阅读说明：本技术 同步电路及与同步电路相关的方法 (Synchronous circuit and method relevant to synchronous circuit ) 是由 金泰平 于 2018-12-27 设计创作，主要内容包括：本申请公开了同步电路和与同步电路相关的方法。所述同步电路可以包括：可变延迟电路,其被配置为将第一时钟信号延迟根据延迟控制信号而变化的变化的延迟时间,并且被配置为输出所述可变延迟电路的经延迟的信号以作为第二时钟信号；相位检测器,其被配置为：通过检测所述第一时钟信号与所述第二时钟信号之间的相位差来产生相位检测信号；以及延迟控制电路,其被配置为根据所述相位检测信号来执行相位不稳定时段检测操作,并且被配置为执行延迟跳过操作以调节所述延迟控制信号来使得在延迟时间调整操作中跳过在所述相位不稳定时段检测操作中检测到的相位不稳定时段。(This application discloses synchronous circuits and method relevant to synchronous circuit.The synchronous circuit may include: variable delay circuit, its delay time for being configured as the variation for changing the first clock signal delay according to delayed control signal, and it is configured as exporting the delayed signal of the variable delay circuit using as second clock signal；Phase detectors are configured as: generating phase detection signal by detecting the phase difference between first clock signal and the second clock signal；And delay control circuit, it is configured as executing the detection operation of phase-unstable period according to the phase detection signal, and is configured as executing and postpones skip operations to adjust the delayed control signal and come so that skipping the phase-unstable period detected in phase-unstable period detection operation in delay time adjustment operation.)

1. a kind of synchronous circuit, comprising:

Variable delay circuit is configured as prolonging variation that the first clock signal delay changes according to delayed control signal The slow time, and it is configured as exporting the delayed signal of the variable delay circuit using as second clock signal；

Phase detectors are configured as by detecting the phase between first clock signal and the second clock signal Difference generates phase detection signal；And

Delay control circuit is configured as executing the detection operation of phase-unstable period according to the phase detection signal, And it is configured as executing and postpones skip operations to adjust the delayed control signal and to jump in delay time adjustment operation Spend the phase-unstable period detected in phase-unstable period detection operation.

2. synchronous circuit according to claim 1, wherein the variable delay circuit includes:

First delay circuit comprising the first unit delay；And

Second delay circuit comprising the second unit delay, second unit delay is configured with to be prolonged than described first The first unit delay smaller delay time of slow circuit.

3. synchronous circuit according to claim 2, wherein first delay circuit includes:

First unit delay is configured as sequentially postponing first clock signal and exports first unit The delayed signal of delay；And

Multiplexer is configured as by selecting institute according to the first delayed control signal among the delayed control signal Any one of described delayed signal of the first unit delay is stated to generate output signal.

4. synchronous circuit according to claim 2, wherein second delay circuit includes:

Second unit delay is configured as sequentially postponing the output signal of first delay circuit and defeated The delayed signal of second unit delay out；And

Multiplexer is configured as by selecting institute according to the second delayed control signal among the delayed control signal Any one of described delayed signal of the second unit delay is stated to generate output signal.

5. synchronous circuit according to claim 1, wherein when the current operation status of the synchronous circuit is power-up sequence When, the delay control circuit executes the phase-unstable period detection operation.

6. synchronous circuit according to claim 5, wherein the delay control circuit is according to the side information of power up signal To identify the power-up sequence.

7. synchronous circuit according to claim 5, wherein when the current operation status of the synchronous circuit is not described adds When electric array, when the delay control circuit uses the phase-unstable executed before executing the delay skip operations Section detects the result of operation to execute the delay skip operations.

8. synchronous circuit according to claim 1,

Wherein, the delay control circuit executes the phase-unstable period by executing multiple phase detection operation set Detection operation,

Wherein, by being arranged differently than to each phase detection operation set the variation of the variable delay circuit Delay time executes the multiple phase detection operation set, and

Wherein, each phase detection operation set includes the delay time quilt in the variation of the variable delay circuit The multiple phase-detections executed when fixed.

9. synchronous circuit according to claim 8, wherein when any one result of the multiple phase-detection have with When the different value of any other result of the multiple phase-detection, the delay control circuit is by corresponding phase detection operation Set is detected as the phase-unstable period.

