- What affects the regulated output voltage as a load to ground is applied to the output voltage of the Band-gap shunt regulator?
A practical method to answer to this question is to simulate the circuit using LTspice.
Consider the band-gap shunt regulator circuits below:
R4 was added as load to the output of the circuit, and a list on 3 values (1kΩ, 10kΩ, 100kΩ) were used as steps for the simulation.
The output voltage vs. input current plot is presented in the figure below:
Where the green trace corresponds to R4 = 1kΩ, blue trace R4 = 10kΩ and red trace R4=100kΩ.
We can notice based on this analysis that the input current range for which the output voltage is constant changes based on the value of the connected load. (lower load resistance -> lower input current range).