CN100409365C - Pseudo-static DASD and its data refresh method - Google Patents
Pseudo-static DASD and its data refresh method Download PDFInfo
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- CN100409365C CN100409365C CNB2003101197907A CN200310119790A CN100409365C CN 100409365 C CN100409365 C CN 100409365C CN B2003101197907 A CNB2003101197907 A CN B2003101197907A CN 200310119790 A CN200310119790 A CN 200310119790A CN 100409365 C CN100409365 C CN 100409365C
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Abstract
The present invention relates to a data refreshing method for pseudo static random access memories. The present invention firstly provides an address series and a refreshing signal, and the address series is a reference of a data reading and writing position. Secondly, the opening time of a word line of the pseudo static random access memory is arranged in at least one address of the address series, and the maximum time is one half of a signal refreshing period. Subsequently, the word line executes refreshing when the word line is closed, and the reading and the writing are carried out when the word line is opened. When the word line is closed in writing, the writing operation can be delayed to the next address translation detection (ATD) signal high level.
Description
Technical field
The invention relates to a kind of pseudo sram (Pseudo Static Random AccessMemory, PSRAM) and Refresh Data (refresh) method.
Background technology
Pseudo sram is that (Dynamic Random AccessMemory, hardware configuration DRAM) carry out the function of SRAM down in dynamic RAM.Under traditional DRAM structure, do not allow to open two word lines (word line) in the same time.DRAM also must carry out the action that refreshes at set intervals except reading and writing, to avoid losing data wherein.Yet this action that refreshes is equivalent to open another word line, thus need reading and writing and the time of refreshing are staggered, to avoid taking place to open simultaneously the conflict situations of two word lines.
With reference to Fig. 1, the reading and writing of DRAM and to refresh be to detect (address transitiondetection) signal ATD according to an address translation to implement.When changing, the address (for example converts address N to by address N-1, or address N converts address N+1 to), atd signal will be converted to high level, and be converted to low level again after (being generally the DRAM cycle or claiming the DRAM running time, represent with TRC_D) through after a while.When atd signal was positioned at low level, the word line of this address was opened (high level), thereby can carry out the action of reading and writing.When atd signal was positioned at high level, word line was closed, and can refresh.
When implementing under the structure of SRAM, an address also can't just know that it will carry out reading and writing or refreshes when ready firm, and word line open with time of carrying out reading and writing can not oversize (being generally a TRC_D), in order to avoid the action that can't refresh when the time comes.Yet this design has many shortcomings.For example, if refresh signal produces, and produce write signal again after refreshing after reading signal, must close refresh before because of this word line this moment, thus fashionablely must open word line again writing, thereby increase considerably the consumption of electric energy.
Summary of the invention
The purpose of this invention is to provide a kind of pseudo sram and method for refreshing data thereof, solving the problem that reading and writing conflict with refresh activity, and can effectively reduce the consumption of electric energy.
For achieving the above object, the present invention discloses a kind of method for refreshing data of pseudo sram, and it at first provides an address serial and a refresh signal, and this address serial is the foundation as data reading and writing position.Secondly, at least one address of this address serial, set the opening time of a word line of this pseudo sram, the longest be this refresh signal cycle 1/2nd.Afterwards, when this word line is closed, carry out and refresh, and when the word line of this address is opened, carry out the action of reading and writing.If writing the fashionable situation that word line is closed of happening, when the action that writes will be delayed to next address transition detection (ATD) signal and be high level.
In an embodiment of the present invention, this method for refreshing data also comprises the following step: finish the data read of this address and next address or the action that writes in the lump in the interval of next address.This next address keeps one 30 to 70ns interval, for the data read of this address or the action that writes.
Pseudo sram of the present invention comprises a memory circuitry and reading and writing and refresh control device.These reading and writing and refresh control device comprise an address transition detector, a refresh mode controller and a control circuit.This address transition detector is to be used to produce an address conversion signal.This refresh mode controller receives the reading and writing signal of this address conversion signal and an outside input, to produce buffer write signal and self-refresh mode signal.This control circuit receives this address conversion signal, buffer write signal, self-refresh mode signal, read-write and a refresh signal by this memory circuitry input, carry out signal and transfer to this memory circuitry to produce refresh execution signal and read-write, thus the action of carrying out reading and writing and refreshing.
