发明授权
US06930955B2 Method and apparatus for establishing and maintaining desired read latency in high-speed DRAM
失效
用于在高速DRAM中建立和维持期望的读延迟的方法和装置
- 专利标题: Method and apparatus for establishing and maintaining desired read latency in high-speed DRAM
- 专利标题(中): 用于在高速DRAM中建立和维持期望的读延迟的方法和装置
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申请号: US10851081申请日: 2004-05-24
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公开(公告)号: US06930955B2公开(公告)日: 2005-08-16
- 发明人: Brian Johnson , Brent Keeth , Feng Lin
- 申请人: Brian Johnson , Brent Keeth , Feng Lin
- 申请人地址: US ID Boise
- 专利权人: Micron Technology, Inc.
- 当前专利权人: Micron Technology, Inc.
- 当前专利权人地址: US ID Boise
- 代理机构: Dickstein Shapiro Morin & Oshinsky LLP
- 主分类号: G11C7/10
- IPC分类号: G11C7/10 ; G11C7/22 ; G11C8/00 ; G11C11/4076
摘要:
A method and apparatus for managing the variable timing of internal clock signals derived from an external clock signal in order to compensate for uncertainty and variations in the amount of read clock back timing relative to data flow to achieve a specified read latency. A reset signal is generated at DRAM initialization and starts an first counter, which counts external clock cycles, and is also passed through the slave delay line of the delay lock loop to start a second counter. The counters run continuously once started and the difference in count values represent the internal delay as an external clock signal passes through the delay lock loop to produce an internal read clock signal. An internal read latency value is used to offset either counter to account for the internal read latency of the DRAM circuit. Once the non-offset counter is equivalent to the offset counter, read data is placed on an output line with a specified read latency and synchronized with the external read clock.
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