TW201501472A - Multiplying delay lock loop - Google Patents
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本發明是有關於一種鎖定迴路,且特別是有關於一種倍頻延遲鎖定迴路。 This invention relates to a locking circuit and, more particularly, to a frequency doubled delay locked loop.
近年來,研究學者針對於影響抖動的雜訊等問題提出進一步的解決方法,例如倍頻延遲鎖相迴路(Multiplying Delay Lock Loop,MDLL)中利用在每一個參考週期時注入乾淨的參考時脈訊號以重新調整對齊時脈訊號。一般倍頻延遲鎖相迴路為利用除頻器或計數器來計算倍頻延遲鎖相迴路的時脈個數,以準確地將時脈訊號的正緣取代為參考時脈訊號的正緣,以達到調整對齊時脈訊號的目的。此方式雖可有效重新調整對齊時脈訊號,然由於除頻器或計數器須不斷地以高頻率運作,因此使得倍頻延遲鎖相迴路的功率消耗相當地大。 In recent years, researchers have proposed further solutions to problems such as noise that affect jitter, such as Multiplying Delay Lock Loop (MDLL), which uses a reference clock signal injected at each reference cycle. To realign the alignment clock signal. Generally, the frequency multiplying delay phase-locked loop is to use a frequency divider or a counter to calculate the number of clocks of the frequency-doubled delay phase-locked loop, so as to accurately replace the positive edge of the clock signal with the positive edge of the reference clock signal to achieve Adjust the purpose of aligning the clock signal. Although this method can effectively re-align the alignment clock signal, since the frequency divider or counter must constantly operate at a high frequency, the power consumption of the frequency doubled delay phase-locked loop is considerably large.
本發明提供一種倍頻延遲鎖定迴路,可有效地大幅降低功率消耗。 The invention provides a frequency doubled delay locking loop, which can effectively reduce power consumption substantially.
本發明的倍頻延遲鎖定迴路,包括第一延遲線單元、第一多工器、第二延遲線單元、除頻單元、鎖定偵測單元、切換單元、相位偵測單元、電荷幫浦以及迴路濾波器。其中第一延遲線單元延遲第一參考時脈訊號以產生起始時脈訊號、輸入參考時脈訊號以及結束時脈訊號,其中輸入參考時脈訊號的延遲時間大於起始時脈訊號且小於結束時脈訊號。第一多工器之第一輸入端耦接第一延遲線單元。第二延遲線單元之輸入端與輸出端分別耦接第一多工器的第二輸入端與輸出端,延遲第一多工器所輸出之訊號,以產生第二參考時脈訊號以及輸出時脈訊號,其中第二參考時脈訊號的延遲時間小於輸出時脈訊號。除頻單元耦接第二延遲線單元,除頻第二參考時脈訊號以產生除頻訊號。鎖定偵測單元耦接除頻單元與第一延遲線單元,於輸出時脈訊號穩定時輸出鎖定訊號。切換單元耦接第一延遲線單元、鎖定偵測單元、第一多工器的控制端,於接受鎖定訊號後被致能,依據起始時脈訊號以及結束時脈訊號輸出選擇控制訊號,以控制第一多工器選擇輸出輸入參考時脈訊號或輸出時脈訊號。相位偵測單元耦接除頻單元與鎖定偵測單元,於接受該鎖定訊號後偵測輸出時脈訊號與輸入參考時脈訊號的相位差而輸出偵測訊號。電荷幫浦耦接相位偵測單元,依據偵測訊號輸出控制訊號。迴路濾波器耦接電荷幫浦與第二延遲線單元,依據控制訊號輸出延遲控制訊號至第二延遲線單元,以控制第二延遲線單元的延遲時間。 The frequency doubled delay locked loop of the present invention comprises a first delay line unit, a first multiplexer, a second delay line unit, a frequency dividing unit, a lock detecting unit, a switching unit, a phase detecting unit, a charge pump and a circuit filter. The first delay line unit delays the first reference clock signal to generate a start clock signal, an input reference clock signal, and an end clock signal, wherein the delay time of the input reference clock signal is greater than the initial clock signal and less than the end. Clock signal. The first input end of the first multiplexer is coupled to the first delay line unit. The input end and the output end of the second delay line unit are respectively coupled to the second input end and the output end of the first multiplexer, delaying the signal output by the first multiplexer to generate the second reference clock signal and the output time The pulse signal, wherein the delay time of the second reference clock signal is less than the output clock signal. The frequency dividing unit is coupled to the second delay line unit, and divides the second reference clock signal to generate a frequency dividing signal. The lock detection unit is coupled to the frequency division unit and the first delay line unit, and outputs a lock signal when the output clock signal is stable. The switching unit is coupled to the first delay line unit, the lock detecting unit, and the control end of the first multiplexer, and is enabled after receiving the lock signal, and selects the control signal according to the start clock signal and the end clock signal output. Control the first multiplexer to select the output input reference clock signal or output clock signal. The phase detecting unit is coupled to the frequency dividing unit and the lock detecting unit, and after receiving the lock signal, detects a phase difference between the output clock signal and the input reference clock signal to output a detection signal. The charge pump is coupled to the phase detection unit to output a control signal according to the detection signal. The loop filter is coupled to the charge pump and the second delay line unit, and outputs a delay control signal to the second delay line unit according to the control signal to control the delay time of the second delay line unit.
