Abstract:
Disclosed is a read timing generation circuit, capable of reducing dynamic power consumption. After a multi-bit address Add 1 , Add 2 , . . . , and AddN passes through an address change monitoring unit ( 100 ), a response pulse signal corresponding the address is generated. After the response pulse signal passes through an address trigger determination unit ( 200 ), a single trigger determination signal ATDPRE is generated. The single trigger determination signal ATDPRE passes through an ATD timing generation unit ( 300 ) and a post-timing generation unit ( 1000 ), thereby forming a read timing generation circuit in a serial link and generating corresponding read timing. Compared with the conventional read timing generation circuit in which each bit of an address signal corresponds to a stage of structures to execute the trigger, ATD control timing output, and ATD determination process separately, the present invention greatly reduces the total dynamic power consumption of the circuit.

Description:
CROSS-REFERENCE OF RELATED APPLICATION(S) 
     This application is a U.S. national stage application of, and claims priority to, International Application No. PCT/CN2011/082926, filed Nov. 25, 2011, which is incorporated by reference herein in its entirety. 
     FIELD OF THE INVENTION 
     The present invention generally relates to the field of design of memory circuits, and more specifically to a read timing generation circuit. 
     BACKGROUND OF THE INVENTION 
     With the popularization of portable personal devices, there has been an increasing need for memories, and memory technologies have become an important subject in information technology studies. 
     Read timing generation circuits are widely applied in the design of memories. A read timing generation circuit generates, in response to the input of a multi-bit address signal, read timing related control signals such as Address Transition Detection (ATD), Sense Amplification Precharge Control (SAPC), Sense Out LATch (SOLAT) and Sense Enable (SEN). 
     In a conventional multi-stage read timing generation circuit, the first stage has a parallel structure. As shown in  FIG. 1 , the first stage of a read timing generation circuit includes an address transition detection unit  10 , an ATD timing generation unit  20  and an ATD decision unit  30 . For each bit of an address signal, there is a corresponding stage which independently performs triggering, ATD control timing outputting and ATD decision. That is, the bits of an address signal are entered in parallel into the address transition detection unit  10 , the outputs of the address transition detection unit  10  are entered in parallel into the ATD timing generation unit  20 , and the outputs of the ATD timing generation unit  20  are entered in parallel into the ATD decision unit  30 . 
     However, the read timing generation circuit has a problem that, with increasing storage capacity and number of bits in an address, since each bit corresponds to a stage, the parallel structure will cause significant increase in the dynamic power consumption of the read timing generation circuit. 
     SUMMARY OF THE INVENTION 
     An embodiment of the present invention provides a read timing generation circuit with reduced dynamic power consumption. 
     In order to achieve the object above, an embodiment of the present invention provides the following technical solution. 
     A read timing generation circuit, includes: an address transition detection unit, an address triggering and decision unit, an ATD timing generation unit and a following-stage timing generation unit, wherein 
     the address transition detection unit has input terminals receiving in parallel a plurality of bits of an address, and is adapted to generate a corresponding set of response pulses; 
     the address triggering and decision unit has input terminals connected in parallel to output terminals of the address transition detection unit, and is adapted to generate a single trigger and decision signal; 
     the ATD timing generation unit has an input terminal receiving the trigger and decision signal, and is adapted to generate an address transition detection signal; and 
     the following-stage timing generation unit has an input terminal receiving the address transition detection signal, and is adapted to generate subsequent control signals. 
     Optionally, the following-stage timing generation unit includes: a read precharge unit, a sense amplification delay unit, a data latch delay unit and a data output parallel delay unit; the subsequent control signals include: Sense Amplification Precharge Control (SAPC), Sense Out LATch (SOLAT) and Sense Enable (SEN); and 
     the read precharge unit has an input terminal receiving the address transition detection signal, and is adapted to generate SAPC; 
     the sense amplification delay unit has an input terminal receiving SAPC and an output terminal connected to an input terminal of the data latch delay unit; 
     the data latch delay unit is adapted to generate SOLAT; and 
     the data output parallel delay unit has an input terminal receiving SOLAT and another input terminal receiving SAPC, and is adapted to generate SEN. 
     Optionally, the address transition detection unit includes a plurality of address transition detection branches, each of which includes a first NOT gate, a second NOT gate and a first XNOR gate; and 
     in each of the address transition detection branches, an input terminal of the first NOT gate receives one of the plurality of bits of the address, an output terminal of the first NOT gate is connected to an input terminal of the first XNOR gate via the second NOT gate; the other input terminal of the first XNOR gate is connected to the bit of the address; and an output terminal of the first XNOR gate outputs a response pulse corresponding to the bit of the address. 
     Optionally, the address triggering and decision unit includes a first AND gate; and an input terminal of the first AND gate is connected to an output terminal of the address transition detection unit, and an output terminal of the first AND gate outputs the single trigger and decision signal. 
