Temperature and Power Supply Compensated CMOS Clock Circuit Based on Ring Oscillator
Round 1
Reviewer 1 Report
Comments for author File: 
Comments.pdf
Author Response
Dear Reviewer
Thank you for your interest and for comments concerning our paper entitled “Temperature and power supply compensated CMOS clock circuit based on ring oscillator”. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. Now, we are submitting the revised version after seriously considering all the comments. We hope that this version will improve the quality of our manuscript and make it more acceptable for publication.
On behalf of my co-authors, I would like to clarify some of the points brought up. The responses to your observations and suggestions are provided in contrast color and are accompanied by a revised version of the manuscript and in final version. We addressed every concern or suggestion individually by providing a detailed answer below it.
Sincerely
The Authors
[Comment 1] The reviewer is convinced that the publication of the manuscript in the current form would be premature. In this paper authors realize a ring oscillator operating at 50 MHz, however it is not clear which is the novelty of this work, which lacks completely any comparison with literature. For example, authors use two
complementary cascode mirrors to increase inverters delay, how this solution is better than the one using current starved inverter? Even if authors use an outdated technology there should be a state-of-art comparison which demonstrates the competitiveness of the proposed design. The proposed oscillator consumes a lot (150 μA) and area occupation is never mentioned, then which advantages brings this work with respect to other solutions existing in literature
[Response] Special thanks to you for your good comment and concern about our research. In the manuscript submitted this time we have reconsidered the second section. Two new subchapters were introduced, to clarify the approach we had on our proposed ring VCO technique. In subchapter 2.1 the classic current-starved ring VCO is presented, together with the architecture’s downside, given by the temperature and supply voltage influence on the oscillator frequency. Subchapter 2.2 presents our proposed ring oscillator technique, using cascaded current mirrors that maintains the drain-source voltage equal, regardless of the supply voltage and temperature, thus frequency deviation is limited. Furthermore, in section 3.1, where schematic level simulations are performed, we compared the current-starved ring VCO architecture that exists in literature with our design approach, with improved performances shown by our circuit, according to your suggestion.
A 250nm technology was used in the manuscript we submitted, because of the stability this technology gives at high temperatures compared to lower ones in terms of leakage current. This is an essential parameter for automotive industry, where our ring VCO is intended to be used. Moreover, this year, an increase of articles that use 250nm technology could be observed.
In section 3.2, where post-layout simulations are accomplished, to see the parasitic effects influence on the frequency and compensation and performance comparison of the designed PLL with previously reported clock circuits in CMOS process is concluded, with superior results such as power consumption die area, temperature range reached. Circuit die area is now mentioned (0.023mm2), we are very sorry for our inattention regarding this aspect. The oscillators maximum current reached with Monte Carlo technique is 125uA (mean + 6σ principle is applied at 25℃) at 5V supply voltage (maximum 75uA for 2V supply voltage). This includes all the circuity (ring VCO + LDO + bandgap circuit + no overlap + level shifter). The ring oscillator itself consumes only maximum 25uA, regardless of the supply voltage and temperature.
We hope that the Reviewer will be satisfied with our replies to the comments and our revised manuscript.
Reviewer 2 Report
In this paper temperature and power supply compensated CMOS clock circuit based on ring oscillator is investigated. The paper can be accepted after below modifications:
1-In Abstract line 7, several capital words are used, which should be modified.
“… Improved Performances Operational Amplifiers”.
2-In line 19, Op-Amp is common abbreviation word for the Operational amplifiers not OA, modify this issue.
3-Compression table should be added and proposed design should be compared wit some related works.
4-Quality of all figures should be improved, In Fig .4 , Fig .5 ,Fig .6, Fig .7 ,Fig .8 written text should be readable in printed version or 100% zoom.
5-Equation which not belongs to authors should be cited.
6-Figures which not belongs to authors should be cited.
7- Performance improvement in the proposed design with compensated CLK circuit compared with circuit without compensated CLK circuit should be added and clearly explained.
8- Introduction section should be improved and some new works should be added.
9-How the suggested design architecture for the ring oscillator circuit, which is depicted in Fig.2 is obtained? Provide design process and compare this circuit with some related works.
10-Provide values of all applied elements and W and L of transistors in Figs 2 and 3.
11-More explanations and details about provided circuit layout, which depicted in Fig.9, should be added.
Author Response
Dear Reviewer
Thank you for your interest and for comments concerning our paper entitled “Temperature and power supply compensated CMOS clock circuit based on ring oscillator”. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. Now, we are submitting the revised version after seriously considering all the comments. We hope that this version will improve the quality of our manuscript and make it more acceptable for publication.
On behalf of my co-authors, I would like to clarify some of the points brought up. The responses to your observations and suggestions are provided in contrast color and are accompanied by a revised version of the manuscript and in final version. We addressed every concern or suggestion individually by providing a detailed answer below it.
Sincerely
The Authors
[Comment 1] In Abstract line 7, several capital words are used, which should be modified. “… Improved Performances Operational Amplifiers”.
[Response] Thank you very much for your time in reviewing our manuscript. Your comments are all valuable and very helpful for revising and improving our paper quality. In the new version, the capital words are modified.
[Comment 2] In line 19, Op-Amp is common abbreviation word for the Operational amplifiers not OA, modify this issue.
[Response] We are very sorry for neglecting this aspect. We modified the abbreviation word for Operational Amplifiers in the new manuscript.
[Comment 3] Compression table should be added and proposed design should be compared with some related works.
[Response] Compression with other related works is important to value our work. Thank you very much for this comment! In section 3.2, performance comparison of the designed PLL with previously reported clock circuits in CMOS process is concluded, with superior results such as power consumption, die area, temperature range reached.
[Comment 4] Quality of all figures should be improved, In Fig .4 , Fig .5 ,Fig .6, Fig .7 ,Fig .8 written text should be readable in printed version or 100% zoom.
[Response] Now we have tried to improve Quality of all figures in the manuscript’s new version, in order to be readable in printed version or 100% zoom.
[Comment 5] Equation which not belongs to authors should be cited.
[Response] The Equations which doesn’t belong to authors are now cited in this revised manuscript form.
[Comment 6] Figures which not belongs to authors should be cited.
[Response] All the figures in our manuscript belongs to the authors. No figure that belongs to other related works were inserted in this revised version of the article.
[Comment 7] Performance improvement in the proposed design with compensated CLK circuit compared with circuit without compensated CLK circuit should be added and clearly explained.
[Response] Thank you very much for this comment! In section 3.1, where schematic level simulations are performed, we compared the current-starved ring VCO architectures that exists in literature with our design approach, with improved performances shown by our circuit.
[Comment 8] Introduction section should be improved and some new works should be added.
[Response] In the new manuscript, several changes are made, so that the ideas presented are better understood. Introduction is improved, with some ideas added in order to have a better text understanding.
[Comment 9] How the suggested design architecture for the ring oscillator circuit, which is depicted in Fig.2 is obtained? Provide design process and compare this circuit with some related works.
[Response] Two new subchapters were introduced, to clarify the approach we had on our proposed ring VCO technique. In Section 2.1, the classic current-starved ring VCO is shown (new Figure 2), together with the architecture’s downside. Subchapter 2.2 presents our proposed ring oscillator technique (new Figure 3), where frequency deviation is limited. Moreover, in section 3.2, post-layout simulation results are performed using parasitic extraction method. The abstract and conclusion presents more details in the new manuscript.
[Comment 10] Provide values of all applied elements and W and L of transistors in Figs 2 and 3.
[Response] All applied elements and W and L of transistors values in Figure 2 (now Figure 3) and Figure 3 (now Figure 4) are listed in Tables 1 and 2.
[Comment 11] More explanations and details about provided circuit layout, which depicted in Fig.9, should be added.
[Response] The layout process for our proposed circuit presents more details in the new manuscript.
We hope that the Reviewer will be more satisfied with our replies to the comments and our revised manuscript.
Reviewer 3 Report
This paper presents a temperature and power supply compensated CMOS clock circuit based on ring oscillator whose application field could be charge pump circuit for Opamp powering.
The paper needs to be better-written because technically does not sufficiently sound.
The novelty of the proposed circuit is quite limited. The schematic solution in its partial part (LDO+RO) is commonly used to obtain a controlled oscillator. Moreover, the exploited topology for each block are well-known.
The analysis is too rough for each block.
It seems that pre-layout simulations are reported, when no measures are provided and the novelty degree is limited, it is better to report post-layout simulation results to account also parasitic effects. This is especially advised for oscillators.
A comparison with the state of the art is missing, your proposal should be compared with prior art.
Bibliography and introduction can be enriched, reviewer would suggest at the least some works
- Corres-Matamoros, A.; Martínez-Guerrero, E.; Rayas-Sanchez, J.E. A programmable CMOS voltage controlled ring oscillator for radio-frequency diathermy on-chip circuit. In Proceedings of the 2017 International Caribbean Conference on Devices, Circuits and Systems (ICCDCS), Cozumel, Mexico, 5–7 June 2017; pp. 65–68.
- Nayak, R.; Kianpoor, I.; Bahubalindruni, P.G. Low power ring oscillator for IoT applications. Analog Integr. Circuits Signal Process. 2017, 93, 257–263.
- Ballo, A.; Pennisi, S.; Scotti, G.; Venezia, C. A 0.5 V Sub-Threshold CMOS Current-Controlled Ring Oscillator for IoT and Implantable Devices. J. Low Power Electron. Appl. 2022, 12, 16. https://doi.org/10.3390/jlpea12010016
- Tianwang, L.; Jiang, J.; Bo, Y.; Xingcheng, H. Ultra low voltage, wide tuning range voltage controlled ring oscillator. In Proceedings of the 2011 9th IEEE International Conference on ASIC, Xiamen, China, 25–28 October 2011; pp. 824–827.
- A. Ballo, A. D. Grasso and G. Palumbo, "The Dickson Charge Pump as a Signal Amplifier," in IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 69, no. 9, pp. 3476-3489, Sept. 2022, doi: 10.1109/TCSI.2022.3175985.
- Ballo, A.; Pennisi, S.; Scotti, G. 0.5 V CMOS Inverter-Based Transconductance Amplifier with Quiescent Current Control. J. Low Power Electron. Appl. 2021, 11, 37. https://doi.org/10.3390/jlpea11040037
Author Response
Dear Reviewer
Thank you for your interest and for comments concerning our paper entitled “Temperature and power supply compensated CMOS clock circuit based on ring oscillator”. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. Now, we are submitting the revised version after seriously considering all the comments. We hope that this version will improve the quality of our manuscript and make it more acceptable for publication.
On behalf of my co-authors, I would like to clarify some of the points brought up. The responses to your observations and suggestions are provided in contrast color and are accompanied by a revised version of the manuscript and in final version. We addressed every concern or suggestion individually by providing a detailed answer below it.
Sincerely
The Authors
[Comment 1] This paper presents a temperature and power supply compensated CMOS clock circuit based on ring oscillator whose application field could be charge pump circuit for Opamp powering.
The paper needs to be better-written because technically does not sufficiently sound.
The novelty of the proposed circuit is quite limited. The schematic solution in its partial part (LDO+RO) is commonly used to obtain a controlled oscillator. Moreover, the exploited topology for each block are well-known.
The analysis is too rough for each block.
[Response] Thank you very much for your time in reviewing our manuscript. Your comments are all valuable and very helpful for revising and improving the quality and the general appearance of our paper. In the new version, changes have been applied in order for our manuscript to be better written. Abstract and conclusion are modified and have more details. After introduction, Section 2.1 presents the classic current-starved ring VCO, with drawbacks regardless temperature and supply voltage compensation highlighted. Section 2.2 shows the proposed ring oscillator technique, with cascaded current mirrors implemented to reduce frequency dependence over temperature. Furthermore, all applied elements and W and L of transistors values in ring oscillator and LDO are listed now in Table 1 and 2.
We hope that the analysis in the new manuscript is refined now.
[Comment 2] It seems that pre-layout simulations are reported, when no measures are provided and the novelty degree is limited, it is better to report post-layout simulation results to account also parasitic effects. This is especially advised for oscillators.
[Response] Thank you very much for the comment! Section 3.2 in the new manuscript provides post-layout simulation results using parasitic extraction method. This was not an easy task but we hope that this new version is more suitable for publication.
[Comment 3] A comparison with the state of the art is missing, your proposal should be compared with prior art.
[Response] Compression with other related works is important to value our work. Thank you very much for this comment! In section 3.2, performance comparison of the designed PLL with previously reported clock circuits in CMOS process is concluded with superior results such as power consumption die area, temperature range reached.
[Comment 4] Bibliography and introduction can be enriched, reviewer would suggest at the least some works
- Corres-Matamoros, A.; Martínez-Guerrero, E.; Rayas-Sanchez, J.E. A programmable CMOS voltage controlled ring oscillator for radio-frequency diathermy on-chip circuit. In Proceedings of the 2017 International Caribbean Conference on Devices, Circuits and Systems (ICCDCS), Cozumel, Mexico, 5–7 June 2017; pp. 65–68.
- Nayak, R.; Kianpoor, I.; Bahubalindruni, P.G. Low power ring oscillator for IoT applications. Analog Integr. Circuits Signal Process. 2017, 93, 257–263.
- Ballo, A.; Pennisi, S.; Scotti, G.; Venezia, C. A 0.5 V Sub-Threshold CMOS Current-Controlled Ring Oscillator for IoT and Implantable Devices. J. Low Power Electron. Appl. 2022, 12, 16. https://doi.org/10.3390/jlpea12010016
- Tianwang, L.; Jiang, J.; Bo, Y.; Xingcheng, H. Ultra low voltage, wide tuning range voltage controlled ring oscillator. In Proceedings of the 2011 9th IEEE International Conference on ASIC, Xiamen, China, 25–28 October 2011; pp. 824–827.
- A. Ballo, A. D. Grasso and G. Palumbo, "The Dickson Charge Pump as a Signal Amplifier," in IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 69, no. 9, pp. 3476-3489, Sept. 2022, doi: 10.1109/TCSI.2022.3175985.
- Ballo, A.; Pennisi, S.; Scotti, G. 0.5 V CMOS Inverter-Based Transconductance Amplifier with Quiescent Current Control. J. Low Power Electron. Appl. 2021, 11, 37. https://doi.org/10.3390/jlpea11040037
[Response] Thank you so much for your time regarding our manuscript! Some of the reviewer’s suggested works are now used in the new version of the manuscript as references.
We hope that the Reviewer will be satisfied with our replies to the comments and our revised manuscript will be suitable for a further publication.
Round 2
Reviewer 2 Report
The authors have addressed most of my concerns, But the quality of the figures have not improved yet.
"[Comment 4] Quality of all figures should be improved, In Fig .4 , Fig .5 ,Fig .6, Fig .7 ,Fig .8 written text should be readable in printed version or 100% zoom.
[Response] Now we have tried to improve Quality of all figures in the manuscript’s new version, in order to be readable in printed version or 100% zoom."
Author Response
Dear Reviewer
Thank you for your interest and comments concerning our paper entitled “Temperature and power supply compensated CMOS clock circuit based on ring oscillator”. We are submitting the manuscript's second revised version where the figures' quality has been improved.
We hope that the Reviewer will be satisfied with our reply and our manuscript will be suitable for publication.
Reviewer 3 Report
Authors have answerred adequately to all my comments. My only suggestion is to include all the suggested work as reference in the paper. For the rest, the manuscript could be accepted in the current version.
Author Response
Dear Reviewer
Thank you for your interest and for comments concerning our paper entitled “Temperature and power supply compensated CMOS clock circuit based on ring oscillator”. We are submitting the manuscript's second revised version where all the suggested work are added as reference.
We hope that the Reviewer will be satisfied with our reply and our manuscript will be suitable for publication.
