What is advantage of using Wilson current mirror?
Now wilson current mirror is less dependent on beta values meaning it is less dependent on transistor parameters but one of the important advantage of wilson current mirror over other current mirror is that it provides high output impedance which improves the efficiency of the current mirror.
What are the advantages of current mirror?
The advantages of a current mirror are:
- low input impedance makes the input current insensitive to the output impedance of the input source.
- high output impedance makes the output current insensitive to the impedance of the output load.
- inversion of sources to sinks or sinks to sources.
- accurate gain.
What is the advantage of widlar current source over constant current source?
It allows you to generate a low output current without using high value resistors.
Why cascode current mirror is better?
Advantages: 1. Cascode current mirror eliminates the channel length modulation effect by keeping Vds1 = Vds2 constant in the ratio: Iout = (W/L) (1+λVds2 ) (W/L) (1+λVds1) 2. Improves output resistance.
What are the disadvantages of basic current mirror?
Drawbacks of Basic current mirror In Basic CM , we have neglected channel modulation. CLM effects result in significant error. ∴ to suppress effect of CLM, cascode CM is used.
Which type of feedback is used in Wilson current mirror?
global negative feedback
A global negative feedback – it is constituted by the simple current mirror (T1 and T2) and the resistor R acting as a simple current-to-voltage converter. It is the important negative feedback that keeps the current constant; we have already discussed it above.
How does a Wilson current mirror work?
A Wilson current mirror is a three-terminal circuit (Fig. 1) that accepts an input current at the input terminal and provides a “mirrored” current source or sink output at the output terminal. The mirrored current is a precise copy of the input current. The circuit is named after George R.
What is current mirror explain Widlar current mirror in detail?
A current mirror is a circuit designed to copy a current through one active device by controlling the current in another active device of a circuit, keeping the output current constant regardless of loading.
How can we improve the performance of a current mirror circuit?
The small signal output resistance is a good measure of the perfection of the current mirror. Higher performance current mirrors will attempt to increase the value of rout. The approach used to increase the output resistance is to use cascode structure.
Why cascode current mirrors are used?
In order to suppress the effect of channel length modulation, a cascode current mirror can be used. As shown in figure below, one more transistor M3 is added. In the circuit of basic current mirror and Vb is chosen such that Vx = Vy, then Iout closely tracks Iref.