Low power low voltage sigma-delta modulators

The aim of this master thesis is to design very low power analog-to-digital modulators. The proposed circuits work under low supply voltages since they are designed for implantable sensing applications. Under low voltage supply, the required modulators should have wide signal input and output swing ranges.; Two low power low voltage analog-to-digital SigmaDelta modulators are implemented. The first one is a second-order modulator, and the second is a fourth-order. Both of them are designed by using half delay switched-capacitor integrator based on switched-opamp technique. Also, we used voltage multiplier to boost the voltage in order to power up the input stage of the operational transconductance amplifier (OTA). A half delay integrator, based on switched-opamp technique, is used to save power and solve low voltage switch driving problem. Voltage multiplier provides boosted voltage to OTA input pair to guarantee the operation of the modeling with rail-to-rail signal swing, thus enlarge dynamic range of modulators. The modulators work under low voltage supply (0.9V) with a wide input (0--1.2V) and output (0.05--0.85V) voltage ranges. (Abstract shortened by UMI.)...