10. synchronous circuit according to claim 1, wherein the delay control circuit includes:

Shift register is configured as sequentially shifting the phase detection signal and exports shifted signal；

Logic gate is configured as executing logical operation to the output signal of the shift register, and is configured as exporting Logic operation result；

Counter is configured as being counted by the output signal to the logic gate to generate phase-unstable period meter Number signal；And

Register is configured as storing the phase-unstable period count signal.

11. a kind of synchronous circuit, comprising:

First delay circuit is configured as the variation for changing the first clock signal delay according to the first delayed control signal Delay time, and be configured as exporting the delayed signal of first delay circuit；

Second delay circuit is configured as the output signal delay of first delay circuit according to the second delay control letter Number and delay time of variation for changing, and be configured as exporting the delayed signal of two delay circuit using as the Two clock signals；

Phase detectors are configured as by detecting the phase between first clock signal and the second clock signal Difference generates phase detection signal；

Period information generative circuit is skipped, is configured as by executing the phase-unstable period according to the phase detection signal Detection operation skips period information to generate；And

Delayed control signal generative circuit is configured as skipping period information according to adjust the second delay control Signal, so that skipping the phase detected in phase-unstable period detection operation in delay time adjustment operation not Stablize the period.

12. synchronous circuit according to claim 11, wherein the second unit delay of second delay circuit is configured For with the first unit delay smaller delay time than first delay circuit.

13. synchronous circuit according to claim 11, wherein first delay circuit includes:

First unit delay is configured as sequentially postponing first clock signal and exports first unit delay Delayed signal；And

Multiplexer is configured as the institute by selecting first unit delay according to first delayed control signal Any one of delayed signal is stated to generate output signal.

14. synchronous circuit according to claim 11, wherein second delay circuit includes:

Second unit delay is configured as that the output signal of first delay circuit is sequentially postponed to and exported described The delayed signal of two unit delays；And

Multiplexer is configured as the institute by selecting second unit delay according to second delayed control signal Any one of delayed signal is stated to generate output signal.

15. synchronous circuit according to claim 11, wherein the period information generative circuit of skipping includes:

Shift register is configured as sequentially shifting the phase detection signal and exports shifted signal；

Logic gate is configured as executing logical operation to the output signal of the shift register, and is configured as exporting Logic operation result；

Counter is configured as being counted by the output signal to the logic gate to generate phase-unstable period meter Number signal；And

Register is configured as storing the phase-unstable period count signal, and is configured as exporting stored Signal is to skip period information as described.

16. synchronous circuit according to claim 15, wherein according to power up signal come by the output of the shift register Signal, the phase-unstable period count signal and the period information of skipping reset.

17. synchronous circuit according to claim 11, wherein when the current operation status of the synchronous circuit is power-up sequence When column, the delayed control signal generative circuit executes the phase-unstable period detection operation.

18. synchronous circuit according to claim 17, wherein the delayed control signal generative circuit is according to power up signal Side information identify the power-up sequence.

19. synchronous circuit according to claim 17, wherein when the current operation status of the synchronous circuit is not When the power-up sequence, the delayed control signal generative circuit will skip period information value and be added to the second delay control letter Number initial value on.

20. synchronous circuit according to claim 11, wherein it is described skip period information generative circuit by execute it is multiple Phase detection operation set operates to execute the phase-unstable period detection,

Wherein, by being arranged differently than to each phase detection operation set the variation of second delay circuit Delay time executes the multiple phase detection operation set, and

Wherein, each phase detection operation set includes the delay time quilt in the variation of second delay circuit The multiple phase-detections executed when fixed.

21. synchronous circuit according to claim 20, wherein when any one result of the multiple phase-detection has When different from any other result of the multiple phase-detection value, the period information generative circuit of skipping is by corresponding phase Position detection operational set is detected as the phase-unstable period.

22. a kind of method for operating synchronous circuit, which comprises

Whether the current operation status for determining the synchronous circuit is power-up sequence；

When the current operation status is the power-up sequence, by the second delay circuit of control come when executing phase-unstable Section detection operation；

By with phase-unstable period corresponding described second for detecting in phase-unstable period detection operation The quantity of the unit delay of delay circuit, which is stored as, skips period information；And

When the current operation status is not the power-up sequence, pass through the first delay circuit of control and second deferred telegram Road operates to execute delay time adjustment,

Wherein, it skips period information according to described and controls second delay circuit, so that when executing the delay time tune The phase-unstable period is skipped when whole operation.

