FCMC

Question 1

Explain the charge balance problem for a 5-level FCMC

Answer 1

For a given node (that isn’t the P or N rail), a current will be injected into it at some point between 0 and T/2. A current will flow out of it at some point between T/2 and Ts. If pf =/= 0, the net change in charge will NOT be 0.

Question 2

How many triangle waves does an n level FCMC need

Answer 2

n-1

Question 3

What are the labels for the graph with the varying-height square wave and sinusoid on top

Answer 3

The square parts are ViNt, the sinusoid bit is current irbt

Question 4

What to include when the question says to identify redundant states and charge change

Answer 4

• Table of switching states
• Draw conduction path of for those states, and say that only states 10 and 01 flow through cap
• Therefore cap will charge/discharge

Question 5

What to include (other than the graph) when sketching gate drive signals for S1i - S4i

Answer 5

• Number of carrier waves
• Phase shift (and equation)
• Switching freq&raquo_space; fo

Question 6

What does state 10 do to the capacitor C2i (charges/discharges)

Answer 6

Charges it

Question 7

What does state 01 do to the capacitor C2i (charges/discharges)

Answer 7

Discharges it

Question 8

What to remember when sketching ViNss

Answer 8

Shaded bit under current is ‘flipped’ each square block

Question 9

What do you need to assume about ii when explaining charge change on C2i

Answer 9

It is constant for one period

Question 10

What do you have to say about the ripple voltage waveform

Answer 10

It is either flat or a linear increase/decrease due to iC2i

Question 11

What do you have to say when drawing the steady state balance network waveforms

Answer 11

Net change over 1 period is 0, and irbss is very small