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| United States Patent | 6553452 |
| Link to this page | http://www.wikipatents.com/6553452.html |
| Inventor(s) | Garlepp; Bruno Werner (Mountain View, CA); Chau; Pak Shing (San Jose, CA); Donnelly; Kevin S. (San Francisco, CA); Portmann; Clemenz (Cupertino, CA); Stark; Donald C. (Los Altos, CA); Sidiropoulos; Stefanos (Stanford, CA); Barth; Richard M. (Palo Alto, CA); Davis; Paul G. (San Jose, CA); Tsern; Ely K. (Los Altos, CA) |
| Abstract | A synchronous dynamic random access memory device having an array of
dynamic memory cells. The memory device includes input receiver circuitry
to sample a value that is representative of a range of temperatures. In
addition, the memory device includes a programmable register, coupled to
the input receiver circuitry, to store the value that is representative of
the range of temperatures. |
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Title Information  |
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| Publication Date |
April 22, 2003 |
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| Filing Date |
January 18, 2002 |
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| Parent Case |
This application is a continuation of application Ser. No. 08/948,774,
filed on Oct. 10, 1997 (still pending). |
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Title Information  |
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References  |
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U.S. References |
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| | Reference | Relevancy | Comments | Reference | Relevancy | Comments | 6438057 Ruckerbauer 365/222 Aug,2002 |      Your vote accepted [0 after 0 votes] | | 6337589 Ooishi 327/156 Jan,2002 |      Your vote accepted [0 after 0 votes] | | 6233190 Cooper 365/212 May,2001 |      Your vote accepted [0 after 0 votes] | | 6160755 Norman
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| Market Size |
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| Reasonable Royalty |
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Market Review  |
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Technical Review  |
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Claims  |
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What is claimed is:
1. A synchronous dynamic random access memory device having an array of dynamic memory cells, wherein the memory device comprises: input receiver circuitry to sample an
externally provided value that is representative of a range of temperatures; and a programmable register, coupled to the input receiver circuitry, to store the value that is representative of the range of temperatures.
2. The memory device of claim 1, further including a register to store data transfer rate information, wherein an internal circuit is adjusted based on the data transfer rate information and the value stored in the programmable register.
3. The memory device of claim 2, further including a clock synchronization circuit to receive an external clock signal and synchronize outputting of data from the memory device with the external clock signal.
4. The memory device of claim 3, wherein the clock synchronization circuit includes one of a delay locked loop circuit and a phase locked loop circuit.
5. The memory device of claim 3, wherein the clock synchronization circuit includes: a phase detector to generate information representative of a difference in phase between the external clock signal and an internal clock signal; and a delay
circuit to generate the internal clock signal, wherein an amount of delay of the internal clock signal is varied based on the information representative of the phase difference between the external clock signal and the internal clock signal.
6. The memory device of claim 3, wherein the programmable register is coupled to the clock synchronization circuit, and wherein the clock synchronization circuit is adjusted in accordance with the value stored within the programmable register.
7. The memory device of claim 3, wherein the clock synchronization circuit includes a mixer circuit to vary a phase of an internal clock signal in response to the value stored in the programmable register.
8. The memory device of claim 1, further including decoder circuitry coupled to the programmable register to decode the value stored within the programmable register.
9. The memory device of claim 1, further including a register to store information indicative of a length of an external signal line coupled to the memory device, wherein the memory device tunes an internal circuit based on the value stored
within the programmable register and the information indicative of the length of the external signal line.
10. The memory device of claim 1, further including a register to store supply voltage information, wherein the memory device tunes an internal circuit based on the supply voltage information and the value stored within the programmable
register.
11. A method of controlling a synchronous dynamic random access memory device by a memory controller, wherein the method comprises: in the memory controller, generating information indicative of a temperature range; and providing the
information indicative of the temperature range to the memory device, wherein the memory device receives the information and stores the information in a register on the memory device.
12. The method of claim 11, wherein the information indicative of the temperature range is provided to the memory device during initialization of the memory device.
13. The method of claim 11, further including providing information indicative of a data transfer rate to the memory device, wherein the memory device times internal circuitry based on the temperature information and the information indicative
of the data transfer rate.
14. The method of claim 11, wherein the memory controller is coupled to the memory device via an external signal line, the method further including: in the controller device, detecting the length of the external signal line; and providing a
value representative of the length of the external signal line to the memory device, wherein the memory device tunes internal circuitry based on the temperature information and the value representative of the length of the external signal line.
15. The method of claim 11, further including: detecting supply voltage information; and providing the supply voltage information to the memory device, wherein the memory device tunes internal circuitry based on the temperature information and
the supply voltage information.
