KR102013934B1 - A ring oscillator including nand gate and an oscillator control circuit controlling the same - Google Patents

Abstract

The present invention relates to an oscillation control circuit controlling oscillation of a ring oscillator. The oscillation control circuit comprises one or more ring oscillator cells. Each of the ring oscillator cells comprises one or more inverters. The one or more ring oscillator cells have at least one NAND gate.

Description

Ring oscillator including NAND gate and oscillation control circuit for controlling it {A RING OSCILLATOR INCLUDING NAND GATE AND AN OSCILLATOR CONTROL CIRCUIT CONTROLLING THE SAME}

The present invention relates to a ring oscillator including a NAND gate and an oscillation control circuit for controlling the same.

The NAND gate is a gate indicating the complement of the AND gate. That is, if all inputs are true at the NAND gate, the output is low, otherwise the output is high.

By combining NAND gates, various gates such as AND, OR, and NOT can be made, which is useful for simplifying the same circuit alone. Therefore, NAND gates are widely used for cost reduction.

The ring oscillator (oscillator) means a sequential logic circuit type oscillator in which odd number of inverting amplifiers or inverters or delay units are connected in series in a loop circulation form. The ring oscillator features no input or output. In addition, the ring oscillator has a simple structure and is widely used in integrated circuits.

A typical ring oscillator is constructed by connecting an odd number of inverters in series.

Patent Registration No. 10-0779108, 2007.11.19 Registration

An object of the present invention is to provide a ring oscillator including a NAND gate and an oscillation control circuit for controlling the same.

Problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, an oscillation control circuit of a ring oscillator includes at least one ring oscillator cell, each of the at least one ring oscillator cell includes at least one inverter, and at least one ring The oscillator cell includes a first ring oscillator cell that includes at least one NAND gate.

The one or more ring oscillator cells may further include a second ring oscillator cell including a plurality of inverters and not including a NAND gate.

The at least one ring oscillator cell may be connected to a fractal structure, and the first ring oscillator cell may be disposed at each vertex of the fractal structure.

In addition, the first ring oscillator cell includes three nodes, and the three nodes may include a first node including one NAND gate, a second node including one inverter, and a third node, respectively. Can be.

The fractal structure may include an odd number of stages, and one or more first ring oscillator cells may be disposed at each odd stage included in the plurality of stages.

In addition, the one or more ring oscillator cells are connected to each other in a stacked structure in which the one or more ring oscillator cells are stacked in a stack, and nodes in phase among nodes included in each of the one or more ring oscillator cells are connected to each other. You can do

In addition, the power supply unit may adjust the oscillation frequency of the ring oscillator by adjusting the voltage applied to the NAND gate.

In a ring oscillator in which a plurality of ring oscillator cells are connected in a fractal structure according to an aspect of the present invention for solving the above problems, each of the plurality of ring oscillator cells includes one or more inverters, and the plurality of ring oscillator cells At least some of which include at least one NAND gate.

In a ring oscillator having a stacked structure in which a plurality of ring oscillator cells are stacked in a stack according to an aspect of the present invention for solving the above problems, the plurality of ring oscillator cells are stacked in the same direction, and the plurality of ring oscillator cells The in-phase nodes of the nodes included in each are connected to each other, and at least some of the plurality of ring oscillator cells may include at least one NAND gate and one or more inverters.

Other specific details of the invention are included in the detailed description and drawings.

According to the disclosed embodiment, various types of circuits capable of controlling oscillation of a ring oscillator using a NAND gate are provided.

Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a diagram schematically illustrating a ring oscillator according to an exemplary embodiment.
2 illustrates a structure of a ring oscillator using a NAND gate in transistor units according to an exemplary embodiment.
3 is a diagram illustrating a structure of a ring oscillator using a three-phase inverter in transistor units according to an exemplary embodiment.
4 is a diagram illustrating an experiment result using the ring oscillator illustrated in FIGS. 2 and 3.
5 illustrates a three-stage ring oscillator using a NAND gate according to an embodiment.
6 is a diagram illustrating a five-stage oscillator using a NAND gate according to an embodiment.
7 illustrates a seven-stage oscillator using a NAND gate according to an embodiment.
8 illustrates a nine-stage oscillator using a NAND gate according to an embodiment.
9 illustrates a three-stage ring oscillator using a three-phase inverter according to an embodiment.
10 illustrates a five-stage ring oscillator using a three-phase inverter according to an embodiment.
FIG. 11 illustrates a seven-stage ring oscillator using a three-phase inverter according to an embodiment.
12 illustrates a nine-stage ring oscillator using a three-phase inverter according to an embodiment.
FIG. 13 illustrates a circuit structure for an experiment of applying a capacitance change to a single node, according to an exemplary embodiment.
FIG. 14 is a graph illustrating a change in output frequency of the ring oscillator when the capacitance of the capacitor changes in the circuit shown in FIG. 13.
15 is a diagram illustrating a circuit structure for an experiment of applying a capacitance change to all nodes according to an embodiment.
FIG. 16 is a graph illustrating a change in output frequency of the ring oscillator when the capacitance of the capacitor changes in the circuit shown in FIG. 15.
FIG. 17 illustrates a circuit structure for an experiment of applying a resistance change to a single node, according to an exemplary embodiment.
FIG. 18 is a graph illustrating a change in output frequency of the ring oscillator when the resistance is changed in the circuit of FIG. 17.
19 is a diagram illustrating a circuit structure for an experiment of applying a resistance change to all nodes according to one embodiment.
FIG. 20 is a graph illustrating a change in output frequency of the ring oscillator when the resistance of the resistor in the circuit shown in FIG. 19 is changed.
21 is a diagram illustrating a laminated structure ring oscillator according to an embodiment.
22 illustrates an oscillation control circuit of a ring oscillator according to an embodiment.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be embodied in various different forms, and the present embodiments only make the disclosure of the present invention complete, and those of ordinary skill in the art to which the present invention belongs. It is provided to fully inform the skilled worker of the scope of the invention, which is defined only by the scope of the claims.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, "comprises" and / or "comprising" does not exclude the presence or addition of one or more other components in addition to the mentioned components. Like reference numerals refer to like elements throughout, and "and / or" includes each and all combinations of one or more of the mentioned components. Although "first", "second", etc. are used to describe various components, these components are of course not limited by these terms. These terms are only used to distinguish one component from another. Therefore, of course, the first component mentioned below may be a second component within the technical spirit of the present invention.

Unless otherwise defined, all terms used in the present specification (including technical and scientific terms) may be used in a sense that can be commonly understood by those skilled in the art. In addition, terms that are defined in a commonly used dictionary are not ideally or excessively interpreted unless they are specifically defined clearly.

As used herein, the term "part" or "module" refers to a hardware component such as software, FPGA, or ASIC, and the "part" or "module" plays certain roles. However, "part" or "module" is not meant to be limited to software or hardware. The “unit” or “module” may be configured to be in an addressable storage medium or may be configured to play one or more processors. Thus, as an example, a "part" or "module" may include components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, Procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. Functions provided within components and "parts" or "modules" may be combined into smaller numbers of components and "parts" or "modules" or into additional components and "parts" or "modules". Can be further separated.

The spatially relative terms " below ", " beneath ", " lower ", " above ", " upper " It can be used to easily describe a component's correlation with other components. Spatially relative terms are to be understood as including terms in different directions of components in use or operation in addition to the directions shown in the figures. For example, when flipping a component shown in the drawing, a component described as "below" or "beneath" of another component may be placed "above" the other component. Can be. Thus, the exemplary term "below" can encompass both an orientation of above and below. Components may be oriented in other directions as well, so spatially relative terms may be interpreted according to orientation.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram schematically illustrating a ring oscillator according to an exemplary embodiment.

In one embodiment, the ring oscillator (oscillator) means a sequential logic circuit type oscillator in which an odd number of inverting amplifiers or inverters or delay units are connected in series in a loop circulation form.

Referring to FIG. 1A, a general ring oscillator 100 including three inverters is shown.

An object of the present invention is to increase the power efficiency of a ring oscillator as an oscillation circuit by controlling oscillation and non-oscillation of a ring oscillator cell connected in a fractal structure, and for this purpose, a NAND gate or a three-phase inverter (Tri-State Inverter) is used. I use it.

For example, referring to FIG. 1B, a ring oscillator for controlling oscillation and non-oscillation of the entire circuit by replacing one of three inverters included in the ring oscillator 100 with a NAND gate 202. 200 is shown.

The ring oscillator 200 outputs the same as B when two of the two inputs A and B of the NAND gate 202 are on, and the output is off regardless of B when A is off. Is a circuit for controlling the oscillation and non-oscillation of the ring oscillator 200 with the NAND gate 202.

In addition, referring to Figure 1 (c), by replacing one of the three inverters included in the ring oscillator 100 with a three-phase inverter 302, ring oscillator (to control the oscillation and non-oscillation of the entire circuit ( 300 is shown.

The ring oscillator 300 outputs the same as B when the output of the three-phase inverter 302 is input A, B is on, and when A is off, the output is Z-state (regardless of B). It is a circuit that controls the oscillation and non-oscillation states of the ring oscillator 300 with a three-phase inverter in terms of being floating).