在本發明的一實施例中,上述的相位偵測單元更於接收 鎖定訊號後,於第一多工器選擇輸出輸出時脈訊號的期間被關閉,並於第一多工器選擇輸出輸入參考時脈訊號的期間被啟動。 In an embodiment of the invention, the phase detecting unit is further configured to receive After the signal is locked, the period of the first multiplexer selects the output output clock signal is turned off, and is started during the period in which the first multiplexer selects the output input reference clock signal.
在本發明的一實施例中,上述的相位偵測單元更於接受該鎖定訊號前,偵測除頻訊號與輸入參考時脈訊號的相位差而輸出偵測訊號。 In an embodiment of the invention, the phase detecting unit detects the phase difference between the de-frequency signal and the input reference clock signal and outputs the detection signal before receiving the lock signal.
在本發明的一實施例中,上述的鎖定偵測單元更判斷除頻訊號與輸入參考時脈訊號的相位差是否小於預設值,當除頻訊號與輸入參考時脈訊號的相位差小於預設值時,判斷輸出時脈訊號為穩定。 In an embodiment of the invention, the lock detecting unit further determines whether the phase difference between the frequency-divided signal and the input reference clock signal is less than a preset value, and the phase difference between the frequency-divided signal and the input reference clock signal is less than a preset value. When setting the value, it is judged that the output clock signal is stable.
在本發明的一實施例中,上述的切換單元於接收到起始時脈訊號後且未接收到結束時脈訊號前,控制第一多工器選擇輸出輸入參考時脈訊號。 In an embodiment of the invention, the switching unit controls the first multiplexer to select an output input reference clock signal after receiving the initial clock signal and before receiving the end pulse signal.
在本發明的一實施例中,上述的相位偵測單元包括第二多工器、相位偵測器以及第一開關。其中第二多工器之第一輸入端、選擇控制端與輸出端分別耦接第二延遲線單元、除頻單元、鎖定偵測單元與相位偵測器,依據鎖定訊號,選擇輸出除頻訊號或輸出時脈訊號。相位偵測器耦接第二多工器的輸出端、第一延遲線單元以及電荷幫浦,偵測第二多工器輸出的訊號與輸入參考時脈訊號的相位差以輸出偵測訊號。第一開關耦接於第二多工器之第二輸入端與第二延遲線單元之間,第一開關的導通狀態受控於選擇控制訊號,其中第一開關於該切換單元接收到起始時脈訊號後且未接收到結束時脈訊號前的期間處於導通狀態,而在切換 單元接收到結束時脈訊號後且未接收到起始時脈訊號前的期間處於斷開狀態。 In an embodiment of the invention, the phase detecting unit includes a second multiplexer, a phase detector, and a first switch. The first input end, the selection control end and the output end of the second multiplexer are respectively coupled to the second delay line unit, the frequency dividing unit, the lock detecting unit and the phase detector, and select the output frequency dividing signal according to the locking signal. Or output a clock signal. The phase detector is coupled to the output end of the second multiplexer, the first delay line unit, and the charge pump, and detects a phase difference between the signal output by the second multiplexer and the input reference clock signal to output the detection signal. The first switch is coupled between the second input end of the second multiplexer and the second delay line unit, and the conductive state of the first switch is controlled by the selection control signal, wherein the first switch receives the start at the switching unit After the clock signal and after the end of the pulse signal is not received, the period before the pulse signal is on, but is switched. The unit is in the off state after receiving the end pulse signal and before receiving the start clock signal.
在本發明的一實施例中,上述的相位偵測單元更包括第二開關、第三多工器、第三開關以及第四開關。其中第二開關耦接於第二多工器的第一輸入端與除頻單元之間。第三多工器之輸出端與選擇控制端分別耦接相位偵測器與鎖定偵測單元。第三開關耦接於第三多工器的第一輸入端與第一延遲線單元之間,用以接收輸入參考時脈訊號。第四開關耦接於第三多工器的第二輸入端與第一延遲線單元之間,用以接收輸入參考時脈訊號,其中第二開關、第三開關以及第四開關為常導通的狀態。 In an embodiment of the invention, the phase detecting unit further includes a second switch, a third multiplexer, a third switch, and a fourth switch. The second switch is coupled between the first input end of the second multiplexer and the frequency dividing unit. The output end of the third multiplexer and the selection control end are respectively coupled to the phase detector and the lock detection unit. The third switch is coupled between the first input end of the third multiplexer and the first delay line unit for receiving the input reference clock signal. The fourth switch is coupled between the second input end of the third multiplexer and the first delay line unit for receiving the input reference clock signal, wherein the second switch, the third switch, and the fourth switch are normally conducting status.
在本發明的一實施例中,上述的第一延遲線單元包括第一延遲元件、第二延遲元件以及第三延遲元件。其中第一延遲元件延遲第一參考時脈訊號以產生起始時脈訊號。第二延遲元件延遲起始時脈訊號以產生輸入參考時脈訊號。其中第一延遲元件、第二延遲元件以及第三延遲元件串接於第一延遲線單元的輸入端與切換單元之間,第三延遲元件延遲輸入參考時脈訊號以產生結束時脈訊號。 In an embodiment of the invention, the first delay line unit includes a first delay element, a second delay element, and a third delay element. The first delay element delays the first reference clock signal to generate a starting clock signal. The second delay element delays the start clock signal to generate an input reference clock signal. The first delay element, the second delay element and the third delay element are connected in series between the input end of the first delay line unit and the switching unit, and the third delay element delays inputting the reference clock signal to generate an end clock signal.
