Environmental Engineering Reference
In-Depth Information
A simpler technique based on a single nulling resistor and illustrated in
Fig. 5.10 was proposed in [LM99]. When applied to the amplifier in Fig. 5.7,
it gives the following loop-gain expression
In this case the
term in the numerator can be simply set equal to zero
by choosing
and the loop-gain only has a negative zero which can be used to increase the
phase margin.
Now equation (5.54) cannot be used, but the same procedure can still be
adopted to achieve simple new equations for and for a given value
of phase margin. After having substituted (5.61) in (5.60) and assuming
we can set
and evaluate the phase margin
