Biquadratic basic cell for programmable analog time-continuous filter

摘要

The invention relates to an elementary biquadratic cell for programmable time-continous analog filters, which is placed between a first supply voltage reference (Vdd) and a second voltage reference (GND) and is of a type having at least one pair of input terminals (I31,I31') and first (O31,O31') and second (O32,O32') pairs of output terminals, and having a pair of half-cells (31,31'), which half-cells are structurally identical with each other and each comprised of at least a first transistor (T31,T31') placed between the first (Vdd) and the second (GND) voltage reference and having a base terminal connected to a respective one of the input terminals (I31,I31'). Each half-cell (31,31') further comprises second (T32,T32') and third (T33,T33') transistors placed between the first (Vdd) and second (GND) voltage references, the second transistor (T32,T32') having a base terminal connected to the first output terminal (O31,O31') of the first pair of output terminals and a collector terminal connected to the second output terminal (O32,O32') of the second pair of output terminals, and the third transistor (T33,T33') having an emitter terminal connected to the first output terminal (O31,O31') of the first pair of output terminals ad a base terminal connected to the second output terminal (O32',O32) of the second pair of output terminals of the other half-cell.