在本發明的一實施例中,上述的第二延遲線單元包括多個第四延遲元件,其串接於第一多工器的第二輸入端與輸出端之間,於第四延遲元件中的最後一個第四延遲元件輸出輸出時脈訊號,並於最後一個第四延遲元件外的第四延遲元件之其一輸出第二參考時脈訊號。 In an embodiment of the invention, the second delay line unit includes a plurality of fourth delay elements connected in series between the second input end and the output end of the first multiplexer, in the fourth delay element. The last fourth delay element outputs an output clock signal, and one of the fourth delay elements outside the last fourth delay element outputs a second reference clock signal.
基於上述,本發明藉由第一延遲線單元延遲第一參考時脈訊號所產生的起始時脈訊號與結束時脈訊號來決定注入輸入參考時脈訊號時間點,如此便不須如習知技術般藉由除頻器或計數器來計算注入輸入參考時脈訊號的時間點,即可週期性地注入輸入參考時脈訊號,進而大幅降低倍頻延遲鎖定迴路的功率消耗。 Based on the above, the first delay line unit delays the start clock signal and the end clock signal generated by the first reference clock signal to determine the time point for injecting the input reference clock signal, so that it is not necessary to be known. The frequency point of the input reference reference clock signal is calculated by the frequency divider or the counter, and the input reference clock signal can be periodically injected, thereby greatly reducing the power consumption of the double frequency delay locked loop.
為讓本發明的上述特徵和優點能更明顯易懂,下文特舉實施例,並配合所附圖式作詳細說明如下。 The above described features and advantages of the invention will be apparent from the following description.
100、300‧‧‧倍頻延遲鎖定迴路 100, 300‧‧‧ double frequency delay locked loop
102‧‧‧延遲線單元 102‧‧‧delay line unit
104、302、304‧‧‧多工器 104, 302, 304‧‧‧ multiplexers
106‧‧‧延遲線單元 106‧‧‧delay line unit
108‧‧‧除頻單元 108‧‧‧Dividing unit
110‧‧‧鎖定偵測單元 110‧‧‧Lock detection unit
112‧‧‧切換單元 112‧‧‧Switch unit
114‧‧‧相位偵測單元 114‧‧‧ phase detection unit
116‧‧‧電荷幫浦 116‧‧‧Charge pump
118‧‧‧迴路濾波器 118‧‧‧ Loop Filter
306‧‧‧相位偵測器 306‧‧‧ phase detector
CLK1‧‧‧參考時脈訊號 CLK1‧‧‧ reference clock signal
CLKS‧‧‧起始時脈訊號 CLKS‧‧‧ starting clock signal
CLKR‧‧‧輸入參考時脈訊號 CLKR‧‧‧ input reference clock signal
CLKE‧‧‧結束時脈訊號 CLKE‧‧‧End clock signal
CLK2‧‧‧參考時脈訊號 CLK2‧‧‧ reference clock signal
CLKO‧‧‧輸出時脈訊號 CLKO‧‧‧ output clock signal
Dclk‧‧‧除頻訊號 Dclk‧‧‧frequency signal
SD1‧‧‧偵測訊號 SD1‧‧‧ detection signal
SC1‧‧‧控制訊號 SC1‧‧‧ control signal
SEL‧‧‧選擇控制訊號 SEL‧‧‧Select control signal
Vcon‧‧‧延遲控制訊號 Vcon‧‧‧delay control signal
LK1‧‧‧鎖定訊號 LK1‧‧‧Lock signal
(1)~(4)‧‧‧時脈訊號的正緣 (1) ~ (4) ‧ ‧ the positive edge of the pulse signal
(5)‧‧‧輸入參考時脈訊號的正緣 (5) ‧‧‧Enter the positive edge of the reference clock signal
(1')~(4')‧‧‧相位差 (1')~(4')‧‧‧ phase difference
D1~D9‧‧‧延遲元件 D1~D9‧‧‧ delay element
SW1~SW4‧‧‧開關 SW1~SW4‧‧‧ switch
圖1繪示為本發明一實施例之倍頻延遲鎖定迴路的示意圖。 FIG. 1 is a schematic diagram of a frequency doubled delay locked loop according to an embodiment of the invention.
圖2繪示為本發明一實施例之倍頻延遲鎖定迴路的時脈訊號的相位調整示意圖。 FIG. 2 is a schematic diagram showing phase adjustment of a clock signal of a frequency doubled delay locked loop according to an embodiment of the invention.
圖3繪示為本發明另一實施例之倍頻延遲鎖定迴路的示意圖。 3 is a schematic diagram of a frequency doubled delay locked loop according to another embodiment of the present invention.