2 illustrates a structure of a ring oscillator using a NAND gate in transistor units according to an exemplary embodiment.

Referring to FIG. 2, as shown in FIG. 1B, a NAND gate and two inverters are sequentially connected. As a result of the simulation using the ring oscillator 200, it was confirmed that the oscillation did not occur when en (enable voltage) = 0 and oscillation when en = 1.

3 is a diagram illustrating a structure of a ring oscillator using a three-phase inverter in transistor units according to an exemplary embodiment.

Referring to FIG. 3, a three-phase inverter and two inverters are sequentially connected as shown in FIG. 1C. As a result of the simulation using the ring oscillator 300, it was confirmed that the oscillation is non-oscillation when the floating state when en = 0, and oscillation when en = 1.

4 is a diagram illustrating an experiment result using the ring oscillator illustrated in FIGS. 2 and 3.

Referring to FIG. 4A, in the ring oscillator 200 of FIG. 2, a change in frequency (in GHz) (vertical axis) according to a change in en (horizontal axis) is illustrated in a graph.

In the ring oscillator 200 illustrated in FIG. 2, the result of measuring the change of frequency according to the change of en is shown in Table 1 below.

en [V] 2 2.25 2.5 2.75 3 frequency [GHz] 1.0547 1.1262 1.1628 1.184 1.1945

Similarly, referring to FIG. 4B, in the ring oscillator 300 shown in FIG. 3, a change in frequency (in GHz) according to a change (horizontal axis) of en is illustrated in a graph.

In the ring oscillator 3200 illustrated in FIG. 3, a result of measuring a change in frequency according to a change in en is shown in Table 2 below.

en [V] One 1.25 1.5 1.75 2 2.25 2.5 2.75 3 freq.
[GHz] 0.4623 0.8029 1.1268 1.2109 1.242 1.2595 1.2711 1.2791 1.2849

As shown in FIG. 4, Table 1, and Table 2, it can be seen that the oscillation frequency of the two types of ring oscillators 200 and 300 increases as the enable voltage increases, and the slope gradually decreases.

However, the ring oscillator 300 using the three-phase inverter has a wider frequency control range than the ring oscillator 200 using the NAND gate, and oscillates even at a lower enable voltage.

Therefore, the ring oscillator 300 using the three-phase inverter has an advantageous side for the oscillation control of the ring oscillator.

5 to 12 are diagrams illustrating an example of controlling the oscillation of n-stage Cellular Oscillatory Networks (CON).

5 to 8 are diagrams illustrating examples of controlling oscillation of an n-stage CON using a NAND gate, according to an exemplary embodiment.

5 illustrates a three-stage ring oscillator using a NAND gate according to an embodiment.

Referring to FIG. 5, a three stage ring oscillator 210 is shown that includes six ring oscillators. In addition, at least some of the six ring oscillators may be configured as a ring oscillator 200 using a NAND gate as shown in FIG. 2.

According to the non-limiting embodiment illustrated in FIG. 5, three ring oscillators, which are shown in shades of gray, of the six ring oscillators are configured as ring oscillators 200 using NAND gates. Therefore, among the total 18 devices included in the three-stage ring oscillator 210, there are 15 inverters, 3 NAND gates, and 16.67% of the total may be NAND gates.

6 is a diagram illustrating a five-stage oscillator using a NAND gate according to an embodiment.

Referring to FIG. 6, a five stage ring oscillator 220 is shown that includes fifteen ring oscillators. In addition, at least some of the fifteen ring oscillators may be configured as a ring oscillator 200 using a NAND gate as shown in FIG. 2.

According to the non-limiting example illustrated in FIG. 6, five ring oscillators, which are indicated by gray shades, of the 15 ring oscillators are configured as the ring oscillator 200 using a NAND gate. Therefore, among the total 45 devices included in the five-stage ring oscillator 220, there are 40 inverters, 5 NAND gates, and 11.11% of the total may be NAND gates.

7 illustrates a seven-stage oscillator using a NAND gate according to an embodiment.

Referring to FIG. 7, there is shown a seven stage ring oscillator 230 comprising 28 ring oscillators. In addition, at least some of the 28 ring oscillators may be configured as a ring oscillator 200 using a NAND gate as shown in FIG. 2.

According to the non-limiting embodiment illustrated in FIG. 7, seven ring oscillators, which are indicated in gray shades, among 28 ring oscillators are configured as the ring oscillator 200 using a NAND gate. Accordingly, 77 inverters, 7 NAND gates, and 8.33% of the total 84 devices included in the seven-stage ring oscillator 230 may be NAND gates.

8 illustrates a nine-stage oscillator using a NAND gate according to an embodiment.

