrodes; and
wherein an additional first memory chip among the additional plurality of stacked memory chips is selected by the additional chip select signals.
8. The memory system as claimed in claim 1 wherein the first plurality of system address signals are bank address signals.
9. The memory system as claimed in claim 1 wherein the first plurality of system address signals comprises 3 signals and the plurality of chip select signals comprise 8 signals.
10. The memory system as claimed in claim 1 wherein the first stacked chip is an IO chip.
11. The memory system as claimed in claim 1 wherein the board is a mother board.
12. The memory system as claimed in claim 1 wherein the first device is a memory controller.
13. The memory system as claimed in claim 1 wherein the first device is a chip set.
14. The memory system as claimed in claim 1 wherein the second device is a memory module.
15. The memory system as claimed in claim 1 wherein the second device comprises an interposer.
16. The memory system as claimed in claim 1 wherein the plurality of stacked memory chips are DRAM chips.