Konstruktion av current conveyors via makromodellering
A current conveyor is an active building block that can be used to implement most active and passive components. It differs from the operation amplifier in that it uses current instead of voltage. The current conveyor also has significantly higher voltage gain over a broader frequency range. To simplify the construction of analogue circuits and increase the construction efficiency it is desirable to use a top-down methodology. This means that the whole system is partitioned into a hierarchy of subsystems. The behavioural description of the whole systems is then partitioned into behavioural descriptions for each subsystem. Such a methodology has been examined through propagation of application level specifications down to a current conveyor. This work has been realised through modelling the current conveyor with a linear macro model. The purpose of this thesis is to examine the functionality of the current conveyor and the possibility to use a top-down methodology in construction. Since the linear macro model played a central role, it was necessary to validate that it was sufficiently accurate in comparison to transistor level simulations. This was realized through calculation of behavioural specifications and then transferred to the linear macro model. A method for calculation of component values in the linear macro model on the basis on specifications for an amplifier has been proposed as well as implemented. The work shows that the linear macro model is sufficiently accurate in modelling circuit topologies of current conveyors to be useable in top-down methodology. The proposed method for calculation of component values in the linear macro model works well. The drawback is that it is only applicable on the current conveyor as an amplifier. An attempt was made to implement a method for the current conveyor as an integrator. But the lack of defined behavioural descriptions for the integrator led to an unsolvable equation system.