Referring to FIG. 8, a nine stage ring oscillator 240 is shown that includes 45 ring oscillators. In addition, at least some of the 45 ring oscillators may be configured as a ring oscillator 200 using a NAND gate as shown in FIG. 2.

According to the non-limiting embodiment illustrated in FIG. 8, 12 ring oscillators, which are indicated in gray shades, among 45 ring oscillators are configured as the ring oscillator 200 using a NAND gate. Accordingly, among the total 135 devices included in the nine-stage ring oscillator 240, there are 123 inverters, 12 NAND gates, and 8.89% of the total may be NAND gates.

9 to 12 are diagrams illustrating examples of controlling oscillation of an n-stage CON using a three-phase inverter according to an embodiment.

9 illustrates a three-stage ring oscillator using a three-phase inverter according to an embodiment.

Referring to FIG. 9, a three stage ring oscillator 310 is shown that includes six ring oscillators. In addition, at least some of the six ring oscillators may be configured as a ring oscillator 300 using a three-phase inverter, as shown in FIG.

According to the non-limiting embodiment illustrated in FIG. 9, three ring oscillators, which are indicated by gray shades, of the six ring oscillators are configured as ring oscillators 300 using a three-phase inverter. Therefore, among the total 18 elements included in the three-stage ring oscillator 310, there are 15 inverters, three three-phase inverters, and 16.67% of the total may be configured as three-phase inverters.

10 illustrates a five-stage ring oscillator using a three-phase inverter according to an embodiment.

Referring to FIG. 10, a five stage ring oscillator 320 is shown that includes fifteen ring oscillators. In addition, at least some of the fifteen ring oscillators may be configured as a ring oscillator 300 using a three-phase inverter, as shown in FIG.

According to the non-limiting embodiment illustrated in FIG. 10, six ring oscillators, which are indicated in gray shades, of the 15 ring oscillators are configured as ring oscillators 300 using a three-phase inverter. Therefore, among the total 45 elements included in the five-stage ring oscillator 320, there are 39 inverters, 6 three-phase inverters, and 13.33% of the total may be configured as a three-phase inverter.

FIG. 11 illustrates a seven-stage ring oscillator using a three-phase inverter according to an embodiment.

Referring to FIG. 11, there is shown a seven stage ring oscillator 330 comprising 28 ring oscillators. In addition, at least some of the 28 ring oscillators may be configured as a ring oscillator 300 using a three-phase inverter, as shown in FIG.

According to the non-limiting exemplary embodiment illustrated in FIG. 11, nine ring oscillators in gray shades of 28 ring oscillators are configured as ring oscillators 300 using a three-phase inverter. Therefore, 75 inverters and 84 three-phase inverters among the 84 elements included in the seven-stage ring oscillator 330 may be configured as three-phase inverters.

12 illustrates a nine-stage ring oscillator using a three-phase inverter according to an embodiment.

Referring to FIG. 12, a nine-stage ring oscillator 340 is shown that includes 45 ring oscillators. In addition, at least some of the 45 ring oscillators may be configured as a ring oscillator 300 using a three-phase inverter, as shown in FIG.

According to the non-limiting embodiment shown in FIG. 12, twelve ring oscillators in gray shades among 45 ring oscillators are configured as ring oscillators 300 using a three-phase inverter. Therefore, among the total 135 elements included in the nine-stage ring oscillator 340, there are 123 inverters, 12 three-phase inverters, and 8.89% of the total may be configured as three-phase inverters.

13 through 16 are diagrams for describing a change in oscillation frequency according to a change in capacitance of a ring oscillator, according to an exemplary embodiment.

The ring oscillators 400 and 500 shown in FIGS. 13 and 15 are circuits composed of three inverters, as shown in FIG. However, the ring oscillators 400 and 500 are not limited to those shown in FIGS. 13 and 15, and circuits shown in FIGS. 1B and 1C may be used, respectively, and FIGS. 9 to 12. The illustrated circuit may be used or another configuration of ring oscillator circuit may be used.

FIG. 13 illustrates a circuit structure for an experiment of applying a capacitance change to a single node, according to an exemplary embodiment.

Referring to FIG. 13, a capacitor is added to one node of the ring oscillator 400. For example, a capacitor may be added between the first inverter and the second inverter of the ring oscillator 400. This is added to test the change in capacitance caused by the external stimulus. When the ring oscillator 400 actually detects the change in capacitance caused by the external stimulus, the external stimulus element is shown in FIG. 13. It can be connected to the position of the capacitance.

FIG. 14 is a graph illustrating a change in output frequency of the ring oscillator when the capacitance of the capacitor changes in the circuit shown in FIG. 13.

