US20100182173A1 - Flip-flop and pipelined analog-to-digital converter utilizing the same - Google Patents
Flip-flop and pipelined analog-to-digital converter utilizing the same Download PDFInfo
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- US20100182173A1 US20100182173A1 US12/354,926 US35492609A US2010182173A1 US 20100182173 A1 US20100182173 A1 US 20100182173A1 US 35492609 A US35492609 A US 35492609A US 2010182173 A1 US2010182173 A1 US 2010182173A1
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
- H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
- H03K3/353—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of field-effect transistors with internal or external positive feedback
- H03K3/356—Bistable circuits
- H03K3/356104—Bistable circuits using complementary field-effect transistors
- H03K3/356182—Bistable circuits using complementary field-effect transistors with additional means for controlling the main nodes
- H03K3/356191—Bistable circuits using complementary field-effect transistors with additional means for controlling the main nodes with synchronous operation
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K23/00—Pulse counters comprising counting chains; Frequency dividers comprising counting chains
- H03K23/40—Gating or clocking signals applied to all stages, i.e. synchronous counters
- H03K23/50—Gating or clocking signals applied to all stages, i.e. synchronous counters using bi-stable regenerative trigger circuits
- H03K23/52—Gating or clocking signals applied to all stages, i.e. synchronous counters using bi-stable regenerative trigger circuits using field-effect transistors
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
- H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
- H03K3/353—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of field-effect transistors with internal or external positive feedback
- H03K3/356—Bistable circuits
- H03K3/356104—Bistable circuits using complementary field-effect transistors
- H03K3/356113—Bistable circuits using complementary field-effect transistors using additional transistors in the input circuit
- H03K3/356121—Bistable circuits using complementary field-effect transistors using additional transistors in the input circuit with synchronous operation
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
- H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
- H03K3/353—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of field-effect transistors with internal or external positive feedback
- H03K3/356—Bistable circuits
- H03K3/356104—Bistable circuits using complementary field-effect transistors
- H03K3/356113—Bistable circuits using complementary field-effect transistors using additional transistors in the input circuit
- H03K3/35613—Bistable circuits using complementary field-effect transistors using additional transistors in the input circuit the input circuit having a differential configuration
- H03K3/356139—Bistable circuits using complementary field-effect transistors using additional transistors in the input circuit the input circuit having a differential configuration with synchronous operation
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K5/00—Manipulating of pulses not covered by one of the other main groups of this subclass
- H03K5/156—Arrangements in which a continuous pulse train is transformed into a train having a desired pattern
- H03K5/1565—Arrangements in which a continuous pulse train is transformed into a train having a desired pattern the output pulses having a constant duty cycle
Definitions
- the invention relates to a flip-flop, and more particularly to a flip-flop applied in a pipelined analog-to-digital converter (ADC).
- ADC analog-to-digital converter
- FIG. 1 is a schematic diagram of a conventional frequency divide-by-2 divider based on a D flip-flop.
- the conventional divider receives a clock signal CLK, it can generate an output signal CLK/2 having a half frequency of the clock signal CLK.
- the clock signal CLK/2 is required to have a precise 50% duty cycle for implementation.
- FIG. 2 which is an internal schematic diagram of the conventional divider, where CLK_ represents an inverse signal of the clock signal CLK. Because the data transmitting path of the conventional divider includes two inverters and two switches and the conventional divider is not a differential circuit, the duty cycle of the output signal CLK/2 will not be 50% and jitter will be introduced into.
- An exemplary embodiment of a flip-flop comprises a sense amplifier stage and a latch stage.
- the sense amplifier stage comprises a first N type transistor, a second N type transistor, a third N type transistor, a fourth N type transistor, a fifth N type transistor, a sixth N type transistor, a seventh N type transistor, a first P type transistor, a second P type transistor, a third P type transistor, a fourth P type transistor, a fifth P type transistor, a sixth P type transistor, and a seventh P type transistor.
- the first N type transistor comprises a gate receiving a clock signal and a source receiving a grounding signal.
- the second N type transistor comprises a gate receiving a first data signal and a source coupled to a drain of the first N type transistor.
- the third N type transistor comprises a gate receiving a second data signal and a source coupled to the drain of the first N type transistor.