23. according to the method for claim 22, wherein the unit delay of second delay circuit is configured as having There is delay time more smaller than the unit delay of first delay circuit.

24. according to the method for claim 22,

Wherein, the execution phase-unstable period detection operation includes executing multiple phase detection operation set,

Wherein, by each phase detection operation set be arranged differently than the delay time of second delay circuit come The multiple phase detection operation set is executed, and

Wherein, each phase detection operation set include second delay circuit the delay time it is fixed When multiple phase-detections for executing.

25. according to the method for claim 24, wherein when any one of the multiple phase-detection result have with When the different value of any other result in the multiple phase-detection, corresponding phase detection operation set is detected as phase The unstable period.

Technical field

Various embodiments are related to semiconductor circuit in general, and more particularly, to synchronous circuit and with synchronous electricity The relevant method in road.

Background technique

Semiconductor devices (such as semiconductor memory or controller for controlling semiconductor memory) utilizes and output Data synchronous clock signals (for example, data strobe signal DQS) transmits output data.

The phase adjusted of clock signal is desired value, and with clock signal synchronization output data by semiconductor devices.

For example, delay lock loop has expectation by delay time adjustment (delay time tuning) operation to export The clock signal of phase, and with clock signal synchronization output data.

With the increase of the frequency of clock signal, the accuracy of delay time adjustment operation and speed be can be used as really An important factor for determining the performance for the semiconductor devices that synchronous circuit is applied to.

Summary of the invention

In one embodiment, a kind of synchronous circuit may include: variable delay circuit, be configured as the first clock The delay time for the variation that signal delay changes according to delayed control signal, and be configured as exporting the variable delay electricity The delayed signal on road is using as second clock signal；Phase detectors are configured as by detecting first clock Phase difference between signal and the second clock signal generates phase detection signal；And delay control circuit, matched It is set to according to the phase detection signal and executes the detection operation of phase-unstable period, and be configured as executing and postpone to skip Operation is come with adjusting the delayed control signal so that skipping in delay time adjustment operation in the phase-unstable period The phase-unstable period detected in detection operation.

In one embodiment, a kind of synchronous circuit may include: the first delay circuit, be configured as the first clock The delay time for the variation that signal delay changes according to the first delayed control signal, and be configured as exporting described first and prolong The delayed signal of slow circuit；Second delay circuit is configured as postponing the output signal of first delay circuit The delay time of the variation changed according to the second delayed control signal, and be configured as exporting second delay circuit Delayed signal is using as second clock signal；Phase detectors are configured as by detecting first clock signal Phase difference between the second clock signal generates phase detection signal；Period information generative circuit is skipped, is matched It is set to and skips period information by executing the detection operation of phase-unstable period according to the phase detection signal to generate；And Delayed control signal generative circuit is configured as skipping period information according to adjust second delayed control signal So that it is unstable to skip the phase detected in phase-unstable period detection operation in delay time adjustment operation Timing section.

In one embodiment, a kind of method for operating synchronous circuit may include: the determining synchronous circuit Whether current operation status is power-up sequence；When the current operation status is the power-up sequence, prolonged by control second Slow circuit operates to execute the detection of phase-unstable period；It will be detected in phase-unstable period detection operation The quantity of the unit delay of phase-unstable period corresponding second delay circuit, which is stored as, skips period information；And When the current operation status is not the power-up sequence, by control the first delay circuit and second delay circuit come Execute delay time adjustment operation.It can skip period information according to described and control second delay circuit, so that working as The phase-unstable period is skipped when executing the delay time adjustment operation.

Detailed description of the invention

Fig. 1 shows the configuration of the synchronous circuit according to one embodiment.

Fig. 2 shows the configurations according to the coarse delay line of Fig. 1 of one embodiment.

Fig. 3 shows the configuration of the thin delay line of Fig. 1 according to one embodiment.

Fig. 4 shows the configuration of the phase detectors of Fig. 1 according to one embodiment.

Fig. 5 shows the operation of the phase detectors of Fig. 4 according to one embodiment.