     Optionally, the ATD timing generation unit includes a third NOT gate, a first capacitor and a second AND gate; and 
     an input terminal of the third NOT gate receives the trigger and decision signal, an output terminal of the third NOT gate is connected to both the first capacitor and an input terminal of the second AND gate, the other input terminal of the second AND gate receives the trigger and decision signal, and an output terminal of the second AND gate outputs the address transition detection signal. 
     Optionally, the read precharge unit includes a fourth NOT gate, a second capacitor and a third AND gate; and 
     an input terminal of the fourth NOT gate receives the address transition detection signal, an output terminal of the fourth NOT gate is connected to both the second capacitor and an input terminal of the third AND gate, the other input terminal of the third AND gate receives the address transition detection signal, and an output terminal of the third AND gate outputs SAPC. 
     Optionally, the sense amplification delay unit includes a fifth NOT gate, a sixth NOT gate, a third capacitor and a first OR gate; and 
     an input terminal of the fifth NOT gate receives SAPC, an output terminal the fifth NOT gate is connected to both the third capacitor and an input terminal of the first OR gate via the sixth NOT gate, and the other input terminal of the first OR gate is connected to an output terminal of the fifth NOT gate. 
     Optionally, the data latch delay unit includes a seventh NOT gate, an eighth NOT gate, a ninth NOT gate, a tenth NOT gate, a fourth capacitor and a fourth AND gate; and 
     an input terminal of the seventh NOT gate is connected to an output terminal of the sense amplification delay unit, an output terminal of the seventh NOT gate is connected to both the fourth capacitor and an input terminal of the ninth NOT gate via the eighth NOT gate, an output terminal of the ninth NOT gate is connected to an input terminal of the fourth AND gate via the tenth NOT gate, the other input terminal of the fourth AND gate is connected to an output terminal of the seventh NOT gate, and an output terminal of the fourth AND gate outputs SOLAT. 
     Optionally, the data output parallel delay unit includes an eleventh NOT gate, a twelfth NOT gate, a thirteenth NOT gate, a second OR gate and a fifth capacitor; and 
     an input terminal of the eleventh NOT gate receives SOLAT, an output terminal of the eleventh NOT gate is connected to both the fifth capacitor and the thirteenth NOT gate via the twelfth NOT gate, an output terminal of the thirteenth NOT gate is connected to an input terminal of the second OR gate, the other input terminal of the second OR gate receives SAPC, and an output terminal of the second OR gate outputs SEN. 
     In comparison with the prior art, the technical solution above has the following advantages. 
     In the read timing generation circuit according to an embodiment of the present invention, a single trigger and decision signal is generated by the address triggering and decision unit. Then through the ATD timing generation unit and the following-stage timing generation unit, which form a serial link in the read timing generation circuit, a corresponding read timing is generated from the trigger and decision signal. As opposed to the conventional read timing generation circuit where for each bit of an address signal there is a corresponding stage which independently performs triggering, ATD control timing outputting and ATD decision, the read timing generation circuit according to an embodiment of the present invention has reduced overall dynamic power consumption, which is even more significant when the number of bits in an address is large. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present invention will become more apparent when read in conjunction with the accompanying drawings. In the accompanying drawings, the same reference numerals denote the same components. The accompanying drawings may not be drawn to scale, in order not to unnecessarily obscure the present invention. 
         FIG. 1  is a structural diagram illustrating a read timing generation circuit in the prior art; 
         FIG. 2  is a structural diagram illustrating a read timing generation circuit according to an embodiment of the present invention; 
         FIG. 3  is a structural diagram illustrating a read timing generation circuit according to an embodiment of the present invention; 
         FIG. 4  illustrates waveforms at main nodes in a read timing generation circuit according to an embodiment of the present invention; and 
         FIG. 5  illustrates waveforms at main nodes in a read timing generation circuit according to an embodiment of the present invention, with increased pulse width. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The above objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention. 
     Specific details are given below to provide a thorough understanding of the present invention. Those skilled in the art will understand, however, that the present invention may be practiced without one or more of the specific details, or with other methods. Hence, the present invention is not limited to the specific implementations described herein. 
     As shown in  FIG. 2 , a structural diagram illustrating a read timing generation circuit according to an embodiment of the present invention, the read timing generation circuit includes: an address transition detection unit  100 , an address triggering and decision unit  200 , an ATD timing generation unit  300  and a following-stage timing generation unit  1000 . 
     The address transition detection unit  100  has input terminals receiving in parallel a plurality bits of an address, Add 1 , Add 2  . . . AddN, and is adapted to generate a corresponding set of response pulses. 
     The address triggering and decision unit  200  has input terminals connected in parallel to output terminals of the address transition detection unit  100 , and is adapted to generate a single trigger and decision signal, ATDPRE. 