- the fourth N type transistor comprises a gate receiving the grounding signal, a source receiving the grounding signal, and a drain coupled to a first node.
- the fifth N type transistor comprises a source coupled to a drain of the second N type transistor and a drain coupled to the first node.
- the sixth N type transistor comprises a gate receiving a reset signal, a source receiving the grounding signal, and a drain coupled to a second node.
- the seventh N type transistor comprises a source coupled to a drain of the third N type transistor and a drain coupled to the second node.
- the first P type transistor comprises a gate receiving the clock signal, a first terminal coupled to a gate of the fifth N type transistor, and a second terminal coupled to a gate of the seventh N type transistor.
- the second P type transistor comprises a gate receiving the clock signal and a drain coupled to the first node.
- the third P type transistor comprises a gate coupled to the gate of the fifth N type transistor and the second node, a drain coupled to the first node, and a source coupled to a source of the second P type transistor.
- the fourth P type transistor comprises a gate receiving the clock signal and a drain coupled to the second node.
- the fifth P type transistor comprises a gate coupled to the gate of the seventh N type transistor and the first node, a drain coupled to the second node, and a source coupled to a source of the fourth P type transistor.
- the sixth P type transistor comprises a gate receiving the grounding signal, a drain coupled to the source of the second P type transistor, and a source receiving a power signal.
- the seventh P type transistor comprises a gate receiving the reset signal, a drain coupled to the source of the fourth P type transistor, and a source receiving the power signal.
- the latch stage comprises an eighth N type transistor, a ninth N type transistor, a tenth N type transistor, an eleventh N type transistor, a twelfth N type transistor, a thirteenth N type transistor, an eighth P type transistor, a ninth P type transistor, and a latch unit.
- the eighth N type transistor comprises a gate receiving a first sensed signal provided by the first node and a source receiving the grounding signal.
- the ninth N type transistor comprises a gate receiving a second sensed signal provided by the second node and a source receiving the grounding signal.
- the tenth N type transistor comprises a gate receiving the second data signal and a source coupled to a drain of the eighth N type transistor.
- the eleventh N type transistor comprises a gate receiving the first data signal and a source coupled to a drain of the ninth N type transistor.
- the twelfth N type transistor comprises a gate receiving the clock signal, a source coupled to a drain of the tenth N type transistor, and a drain receiving a first output signal provided by a third node.
- the thirteenth N type transistor comprises a gate receiving the clock signal, a source coupled to a drain of the eleventh N type transistor, and a drain receiving a second output signal provided by a fourth node.
- the eighth P type transistor comprises a gate receiving the first sensed signal, a source receiving the power signal, and a drain receiving the first output signal.
- the ninth P type transistor comprises a gate receiving the second sensed signal, a source receiving the power signal, and a drain receiving the second output signal.
- the latch unit is coupled between the third and the fourth nodes.
- a flip-flop comprises a first latch unit, a switching transistor, and a second latch unit.
- the first latch unit receives an input data signal and generates a sensed signal and an inverse of the sensed signal according to a clock signal and the input data signal at a first output node and a second output node of the first latch circuit respectively.
- the switching transistor comprises a first terminal coupled to the first output node of the first latch unit, a second terminal coupled to the second output node of the first latch unit, and a control terminal receiving the clock signal, for coupling the first output node to the second output node according to the clock signal.
- the second latch unit generates an output signal and an inverse of the output signal according to the clock signal, the input data signal, the sensed signal and the inverse of the sensed signal.
- Pipelined analog to digital converters are also provided.
- An exemplary embodiment of a pipelined analog to digital converter comprises transformation stages connected in serial, the previous flip flop, and a clock generator.
- the clock generator generates a first phase signal and a second phase signal according to the first output signal and the second output signal provided by the third node and the fourth node of the flip-flop.
- Each transformation stage comprises a sub-ADC and a multiplying digital to analog converter (MDAC).
- the sub-ADC processes an input signal to generate a digital signal according to the first and the second phase signals.
- the MDAC processes the input signal and the digital signal according to the first and the second phase signals.