For example, the capacitance may be varied from 0% to 10% (step: 1%) and 10% to 30% (step: 10%) relative to the gate capacitance of the MOSFET. The results according to the change in capacitance are shown in Table 3 below.

capacitance change rate [%] 0 One 2 3 4 5 6 frequency [GHz] 1.4742 1.4738 1.4733 1.4728 1.4724 1.4719 1.4715 capacitance change rate [%] 7 8 9 10 20 30 - frequency [GHz] 1.4710 1.4705 1.4701 1.4696 1.4651 1.4606 -

When the capacitance changes in the ring oscillator 400 circuit, the output is represented by a change in frequency. Referring to FIG. 14 and Table 3, the change in the output frequency according to the change of the ratio capacitance to the gate capacitance is shown.

It is confirmed that the frequency decreases linearly as the capacitance increases, and the frequency reduction is expressed by the following equation (1).

In Equation 1, f is the output frequency of the ring oscillator 400, C is the capacitance change rate due to external stimulus compared to the gate capacitance, y-intercept 1.4742 is the output when there is no capacitance by the external stimulus Frequency.

From this, Equation 1 may be arranged as Equation 2 below.

15 is a diagram illustrating a circuit structure for an experiment of applying a capacitance change to all nodes according to an embodiment.

Referring to FIG. 15, capacitors are added to all nodes of the ring oscillator 400. For example, a capacitor may be added between all inverters of the ring oscillator 400, respectively. This is added to test the capacitance change caused by the external stimulus. When the ring oscillator 400 actually detects the capacitance change caused by the external stimulus, the external stimulus element is shown in FIG. 15. Each may be connected to a position of the capacitance.

FIG. 16 is a graph illustrating a change in output frequency of the ring oscillator when the capacitance of the capacitor changes in the circuit shown in FIG. 15.

For example, the capacitance may be varied from 0% to 10% (step: 1%) and 10% to 30% (step: 10%) relative to the gate capacitance of the MOSFET. If all capacitors are given the same capacitance change, the result of capacitance change is shown in Table 4 below.

capacitance change rate [%] 0 One 2 3 4 5 6 frequency [GHz] 1.4742 1.4728 1.4715 1.4701 1.4686 1.4672 1.4658 capacitance change rate [%] 7 8 9 10 20 30 - frequency [GHz] 1.4644 1.4630 1.4616 1.4602 1.4462 1.4322 -

When the capacitance in the ring oscillator 500 circuit changes, the output is represented by a change in frequency. Referring to FIG. 16 and Table 4, the change in the output frequency according to the change in the ratio capacitance to the gate capacitance is shown.

It is confirmed that the frequency decreases linearly as the capacitance increases, and it is expressed as Equation 3 below.

Compared with Equation 1, it is confirmed that only the proportional coefficient for capacitance increases about three times.

Also, in the circuit shown in FIG. 15, different capacitance changes may be given to three nodes. Given three different capacitance changes for each of the three nodes, the experimental results are shown in Table 5 below.

capacitance change rate [%] frequency [GHz] ca: 1% cb: 3% cc: 5% 1.4701 ca: 1% cb: 5% cc: 9% 1.4673 ca: 10% cb: 20% cc: 30% 1.4463

Table 5 shows the output frequencies when the three nodes are subjected to capacitance changes of 2% step, 4% step, and 10% step relative to the MOSFET gate capacitance, respectively. Although different capacitance changes, the area of the capacitor is the same on the circuit diagram, so it can be seen that the waveform shown in FIG. 16 is output when compared with the sum of the capacitances of the entire circuit.

Therefore, when experimenting by varying the capacitance value in the ring oscillator circuit according to the disclosed embodiment, it is preferable that the output frequency decreases linearly as the capacitance value increases as shown in Equation 4 below according to the capacitance value. Confirmed.

In Equation 4 above, N is the number of capacitors included in the ring oscillator.

Therefore, when the capacitance change occurs in the circuit by the external stimulus, the external stimulus can be detected by changing the oscillation frequency of the ring oscillator under the influence. As a result, it can be seen that the ring oscillator can be used not only as a simple oscillator but also as a sensor circuit capable of detecting a substance in contact with the circuit and affecting the capacitance of the entire circuit.

17 to 20 are diagrams for describing a change in oscillation frequency according to a change in resistance of a ring oscillator, according to an exemplary embodiment.

The ring oscillators 600 and 700 shown in FIGS. 17 and 19 are circuits composed of three inverters, as shown in FIG. However, the ring oscillators 600 and 700 are not limited to those shown in FIGS. 17 and 19, and circuits shown in FIGS. 1B and 1C may be used, respectively, and FIGS. 9 to 12. The illustrated circuit may be used or another configuration of ring oscillator circuit may be used.

