Modified Kuijk Bandgap Reference with VGO Extraction
This creative component presents an innovative CMOS Bandgap Reference Generator topology targeting sub-ppm temperature coefficient over a wide temperature range. The proposed circuit consists of extracting VGO from the temperature characteristics of VBE. VGO is the bandgap voltage of the silicon that is extrapolated at 0K and is temperature independent over a wide range of temperature (-40°C to 125°C). Analytical constraints are carefully investigated which lead to the output voltage that is proportional to VGO when certain mismatches and opamp offsets are accurately trimmed using two temperatures trimming. The modified circuit, less number of operational amplifiers and resistors which make the circuit less complex, reduces area and power requirements. Transistor level simulations are implemented in GlobalFoundries 130nm process and achieve temperature coefficient about 3.5ppm/°C across the industrial temperature range (-40 °C to 80 °C).