圖1繪示為本發明一實施例之倍頻延遲鎖定迴路的示意圖。請參照圖1,倍頻延遲鎖定迴路100包括延遲線單元102、多工器104、延遲線單元106、除頻單元108、鎖定偵測單元110、切換單元112、相位偵測單元114、電荷幫浦116以及迴路濾波器118。其中延遲線單元102耦接多工器104的第一輸入端,延遲線 單元106耦接於多工器104的第二輸入端與輸出端之間,切換單元112耦接延遲線單元102、多工器104的選擇控制端以及鎖定偵測單元110。除頻單元108耦接延遲線單元106、鎖定偵測單元110以及相位偵測單元114,其中鎖定偵測單元110更耦接延遲線單元102與相位偵測單元114,相位偵測單元114更耦接延遲線單元102與延遲線單元106。電荷幫浦116耦接相位偵測單元114與迴路濾波器118,迴路濾波器118則耦接延遲線單元106。 FIG. 1 is a schematic diagram of a frequency doubled delay locked loop according to an embodiment of the invention. Referring to FIG. 1 , the multi-frequency delay locked loop 100 includes a delay line unit 102 , a multiplexer 104 , a delay line unit 106 , a frequency dividing unit 108 , a lock detecting unit 110 , a switching unit 112 , a phase detecting unit 114 , and a charge Pu 116 and loop filter 118. The delay line unit 102 is coupled to the first input end of the multiplexer 104, and the delay line The unit 106 is coupled between the second input end and the output end of the multiplexer 104. The switching unit 112 is coupled to the delay line unit 102, the selection control end of the multiplexer 104, and the lock detecting unit 110. The frequency dividing unit 108 is coupled to the delay line unit 106, the lock detecting unit 110, and the phase detecting unit 114. The lock detecting unit 110 is further coupled to the delay line unit 102 and the phase detecting unit 114. The phase detecting unit 114 is more coupled. The delay line unit 102 and the delay line unit 106 are connected. The charge pump 116 is coupled to the phase detecting unit 114 and the loop filter 118, and the loop filter 118 is coupled to the delay line unit 106.
延遲線單元102用以延遲參考時脈訊號CLK1,以產生起始時脈訊號CLKS、輸入參考時脈訊號CLKR以及結束時脈訊號CLKE,其中輸入參考時脈訊號CLKR的延遲時間大於起始時脈訊號CLKS且小於結束時脈訊號CLKE。輸入參考時脈訊號CLKR被輸入至多工器104的第一輸入端以及相位偵測單元114。延遲線單元106延遲多工器104所輸出之訊號而產生參考時脈訊號CLK2與輸出時脈訊號CLKO,其中參考時脈訊號CLK2的延遲時間小於輸出時脈訊號CLKO。除頻單元108對參考時脈訊號CLK2進行除頻,以產生除頻訊號Dclk。相位偵測單元114比較除頻訊號Dclk與輸入參考時脈訊號CLKR的相位差而輸出偵測訊號SD1,電荷幫浦116依據偵測訊號SD1產生控制訊號SC1至迴路濾波器118,以使迴路濾波器118依據控制訊號SC1輸出延遲控制訊號Vcon至延遲線單元106,進而控制延遲線單元106的延遲時間,以調整輸出時脈訊號CLKO的頻率,鎖定輸出時脈訊號_CLKO的相位。 The delay line unit 102 is configured to delay the reference clock signal CLK1 to generate a start clock signal CLKS, an input reference clock signal CLKR, and an end clock signal CLKE, wherein the delay time of the input reference clock signal CLKR is greater than the start clock. The signal CLKS is less than the end pulse signal CLKE. The input reference clock signal CLKR is input to the first input of the multiplexer 104 and the phase detecting unit 114. The delay line unit 106 delays the signal output by the multiplexer 104 to generate the reference clock signal CLK2 and the output clock signal CLKO, wherein the delay time of the reference clock signal CLK2 is smaller than the output clock signal CLKO. The frequency dividing unit 108 divides the reference clock signal CLK2 to generate the frequency dividing signal Dclk. The phase detecting unit 114 compares the phase difference between the frequency signal Dclk and the input reference clock signal CLKR to output a detection signal SD1, and the charge pump 116 generates a control signal SC1 to the loop filter 118 according to the detection signal SD1 to filter the loop. The controller 118 outputs the delay control signal Vcon to the delay line unit 106 according to the control signal SC1, thereby controlling the delay time of the delay line unit 106 to adjust the frequency of the output clock signal CLKO, and locks the phase of the output clock signal _CLKO.
在倍頻延遲鎖定迴路100的時脈訊號尚未穩定時,延遲 線單元102、多工器104、延遲線單元106、除頻單元108、相位偵測單元114、電荷幫浦116以及迴路濾波器118構成的鎖相迴路對倍頻延遲鎖定迴路100的時脈訊號進行鎖相。待鎖定偵測單元110偵測到除頻單元108所輸出的除頻訊號Dclk與輸入參考時脈訊號CLKR的相位差小於一預設值,亦即倍頻延遲鎖定迴路100的時脈訊號穩定後,鎖定偵測單元110輸出鎖定訊號LK1至切換單元112與相位偵測單元114。 Delay when the clock signal of the frequency doubled delay locked loop 100 has not stabilized The clock signal formed by the line-locking loop formed by the line unit 102, the multiplexer 104, the delay line unit 106, the frequency dividing unit 108, the phase detecting unit 114, the charge pump 116, and the loop filter 118 is applied to the multi-frequency delay locked loop 100. Make phase locks. The lock detection unit 110 detects that the phase difference between the frequency-divided signal Dclk output by the frequency-dividing unit 108 and the input reference clock signal CLKR is less than a preset value, that is, after the clock signal of the double-frequency delay lock loop 100 is stabilized. The lock detecting unit 110 outputs the lock signal LK1 to the switching unit 112 and the phase detecting unit 114.