- FIG. 1 is a schematic diagram of a conventional frequency divide-by-2 divider based on a flip flop
- FIG. 2 is an internal schematic diagram of the conventional frequency divide-by-2 divider
- FIG. 3 is a schematic diagram of an exemplary embodiment of a flip flop
- FIG. 4A is a schematic diagram of an exemplary embodiment of the sense amplifier stage
- FIG. 4B is a schematic diagram of an exemplary embodiment of the latch stage
- FIG. 5 is a schematic diagram of an exemplary embodiment of a pipelined analog to digital converter
- FIG. 6 is a schematic diagram of an exemplary embodiment of the transforming stage.
- a flip-flop having differential circuit architecture is provided.
- a better performance e.g. a precise 50% duty cycle output signal
- the flip-flop is utilized to form a frequency divider.
- FIG. 3 is a schematic diagram of an exemplary embodiment of a flip-flop.
- the flip-flop 300 comprises a sense amplifier stage 310 and a latch stage 320 .
- the sense amplifier stage 310 generates a sensed signal d 1 and an inverse sensed signal d 1 b according to a signal group S CG comprising a clock signal CLK.
- the latch stage 320 is capable of generating a clock signal CLK/2 according to the signal group S CG , and sensed signals d 1 and d 1 b .
- the clock signal CLK/2 has a half frequency of the clock signal CLK.
- the signal group SCG maybe comprises a clock signal CLK, a reset signal RST, data signals d and db, a grounding signal GND, a power signal VDD, or any combinations of above-mentioned signals.
- FIG. 4A is a schematic diagram of an exemplary embodiment of the sense amplifier stage.
- the sense amplifier stage 310 comprises N type transistors N 1 ⁇ N 7 and P type transistors P 1 ⁇ P 7 .
- the P type transistors P 3 and P 5 and the N type transistors N 5 and N 7 constitute a first latch unit. Please note that the types of the transistors shown in FIG. 4A are examples rather than limitations of the present invention.
- the sense amplifier stage 310 generates sensed signal d 1 and inverse sensed signal d 1 b to nodes 411 and 412 , respectively. When the switching transistor P 1 is turned on by the clock signal CLK, the node 411 is connected to the node 412 .
- FIG. 4B is a schematic diagram of an exemplary embodiment of the latch stage.
- the latch stage 320 comprises N type transistors N 8 ⁇ N 15 and P type transistors P 8 ⁇ P 11 , wherein the N type transistors N 14 and N 15 and P type transistors P 10 and P 11 constitute a second latch unit.
- the latch stage 320 respectively generates output signal q and inverse output signal qb to nodes 413 and 414 according to the sensed signal d 1 and the inverse sensed signal d 1 b . Since the connected relationships between transistors N 1 ⁇ N 15 and P 1 ⁇ P 11 are shown in FIGS. 4A and 4B , the connected relationships are omitted here for brevity.
- the operating principles of the sense amplifier stage 310 and the latch stage 320 are described in the following.
- the sense amplifier stage 310 can be reset according to a reset signal RST of the signal group S CG .
- the reset signal RST is at a high level
- the node 412 is at a low level, turning on the P type switch P 3 . Since the P type transistors P 3 and P 6 are turned on, the node 411 is at the high level.
- the sensed signal d 1 is provided by the node 411 and the inverse sensed signal d 1 b is provided by the node 412 .
- the first latch unit constituted of two inverters formed by the transistors P 3 , P 5 , N 5 and N 7 senses the data signal d and db, and keeps the values of the data signals d and db at the node 412 and node 411 , respectively.
- the value of sensed signal d 1 is equal to the value of the inverse data signal db
- the value of the inverse sensed signal d 1 b is equal to the value of the data signal d at this time.
- the P type transistor P 1 is turned on and therefore the node 411 is coupled to the node 412 . This helps the first latch unit save time sensing the data signal d and the inverse data signal db when next pulse of the clock signal CLK arrives.
- the latch stage receives the data signal d, inverse data signal db, sensed signal d 1 and inverse sensed signal d 1 b provided by the sense amplifier stage, and generates an output signal q and an inverse output signal qb.
- the transistors N 8 , N 10 and P 9 are turned off, and the transistors P 8 , N 11 and N 9 are turned on.
- the node 413 is connected to the power signal VDD, and the node 414 is connected to the ground, therefore the output signal q is high and the inverse output signal qb is low.
