High speed data bus

• US 6,747,888 B2
• Filed: 12/06/2001
• Issued: 06/08/2004
• Est. Priority Date: 01/29/1998
• Status: Expired due to Term

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Klein, Dean A.
• Primary Examiner(s): Dinh, Son T.
• Application Number:
  US10/017,257
• Publication Number:
  US 20020041522A1
• Time in Patent Office: 915 Days
• Field of Search: 365/63, 365/51, 365/189.05, 365/230.06
• US Class Current: 365/63
• CPC Class Codes: G06F 13/1684 using multiple buses
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence
• CPC Class Codes: G06F 13/4068 Electrical coupling
• CPC Class Codes: G06F 13/4234 being a memory bus
• CPC Class Codes: G11C 11/4096 Input/output [I/O] data management or control circuits, e.g. reading or writing circuits, I/O drivers or bit-line switches
• CPC Class Codes: G11C 7/1006 Data managing, e.g. manipulating data before writing or reading out, data bus switches or control circuits therefor
• CPC Class Codes: G11C 7/1048 Data bus control circuits, e.g. precharging, presetting, equalising
• CPC Class Codes: G11C 7/1072 for memories with random access ports synchronised on clock signal pulse trains, e.g. synchronous memories, self timed memories

Abstract

The invention comprises data processing systems and components thereof. Such systems may include a memory controller, a plurality of memory devices, a data bus coupling the memory controller with the plurality of memory devices, and at least one bus switch located in the data bus between the memory controller and one of the plurality of memory devices. Memory integrated circuits and memory modules including at least one switch in the data bus are also provided.

Claims

1. A memory module comprising:

a printed circuit board;

a first plurality of electrical contacts arranged on said printed circuit board to connect to a data bus;

a second plurality of electrical contacts arranged on said printed circuit board to connect to memory control signals for performing memory access cycles, said memory control signals including a row address strobe signal and a column address strobe signal;

at least one memory integrated circuit attached to said printed circuit board and receiving one or more memory control signals from said second plurality of electrical contacts;

a state decoder circuit separate from said memory integrated circuit having an input coupled to at least some of said memory control signals and an output, wherein said state decoder circuit is configured to have an output signal having a first state during a memory access and a second state in the absence of a memory access; and

at least one switch having a plurality of inputs connected to corresponding ones of said first plurality of electrical contacts, and a plurality of outputs connected to said at least one memory integrated circuit so as to couple said data bus from said first plurality of electrical contacts to said memory integrated circuit, said at least one switch having an additional input coupled to said state decoder circuit output, and responsive to said state decoder circuit output to decouple said memory circuit from said data bus when no memory access cycle is being performed.

2. The memory module of claim 1, wherein the memory integrated circuit includes synchronous-DRAM memory.

3. The memory module of claim 1, wherein the switch, the memory integrated circuit, and a memory controller each collectively reside within a single integrated circuit.

4. A printed circuit board, comprising:

a first plurality of electrical contacts arranged on said printed circuit board to connect to a data bus;

a second plurality of electrical contacts arranged on said printed circuit board to connect to memory control signals for performing memory access cycles, said memory control signals including a row address strobe signal and a column address strobe signal;

at least one memory integrated circuit attached to said printed circuit board and receiving one or more memory control signals from said second plurality of electrical contacts;

a state decoder circuit separate from said memory integrated circuit having an input coupled to at least some of said memory control signals and an output, wherein said state decoder circuit is configured to have an output signal having a first state during a memory access and a second state in the absence of a memory access; and

at least one switch having a plurality of inputs connected to corresponding ones of said first plurality of electrical contacts, and a plurality of outputs connected to said at least one memory integrated circuit so as to couple said data bus from said first plurality of electrical contacts to said memory integrated circuit, said at least one switch having an additional input coupled to said state decoder circuit output, and responsive to said state decoder circuit output to decouple said memory circuit from said data bus when no memory access cycle is being performed.

5. The printed circuit board of claim 4, wherein the memory integrated circuit includes synchronous-DRAM memory.

6. The printed circuit board of claim 4, wherein the switch, the memory integrated circuit, and a memory controller each collectively reside within a single integrated circuit.

7. A state decoder circuit, comprising:

a state decoder for receiving a chip select signal targeted for a memory circuit and having an input coupled to memory control signals and an output, wherein said state decoder is configured to have an output signal having a first state during a memory access and a second state in the absence of a memory access, and wherein the state decoder is configured to activate a switch to decouple a memory circuit from a data bus when no memory access cycle is being performed.

8. The state decoder circuit of claim 7, wherein the state decoder is integrated with a printed circuited circuit board.

9. The state decoder circuit of claim 8, wherein the printed circuit board is integrated with the memory circuit.

10. The state decoder circuit of claim 9, wherein the memory circuit comprises synchronous-DRAM memory.

11. A switch, comprising:

a plurality of inputs connected to corresponding ones of first plurality of electrical contacts, and a plurality of outputs connected to at least one memory integrated circuit so as to couple a data bus from said first plurality of electrical contacts to said memory integrated circuit, said at least one switch having an additional input coupled to a state decoder circuit output that is responsive to a chip select signal, and responsive to said state decoder circuit output to decouple said memory circuit from said data bus when no memory access cycle is being performed.

12. The switch of claim 11, wherein the switch is integrated with a printed circuit board.