Fig. 6 shows the configuration of the delay control circuit of Fig. 1 according to one embodiment.

Fig. 7 is the flow chart for showing the operation of the synchronous circuit according to one embodiment.

Fig. 8 shows the phase-unstable period detection method according to Fig. 7 of one embodiment.

Specific embodiment

Hereinafter, the synchronous circuit according to the disclosure will be described below with reference to attached drawing by the example of embodiment.

Various embodiments can be for the synchronous circuit that can be improved its accuracy and speed.

Fig. 1 shows the configuration of the synchronous circuit according to one embodiment.

It as shown in fig. 1, may include variable delay circuit 200, phase inspection according to the synchronous circuit of one embodiment 100 Survey device 300, delay control circuit 400 and buffer 500.

Variable delay circuit 200 can postpone the first clock signal ICLK according to delayed control signal (the i.e. first delay Control signal CDC and the second delayed control signal FDC) and change variation delay time, and export delayed signal with As second clock signal FBCLK.

Variable delay circuit 200 may include delay circuit, i.e. the first delay circuit and the second delay circuit.

First delay circuit may include coarse delay line (CDL) 210, and the second delay circuit may include thin delay line (FDL)220。

CDL 210 can be used for the first adjustment operation of delay time adjustment operation, i.e. coarse adjustment operates.

FDL 220 can be used for the second adjustment operation of delay time adjustment operation, i.e. fine tuning is operated, be can have Smaller unit delay time is operated than coarse adjustment.

CDL 210 can be by generating output signal for the delay time of the first clock signal ICLK delay variation ICLKD, and output signal ICLKD is supplied to FDL 220.

Phase detectors 300 can pass through the phase between detection the first clock signal ICLK and second clock signal FBCLK Potential difference generates phase detection signal PD.

Delay control circuit 400 can receive power up signal PWRUP, the first clock signal ICLK, phase detection signal PD With enable signal DLLEN, and delayed control signal is generated, i.e. the first delayed control signal CDC and the second delayed control signal FDC。

In the system for including synchronous circuit 100, enable signal DLLEN can be generated in each predetermined time interval.

It specifically, can be in power-up sequence and every during the normal operating period in the system for including synchronous circuit 100 A predetermined time interval generates enable signal DLLEN.

Delay control circuit 400 can execute delay time adjustment operation during the activation period of enable signal DLLEN.

Delay control circuit 400 can generate the first delayed control signal CDC and second according to phase detection signal PD Delayed control signal FDC is to adjust delay time of variable delay circuit 200, to execute delay time adjustment, i.e., coarse adjustment and/ Or fine tuning.

Delay control circuit 400 can execute coarse adjustment, and determine that coarse adjustment has been completed when thick locking is detected. In addition, delay control circuit 400 can execute fine tuning, and determine that fine tuning has been completed when thin locking is detected.

Delay control circuit 400 can determine whether phase detection signal PD changes, to detect thick locking or thin locking.

For example, when phase detection signal PD during coarse tuning process from ' 0' be changed into ' 1' when, delay control circuit 400 can To determine that thick locking is detected.The detection carefully locked can determine in an identical manner.

Delay control circuit 400 can execute coarse adjustment when increasing the quantity of the unit delay of CDL 210 one by one, Wherein unit delay is used for coarse adjustment.When thick locking is detected, delay control circuit 400 can be by the unit of CDL 210 The quantity of delay reduces one, and then executes fine tuning using the unit delay of FDL 220.

Delay control circuit 400 can execute when executing delay time adjustment operation according to phase detection signal PD The detection operation of phase-unstable period.

Delay control circuit 400 can execute the operation for adjusting delayed control signal, operate so that adjusting in delay time Middle skip detection to the phase-unstable period (i.e. phase-unstable period for detecting in phase-unstable detection operation). Hereinafter, which will be referred to as delay skip operations.

At this point, delay skip operations may include adjusting the first delayed control signal CDC and/or the second delayed control signal The operation of FDC, so that skipping unit corresponding with the phase-unstable period being detected in delay time adjustment operation Postpone (that is, unit delay of the unit delay of CDL 210 and/or FDL 220).

Delay control circuit 400 can determine that synchronous circuit 100 (includes synchronous circuit according to power up signal PWRUP 100 system) power-up sequence.

Delay control circuit 400 can be determined according to the side information (rising edge or failing edge) of power up signal PWRUP Power-up sequence.

In the case where power-up sequence (that is, when current operation status is power-up sequence), delay control circuit 400 can be with The detection operation of phase-unstable period is executed when executing delay time adjustment operation according to phase detection signal PD.

When current state is not power-up sequence, delay control circuit 400 may not execute the detection of phase-unstable period Operation, and delay skip operations are executed using the result of previous phase-unstable period detection operation.In one embodiment In, delay control circuit 400 can execute the detection operation of phase-unstable period before executing delay skip operations.

The detection operation of phase-unstable period may include multiple phase detection operation set (sets).

It can be by the way that prolonging for variable delay circuit 200 be arranged differently than or increased according to the sequence of phase detection operation set The slow time executes multiple phase detection operation set.For example, can be directed to when multiple phase detection operation set are performed Each of phase detection operation set is arranged differently than delay time of variable delay circuit 200.

Each phase detection operation set may include holding when the delay time of variable delay circuit 200 is fixed Capable multiple phase-detections.

Buffer 500 can receive second clock signal FBCLK, and the signal received is exported as delay lock loop (DLL) clock signal DLLCLK.

Fig. 2 shows the configurations according to the CDL of Fig. 1 of one embodiment.

As shown in Figure 2, CDL 210 may include the first unit delay (UD) 211 and multiplexer 213.

First unit delay 211 can sequentially postpone the first clock signal ICLK, and export delayed signal.

First unit delay 211 can be designed as delay time having the same.First unit delay 211 can be matched It is set to substantially the same delay time.

Multiplexer 213 can select the output of the first unit delay 211 to believe according to the first delayed control signal CDC Any one of number, and by the way that the delay time of the first clock signal ICLK delay variation is generated output signal ICLKD。

Fig. 3 shows the configuration of the FDL of Fig. 1 according to one embodiment.

As shown in Figure 3, FDL 220 may include the second unit delay (UD) 221 and multiplexer 223.

Second unit delay 221 can sequentially postpone the output signal ICLKD of CDL 210, and export delayed Signal.

Second unit delay 221 can be designed as delay time having the same.Second unit delay 221 can be matched It is set to substantially the same delay time.

Multiplexer 223 can select the output of the second unit delay 221 to believe according to the second delayed control signal FDC Number any one of, and by by the delay time of the output signal ICLKD delay variation of CDL 210 come when generating second Clock signal FBCLK.

The second unit delay 221 of FDL 220 can be designed as with the first unit delay 211 than CDL 210 more Small delay time.The second unit delay 221 of FDL 220 can be configured as with the first unit delay than CDL 210 211 smaller delay times.

Fig. 4 shows the configuration of the phase detectors of Fig. 1 according to one embodiment.

As shown in Figure 4, phase detectors 300 may include d type flip flop.

D type flip flop can have the input terminal for being configured as receiving second clock signal FBCLK and be configured as receiving The clock terminal of first clock signal ICLK.

D type flip flop can latch second clock signal FBCLK according to the first clock signal ICLK, and export latched Signal is using as phase detection signal PD.

Fig. 5 is the waveform diagram for showing the operation of phase detectors of Fig. 4 according to one embodiment.

In Fig. 5, the waveform at top indicates the ideal waveform of the first clock signal ICLK and second clock signal FBCLK, And the waveform of bottom indicates practical wave of the first clock signal ICLK and second clock signal FBCLK in the rising edge period Shape.

As shown in the bottom of Fig. 5, based on the first clock signal ICLK and second clock signal FBCLK in the rising edge period The phase detection signal PD of waveform may not be fixed to ' 0' or ' 1', but can have any value of ' 0' or ' 1'.Cause This, which can be referred to as the phase-unstable period.

When being fixed the delay time of variable delay circuit 200, phase-detection can be performed a number of times, and can root The phase-unstable period is detected according to whether the value of the phase detection signal PD generated by multiple phase-detections is consistent with each other.

There is the smaller delay of the first unit delay 211 than CDL 210 due to the second unit delay 221 of FDL 220 Time, therefore the phase-unstable period can reduce the accuracy and speed of fine tuning.

