bandgap ppt
-
Upload
lingadhar-reddy -
Category
Documents
-
view
444 -
download
4
Transcript of bandgap ppt
![Page 1: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/1.jpg)
IMPLEMENTATION OF BANDGAP REFERENCE CIRCUITS
M. LINGADHAR REDDY2221213122
M.Tech-VLSI Design(2013-2015)
Under the guidance of Mr. G.SHIVA KUMAR
Assistant Professor,GITAM University,
Hyderabad.
![Page 2: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/2.jpg)
CONTENTS
Introduction
Tool & technology
Approaches
Basic operation
Methodology
2 stage opamp
Implemented opamp
Simulation results
![Page 3: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/3.jpg)
Here, we will learn how to produce a reference voltage
for given supply voltage. The band gap reference is an
electronic circuit to provide an accurate and stable voltage that
is very insensitive to the change in supply voltage and
temperature and also process parameters.
INTRODUCTION
![Page 4: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/4.jpg)
Tool used - CADENCE VIRTUOSO
Technology – 90nm CMOS technology
TOOL & TECHNOLOGY
![Page 5: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/5.jpg)
WHAT IS BGR AND WHY ??
In the design of analog integrated circuits its
important to create reference voltages and currents with
well defined values (constant). Especially in analog to
digital conversion, where the input voltage is compared to
several reference levels in order to determine the
corresponding digital value, a best application is this
bandgap reference voltages .
![Page 6: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/6.jpg)
APPROACHES
Zener diode reference method
Enhancement and depletion reference method
Bandgap reference method
![Page 7: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/7.jpg)
BASIC OPERATION
![Page 8: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/8.jpg)
HOW BGR WORKS ?
Target: A fixed dc reference voltage that does not change with temperature.
kT/q has a positive temperature coefficient - PTAT proportional to absolute temperature
VBE of a BJT decreases with temperature - negative temperature coefficient
combine both to yield an approximatelyzero TC voltage reference
![Page 9: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/9.jpg)
BASIC2 STAGE CMOS OPAMP
![Page 10: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/10.jpg)
WHY OPAMP IN BGR ?
The first and probably the most important requirement is the DC
open-loop gain.
The bandwidth in which the application that uses VREF is operating
The noise from supply lines are strongly depend on the amplifier
design, consequently it is important to choose the best op-amp
architecture when the noise coming from the supply is a problem
![Page 11: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/11.jpg)
IMPLEMENTED OPAMP
![Page 12: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/12.jpg)
OPAMP RESULTS
Gain = 70 dB
Phase margin = 56
UGB= 60 MHz
![Page 13: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/13.jpg)
IMPLEMENTED BGR
![Page 14: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/14.jpg)
BGR results
Temperature vs. reference voltage
![Page 15: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/15.jpg)
Noise analysis
![Page 16: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/16.jpg)
Supply voltage vs. reference voltage
![Page 17: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/17.jpg)
CONCLUSION
Here the detail study of operational amplifier design was studied and
implemented according to our requirement. Later different types of bandgap
reference methods discussed and finally bandgap voltage references
implemented as it is independent of temperature, power supply and noise.
Future work:
The present implemented circuit has some drawback (less variation)
with process parameters and would certainly need to have a constant
reference implementation.
![Page 18: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/18.jpg)
![Page 19: bandgap ppt](https://reader035.fdocument.pub/reader035/viewer/2022062522/589e2d191a28ab5c128b5c01/html5/thumbnails/19.jpg)
thank you