- the second latch unit constituted of the transistors P 10 , P 11 , N 14 and N 15 can keep the output signal q and the inverse output signal qb when the clock signal CLK is at the low level.
- the level of the output signal q is same as the level of the data signal d.
- the clock signal CLK is changed from the high level to the low level, the level of the output signal q is maintained. For example, assuming the data signal d is at the high level when the clock signal is at the high level.
- the clock signal CLK is changed from the high level to the low level, the level of the output signal q is at the high level.
- FIG. 5 is a schematic diagram of an exemplary embodiment of a pipelined analog to digital converter (ADC).
- the pipelined ADC 500 comprises a frequency divider 610 , a clock generator 620 , and transforming stages T 1 ⁇ T n .
- Transforming stages T 1 ⁇ T n transform an input signal IN into digital signals D 1 ⁇ D n . Since a person having ordinary skill in the art can readily appreciate the operations of transforming stages T 1 ⁇ T n after reading the description of transforming stage T 1 , the following takes the transforming stage T 1 as an example.
- FIG. 6 is a schematic diagram of an exemplary embodiment of the transforming stage T 1 .
- the transforming stage T 1 comprises a multiplying digital to analog converter (MDAC) 630 and a sub-ADC 640 .
- MDAC multiplying digital to analog converter
- the frequency divider 610 generates the clock signal CLK/2 and its inverse CLK/2_ according to the clock signal CLK. Because the flip-flop 300 has a differential circuit structure, each of the clock signal CLK/2 and the inverse clock signal CLK/2_ has a precise 50% duty cycle. The difference between the falling edges of the clock signals CLK/2 and CLK/2_ is T/2, wherein T is a period of the clock signal CLK/2.
- the frequency divider 610 is constituted by the flip-flop 300 .
- the flip-flop 300 is capable of providing the functions of the frequency divider 610 when the connected relationship of the flip-flop 300 is controlled.
- the inverse output signal qb serves as the clock signal CLK/2_.
- the clock generator 620 generates phase signals Ph 1 and Ph 2 according to the clock signals CLK/2 and CLK/2_.
- the sub-ADC 640 processes the input signal IN to generate the digital signal D 1 according to phase signals Ph 1 and Ph 2 .
- the MDAC processes the input signal IN and the digital signal D 1 according to the phase signals Ph 1 and Ph 2 . Since the clock signals CLK/2 and CLK/2_ are both 50% duty cycle clocks, the sampling edge of each transforming stage T 1 ⁇ Tn can be well-determined, and thereby the performance of the pipelined ADC 500 can be improved.
Abstract
Description
- 1. Field of the Invention
- The invention relates to a flip-flop, and more particularly to a flip-flop applied in a pipelined analog-to-digital converter (ADC).
- 2. Description of the Related Art
- A flip-flop is capable of providing the functions of a frequency divide-by-2 divider.
FIG. 1 is a schematic diagram of a conventional frequency divide-by-2 divider based on a D flip-flop. When the conventional divider receives a clock signal CLK, it can generate an output signal CLK/2 having a half frequency of the clock signal CLK. The clock signal CLK/2 is required to have a precise 50% duty cycle for implementation. Please refer toFIG. 2 , which is an internal schematic diagram of the conventional divider, where CLK_ represents an inverse signal of the clock signal CLK. Because the data transmitting path of the conventional divider includes two inverters and two switches and the conventional divider is not a differential circuit, the duty cycle of the output signal CLK/2 will not be 50% and jitter will be introduced into. - Flip-flops are provided. An exemplary embodiment of a flip-flop comprises a sense amplifier stage and a latch stage. The sense amplifier stage comprises a first N type transistor, a second N type transistor, a third N type transistor, a fourth N type transistor, a fifth N type transistor, a sixth N type transistor, a seventh N type transistor, a first P type transistor, a second P type transistor, a third P type transistor, a fourth P type transistor, a fifth P type transistor, a sixth P type transistor, and a seventh P type transistor. The first N type transistor comprises a gate receiving a clock signal and a source receiving a grounding signal. The second N type transistor comprises a gate receiving a first data signal and a source coupled to a drain of the first N type transistor. The third N type transistor comprises a gate receiving a second data signal and a source coupled to the drain of the first N type transistor. The fourth N type transistor comprises a gate receiving the grounding signal, a source receiving the grounding signal, and a drain coupled to a first node. The fifth N type transistor comprises a source coupled to a drain of the second N type transistor and a drain coupled to the first