Graduate Exam Abstract

Abhay Rai

M.S. Final
July 8, 2010, 8:00AM
Engr B105
Buck converter for on chip reference generation

Abstract: Most modern day chips use on chip voltage reference, also known as bandgap voltage reference generator to provide a stable reference, independent of VDD ripples and compensated for temperature variations. When rail voltage is scaling down with process, it imposes challenges in terms of headroom etc to achieve a stable bandgap voltage reference. It also need to be scaled down to VDD/2 for prectical uses and provide a common mode voltage of VDD/2 for onchip circuits. This thesis discusses a buck converter which uses PWM for stable reference generation and directly generates a VDD/2 reference, a novel inductor ripple current cancellation technique, which cancles inductor ripple current and therefore it does not require big capacitor for filtering of inductor ripple . A pulse width modulation technique is used which keeps reference output constant for variable loads and a temperature compensation technique is used to minimise temp sensitivity.

Adviser: Dr George Collins
Co-Adviser: N/A
Non-ECE Member: Dr Azer Yalin
Member 3: Dr Steven Reising
Addional Members: N/A


Program of Study: