Akshe
Junior Member level 2
Subthreshold bandgap reference design
Hi All,
I am new to design and have been working on designing a low power bandgap reference circuit using subthreshold transistors for my college project. The design is based on a reference paper and i am trying to implement it on a different technology node. But i am unable to achieve the desired results.
I believe i am unable to size the devices appropriately and hence not getting the expected results. Currently i have tried two approaches for sizing - 1) Using the mentioned sizes in the paper 2) Starting from some scratch values and trying to use the equation to match the values. But with both i am unable to get results.
The design is as below:
![Ckt.png Ckt.png](https://www.edaboard.com/data/attachments/32/32859-f031d26c1053b50f45135345f2e3079f.jpg)
Ref. Paper - JSSC Jul 09 - A 300 nW 15 ppmC 20 ppmV CMOS Voltage Reference Circuit Consisting of Subthreshold MOSFETs
View attachment JSSC Jul 09 - A 300 nW 15 ppmC 20 ppmV CMOS Voltage Reference Circuit Consisting of Subthreshold.pdf
Technology and specifications - 130nm process, BSIM4 model, Supply voltage- 0.9-1.5 V, 1.2V transistors
According to calculations and as per threshold modelling in BSIM4 the corresponding reference voltage should be nearly around 560mV.
The results that i obtain with the two approaches are as seen in the images..
1) Using Paper sizes
![PaperSize_Schm.png PaperSize_Schm.png](https://www.edaboard.com/data/attachments/32/32860-2e87f0663778c99c78818b046cbf6c0f.jpg)
![PaperSize_Results.png PaperSize_Results.png](https://www.edaboard.com/data/attachments/32/32861-6ed101e1c5d807db9d9c2120a71ac9bd.jpg)
2) Using sizes from scratch
![ScratchSize_Schm.png ScratchSize_Schm.png](https://www.edaboard.com/data/attachments/32/32862-fe98cdd38545e11fbc13416af29bf2a3.jpg)
![ScratchSize_Results.png ScratchSize_Results.png](https://www.edaboard.com/data/attachments/32/32863-f7a91996f020ed2af1b6bffef4e3b9f0.jpg)
It would be of immense help to me if someone could help me in progressing with this as i have been stuck with this for a very long time now :sad:
Hi All,
I am new to design and have been working on designing a low power bandgap reference circuit using subthreshold transistors for my college project. The design is based on a reference paper and i am trying to implement it on a different technology node. But i am unable to achieve the desired results.
I believe i am unable to size the devices appropriately and hence not getting the expected results. Currently i have tried two approaches for sizing - 1) Using the mentioned sizes in the paper 2) Starting from some scratch values and trying to use the equation to match the values. But with both i am unable to get results.
The design is as below:
![Ckt.png Ckt.png](https://www.edaboard.com/data/attachments/32/32859-f031d26c1053b50f45135345f2e3079f.jpg)
Ref. Paper - JSSC Jul 09 - A 300 nW 15 ppmC 20 ppmV CMOS Voltage Reference Circuit Consisting of Subthreshold MOSFETs
View attachment JSSC Jul 09 - A 300 nW 15 ppmC 20 ppmV CMOS Voltage Reference Circuit Consisting of Subthreshold.pdf
Technology and specifications - 130nm process, BSIM4 model, Supply voltage- 0.9-1.5 V, 1.2V transistors
According to calculations and as per threshold modelling in BSIM4 the corresponding reference voltage should be nearly around 560mV.
The results that i obtain with the two approaches are as seen in the images..
1) Using Paper sizes
![PaperSize_Schm.png PaperSize_Schm.png](https://www.edaboard.com/data/attachments/32/32860-2e87f0663778c99c78818b046cbf6c0f.jpg)
![PaperSize_Results.png PaperSize_Results.png](https://www.edaboard.com/data/attachments/32/32861-6ed101e1c5d807db9d9c2120a71ac9bd.jpg)
2) Using sizes from scratch
![ScratchSize_Schm.png ScratchSize_Schm.png](https://www.edaboard.com/data/attachments/32/32862-fe98cdd38545e11fbc13416af29bf2a3.jpg)
![ScratchSize_Results.png ScratchSize_Results.png](https://www.edaboard.com/data/attachments/32/32863-f7a91996f020ed2af1b6bffef4e3b9f0.jpg)
It would be of immense help to me if someone could help me in progressing with this as i have been stuck with this for a very long time now :sad: