Author:

Abstract:

Portable electronic systems require low-voltage low power building blocks. An important building blocks is an analog to digital converter (ADC). Delta-sigma ADC provide an efficient way of trading off speed for resolution. The switched opamp (SO) technique allow design of switched-capacitor (SC) circuits at very low supply voltage without the use of multi-threshold technologies. The basic idea of it is to leave out the switches connected to the output of the amplifier in a SC integrator, because those are the ones that fail to conduct when the supply voltage is low. Switches can only be connected to well-chosen reference voltages. In this implementation the differential modified switched opamp integrator cell is used which allows maximum overdrive.