Description of drawings
Fig. 1 is the signal timing diagram of known pseudo sram;
Fig. 2 is the signal timing diagram of the pseudo sram of first preferred embodiment of the present invention;
Fig. 3 is the signal timing diagram of the pseudo sram of second preferred embodiment of the present invention;
Fig. 4 is the signal timing diagram of the pseudo sram of the 3rd preferred embodiment of the present invention;
Fig. 5 is the state transition graph of pseudo sram of the present invention;
Fig. 6 is the synoptic diagram of pseudo sram of the present invention.
Embodiment
Principle of the present invention is the cycle according to refresh signal to prolong the time that word line is opened, the conflict of avoiding reading and writing by this and refreshing, and can reduce power consumption.Below will be illustrated by several embodiment.
Generally speaking, the data of 4Kb need to refresh in 64 microseconds (μ s) to finish, so the refresh interval time of each kb data is about 16 microseconds (μ s), promptly the cycle of refresh signal is about 16 μ s/ time.Be to illustrate under the situation of 16 μ s promptly below with the refresh interval time.
The interval of Fig. 2 sample address N is less than the situation of 8 μ s.When the address N-1 in the address serial was converted to address N, an address conversion signal ATD promptly was converted to high level, and closed with the word line that is about to N-1, and this moment is because refresh signal REFQ is a low level, so do not open any word line.Afterwards, when ATD gets back to low level, N address word line is opened when being converted to address N+1, for the data among the reading, writing address N.In the present embodiment, do not turn off at once when the word line opening time reaches TRC_D, and when next atd signal is converted to high level, just close.Because of the interval of the address N of present embodiment less than 8 μ s, deduct the length of ATD so the word line opening time is the length of address N, promptly the word line opening time is less than or equal to half of interval time of refreshing.After ATD converts high level to, just receive a refresh signal REFQ among Fig. 2, so promptly open subsequently and can't refresh at once, when the action that needs to refresh is extended down to the initial ATD high level of next address N+1 because of word line.Please note, to refresh the sequential chart that is presented at word line with the time of reading and writing jointly among the present invention, and when carrying out refresh activity, indicate " refreshing " especially with clear both mutual relationships in time that show, and be not to open the word line of reading and writing when " refreshing ", illustrate earlier at this.In addition, if this refresh signal produces when word line is opened, also must be delayed to and just refresh after this word line is closed.
With reference to Fig. 3, the longest opening time of its word line also is made as 8 μ s, and it is to occur under the situation of interval greater than 8 μ s of N address, may occur in low frequency and lower powered pseudo sram.For the purpose of convenient control, the design one LRAS pattern about refresh control promptly enters control model signal (LRAS) in the present embodiment after word line is closed, and it is a high level, and can carry out the action that refreshes this moment.For example receive a refresh signal REFQ at LRAS during for high level among Fig. 3, promptly refresh at once.
Signal timing diagram shown in Figure 4 is similar to Fig. 3.When the XWE signal was reduced to low level, the opening time that has reached the longest 8 μ s because of word line closed, so can't write in the N of address immediately.Therefore, must be earlier with the data storing desiring to write in a register, when treating next address (being address N+1) beginning, it is that high level writes again that address translation detects (ATD) signal.For cooperating this situation, need to open twice word line in the interval of address N+1, identical with known skill; But this moment, address cycle significantly increased, and the maximum duration 8 μ s that open with word line are example, and the time that is equivalent to the word line unlatching is that traditional about 70ns prolongs about 100 times.If original electric current is 20mA, the electric current of this moment will be reduced to about 200 μ A, if entirely for the situation of Fig. 4 then electric current only be 400 μ A, still maintain the characteristic of low-power consumption.In fact, but half (the longest situation) in self refresh signal cycle time of word line unlatching shortened in the foregoing description, but must consideration whether have influence on the amplitude that current drain reduces.If the time that word line is opened is too short, tool is not reduced the function of current drain.The time that this word line is opened is good with 1/4th to 1/2nd of the refresh signal cycle.Promptly be set in an embodiment of the present invention from 4 μ s to 8 μ s.
