Problem 7 In the current mirror circuit on the right, assume that all transistor
ID: 2248663 • Letter: P
Question
Problem 7 In the current mirror circuit on the right, assume that all transistorsv are in forward active mode and have the same characteristics (including gain ). The output node is where the collector of both | Q2 and Qs join into a single output current lo. The reference current IREP is the current flowing through Ri. 0 1 2 3 pts R1 Doing so will lead to a current lo that is nearly double IREF. Explain briefly what the advantages are of using this scheme, as opposed to simply designing a two-transistor current source with a reference current that is double the IREF here. 03 02 01Explanation / Answer
Here , we use two transistors Q2 &Q3 with common gate signal ,This technique is called fingering technique in MoSfet transistors .Advantages of this fingering technique is:
1:Multiple finger provide more flexibility in layout planning.
2:Multiple fingers allows better matching when needed.
3:it also reduces gate resistance and current density.
Advantages of this current mirror circuit is that it mirrors the current .i.e same current is given to both the transistors Q2 &Q3 and there gate signal is also common so the current at output node will added by both the currents of Q2 & Q3 so the output current is doubled then i reference. If we use more fingers which are having common gate signal, so the output current will be increases to same ratio.