node. The sixth N type transistor comprises a gate receiving a reset signal, a source receiving the grounding signal, and a drain coupled to a second node. The seventh N type transistor comprises a source coupled to a drain of the third N type transistor and a drain coupled to the second node. The first P type transistor comprises a gate receiving the clock signal, a first terminal coupled to a gate of the fifth N type transistor, and a second terminal coupled to a gate of the seventh N type transistor. The second P type transistor comprises a gate receiving the clock signal and a drain coupled to the first node. The third P type transistor comprises a gate coupled to the gate of the fifth N type transistor and the second node, a drain coupled to the first node, and a source coupled to a source of the second P type transistor. The fourth P type transistor comprises a gate receiving the clock signal and a drain coupled to the second node. The fifth P type transistor comprises a gate coupled to the gate of the seventh N type transistor and the first node, a drain coupled to the second node, and a source coupled to a source of the fourth P type transistor. The sixth P type transistor comprises a gate receiving the grounding signal, a drain coupled to the source of the second P type transistor, and a source receiving a power signal. The seventh P type transistor comprises a gate receiving the reset signal, a drain coupled to the source of the fourth P type transistor, and a source receiving the power signal.
- The latch stage comprises an eighth N type transistor, a ninth N type transistor, a tenth N type transistor, an eleventh N type transistor, a twelfth N type transistor, a thirteenth N type transistor, an eighth P type transistor, a ninth P type transistor, and a latch unit. The eighth N type transistor comprises a gate receiving a first sensed signal provided by the first node and a source receiving the grounding signal. The ninth N type transistor comprises a gate receiving a second sensed signal provided by the second node and a source receiving the grounding signal. The tenth N type transistor comprises a gate receiving the second data signal and a source coupled to a drain of the eighth N type transistor. The eleventh N type transistor comprises a gate receiving the first data signal and a source coupled to a drain of the ninth N type transistor. The twelfth N type transistor comprises a gate receiving the clock signal, a source coupled to a drain of the tenth N type transistor, and a drain receiving a first output signal provided by a third node. The thirteenth N type transistor comprises a gate receiving the clock signal, a source coupled to a drain of the eleventh N type transistor, and a drain receiving a second output signal provided by a fourth node. The eighth P type transistor comprises a gate receiving the first sensed signal, a source receiving the power signal, and a drain receiving the first output signal. The ninth P type transistor comprises a gate receiving the second sensed signal, a source receiving the power signal, and a drain receiving the second output signal. The latch unit is coupled between the third and the fourth nodes.
- Another exemplary embodiment of a flip-flop comprises a first latch unit, a switching transistor, and a second latch unit. The first latch unit receives an input data signal and generates a sensed signal and an inverse of the sensed signal according to a clock signal and the input data signal at a first output node and a second output node of the first latch circuit respectively. The switching transistor comprises a first terminal coupled to the first output node of the first latch unit, a second terminal coupled to the second output node of the first latch unit, and a control terminal receiving the clock signal, for coupling the first output node to the second output node according to the clock signal. The second latch unit generates an output signal and an inverse of the output signal according to the clock signal, the input data signal, the sensed signal and the inverse of the sensed signal.
- Pipelined analog to digital converters are also provided. An exemplary embodiment of a pipelined analog to digital converter comprises transformation stages connected in serial, the previous flip flop, and a clock generator. The clock generator generates a first phase signal and a second phase signal according to the first output signal and the second output signal provided by the third node and the fourth node of the flip-flop. Each transformation stage comprises a sub-ADC and a multiplying digital to analog converter (MDAC). The sub-ADC processes an input signal to generate a digital signal according to the first and the second phase signals. The MDAC processes the input signal and the digital signal according to the first and the second phase signals.
- A detailed description is given in the following embodiments with reference to the accompanying drawings.