Fig. 5 is the state transition graph (statetransition diagram) of the method for refreshing data of pseudo sram of the present invention, is used for the working method of the embodiment of key diagram 2 to Fig. 4 examples.Its word line is to close the word line of just opening this address behind the word line of previous address earlier in the address, refreshes and opportunity of reading and writing to provide respectively.Under the situation of standby (idle), when atd signal is converted to high level and does not have the REFQ signal, promptly enter NOP (No Operation) pattern, just do not do any action.(being equivalent to word line opens) if the XWE signal is 1, then reads when atd signal is converted to low level; If the XWE signal is 0, then write.Read and write and to last till that next atd signal produces and after a DRAM signal cycle length TRAS is converted to low level, just to return standby mode.This DRAM signal cycling time TRAS is used to judge whether passed through the aforesaid TRC_D time.When reading or writing, execution happens the LRAS conversion of signals when being high level (aforesaid LRAS pattern), the action that promptly refreshes.Under the LRAS pattern,, when being converted to low level, finishes signal TREF up to a running time if the REFQ conversion of signals refreshes when being high level immediately.This TREF signal is to be used to judge whether the running time of refreshing finishes.The LRAS pattern will last till after next atd signal is converted to high level just gets back to standby mode.Under the LRAS pattern, if the XWE signal equals 0, be equivalent to embodiment shown in Figure 3 and under the situation that word line is closed, accept write signal, will impel a buffer write signal WRQ (WRQ=1) this moment.If the WRQ signal equal 1 and the REFQ signal equal at 1 o'clock, when next atd signal is converted to high level, will carry out a buffer write activity, after this TREF conversion of signals is low level just the end.If the REFQ signal equal 1 and the WRQ signal equal at 0 o'clock, then refresh.
Fig. 6 is the synoptic diagram of pseudo sram of the present invention.One pseudo sram 10 comprises a known memory circuitry 11 and newly-increased reading and writing and a refresh control device 12 substantially.This memory circuitry 11 comprises one and refreshes oscillator (auto-refresh oscillator) 111, one counter 112, an Address Register 113, an address decoder 114, a memory cell array (memory cellarray) 115, one pre-charge circuit 116, a write circuit 117 and a data buffer 118 automatically.This read-write and refresh control device 12 comprise a control circuit 121, a refresh mode controller (LRAS controller) 122, one address transition detector (Address Transition Detector, ATD) 123 and one read-write buffer 124.Whether this address transition detector 123 is connected in this Address Register 113, be used to detect the address and change, to produce an atd signal and to deliver to this LRAS controller 122 and control circuit 121.This read-write buffer 124 can be kept in outside read-write XWE, and delivers to this LRAS controller 122 and control circuit 121.This control circuit 121 is except receiving this ATD and XWE signal, also receive LRAS and WRQ signal that LRAS controller 122 is produced, reach and refresh the REFQ signal that oscillator 111 is produced automatically, to produce refresh execution signal REFRESH and read-write execution signal R_W, transfer to this counter 112 and Address Register 113 respectively, the action of carrying out reading and writing in good time and refreshing.
Technology contents of the present invention and technical characterstic disclose as above, yet those skilled in the art still may be based on teaching of the present invention and announcement and done all replacement and modifications that does not deviate from spirit of the present invention.Therefore, protection scope of the present invention should be not limited to the content that embodiment discloses, and should comprise various do not deviate from replacement of the present invention and modifications, and is contained by the present patent application protection domain.
Claims (7)
1. the method for refreshing data of a pseudo sram is characterized in that it comprises the following step:
One address serial is provided;
One refresh signal is provided;
In at least one address of this address serial, set the opening time of a word line of this pseudo sram, the longest be this refresh signal cycle 1/2nd;
When closing, carries out this word line the action that refreshes; And
The action of when this word line is opened, finishing data read in the lump and writing.