FIG. 17 illustrates a circuit structure for an experiment of applying a resistance change to a single node, according to an exemplary embodiment.

Referring to FIG. 17, a resistor is added to one node of the ring oscillator 600. For example, a resistor may be added between the first inverter of the ring oscillator 600 and VDD. This is added to test the resistance change caused by the external stimulus. When the ring oscillator 600 is used to actually detect the change in capacitance caused by the external stimulus, the external stimulus element is shown in FIG. 17. It can be connected to the position of.

FIG. 18 is a graph illustrating a change in output frequency of the ring oscillator when the resistance is changed in the circuit of FIG. 17.

For example, the resistance may be given a change of 0k to 10k (step: 1k) and 10k to 30k (step: 10k). Results of the resistance change are shown in Table 6 below.

Resistance [Ω] 0 1k 2k 3k 4k 5k 6k frequency [GHz] 1.4742 1.4309 1.3929 1.3591 1.3286 1.3008 1.2752 resistance [Ω] 7k 8k 9k 10k 20k 30k - frequency [GHz] 1.2515 1.2294 1.2087 1.1891 1.0362 0.9284 -

When the resistance in the ring oscillator 600 circuit changes, the output is represented by a change in frequency. Referring to Figure 18 and Table 6, the change in the output frequency according to the resistance change is shown. According to this, as the resistance increases, the output frequency decreases, and the slope thereof also decreases.

19 is a diagram illustrating a circuit structure for an experiment of applying a resistance change to all nodes according to one embodiment.

Referring to FIG. 19, resistors are added to all nodes of the ring oscillator 700. For example, resistors may be added between VDD and all inverters of the ring oscillator 700, respectively. This is added to test the resistance change caused by the external stimulus. When the ring oscillator 700 actually detects the resistance change due to the external stimulus, the external stimulus elements are respectively positioned at the resistances shown in FIG. 19. Can be connected.

FIG. 20 is a graph illustrating a change in output frequency of the ring oscillator when the resistance of the resistor in the circuit shown in FIG. 19 is changed.

For example, the resistances may be equally changed to 0k to 10k (step: 1k) and 10k to 30k (step: 10k). Results of the resistance change are shown in Table 7 below.

resistance [Ω] 0 1k 2k 3k 4k 5k 6k frequency [GHz] 1.4742 1.3591 1.2669 1.1911 1.1273 1.0728 1.0254 resistance [Ω] 7k 8k 9k 10k 20k 30k - frequency [GHz] 0.9835 0.9469 0.9140 0.8857 0.6968 0.6026 -

20 and Table 7 are graphs and result tables of changes in the output frequency of the ring oscillator 700 when the same resistance change is applied to all inverters. Experimental results show that the output frequency decreases about three times faster than when a single node changes resistance.

Also, in the circuit shown in FIG. 19, different resistance changes may be given to three nodes. When different resistance change is given to each of the three nodes, the experimental results are shown in Table 8.

resistance [Ω] frequency [GHz] a: 1k b: 2k c: 3k 1.2047 a: 1k b: 5k c: 9k 1.0957 a: 10k b: 20k c: 30k 0.7011

Table 8 shows the output frequencies when the three inverters are subjected to resistance changes of 1k steps, 4k steps, and 10k steps, respectively.

Although different resistances were given to each other, it was confirmed that a waveform of a frequency close to that of FIG. 20 was output.

Therefore, it was confirmed that the ring oscillator circuit can be extended to the sensor circuit because the output changes with the change of the resistance value.

That is, when the resistance change occurs in the circuit by the external stimulus, the external stimulus can be detected by changing the oscillation frequency of the ring oscillator under the influence. As a result, it can be seen that the ring oscillator can be used not only as a simple oscillator but also as a sensor circuit capable of detecting a substance in contact with the circuit and affecting the resistance of the entire circuit.

In addition, it is possible to operate as a more accurate and efficient sensor device through the specific theorem of the relation between the output value of the resistance and the different output frequency and the method of detecting a specific object when the stimulus occurs at the same time as the capacitance change. have.

21 is a diagram illustrating a laminated structure ring oscillator according to an embodiment.

Referring to FIG. 21, simple stacked structure ring oscillators 810-830 are shown in which one or more CONs are simply stacked in a stack without changing direction.

This is simply a structure that connects in-phase nodes, and is not a problem in outputting an oscillation waveform. The frequency was also confirmed to appear the same (eg 1.4742 GHz).

In another embodiment, in the case of a multi-layer stacked ring oscillator stacked in the opposite direction of some CON layers by layer, different results are obtained by mixing forward and reverse.