- The invention can be more fully understood by referring to the following detailed description and examples with references made to the accompanying drawings, wherein:
-
FIG. 1 is a schematic diagram of a conventional frequency divide-by-2 divider based on a flip flop; -
FIG. 2 is an internal schematic diagram of the conventional frequency divide-by-2 divider; -
FIG. 3 is a schematic diagram of an exemplary embodiment of a flip flop; -
FIG. 4A is a schematic diagram of an exemplary embodiment of the sense amplifier stage; -
FIG. 4B is a schematic diagram of an exemplary embodiment of the latch stage; -
FIG. 5 is a schematic diagram of an exemplary embodiment of a pipelined analog to digital converter; and -
FIG. 6 is a schematic diagram of an exemplary embodiment of the transforming stage. - The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
- In order to overcome the problems of prior arts, a flip-flop having differential circuit architecture is provided. A better performance (e.g. a precise 50% duty cycle output signal) can therefore be achieved when the flip-flop is utilized to form a frequency divider.
-
FIG. 3 is a schematic diagram of an exemplary embodiment of a flip-flop. The flip-flop 300 comprises asense amplifier stage 310 and alatch stage 320. Thesense amplifier stage 310 generates a sensed signal d1 and an inverse sensed signal d1 b according to a signal group SCG comprising a clock signal CLK. Thelatch stage 320 is capable of generating a clock signal CLK/2 according to the signal group SCG, and sensed signals d1 and d1 b. In this embodiment, the clock signal CLK/2 has a half frequency of the clock signal CLK. Additionally the signal group SCG maybe comprises a clock signal CLK, a reset signal RST, data signals d and db, a grounding signal GND, a power signal VDD, or any combinations of above-mentioned signals. -
FIG. 4A is a schematic diagram of an exemplary embodiment of the sense amplifier stage. Thesense amplifier stage 310 comprises N type transistors N1˜N7 and P type transistors P1˜P7. The P type transistors P3 and P5 and the N type transistors N5 and N7 constitute a first latch unit. Please note that the types of the transistors shown inFIG. 4A are examples rather than limitations of the present invention. Thesense amplifier stage 310 generates sensed signal d1 and inverse sensed signal d1 b tonodes node 411 is connected to thenode 412.FIG. 4B is a schematic diagram of an exemplary embodiment of the latch stage. Thelatch stage 320 comprises N type transistors N8˜N15 and P type transistors P8˜P11, wherein the N type transistors N14 and N15 and P type transistors P10 and P11 constitute a second latch unit. Thelatch stage 320 respectively generates output signal q and inverse output signal qb tonodes FIGS. 4A and 4B , the connected relationships are omitted here for brevity. The operating principles of thesense amplifier stage 310 and thelatch stage 320 are described in the following. - Referring to
FIG. 4A , thesense amplifier stage 310 can be reset according to a reset signal RST of the signal group SCG. When the reset signal RST is at a high level, thenode 412 is at a low level, turning on the P type switch P3. Since the P type transistors P3 and P6 are turned on, thenode 411 is at the high level. In this embodiment, the sensed signal d1 is provided by thenode 411 and the inverse sensed signal d1 b is provided by thenode 412. - When the clock signal CLK is at the high level, the N type transistor N1 is turned on. The first latch unit constituted of two inverters formed by the transistors P3, P5, N5 and N7 senses the data signal d and db, and keeps the values of the data signals d and db at the
node 412 andnode 411, respectively. In other words, the value of sensed signal d1 is equal to the value of the inverse data signal db, and the value of the inverse sensed signal d1 b is equal to the value of the data signal d at this time. When the clock signal CLK transits to the low level, the P type transistor P1 is turned on and therefore thenode 411 is coupled to thenode 412. This helps the first latch unit save time sensing the data signal d and the inverse data signal db when next pulse of the clock signal CLK arrives. - Referring to
FIG. 4B , the latch stage receives the data signal d, inverse data signal db, sensed signal d1 and inverse sensed signal d1 b provided by the sense amplifier stage, and generates an output signal q and an inverse output signal qb. For example, when the data signal d is high, the inverse data signal db is low, the sensed signal d1 is low, and the inverse sensed signal d1 b is high, the transistors N8, N10 and P9 are turned off, and the transistors P8, N11 and N9 are turned on. Thenode 413 is connected to the power signal VDD, and thenode 414 is connected to the ground, therefore the output signal q is high and the inverse output signal qb is low. The second latch unit constituted of the transistors P10, P11, N14 and N15 can keep the output signal q and the inverse output signal qb when the clock signal CLK is at the low level. - In this embodiment, when the clock signal CLK is at the high level, the level of the output signal q is same as the level of the data signal d. When the clock signal CLK is changed from the high level to the low level, the level of the output signal q is maintained. For example, assuming the data signal d is at the high level when the clock signal is at the high level. When the clock signal CLK is changed from the high level to the low level, the level of the output signal q is at the high level.
-
FIG. 5 is a schematic diagram of an exemplary embodiment of a pipelined analog to digital converter (ADC). The pipelinedADC 500 comprises afrequency divider 610, aclock generator 620, and transforming stages T1˜Tn. Transforming stages T1˜Tn transform an input signal IN into digital signals D1˜Dn. Since a person having ordinary skill in the art can readily appreciate the operations of transforming stages T1˜Tn after reading the description of transforming stage T1, the following takes the transforming stage T1 as an example. -
FIG. 6 is a schematic diagram of an exemplary embodiment of the transforming stage T1. The transforming stage T1 comprises a multiplying digital to analog converter (MDAC) 630 and asub-ADC 640. Please refer toFIG. 6 in conjunction withFIG. 5 . Thefrequency divider 610 generates the clock signal CLK/2 and its inverse CLK/2_ according to the clock signal CLK. Because the flip-flop 300 has a differential circuit structure, each of the clock signal CLK/2 and the inverse clock signal CLK/2_ has a precise 50% duty cycle. The difference between the falling edges of the clock signals CLK/2 and CLK/2_ is T/2, wherein T is a period of the clock signal CLK/2. - In this embodiment, the
frequency divider 610 is constituted by the flip-flop 300. The flip-flop 300 is capable of providing the functions of thefrequency divider 610 when the connected relationship of the flip-flop 300 is controlled. In one embodiment, when the gates of the N type transistors N2 and N11 receive the inverse output signal qb, the inverse output signal qb serves as the clock signal CLK/2_. - The
clock generator 620 generates phase signals Ph1 and Ph2 according to the clock signals CLK/2 and CLK/2_. Thesub-ADC 640 processes the input signal IN to generate the digital signal D1 according to phase signals Ph1 and Ph2. The MDAC processes the input signal IN and the digital signal D1 according to the phase signals Ph1 and Ph2. Since the clock signals CLK/2 and CLK/2_ are both 50% duty cycle clocks, the sampling edge of each transforming stage T1˜Tn can be well-determined, and thereby the performance of the pipelinedADC 500 can be improved. - While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
Claims (9)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/354,926 US7760117B1 (en) | 2009-01-16 | 2009-01-16 | Flip-flop and pipelined analog-to-digital converter utilizing the same |
TW098113442A TWI380588B (en) | 2009-01-16 | 2009-04-23 | Flip flops and pipelined analog to digital converter |
CN2009101375140A CN101783660B (en) | 2009-01-16 | 2009-04-28 | Flip-flop and pipelined analog-to-digital converter |
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US12/354,926 US7760117B1 (en) | 2009-01-16 | 2009-01-16 | Flip-flop and pipelined analog-to-digital converter utilizing the same |
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US7760117B1 US7760117B1 (en) | 2010-07-20 |
US20100182173A1 true US20100182173A1 (en) | 2010-07-22 |
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US12/354,926 Active 2029-02-13 US7760117B1 (en) | 2009-01-16 | 2009-01-16 | Flip-flop and pipelined analog-to-digital converter utilizing the same |
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US (1) | US7760117B1 (en) |
CN (1) | CN101783660B (en) |
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Families Citing this family (12)
Publication number | Priority date | Publication date | Assignee | Title |
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US8217824B2 (en) * | 2007-12-13 | 2012-07-10 | Arctic Silicon Devices, As | Analog-to-digital converter timing circuits |
US8742796B2 (en) * | 2011-01-18 | 2014-06-03 | Nvidia Corporation | Low energy flip-flops |
