Design of Sub Volt High Impedance Wide Bandwidth Current Mirror for High Performance Analog Circuit

Abstract

The trend of technology scaling not only offers increased density but also low voltage operation of chip. However such scaling is not always found to be advantageous especially in analog circuits where precision and performance is an important parameter. To meet the low power goals under sub volt supply new design principles need to be adopted. The circuit requirements can be met in two ways either at circuits level else at structure level. Here the structure level indicates the use of Metal oxide semiconductor field effect semiconductor transistor (MOSFET) which can be easily operated at low supply for example in the present research work the quasi-floating gate(QFG) MOSFET has been adopted. At circuit level the low power can be achieved by using low voltage processing block, in the present research work the flipped voltage follower (FVF) has been adopted. In analog any information can be processed using lumped networks which can be in the form of nodal voltages or branch currents. Based on type of processing two broad classifications of circuits is possible: Voltage mode and Current mode. Also over decades voltage mode based circuits have got broader attention and found wide variety of different applications. However, in current scenario, scaling of threshold and supply voltage of Complementary metal oxide semiconductor (CMOS) voltage mode circuit has reflected in degraded performances. Such adverse effect is less visible in current-mode circuits compared to voltage-mode circuits. This is mainly due to the fact that branch current is considered rather than node voltages. The current-mode circuits also result in high speed circuits. newlineIn this thesis, design of fundamental block of current mode circuit: Current mirror is presented with improved performance parameters. Current mirror (CM) has extensive use in biasing of amplifiers, converters, active load etc. The proposed design of current mirror is in 0.18 micron using low voltage approach at circuit level: flipped voltage follower (FVF) and also using MOSFET stru