For example, in the laminated ring oscillator structure in which the forward and reverse directions are mixed, oscillation is not performed at the even stages (two stages, four stages,…, 2n stages), and the odd stages (three stages, five stages,…, 2n-1 stages). ), It was confirmed that the rash occurred.

In addition, it was confirmed that the oscillation frequency was greatly decreased when two or more pairs of components in opposite directions formed in the odd stages.

That is, it is confirmed that the forward and reverse CONs are canceled as the respective oscillation signals are synthesized.

In the case of the laminated ring oscillator, it can be used to fabricate the chip in the 3D structure. In this process, the voltage drop according to the distance between the power line and the power line, the heat generation control by the distance difference between the heat sink and each layer, Design should take into account variables such as resistance of vias connecting layers.

For example, when it is determined that a problem occurs in heat generation control due to a narrow distance difference between each layer, the oscillation signals may be canceled by stacking ring oscillators in opposite directions. On the contrary, when the distance difference between each layer is wide, ring oscillators in the same direction may be stacked, but is not limited thereto.

22 illustrates an oscillation control circuit of a ring oscillator according to an embodiment.

Referring to FIG. 22, the oscillation control circuit 900 of the ring oscillator includes a first ring oscillator cell 910.

In the disclosed embodiment, the first ring oscillator cell 910 provides a power supply unit 916 for controlling oscillation by applying a voltage to at least one NAND gate 912, one or more inverters 914, and the NAND gate 912. Include.

For example, the first ring oscillator cell 910 may include one NAND gate and two inverters, but is not limited thereto. For example, the first ring oscillator cell may include three nodes, which may include a first node including one NAND gate, a second node including one inverter, and a third node.

The first ring oscillator cell 910 shown in FIG. 22 corresponds to the ring oscillator 200 shown in FIG. 2. In addition, the power supply unit 916 corresponds to the power supply unit 204 shown in FIG.

In one embodiment, the power supply unit 916 may adjust the oscillation frequency of the ring oscillator by adjusting the voltage applied to the NAND gate 912. As described above, the oscillation frequency of the ring oscillator increases as en applied to the NAND gate 912 increases, and the oscillation frequency of the ring oscillator decreases as en decreases.

In one embodiment, the oscillation control circuit 900 further includes a second ring oscillator cell 920 that includes a plurality of inverters 922. For example, the second ring oscillator cell 920 may include three inverters, but is not limited thereto.

In one embodiment, the oscillation control circuit 900 includes a plurality of first ring oscillator cells 910 and a plurality of second ring oscillator cells 920, and a plurality of first ring oscillator cells 910 and a plurality of. The second ring oscillator cell 920 may be connected in a fractal structure.

For example, non-limiting embodiments in which a plurality of first ring oscillator cells 910 and a plurality of second ring oscillator cells 920 are connected in a fractal structure are shown in FIGS. 5 to 8.

5 to 8, the first ring oscillator cell 910 may be disposed at each vertex of the fractal structure.

Similarly, according to the embodiment shown in FIGS. 9 to 12, the fractal structure is composed of an odd number of stages, and at least one first ring oscillator cell 910 is disposed at each odd numbered stage included in the plurality of stages. Can be arranged.

According to the disclosed embodiment, as shown in FIGS. 5 to 8, a ring oscillator may be provided in which a plurality of ring oscillator cells are connected in a fractal structure. At least some of the plurality of ring oscillator cells may include at least one NAND gate and a plurality of inverters.

In addition, as described with reference to FIG. 21, a ring oscillator having a stacked structure in which a plurality of ring oscillator cells are stacked in a stack may be provided.

In one embodiment, the plurality of ring oscillator cells are stacked in the same direction so that in-phase nodes of nodes included in each of the plurality of ring oscillator cells are connected to each other, and at least some of the plurality of ring oscillator cells are at least one. It may include a NAND gate and one or more inverters.

In another embodiment, at least some of the plurality of ring oscillator cells stacked are stacked in different directions, and pairs of ring oscillator cells stacked in different directions cancel each other.

In one embodiment, when the plurality of ring oscillator cells are connected in a fractal form or stacked in a stack, the plurality of ring oscillator cells included in the ring oscillator 200 may include a ring oscillator 200 including a NAND gate as illustrated in FIG. 2. As shown in FIG. 3, the ring oscillator 300 may include all three-phase inverters.

For example, in each of the disclosed embodiments, an oscillation control circuit including at least one ring oscillator 200 and at least one ring oscillator 300, a ring oscillator, a stacked ring oscillator and a fractal ring oscillator and oscillation control thereof. Circuitry can be provided.