Therefore, the phase-unstable period can detecte according to the synchronous circuit 100 of one embodiment of the disclosure, and holds When row delay skip operations are with the phase-unstable that skip detection arrives in delay time adjustment process (for example, fine-tuning process) Section, this can enable be possible to improve the operation precision and speed of synchronous circuit 100.

Fig. 6 shows the configuration of the delay control circuit of Fig. 1 according to one embodiment.

As shown in Figure 6, delay control circuit 400 can be by according to the first clock signal ICLK and phase detection signal PD executes the detection operation of phase-unstable period and skips period information SPI for postpone skip operations to generate.

Delay control circuit 400 may include skipping period information generative circuit 410 and delayed control signal generative circuit 430。

Skip period information generative circuit 410 can be by holding according to the first clock signal ICLK and phase detection signal PD The detection operation of row phase-unstable period skips period information SPI to generate.In one embodiment, period information generation is skipped Circuit 410 can execute the detection operation of phase-unstable period by executing multiple phase detection operation set.

The value for skipping period information SPI can be answered according to power up signal PWRUP by skipping period information generative circuit 410 Position.

Skipping period information generative circuit 410 may include shift register 411, logic gate 412, counter 413 and posts Storage 414.

Shift register 411 can sequentially shift phase detection signal PD, and export shifted signal.

Shift register 411 can reset the output signal of shift register 411 according to power up signal PWRUP.

Logic gate 412 can execute XOR operation to the output signal of shift register 411.Logic gate 412 can export The result of XOR operation.

Counter 413 can be counted to generate phase-unstable period meter by the output signal to logic gate 412 Number signal USTCNT.

Counter 413 can reset phase-unstable period count signal USTCNT according to power up signal PWRUP.

Register 414 can store phase-unstable period count signal USTCNT, and export stored signal to make To skip period information SPI.

Register 414 can will skip period information SPI reset according to power up signal PWRUP.

Delayed control signal generative circuit 430 can execute coarse adjustment, and determine that coarse adjustment is when thick locking is detected Through completing.In addition, delayed control signal generative circuit 430 can execute fine tuning, and determine thin when thin locking is detected Tune has been completed.

Delayed control signal generative circuit 430 can receive the first clock signal ICLK, power up signal PWRUP, phase inspection It surveys signal PD, skip period information SPI and enable signal DLLEN, and generate the delay control of the first delayed control signal CDC and second Signal FDC processed.

Delayed control signal generative circuit 430 can execute delay skip operations according to period information SPI is skipped.

Delayed control signal generative circuit 430 can be when enable signal DLLEN be activated in power-up sequence differently The delay time of multiple phase detection operation set is set, and adjusts the delay control of the first delayed control signal CDC and second Signal FDC so that respective phase detection operational set delay time can balancedly be kept.For example, working as enable signal It, can be by will include FDL's 220 via delayed control signal generative circuit 430 when DLLEN is activated in power-up sequence The delay time of second delay circuit was set as the first delay time to execute first phase detection operational set, and then might be used By setting the delay time of the second delay circuit including FDL 220 to via delayed control signal generative circuit 430 Second delay time executed second phase detection operational set.In addition, for example, first phase detection operational set may include Second including FDL 220 is being prolonged via the second delayed control signal FDC adjusted by delayed control signal generative circuit 430 The delay time of slow circuit is fixed as the multiple phase-detections executed when the first delay time, and second phase detection behaviour Making set may include that will include via the second delayed control signal FDC adjusted by delayed control signal generative circuit 430 The delay time of the second delay circuit of FDL 220 is fixed as the multiple phase-detections executed when the second delay time.

When enable signal DLLEN is activated in other periods other than the power-up sequence period, delay control letter Number generative circuit 430 can be added on the initial value of the second delayed control signal FDC by will skip period information SPI and be executed Postpone skip operations.

In one embodiment, delay control circuit 400 may include skipping period information generative circuit 410 and delay control Signal generating circuit 430 processed, and skip period information generative circuit 410 may include shift register 411, logic gate 412, Counter 413 and register 414.However, this is only example arrangement, and delayed control signal generative circuit 430 can use shape State machine is realized, or entire delay control circuit 400 can be realized with state machine.

Hereinafter, by description according to the operation of the synchronous circuit of one embodiment of the disclosure.