     The ATD timing generation unit  300  has an input terminal receiving the trigger and decision signal ATDPRE, and is adapted to generate an address transition detection signal, ATD. 
     The following-stage timing generation unit  1000  has an input terminal receiving the address transition detection signal ATD, and is adapted to generate subsequent control signals. 
     The address transition detection unit  100  outputs a set of response pulses each of which corresponds to one of the plurality of bits of the address. The response pulses are entered in parallel to the input terminals of the address triggering and decision unit  200 , which generates a single trigger and decision signal ATDPRE after logical operations. Therefore, the high power consumption in the prior art due to the use of a parallel structure for ATD timing outputting is avoided. 
     In the read timing generation circuit according to an embodiment of the present invention, response pulse signals corresponding to a multi-bit address Add 1 , Add 2  . . . AddN are generated by the address transition detection unit  100 , and a single trigger and decision signal ATDPRE is generated by the address triggering and decision unit  200 . Then through the ATD timing generation unit and the following-stage timing generation unit, which form a serial link in the read timing generation circuit, a corresponding read timing is generated from the trigger and decision signal ATDPRE. As opposed to the conventional read timing generation circuit where for each bit of an address signal there is a corresponding stage which independently performs triggering, ATD control timing outputting and ATD decision, the read timing generation circuit according to an embodiment of the present invention has reduced overall dynamic power consumption, which is even more significant when the number of bits in an address is large. 
     The following-stage timing generation unit  1000  can be designed according to specific needs. In an embodiment of the present invention, the following-stage timing generation unit  1000  includes a read precharge unit  400 , a sense amplification delay unit  500 , a data latch delay unit  600  and a data output parallel delay unit  700 . And the subsequent control signals include Sense Amplification Precharge Control (SAPC), Sense Out LATch (SOLAT) and Sense Enable (SEN). 
     The read precharge unit  400  has an input terminal receiving the address transition detection signal ATD, and is adapted to generate SAPC. 
     An input terminal of the sense amplification delay unit  500  receives SAPC, an output terminal of the sense amplification delay unit  500  is connected to an input terminal of the data latch delay unit  600 . The data latch delay unit  600  is adapted to generate SOLAT. 
     The sense amplification delay unit  500  is for providing processing time for sense amplification of the memory chip. 
     The data output parallel delay unit  700  has an input terminal receiving SOLAT and another input terminal receiving SAPC, and is adapted to generate SEN. 
     In the read timing generation circuit above, after the trigger and decision signal ATDPRE is generated, a series of read timing signals including ATD, SAPC, SOLAT and SEN are generated by a serial link. The circuit has relatively low dynamic power consumption and ensures tight timing of the output signals. 
     For a better understanding of the present invention, a specific embodiment and output waveforms will be described in detail hereinafter. 
     Reference is made to  FIG. 3  and  FIG. 4 .  FIG. 3  is a structural diagram illustrating a read timing generation circuit according to an embodiment of the present invention.  FIG. 4  illustrates waveforms at main nodes in the read timing generation circuit according to an embodiment of the present invention. 
     In the embodiment, the address transition detection unit  100  includes a plurality of address transition detection branches,  100 - 1  . . .  100 -N, each address transition detection branch  100 - 1  or  100 -N includes a first NOT gate  101 , a second NOT gate  102  and a first XNOR gate  103 . In each of the address transition detection branches, for example, in the first address transition detection branch  100 - 1  which receives the first bit of an address, an input terminal of the first NOT gate  101  receives a bit Add 1 , an output terminal of the first NOT gate  101  is connected to an input terminal of the first XNOR gate  103  via the second NOT gate  102 , the other input terminal of the first XNOR gate  103  is connected to the bit Add 1 , and an output terminal of first XNOR gate  103  outputs a response pulse corresponding to the bit Add 1 . 
     The address triggering and decision unit  200  includes a first AND gate  201 . An input terminal of the first AND gate  201  is connected to an output terminal of the address transition detection unit  100 , and an output terminal of the first AND gate  201  outputs a single trigger and decision signal ATDPRE. 
     The ATD timing generation unit  300  includes a third NOT gate  301 , a first capacitor  302  and a second AND gate  303 . An input terminal of the third NOT gate  301  receives the trigger and decision signal ATDPRE, an output terminal of the third NOT gate  301  is connected to both the first capacitor  302  and an input terminal of the second AND gate  303 , the other input terminal of the second AND gate  303  receives the trigger and decision signal ATDPRE, and an output terminal of the second AND gate  303  outputs the address transition detection signal ATD. 