其中,當相位偵測單元114接收到鎖定訊號LK1後,相位偵測單元114便轉為藉由偵測輸出時脈訊號CLKO與輸入參考時脈訊號CLKR的相位差來輸出偵測訊號SD1。而切換單元112被鎖定訊號LK1致能後,則開始依據起始時脈訊號CLKS以及結束時脈訊號CLKE來輸出選擇控制訊號SEL至多工器104,以控制多工器104將輸入參考時脈訊號CLKR或輸出時脈訊號CLKO輸出至延遲線單元106。詳細來說,切換單元112於接收到起始時脈訊號CLKS後到接收到結束時脈訊號CLKE前的期間內控制多工器104輸出其第一輸入端所接收的訊號,而於接收到結束時脈訊號CLKE後到接收到起始時脈訊號CLKS前的期間內控制多工器104輸出其第二輸入端所接收的訊號。此外,相位偵測單元114在接收到鎖定訊號LK1後,於多工器104輸出其第一輸入端所接收的訊號的期間被啟動,並於多工器104輸出其第二輸入端所接收的訊號的期間處於被關閉。由於輸入參考時脈訊號CLKR的延遲時間大於起始時脈訊號CLKS且小於結束時脈訊號CLKE,因此 輸入參考時脈訊號CLKR可在切換單元112接收到起始時脈訊號CLKS後且未接收到結束時脈訊號CLKE前,透過多工器104被輸入至延遲線單元106,以重新調整倍頻延遲鎖定迴路100的時脈訊號的相位,使其與輸入參考時脈訊號CLKR對齊,進而消除輸出時脈訊號CLKO的抖動,使輸出時脈訊號CLKO更加穩定。 After the phase detecting unit 114 receives the lock signal LK1, the phase detecting unit 114 converts the detection signal SD1 by detecting the phase difference between the output clock signal CLKO and the input reference clock signal CLKR. After the switching unit 112 is enabled by the lock signal LK1, the selection control signal SEL is output to the multiplexer 104 according to the start clock signal CLKS and the end clock signal CLKE to control the multiplexer 104 to input the reference clock signal. The CLKR or output clock signal CLKO is output to the delay line unit 106. In detail, the switching unit 112 controls the multiplexer 104 to output the signal received by the first input terminal after receiving the initial clock signal CLKS and before receiving the end pulse signal CLKE, and the end of the reception is received. The multiplexer 104 outputs the signal received by the second input terminal thereof after the clock signal CLKE and before the start of the start pulse signal CLKS. In addition, after receiving the lock signal LK1, the phase detecting unit 114 is activated during the period when the multiplexer 104 outputs the signal received by the first input terminal, and outputs the second input terminal received by the multiplexer 104. The period of the signal is being turned off. Since the delay time of the input reference clock signal CLKR is greater than the start pulse signal CLKS and less than the end pulse signal CLKE, The input reference clock signal CLKR can be input to the delay line unit 106 through the multiplexer 104 after the switching unit 112 receives the start clock signal CLKS and does not receive the end pulse signal CLKE to re-adjust the frequency doubling delay. The phase of the clock signal of the loop 100 is locked to be aligned with the input reference clock signal CLKR, thereby eliminating the jitter of the output clock signal CLKO and making the output clock signal CLKO more stable.
如圖2之倍頻延遲鎖定迴路的時脈訊號的相位調整示意圖所示,其中編號(1)~(4)的訊號波形為相位領先或落後的倍頻延遲鎖定迴路100的時脈訊號的正緣,編號(5)則為輸入參考時脈訊號CLKR的正緣,虛線所圍的區間則為多工器104輸出其第一輸入端所接收之訊號(亦即輸入參考時脈訊號CLKR)的期間,在本實施例中,其可視為選擇控制訊號SEL被致能而處於高電壓準位的期間。 As shown in the phase adjustment diagram of the clock signal of the double-frequency delay locked loop of FIG. 2, the signal waveforms of the numbers (1) to (4) are positive of the clock signal of the multi-frequency delay locked loop 100 with phase leading or backward. Edge, number (5) is the positive edge of the input reference clock signal CLKR, and the interval surrounded by the dotted line is the signal that the multiplexer 104 outputs at the first input end (ie, the input reference clock signal CLKR) During this embodiment, it can be regarded as a period during which the selection control signal SEL is enabled and is at a high voltage level.