Fig. 7 is the flow chart for showing the operation of the synchronous circuit according to one embodiment, and Fig. 8 is shown according to a reality Apply the phase-unstable period detection method of Fig. 7 of example.

With reference to Fig. 7, in step sl, when enable signal DLLEN is activated, synchronous circuit 100 can determine current shape Whether state is power-up sequence.

The determination of power-up sequence can be according to side information (rising edge or failing edge) Lai Zhihang of power up signal PWRUP.

When the definitive result of step S1 instruction current state is power-up sequence, synchronous circuit 100 can be in step s 2 Execute the detection operation of phase-unstable period.

With reference to Fig. 8, after detecting thick locking, the detection operation of phase-unstable period may include passing through control figure 2 FDL 220 and multiple phase detection operation set in the fine-tuning process that executes.

During first phase detects operational set PDOSET, it is fixed not change in the delay time of FDL 220 When second unit delay 221 [for example, UD (FDL) ← fixation], phase-detection can be performed N times (for example, five times).

When the value of a phase detection signal PD of N (for example, five) is consistent with each other (that is, when all values are all ' 0' or be all ' When 1'), the corresponding period can be determined that the phase stabilization period.

When the value of a phase detection signal PD of N (for example, five) is consistent with each other, the logic gate 412 of Fig. 6 can export low electricity Ordinary mail number.Therefore, the value of phase-unstable period count signal USTCNT may not increase, and be held in preset value (example Such as, ' 0').

Then, the delay time of FDL 220 can increase a step-length (step) [for example, UD (FDL) ← UD+1], i.e., and Two unit delays 221 can be changed.When the state is kept, phase-detection can be performed N times (for example, five times) to hold Row second phase detects operational set.

When any one of value of a phase detection signal PD of N (for example, five) has different values, the corresponding period It can be determined that the phase-unstable period.In one embodiment, when in the value of a phase detection signal PD of N (for example, five) Any one have different values when, corresponding phase detection operation set be skipped period information generative circuit 410 detection For the phase-unstable period.

When any one of a phase detection signal PD of N (for example, five) has different values, the logic gate 412 of Fig. 6 High level signal can be exported.Therefore, phase-unstable period count USTCNT can increase.

Phase detection operation set is being repeated until detecting the phase stabilization period, synchronous circuit 100 can be completed The detection operation of phase-unstable period.

Then, in step s3, synchronous circuit 100 can by with phase-unstable period corresponding second for detecting The quantity (for example, quantity of UD) of unit delay 221, which is stored as, skips period information SPI.

For example, when detecting M phase-unstable period, it may be an indicator that the second unit is prolonged during phase-unstable Slow 221 quantity increases M [for example, increasing UD (FDL) X M].

In this case, the phase-unstable period count signal USTCNT of Fig. 6 can have corresponding with ' M' Value, and register 414 can store the value of phase-unstable period count signal USTCNT, and export stored value to make To skip period information SPI.

When the definitive result of step S1 instruction current state is not power-up sequence, synchronous circuit 100 can be in step S4 Middle execution normal delay time adjustment operation (i.e. coarse adjustment), and determine whether thick locking is detected.

When the thick locking of the definitive result of step S4 instruction is detected, synchronous circuit 100 can be in step s 5 by FDL The initial number increase of the second unit delay 221 in 220 skips period information SPI [for example, initial UD ← UD of fine-tuning process +SPI]。

Then, in step s 6, synchronous circuit 100 can execute fine tuning to determine whether thin locking is detected.

When the thin locking of the definitive result of step S6 instruction is detected, synchronous circuit 100 can determine that fine tuning is complete At, and end operation.

As described above, the initial stage with fine tuning can be skipped according to the synchronous circuit 100 of one embodiment of the disclosure Phase-unstable period corresponding second unit delay 221, and select and next phase stabilization period corresponding second Unit delay 221 is to start fine tuning.

Therefore, compared with when starting fine tuning and increasing the quantity of the second unit delay 221 one by one, synchronous circuit 100 can be more quickly completed delay time adjustment operation.Further, since the phase-unstable period is skipped, therefore delay time Adjustment operation can be precisely performed.

Although various embodiments are described above, it will be appreciated, however, by one skilled in the art that described embodiment It is only example.Therefore, the operating method of data memory device described herein should not be limited based on described embodiment.