16. A method of operation in a memory device that includes a plurality of memory cells, the method comprising: receiving, from a controller, a value which is representative of a range of temperatures; and storing the value in a programmable
register on the memory device.
17. The method of claim 16, wherein the value is issued to the memory device during an initialization period.
18. The method of claim 16, further including tuning an internal circuit based on the value that is representative of a range of temperatures.
19. The method of claim 16, further including: decoding the value to generate an internal control signal; and adjusting an internal clock synchronization circuit in response to the internal control signal.
20. The method of claim 19, wherein adjusting the internal clock synchronization circuit includes adjusting a phase mixer in accordance with the value.
21. The method of claim 19, wherein the clock synchronization circuit is a delay lock loop circuit, wherein the delay lock loop circuit generates an internal clock signal having a predetermined timing relationship with an external clock signal.
22. The method of 19, wherein the clock synchronization circuit is a phase lock loop circuit, wherein the phase lock loop circuit generates an internal clock signal having a predetermined timing relationship with an external clock signal.
23. The method of claim 16, further including: receiving a value that is representative of one of a plurality of data transfer rates; and tuning an internal circuit based on the value that is representative of the one of the plurality of data
transfer rates.
24. The method of claim 16, further including adjusting a locking frequency range of an internal clack synchronization circuit, wherein the locking frequency range is adjusted based on the value stored in the programmable register.
25. The method of claim 16, further including generating an internal clock signal having a predetermined phase relationship with an external clock signal, wherein the internal clock signal synchronizes the outputting of data from the memory
device.
26. The method of claim 25, further including: detecting a phase differential between the external clock signal and the internal clock signal; generating the internal clock signal using a plurality of delay elements; and varying the amount of
delay in each delay element based on the phase differential.
27. The method of claim 16, further including: receiving supply voltage information from the controller; and storing the supply voltage information within the memory device.
28. The method of claim 16, further including: receiving information which is representative of a data transfer rate from the controller; and storing the information which is representative of a data transfer rate in a register disposed within
the memory device.
29. An integrated circuit device having an array of memory cells, wherein the integrated circuit device comprises: a programmable register to store a value that is representative of a range of temperatures; and a clock synchronization circuit
to receive an external clock signal and generate an internal clock signal, wherein the clock synchronization circuit is adjusted in accordance with the value stored in the programmable register, wherein the clock synchronization circuit includes: a phase
detector to generate information representative of a difference in phase between the external clock signal and the internal clock signal; and a delay element to generate the internal clock signal, wherein an amount of delay of the delay element is
varied based on the information representative of the difference in phase between the external clock signal and the internal clock signal; and output driver circuitry to output data in response to the internal clock signal.
30. The integrated circuit device of claim 29, wherein the clock synchronization circuit further includes a mixer circuit to vary a phase range of the internal clock signal in response to the value stored in the programmable register.
31. The integrated circuit device of claim 29 further including decoder circuitry coupled to the programmable register to decode the value stored within the programmable register.
32. The integrated circuit device of claim 29, further including a register to store information that is representative of a length of an external signal line coupled to the integrated circuit device, wherein the clock synchronization circuit is
adjusted in accordance with the value stored in the programmable register and the information that is representative of the length of the external signal line.
33. The integrated circuit device of claim 29, further including a register to store supply voltage information, wherein the clock synchronization circuit is adjusted in accordance with the value stored in the programmable register and the
supply voltage information.
34. The integrated circuit device of claim 29, further including a register to store data transfer rate information, wherein the clock synchronization circuit is adjusted in accordance with the value stored in the programmable register and the
data transfer rate information.
35. An integrated circuit device having an array of memory cells, wherein the integrated circuit device comprises: a programmable register to store a value that is representative of the range of temperatures; and a clock synchronization circuit
to receive an external clock signal and generate an internal clock signal, wherein the clock synchronization circuit is adjusted in accordance with the value stored in the programmable register, wherein the clock synchronization circuit includes: a phase
detector to generate information representative of a difference in phase between the external clock signal and the internal clock signal; and an oscillator circuit, coupled to the phase detector, to generate the internal clock signal, wherein a phase of
the internal clock signal is varied based on the information representative of the phase difference between the external clock signal and the internal clock signal; and output driver circuitry to output data in response to the internal clock signal.
36. The integrated circuit device of claim 35, wherein the clock synchronization circuit further includes a mixer circuit.
37. The integrated circuit device of claim 35, further including decoder circuitry coupled to the programmable register to decode the value stored within the programmable register.