如圖2所示,當倍頻延遲鎖定迴路100的時脈訊號的相位領先或落後的程度不大時,如編號(3)、(4)的正緣仍落在虛線所圍的區間,亦即倍頻延遲鎖定迴路100的時脈訊號與輸入參考時脈訊號CLKR的相位差(編號(3')、(4'))仍不大時,藉由注入輸入參考時脈訊號CLKR,將倍頻延遲鎖定迴路100的時脈訊號的正緣取代為輸入參考時脈訊號CLKR的正緣,以將輸入參考時脈訊號CLKR與倍頻延遲鎖定迴路100的時脈訊號的相位差傳送到電荷幫浦116。此外,若倍頻延遲鎖定迴路100的時脈訊號與輸入參考時脈訊號CLKR的相位差較大時,由於倍頻延遲鎖定迴路100的時脈訊號的正緣已落在虛線所圍的區間外,因此藉由注入輸入參 考時脈訊號CLKR所傳送給電荷幫浦116的相位差有限(如編號(1')、(2')),但仍可藉由下一次輸入參考時脈訊號CLKR的注入來完成相位差的調整。 As shown in FIG. 2, when the phase of the clock signal of the double-frequency delay locked loop 100 is not leading or falling behind, the positive edges of the numbers (3) and (4) still fall within the interval surrounded by the dotted line. That is, when the phase difference between the clock signal of the multi-frequency delay locked loop 100 and the input reference clock signal CLKR (number (3'), (4')) is still not large, the injection reference signal pulse signal CLKR is injected. The positive edge of the clock signal of the frequency delay locked loop 100 is replaced by the positive edge of the input reference clock signal CLKR to transmit the phase difference between the input reference clock signal CLKR and the clock signal of the double frequency delay locked loop 100 to the charge Pu 116. In addition, if the phase difference between the clock signal of the double-frequency delay locked loop 100 and the input reference clock signal CLKR is large, the positive edge of the clock signal of the double-frequency delay locked loop 100 has fallen outside the interval surrounded by the dotted line. Therefore, by injecting input parameters The phase difference transmitted by the clock signal CLKR to the charge pump 116 is limited (such as number (1'), (2')), but the phase difference can still be completed by the injection of the next input reference clock signal CLKR. Adjustment.
值得注意的是,本實施例的8在輸出時脈訊號CLKO穩定後,亦即鎖定偵測單元110輸出鎖定訊號LK1後,除頻單元10即可被禁能,而不須再執行除頻的操作,因此可大幅遞減低功率的消耗。此外,由於藉由切換單元112即可延遲線單元102所產生的起始時脈訊號CLKS以及結束時脈訊號CLKE來控制注入參考時脈訊號CLKR的時間點,因此不須除頻器或計數器來計數時脈訊號的時脈個數,即可週期性地持續注入參考時脈訊號CLKR來消除輸出時脈訊號CLKO的抖動,使輸出時脈訊號CLKO更加穩定,大幅地降低倍頻延遲鎖定迴路100的功率消耗。 It should be noted that after the output clock signal CLKO is stabilized, that is, after the lock detecting unit 110 outputs the lock signal LK1, the frequency dividing unit 10 can be disabled without performing frequency division. Operation, so the power consumption of the low power can be greatly reduced. In addition, since the switching unit 112 can delay the start clock signal CLKS and the end clock signal CLKE generated by the line unit 102 to control the time point of injecting the reference clock signal CLKR, the frequency divider or counter is not required. By counting the number of clocks of the clock signal, the reference clock signal CLKR can be continuously injected periodically to eliminate the jitter of the output clock signal CLKO, so that the output clock signal CLKO is more stable, and the double frequency delay lock loop 100 is greatly reduced. Power consumption.
圖3繪示為本發明另一實施例之倍頻延遲鎖定迴路的示意圖。請參照圖3,進一步來說,圖1之延遲線單元102、延遲線單元106以及相位偵測單元114的實施方式可如圖3所示。在本實施例之倍頻延遲鎖定迴路300中,延遲線單元102包括延遲元件D1~D3,延遲線單元106則包括延遲元件D4~D9,值得注意的是,上述延遲元件的編號方式僅是為了說明方便,並非用以限定各個延遲元件間是否具有相同或不同的特性。此外,相位偵測單元114則包括開關SW1~SW4、多工器302、多工器304以及相位偵測器306。其中延遲元件D1~D3串接於延遲線單元102的輸入端與切換單元112之間,延遲元件D1用以延遲參考時脈訊號CLK1 以產生起始時脈訊號CLKS,延遲元件D2用以延遲起始時脈訊號CLKS以產生輸入參考時脈訊號CLKR,延遲元件D3則用以延遲輸入參考時脈訊號CLKR以產生結束時脈訊號CLKE。 3 is a schematic diagram of a frequency doubled delay locked loop according to another embodiment of the present invention. Referring to FIG. 3, further, the implementation of the delay line unit 102, the delay line unit 106, and the phase detecting unit 114 of FIG. 1 can be as shown in FIG. In the frequency doubled delay locked loop 300 of the present embodiment, the delay line unit 102 includes delay elements D1 to D3, and the delay line unit 106 includes delay elements D4 to D9. It is noted that the delay elements are numbered only for the purpose of The description is convenient and is not intended to define whether the individual delay elements have the same or different characteristics. In addition, the phase detecting unit 114 includes switches SW1 SW SW4 , a multiplexer 302 , a multiplexer 304 , and a phase detector 306 . The delay elements D1 D D3 are connected in series between the input end of the delay line unit 102 and the switching unit 112, and the delay element D1 is used to delay the reference clock signal CLK1. To generate the initial clock signal CLKS, the delay element D2 is used to delay the start clock signal CLKS to generate the input reference clock signal CLKR, and the delay element D3 is used to delay the input reference clock signal CLKR to generate the end clock signal CLKE. .