     The read precharge unit includes a fourth NOT gate  401 , a second capacitor  402  and a third AND gate  403 . An input terminal of the fourth NOT gate  401  receives the address transition detection signal ATD, an output terminal of the fourth NOT gate  401  is connected to both the second capacitor  402  and an input terminal of the third AND gate  403 , the other input terminal of the third AND gate  403  receives the address transition detection signal ATD, and an output terminal of the third AND gate  403  outputs SAPC. 
     The sense amplification delay unit  500  includes a fifth NOT gate  501 , a sixth NOT gate  502 , a third capacitor  503  and a first OR gate  504 . An input terminal of the fifth NOT gate  501  receives SAPC, an output terminal the fifth NOT gate  501  is connected to both the third capacitor  503  and an input terminal of the first OR gate  504  via the sixth NOT gate  502 , the other input terminal of the first OR gate  504  is connected to an output terminal of the fifth NOT gate  501 . 
     The data latch delay unit  600  includes a seventh NOT gate  601 , an eighth NOT gate  602 , a ninth NOT gate  604 , a tenth NOT gate  605 , a fourth capacitor  603  and a fourth AND gate  606 . An input terminal of the seventh NOT gate  601  is connected to an output terminal of the sense amplification delay unit  500 , an output terminal of the seventh NOT gate  601  is connected to both the fourth capacitor  603  and an input terminal of the ninth NOT gate  604  via the eighth NOT gate  602 , an output terminal of the ninth NOT gate  604  is connected to an input terminal of the fourth AND gate  606  via the tenth NOT gate  605 , the other input terminal of the fourth AND gate  606  is connected to an output terminal of the seventh NOT gate  601 , and an output terminal of the fourth AND gate  606  outputs SOLAT. 
     The data output parallel delay unit  700  includes an eleventh NOT gate  701 , a twelfth NOT gate  702 , a thirteenth NOT gate  704 , a second OR gate  705  and a fifth capacitor  703 . An input terminal of the eleventh NOT gate  701  receives SOLAT, an output terminal of the eleventh NOT gate  701  is connected to both the fifth capacitor  703  and an input terminal of the thirteenth NOT gate  704  via the twelfth NOT gate  702 , an output terminal of the thirteenth NOT gate  704  is connected to an input terminal of the second OR gate  705 , the other input terminal of the second OR gate  705  receives SAPC, and an output terminal of the second OR gate  705  outputs SEN. 
     As shown in  FIG. 4 , from the input of an address Add(1:N), a single trigger and decision signal ATDPRE is generated through the address transition detection unit  100  and the address triggering and decision unit  200 . From the single trigger and decision signal ATDPRE, an address transition detection signal ATD is generated by the ATD timing generation unit  300 . The rising edge of the address transition detection signal ATD is triggered by the rising edge of the single trigger and decision signal ATDPRE, and the pulse width of the address transition detection signal ATD is larger than the pulse width of the single trigger and decision signal ATDPRE due to the presence of the first capacitor. From the address transition detection signal ATD, SAPC is generated by the read precharge unit  400 . The rising edge of SAPC is triggered by the rising edge of the address transition detection signal ATD, and the pulse width of SAPC is lengthened to the desired duration T 1  due to the presence of the second capacitor. From SAPC, SOLAT is generated through the sense amplification delay unit  500  and the data latch delay unit  600 . The rising edge of SOLAT is delayed as compared with the falling edge of SAPC, as an example, the delay is T 2 . From SAPC and SOLAT, SEN is generated by the data output parallel delay unit  700 . The rising edge of SEN is triggered by the rising edge of SAPC, and the falling edge of SEN is triggered by the falling edge of SOLAT with a delay of T 4 . Thus, SEN has a pulse width of T=T 1 +T 2 +T 3 +T 4 . 
     As shown in  FIG. 5 , when the pulse width T 1  of SAPC is increased by Δt, i.e., T 1 ′=T 1 +Δt, T 2 ′=T 2 −Δt+Δt=T 2 . Similarly, the values and sequences of both T 3  and T 4  remain unchanged. Therefore, the read timing control signals SAPC, SEN and SOLAT generated by the read timing generation circuit according to an embodiment of the present invention are tight. If one of the control signals changes, it is ensured that the relationships in time between first-stage and following-stage signals are not affected, providing a strict correspondence between read timing signals. That is, each of the read timings can change independently without affecting the other timings. 
     Therefore, the read timing generation circuit according to an embodiment of the present invention generates a series of read timing signals and has low dynamic power consumption, and the generated timings are tight and of good stability. 
     While the foregoing illustrates and describes preferred embodiments of the present invention, it should not be taken to limit the invention as disclosed in certain preferred embodiments herein. 
     Variations and modifications may be made to the technical solutions of the present invention by those skilled in the art in light of the methods and technical content disclosed herein without deviation from the scope of the present invention. Therefore, any variations, equivalents, and modifications made to the embodiments herein according to the technical essential of the present invention without deviation from the scope of the present invention shall fall within the scope of protection of the present invention.