38. The integrated circuit device of claim 35, further including a circuit to store information indicative of a length of an external signal line coupled to the integrated circuit device.
39. The integrated circuit device of claim 35, further including a circuit to store supply voltage information.
40. The integrated circuit device of claim 35, further including a circuit to store data transfer rate information.
41. A synchronous integrated circuit memory device having an array of dynamic memory cells, wherein the memory device comprises: transceiver circuitry including: a plurality of input receivers to receive an externally provided value that is
representative of a range of temperatures; and a plurality of output drivers to transmit data; a locked loop circuit, coupled to the plurality of output drivers, to synchronize transmission of data from the memory device with an external clock signal;
and a programmable register, coupled to the plurality of input receivers, to store the value that is representative of a range of temperatures.
42. The memory device of claim 41, wherein the transmission of data is synchronized to the external clock signal using an internal clock signal, wherein the locked loop circuit further includes: a phase detector to generate information
representative of a phase difference between the external clock signal and the internal clock signal; and a delay element to generate the internal clock signal, wherein an amount of delay of the delay element is varied based on the information
representative of the phase difference between the external clock signal and the internal clock signal.
43. The memory device of claim 42, wherein the clock synchronization circuit further includes a mixer circuit to vary a phase of the internal clock signal in response to the value stored in the programmable register.
44. The memory device of claim 41, wherein the transmission of data is synchronized to the external clock signal using an internal clock signal, wherein the locked loop circuit further includes: a phase detector to generate information
representative of a phase difference between the external clock signal and the internal clock signal; and an oscillator circuit, coupled to the phase detector, to generate the internal clock signal, wherein a phase of the internal clock signal is varied
based on the information representative of the phase difference between the external clock signal and the internal clock signal.
45. The memory device of claim 44, wherein the locked loop circuit further includes a mixer circuit to vary a phase range of the internal clock signal in response to the value stored in the programmable register. |
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Claims  |
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Description  |
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The present invention relates to digital memory systems, and more specifically, to synchronous memory systems.
BACKGROUND OF THE INVENTION
As the operational frequencies of digital computing systems continue to increase, it has become increasingly necessary to use synchronous memory systems instead of the slower asynchronous memory systems. In synchronous memory systems, data is
sent between a master device and one or more memory devices in the form of data packets which travel in parallel with, and must maintain precise timing relationships with, a system clock signal.
Because synchronous memory systems impose tight timing relationships between the clock and data signals, the memory interface circuits in the memory devices of the synchronous memory system generally require clock recovery and alignment circuits
such as phase locked loops (PLLs) or delay locked loops (DLLs). One drawback of these clock recovery and alignment circuits, however, is that they typically operate effectively only over a limited range of frequencies. For example, a PLL may not be
able to lock to the system's clock frequency if the frequency is either too low or too high. Additionally, the performance of these clock recovery and alignment circuits is degraded due to conditions such as temperature, supply voltage, speed binning
codes, process, dimensions (i.e. length) of the memory bus, etc.
SUMMARY OF THE INVENTION
It is an object of this invention to provide for an adjustable synchronous memory control system.
It is a further object of this invention to provide for a synchronous memory control system that uses frequency information to improve the performance of the circuits at the system clock frequency.
It is a further object of this invention to provide for a synchronous memory system that uses system parameters to improve the performance of the circuits at the system clock frequency.
The present invention is a method for adjusting the performance of a synchronous memory control system. A memory system comprises a master device and a slave device. A memory channel couples the master device to the slave device such that the
slave device receives the system operating information from the master device via the memory channel. The slave device further includes means for tuning circuitry within the slave device such that the performance of the memory system is improved.
Other objects, features, and advantages of the present invention will be apparent from the accompanying drawings and from the detailed description that follows below.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:
FIG. 1 illustrates one embodiment of the synchronous memory system of the present invention.
FIG. 2 illustrates a portion of the synchronous memory system of FIG. 1.
FIG. 3 illustrates one embodiment of the memory interface circuitry inside a memory device of the present invention.
FIG. 4 illustrates a block diagram of one embodiment of a phase locked loop (PLL) circuit that may be used in the present invention.
FIG. 5 illustrates a block diagram of one embodiment of a delay locked loop (DLL) circuit that may be used in the present invention.
DETAILED DESCRIPTION
A method and apparatus for adjusting the performance of a memory system is described. The present invention is for a synchronous memory system wherein the master device has information about its operating frequency and transmits this frequency
information to the memory devices. The memory devices then use this frequency information to adjust their clock recovery and alignment circuits to improve their performance at the system cl | | |