延遲元件D4~D9串接於多工器104的第二輸入端與輸出端之間,在本實施例中,參考時脈訊號CLK2為由延遲元件D6所輸出,然實際應用上並不以此為限,在其他實施例中亦可選擇其他的延遲元件來輸出,此外輸出時脈訊號CLKO則由延遲元件D9所輸出。此外,在實際應用上,上述延遲線單元102與延遲線單元106所包含的延遲元件個數並不以本實施例為限,電路設計者可依實際應用需求增減延遲元件的個數來調整延遲時間,或直接藉由調整延遲控制訊號Vcon的電壓值來控制延遲時間。 The delay elements D4 to D9 are connected in series between the second input end and the output end of the multiplexer 104. In this embodiment, the reference clock signal CLK2 is output by the delay element D6, but the actual application does not In other embodiments, other delay elements may be selected for output, and the output clock signal CLKO is output by the delay element D9. In addition, in practical applications, the number of delay elements included in the delay line unit 102 and the delay line unit 106 is not limited to this embodiment, and the circuit designer can adjust the number of delay elements according to actual application requirements. The delay time, or directly by adjusting the voltage value of the delay control signal Vcon to control the delay time.
此外,在相位偵測單元114中,開關SW1耦接於延遲元件D9的輸出端與多工器302的第二輸入端之間,開關SW2耦接於除頻單元108與多工器302的第一輸入端之間,開關SW3耦接於延遲元件D2的輸出端與多工器304的第一輸入端之間,開關SW4耦接於延遲元件D2的輸出端與多工器304的第二輸入端之間。多工器302與多工器304的選擇控制端接耦接至鎖定偵測單元110,多工器302與多工器304的輸出端則耦接相位偵測器306,而相位偵測器306則更耦接至電荷幫浦116。 In addition, in the phase detecting unit 114, the switch SW1 is coupled between the output end of the delay element D9 and the second input end of the multiplexer 302, and the switch SW2 is coupled to the frequency dividing unit 108 and the multiplexer 302. Between an input terminal, the switch SW3 is coupled between the output end of the delay element D2 and the first input end of the multiplexer 304, and the switch SW4 is coupled to the output end of the delay element D2 and the second input of the multiplexer 304. Between the ends. The multiplexer 302 and the selection control terminal of the multiplexer 304 are coupled to the lock detection unit 110, and the outputs of the multiplexer 302 and the multiplexer 304 are coupled to the phase detector 306, and the phase detector 306 It is further coupled to the charge pump 116.
其中,多工器302受控於鎖定偵測單元110輸出鎖定訊號LK1,而在倍頻延遲鎖定迴路100的時脈訊號尚未穩定時,亦即在接收到鎖定訊號LK1前,輸出第一輸入端所接收的訊號,亦 即輸出除頻訊號Dclk,而在接收到鎖定訊號LK1後,輸出第二輸入端所接收的訊號,亦即輸出輸出時脈訊號CLKO,以使相位偵測器306可在不同的狀態下,偵測多工器104所輸出的訊號(除頻訊號Dclk或輸出時脈訊號CLKO)與參考時脈訊號CLKR的的相位差而輸出偵測訊號SD1。 The multiplexer 302 is controlled by the lock detecting unit 110 to output the lock signal LK1, and when the clock signal of the double frequency delay lock loop 100 is not stable, that is, before the lock signal LK1 is received, the first input end is output. Received signal, also That is, after the frequency signal Dclk is output, after receiving the lock signal LK1, the signal received by the second input terminal is output, that is, the output clock signal CLKO is output, so that the phase detector 306 can detect in different states. The phase difference between the signal output by the multiplexer 104 (except the frequency signal Dclk or the output clock signal CLKO) and the reference clock signal CLKR is outputted to output the detection signal SD1.
其中,在鎖定偵測單元110輸出鎖定訊號LK1致能切換112後,開關SW1的導通狀態受控於選擇控制訊號SEL,亦即開關SW1在切換單元112接收到起始時脈訊號CLKS後且未接收到結束時脈訊號CLKE前的期間為處於導通狀態,而切換單元112接收到結束時脈訊號CLKE後且未接收到起始時脈訊號CLKS前的期間為處於斷開狀態。如此一來,相位偵測器306便可在多工器104輸出參考時脈訊號CLKR的期間被致能而偵測輸出時脈訊號CLKO與輸入參考時脈訊號CLKR的相位差以輸出偵測訊號SD1,並在多工器104輸出回授的輸出時脈訊號CLKO的期間被禁能。 After the lock detection unit 110 outputs the lock signal LK1 enable switch 112, the on state of the switch SW1 is controlled by the selection control signal SEL, that is, the switch SW1 is not after the switch unit 112 receives the start pulse signal CLKS. The period before the end of the pulse signal CLKE is received, and the period after the switching unit 112 receives the end pulse signal CLKE and before the start pulse signal CLKS is received is in the off state. In this way, the phase detector 306 can be enabled during the output of the reference clock signal CLKR by the multiplexer 104 to detect the phase difference between the output clock signal CLKO and the input reference clock signal CLKR to output the detection signal. SD1 is disabled during the period when the multiplexer 104 outputs the feedback output clock signal CLKO.
