Response to the following:
Consider the voltage-regulator circuit shown in Figure. The value of R is selected to obtain an output voltage VO (across the diode) of 0.7 V.
(a) Use the diode small-signal model to show that the change in output voltage corresponding to a change of 1 V in V+ is
This quantity is known as the line regulation and is usually expressed in mV/V.
(b) Generalize the expression above for the case of m diodes connected in series and the value of R adjusted so that the voltage across each diode is 0.7 V (and VO = 0.7mV).
(c) Calculate the value of line regulation for the case V+ = 15 V (nominally) and (i) m = 1 and (ii) m = 4.