US9911470B2 (en) | 2011-12-15 | 2018-03-06 | Nvidia Corporation | Fast-bypass memory circuit |
US9435861B2 (en) | 2012-10-29 | 2016-09-06 | Nvidia Corporation | Efficient scan latch systems and methods |
US9842631B2 (en) | 2012-12-14 | 2017-12-12 | Nvidia Corporation | Mitigating external influences on long signal lines |
US8988123B2 (en) | 2012-12-14 | 2015-03-24 | Nvidia Corporation | Small area low power data retention flop |
US10141930B2 (en) | 2013-06-04 | 2018-11-27 | Nvidia Corporation | Three state latch |
US9786456B2 (en) * | 2014-11-20 | 2017-10-10 | Ryan Patrick CLAGGETT | Fail-safe system for process machine |
US9525401B2 (en) | 2015-03-11 | 2016-12-20 | Nvidia Corporation | Low clocking power flip-flop |
US9559674B2 (en) * | 2015-05-14 | 2017-01-31 | Mediatek Inc. | Low-ripple latch circuit for reducing short-circuit current effect |
US10038429B1 (en) * | 2017-08-22 | 2018-07-31 | Qualcomm Incorporated | High-speed soft-edge sense-amplifier-based flip-flop |
US20230208424A1 (en) * | 2021-12-28 | 2023-06-29 | Advanced Micro Devices, Inc. | Low power single phase logic gate latch for clock-gating |
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US6147514A (en) * | 1997-12-11 | 2000-11-14 | Kabushiki Kaisha Toshiba | Sense amplifier circuit |
US6396309B1 (en) * | 2001-04-02 | 2002-05-28 | Intel Corporation | Clocked sense amplifier flip flop with keepers to prevent floating nodes |
US6459317B1 (en) * | 1999-12-22 | 2002-10-01 | Texas Instruments Incorporated | Sense amplifier flip-flop |
US6480037B1 (en) * | 2001-05-31 | 2002-11-12 | Samsung Electronics Co., Ltd. | Sense amplifier circuit of semiconductor memory device |
US6703867B1 (en) * | 2002-08-23 | 2004-03-09 | Sun Microsystems, Inc. | Clocked full-rail differential logic with sense amplifier and shut-off |
US7439775B2 (en) * | 2006-04-28 | 2008-10-21 | Samsung Electronics Co., Ltd. | Sense amplifier circuit and sense amplifier-based flip-flop having the same |
Family Cites Families (2)
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US6107853A (en) * | 1998-11-09 | 2000-08-22 | Texas Instruments Incorporated | Sense amplifier based flip-flop |
CN101051827A (en) * | 2007-04-02 | 2007-10-10 | 智原科技股份有限公司 | Scanning trigger circuit with lenghtening maintenance time margin |
-
2009
- 2009-01-16 US US12/354,926 patent/US7760117B1/en active Active
- 2009-04-23 TW TW098113442A patent/TWI380588B/en not_active IP Right Cessation
- 2009-04-28 CN CN2009101375140A patent/CN101783660B/en not_active Expired - Fee Related
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
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US6147514A (en) * | 1997-12-11 | 2000-11-14 | Kabushiki Kaisha Toshiba | Sense amplifier circuit |
US6459317B1 (en) * | 1999-12-22 | 2002-10-01 | Texas Instruments Incorporated | Sense amplifier flip-flop |
US6396309B1 (en) * | 2001-04-02 | 2002-05-28 | Intel Corporation | Clocked sense amplifier flip flop with keepers to prevent floating nodes |
US6480037B1 (en) * | 2001-05-31 | 2002-11-12 | Samsung Electronics Co., Ltd. | Sense amplifier circuit of semiconductor memory device |
US6703867B1 (en) * | 2002-08-23 | 2004-03-09 | Sun Microsystems, Inc. | Clocked full-rail differential logic with sense amplifier and shut-off |
US7439775B2 (en) * | 2006-04-28 | 2008-10-21 | Samsung Electronics Co., Ltd. | Sense amplifier circuit and sense amplifier-based flip-flop having the same |
Also Published As
Publication number | Publication date |
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TW201029328A (en) | 2010-08-01 |
US7760117B1 (en) | 2010-07-20 |
CN101783660A (en) | 2010-07-21 |
CN101783660B (en) | 2012-03-28 |
TWI380588B (en) | 2012-12-21 |
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