2. the method for refreshing data of pseudo sram as claimed in claim 1 is characterized in that comprising in addition the following step: finish the data read of this address and next address or the action that writes in the lump in the interval of next address.
3. the method for refreshing data of pseudo sram as claimed in claim 2 is characterized in that the interval that described next address keeps 30 to 70ns, for the data read of this address or the action that writes.
4. the method for refreshing data of pseudo sram as claimed in claim 1 is characterized in that in the reading and writing cycle of described this word line, was to close the word line of just opening this address behind the word line of previous address earlier.
5. the method for refreshing data of pseudo sram as claimed in claim 1 is characterized in that described word line is to be held open after next address occurs just to close always.
6. the method for refreshing data of pseudo sram as claimed in claim 1, the opening time that it is characterized in that described word line is 1/4th to 1/2nd of cycle of this refresh signal.
7. the method for refreshing data of pseudo sram as claimed in claim 1, the opening time that it is characterized in that described word line is 4 microsecond to 8 microseconds.
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2003101197907A CN100409365C (en) | 2003-12-05 | 2003-12-05 | Pseudo-static DASD and its data refresh method |
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| CNB2003101197907A CN100409365C (en) | 2003-12-05 | 2003-12-05 | Pseudo-static DASD and its data refresh method |
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| CN1624801A CN1624801A (en) | 2005-06-08 |
| CN100409365C true CN100409365C (en) | 2008-08-06 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10665286B2 (en) | 2018-02-01 | 2020-05-26 | Windbond Electronics Corp. | Pseudo static random access memory and control method thereof |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100776737B1 (en) | 2006-02-10 | 2007-11-19 | 주식회사 하이닉스반도체 | Apparatus and Method for Controlling Active Cycle of Semiconductor Memory |
| CN102024490B (en) * | 2009-09-23 | 2012-12-05 | 北京兆易创新科技有限公司 | Pseudo-static memory, and reading operation and refreshing operation control method thereof |
| CN102024492B (en) * | 2009-09-23 | 2012-10-03 | 北京兆易创新科技有限公司 | Pseudo-static memory and method for controlling write operation and refresh operation of pseudo-static memory |
| US8659936B2 (en) * | 2010-07-06 | 2014-02-25 | Faraday Technology Corp. | Low power static random access memory |
| TWI498890B (en) * | 2012-08-10 | 2015-09-01 | Etron Technology Inc | Method of operating psram and related memory device |
| JP6751460B1 (en) | 2019-05-30 | 2020-09-02 | 華邦電子股▲ふん▼有限公司Ｗｉｎｂｏｎｄ Ｅｌｅｃｔｒｏｎｉｃｓ Ｃｏｒｐ． | Pseudo static random access memory and data writing method thereof |
| CN115083467B (en) * | 2021-03-15 | 2024-05-03 | 长鑫存储技术有限公司 | Refresh control circuit and memory |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5075886A (en) * | 1988-07-06 | 1991-12-24 | Kabushiki Kaisha Toshiba | Refresh control circuit of pseudo static random access memory and pseudo static random access memory apparatus |
| CN1221511A (en) * | 1996-06-04 | 1999-06-30 | 西门子公司 | Method for reading and refreshing dynamic semiconductor memory |
| CN1234901A (en) * | 1997-06-12 | 1999-11-10 | 松下电器产业株式会社 | Semiconductor circuit and method of controlling same |
-
2003
- 2003-12-05 CN CNB2003101197907A patent/CN100409365C/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5075886A (en) * | 1988-07-06 | 1991-12-24 | Kabushiki Kaisha Toshiba | Refresh control circuit of pseudo static random access memory and pseudo static random access memory apparatus |
| CN1221511A (en) * | 1996-06-04 | 1999-06-30 | 西门子公司 | Method for reading and refreshing dynamic semiconductor memory |
| CN1234901A (en) * | 1997-06-12 | 1999-11-10 | 松下电器产业株式会社 | Semiconductor circuit and method of controlling same |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10665286B2 (en) | 2018-02-01 | 2020-05-26 | Windbond Electronics Corp. | Pseudo static random access memory and control method thereof |
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| CN1624801A (en) | 2005-06-08 |
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