此外,在本實施例中,開關SW2~SW4為常導通的狀態,另外由於多工器304的兩個輸入端皆接收輸入參考時脈訊號CLKR,因此多工器304是否接收到鎖定訊號LK1並不影響多工器304的輸出,開關SW2~SW4以及多工器304的設置僅是為了使傳輸輸出時脈訊號CLKO與除頻訊號Dclk的通道與傳輸輸入參考時脈訊號CLKR的通道特性能夠匹配,在部分實施例中相位偵測單元114亦可不包括開關SW2~SW4以及多工器304。 In addition, in the embodiment, the switches SW2 SW SW4 are in a normally-on state, and since both input terminals of the multiplexer 304 receive the input reference clock signal CLKR, whether the multiplexer 304 receives the lock signal LK1 and The output of the multiplexer 304 is not affected, and the switches SW2~SW4 and the multiplexer 304 are only set to match the channel characteristics of the channel of the transmission output clock signal CLKO and the frequency division signal Dclk and the transmission input reference clock signal CLKR. In some embodiments, the phase detecting unit 114 may not include the switches SW2 SW SW4 and the multiplexer 304.
綜上所述,本發明藉由第一延遲線單元延遲第一參考時脈訊號所產生的起始時脈訊號與結束時脈訊號來決定注入輸入參考時脈訊號時間點,如此便不須如習知技術般藉由除頻器或計數器來計算注入輸入參考時脈訊號的時間點,即可週期性地注入輸入參考時脈訊號,進而大幅降低倍頻延遲鎖定迴路的功率消耗。 In summary, the first delay line unit delays the start clock signal and the end clock signal generated by the first reference clock signal to determine the time point for injecting the input reference clock signal, so that it is not necessary As is known in the art, by using a frequency divider or a counter to calculate the time point at which the input reference clock signal is injected, the input reference clock signal can be periodically injected, thereby greatly reducing the power consumption of the double frequency delay locked loop.
100‧‧‧倍頻延遲鎖定迴路 100‧‧‧Multiplier delay locked loop
102‧‧‧延遲線單元 102‧‧‧delay line unit
104‧‧‧多工器 104‧‧‧Multiplexer
106‧‧‧延遲線單元 106‧‧‧delay line unit
108‧‧‧除頻單元 108‧‧‧Dividing unit
110‧‧‧鎖定偵測單元 110‧‧‧Lock detection unit
112‧‧‧切換單元 112‧‧‧Switch unit
114‧‧‧相位偵測單元 114‧‧‧ phase detection unit
116‧‧‧電荷幫浦 116‧‧‧Charge pump
118‧‧‧迴路濾波器 118‧‧‧ Loop Filter
CLK1‧‧‧參考時脈訊號 CLK1‧‧‧ reference clock signal
CLKS‧‧‧起始時脈訊號 CLKS‧‧‧ starting clock signal
CLKR‧‧‧輸入參考時脈訊號 CLKR‧‧‧ input reference clock signal
CLKE‧‧‧結束時脈訊號 CLKE‧‧‧End clock signal
CLK2‧‧‧參考時脈訊號 CLK2‧‧‧ reference clock signal
CLKO‧‧‧輸出時脈訊號 CLKO‧‧‧ output clock signal
Dclk‧‧‧除頻訊號 Dclk‧‧‧frequency signal
SD1‧‧‧偵測訊號 SD1‧‧‧ detection signal
SC1‧‧‧控制訊號 SC1‧‧‧ control signal
Vcon‧‧‧延遲控制訊號 Vcon‧‧‧delay control signal
LK1‧‧‧鎖定訊號 LK1‧‧‧Lock signal
SEL‧‧‧選擇控制訊號 SEL‧‧‧Select control signal
Claims (9)
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TW102121759A TWI483554B (en) | 2013-06-19 | 2013-06-19 | Multiplying delay lock loop |
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TW102121759A TWI483554B (en) | 2013-06-19 | 2013-06-19 | Multiplying delay lock loop |
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TW201501472A true TW201501472A (en) | 2015-01-01 |
TWI483554B TWI483554B (en) | 2015-05-01 |
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TW102121759A TWI483554B (en) | 2013-06-19 | 2013-06-19 | Multiplying delay lock loop |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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TWI744143B (en) * | 2020-08-13 | 2021-10-21 | 瑞昱半導體股份有限公司 | Frequency doubler with duty cycle control and method thereof |
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US5724007A (en) * | 1996-03-25 | 1998-03-03 | Cypress Semiconductor Corporation | Adjustable lock detector for a phase-locked loop circuit |
US6731667B1 (en) * | 1999-11-18 | 2004-05-04 | Anapass Inc. | Zero-delay buffer circuit for a spread spectrum clock system and method therefor |
US7190201B2 (en) * | 2005-02-03 | 2007-03-13 | Mosaid Technologies, Inc. | Method and apparatus for initializing a delay locked loop |
US7323915B2 (en) * | 2006-01-19 | 2008-01-29 | Honeywell International, Inc. | Delay locked loop with selectable delay |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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TWI744143B (en) * | 2020-08-13 | 2021-10-21 | 瑞昱半導體股份有限公司 | Frequency doubler with duty cycle control and method thereof |
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