In the disclosed embodiment, a sensing unit (not shown) connected to at least a portion of the first ring oscillator 910 or the second ring oscillator 920 may be further included in the oscillation control circuit according to the disclosed embodiment. The sensing unit may be connected to at least one of a plurality of nodes included in the ring oscillator.

In addition, an output measuring unit (not shown) for measuring the output of the ring oscillator and a control unit (not shown) for determining the resistance or capacitance change of the object connected to the sensing unit based on the change in the output measured by the output measuring unit It may be further included in the oscillation control circuit according to the disclosed embodiment.

For example, the sensing unit may be connected to the positions of the capacitors and the resistors shown in FIGS. 17 and 19. The sensing unit connected to the position of the capacitor shown in FIG. 17 may be used to determine the change in capacitance, and the sensing unit connected to the position of the resistor shown in FIG. 19 may be used to determine the change in resistance.

As described with reference to FIGS. 17 to 20, the controller may determine a change in capacitance or resistance of an object such as an external circuit.

17 and 19, the sensing unit may be connected to a NAND gate or a three-phase inverter, not an inverter. For example, a sensing unit may be connected between the NAND gate or the three-phase inverter and the inverter, and a sensing unit may be connected between the NAND gate or the three phase inverter and the VDD.

In one embodiment, the change in output frequency according to the change in capacitance is linear, as shown in FIGS. 14 and 16.

In one embodiment, the change in the output frequency according to the change of the resistance is non-linear, as shown in Figure 18 and 20 it can be seen that the frequency increases as the resistance increases, the slope becomes smaller. Therefore, when measuring the change in resistance, not only the amount of change in frequency but also its slope may be considered together.

In addition, when the resistance and the capacitance changes at the same time, in order to detect this from the change in the output frequency it can be used that the change pattern of the output frequency according to the change in the resistance and capacitance is different from each other.

For example, if the output frequency changes, it is assumed that the change is due to the change in capacitance, and the amount of change in capacitance is calculated, and similarly, it is assumed that the change is due to the change in resistance. Can be. From the results of the calculations, we obtain the slope of each change, and when the slope is close to the linear change, the change in capacitance has more influence. When the slope is close to the non-linear change, the change in resistance is more It can be seen that it affected.

Therefore, it is possible to calculate the ratio of the change amount of the resistance and the capacitance based on the change amount of the slope according to each calculation result, and from this, it is possible to calculate the change amount of the resistance and the capacitance.

Also, since the sensing units used to measure the resistance and the capacitance are disposed at different places, the change of the resistance and the capacitance may be separately calculated by using each sensing unit alternately.

The steps of a method or algorithm described in connection with an embodiment of the present invention may be implemented directly in hardware, in a software module executed by hardware, or by a combination thereof. The software module may include random access memory (RAM), read only memory (ROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, hard disk, removable disk, CD-ROM, or It may reside in any form of computer readable recording medium well known in the art.

In the above, embodiments of the present invention have been described with reference to the accompanying drawings, but those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

900: oscillation control circuit
910: first ring oscillator cell
912: three-phase inverter
914: inverter
916: power supply
920: second ring oscillator cell
922: inverter

Claims (9)

In the oscillation control circuit that controls the oscillation of the ring oscillator,
The oscillation control circuit comprises one or more ring oscillator cells,
Each of the one or more ring oscillator cells comprises one or more inverters,
The at least one ring oscillator cell comprises a first ring oscillator cell comprising at least one NAND gate; And
And a second ring oscillator cell including a plurality of inverters and not including a NAND gate.
The one or more ring oscillator cells are connected in a fractal structure,
And the first ring oscillator cell is disposed at each vertex of the fractal structure. delete delete According to claim 1,
The first ring oscillator cell comprises three nodes,
The three nodes,
A first node including one NAND gate;
A second node and a third node each including one inverter; Including, the oscillation control circuit of the ring oscillator. According to claim 1,
The fractal structure is composed of an odd number of stages,
The oscillation control circuit of the ring oscillator, characterized in that at least one of the first ring oscillator cell is disposed at each odd-numbered stage included in the plurality of stages. According to claim 1,
The one or more ring oscillator cells,
Connected to each other in a stacked structure stacked up in a stack,
Nodes included in each of the one or more ring oscillator cells
A node located at an output of the at least one inverter or a node located at an output of the at least one NAND gate,
When the ring oscillator is plural, nodes included in one ring oscillator cell and nodes included in another ring oscillator cell in phase with respect to the stacking direction are connected to each other, oscillation control of the ring oscillator Circuit. According to claim 1,
The oscillation control circuit
And a power supply unit configured to adjust an oscillation frequency of a ring oscillator by adjusting a voltage applied to the NAND gate. delete delete

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