81.2. Discussion and Analysis

So, this application and this application circuit all together they are different. But as long as we ensure that M1, M2, and M3 are similar in nature, then we can say that this current I3 is also satisfying all these conditions and so, this I3 can be obtained from the same reference current. In fact, you can generate n number of such kind of current reference.

This chunk discusses the concept of generating multiple current references in a circuit. It explains that even though the applications and circuit designs may differ, maintaining certain characteristics in the components—specifically the transistors M1, M2, and M3—ensures that the current I3 can be derived from a singular reference current. This implies that with a high-quality current reference, one can produce multiple current outputs, which is essential for various applications in electronics.

Imagine you have a wellspring from which you can draw water. This wellspring represents your reference current. Just like how you can fill many buckets from this single source, in electronics, a good current reference allows engineers to create multiple outputs (current references) from one main source, much like having different taps drawing water from the same well.

So, that is why we are using current mirror. So, we do have one current mirror here we do have these two together making another current mirror and so and so.

This chunk introduces the concept of a current mirror, a crucial element in analog circuit design. A 'current mirror' is a circuit that copies (mirrors) the current flowing through one active device (like a transistor or MOSFET) to another active device. It suggests that two current mirrors are being used, which can help in providing stable and consistent current outputs across various parts of a circuit, ensuring that each component receives the necessary current without fluctuations.

Think of a current mirror like a pair of identical twins. If one twin (the first active device) decides to wear a red shirt (representing the current), the other twin (the second device) will also wear a red shirt to look exactly like the first. This mirroring ensures that both twins align in appearance, just as a current mirror ensures that the currents in various parts of the circuit match and stay stable.

So, this is MOSFET version current mirror. And we can have a BJT counterpart. So, in the next slide, we are having the current reference here. So, you can see here it is very similar this circuit is very similar only thing is that we do have Q1 and Q2 instead of M1 and M2.

In this section, we learn that current mirrors can be implemented using different types of transistors. Here, the circuit is referred to as a 'MOSFET version current mirror,' indicating that MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) are being used to create the mirror effect. Additionally, it mentions the existence of a 'BJT counterpart,' which refers to a similar setup utilizing Bipolar Junction Transistors instead. This shows the versatility in building current mirrors with different transistor types while maintaining similar functionalities.

Consider the use of different types of vehicles for the same purpose, like cars and motorcycles. A car can easily mirror the functionality of a motorcycle for transportation even though they are different in design. Similarly, in electronics, both MOSFETs and BJTs can serve the same purpose in current mirror circuits despite being different types of transistors.

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