Choosing bias voltage

[predator89]

Hi,
I want to implement class AB folded cascode design. I am referring to the circuit from J Baker (attached the screenshot) .

To implement this schematic what bias voltages (Vbias1,2..) should I assume for a known current value flowing through cascode branches.

 

[Dominik Przyborowski]

You shouldn't assuming any bias voltages, but biasing all transistors using a current from proper current mirrors.

 

[erikl]

... but biasing all transistors using a current from proper current mirrors.

... which means: the drain=base-voltage of the proper current mirror ;-) ;-)

SCNR ;-)

 

[predator89]

This means I have to design a biasing circuit first before proceeding to the amplifier design.
And what about Vncas and Vpcas, should it have bias voltage such that it supplies half current through transistor for class AB operation.

 

[Dominik Przyborowski]

Look to the original articles which should be quoted in references to this chapter. Monticelli and/or Hoegevorst, Tiero.