Just starting to learn analog circuits? Do you feel that the clouds in the clouds are in the fog? Do you think the teacher is not good? I feel that the teaching materials are bad? Ok, don't look for a reason. If you don't learn well, you shouldn't find a way to share the experience of the three seniors. See how the seniors became a rookie.
The first, senior analog ic design engineer, knows the user Yike, in a strong sense of responsibility to preach for everyone, so that everyone who sees this text learns to take less detours, there are more Time to kick the ball and chat with the sisters...
Know that your studies are heavy, and quickly enter the topic:
When I was in college, I also felt that the course of analog circuits was boring.
Especially after playing a CS, this feeling is more obvious.
First of all, we must be sure that the subject is a good child with self-motivation. I want to make the mold electricity good.
When I felt the fog in the clouds, I never thought about learning the model. The thing I do is to have a good relationship with the classmates who study well in the class. When I wait for the end of the expiration, I can borrow the notes smoothly, and the high score is very simple.
So when it comes to this, the first step is to be clear: What is the "learning" analog circuit.
If your appeal is to get a high score at the end of the period, then you don't have to look down. Going out to the right, the Electronic Technology Bookstore has exam questions and courseware over the years. What should I do on weekdays? Take the words of Xingye, and the girl dances like a bubble dance. Wait until the end of the expiration.
If the score does not indicate the problem. So how do you learn to learn analog circuits?
Ask yourself a question: What can I do to learn analog circuits?
In order to design an amplifier with a gain of 5?
Many years later, I reviewed the time in my own university and finally figured out why I always felt that I didn't learn analog circuits. The answer is actually very simple. I feel that I have learned a lot of things, but I don't know what these things have learned. I don't know if you think that you are a strange friend. Is there a similar feeling?
__What do analog circuits do? __
I want to answer this question. This is an important issue. Many people have doubts, now is a digital age, why should I learn analog circuits. Another problem in Zhihu is that "the analog circuit designer will disappear."
The answer is: no.
As long as we still need to be in contact with the real world, we will inevitably need analog circuits, so we need cute analog circuit designers.
Make an analogy. Just take the CPU. The CPU processes all digital signals. But there is no way to monitor its temperature with digital circuitry. This interface will always be an analog interface.
The operating voltage required by the CPU is very precise. For example, it is 1V. Think about it, how is this 1V realized? There is no way to achieve this with digital circuits.
You made a stroke on your mobile phone screen. How can your mobile phone know that you have made a stroke?
How to achieve gravity sensing?
You can't do without analog circuits. The analog circuit is like your eyes, ears, mouth, nose, hands and feet. Digital circuits are like your brain. As long as the future world does not develop to connect two lines directly to the brain, doping with dopamine when needed, the world needs analog circuits to complete the interface between the virtual world and the real world.
Now let's talk about how we did this interface.
Now suppose we have to take a circuit to sense the temperature of your Mobile Phone Battery, lest it get higher and higher, and finally burst when you are chatting with your sister. Disfigurement is small, and you have to spend money to buy a mobile phone again.
The engineer responsible for the peripheral application gave you a thermistor intimately. The resistance of the resistor will decrease as the temperature rises. He hopes that you can do one thing, when the temperature is higher than a certain value, give a digital signal with a magnitude of 3V, so that the system can turn off the battery.
What do we need? First we need a power supply. Without power, nothing can work.
What do you need to do with the power supply? It may be a good idea to take power directly from the battery, but the amplitude of the output voltage is limited. What should I do?
With it, do a local 3V power supply. What are the requirements for the power supply? The lower the internal resistance, the better. What kind of circuit can give a low output internal resistance? Voltage-voltage feedback op amp.
So the first block you need is an op amp.
(Off topic: In the era of discrete devices, we can buy an op amp.
If the subject wants to do chip-level design, then we need to select the appropriate device and put the op amp on the chip. )
Ok, the op amp is there, but without the reference voltage, how can the op amp output a voltage of exactly 3V?
The second required block is a reference voltage source.
(In the era of discrete devices, we can buy a reference voltage source. If the subject wants to make a chip-level design, then we need to make a reference voltage on the chip. At present, almost all reference voltages rely on the energy band of silicon itself. It is called a bandgap reference. It is about 1.2V. The process of implementing the bandgap reference is not realized by open loop, but is a closed loop process. It needs to perform loop analysis, stability analysis, and mismatch analysis. )
Now, you get the 1.2V voltage source, then make a 1.2:1.8 resistance as a feedback resistor, and use the op amp to get a 3V supply voltage. You use loop stability analysis to analyze that the loop is stable. Calculate the output resistance of the circuit, know how much current output capability this circuit has, and how much load it can carry. Not bad, you think. The analysis method of the virtual short circuit virtual circuit is quite reliable.
This is followed by a really useful part. You need a comparator to compare the voltage divider of the thermistor with the non-thermistor to a reference voltage. Then use a comparator.
(In the era of discrete devices, you can buy a comparator and want to finish it on a single chip, then design a comparator yourself. The comparators you design are often less than ideal. There is no full voltage output range, and there is no full voltage output. Range. The gain may also be only 60 dB. But when you look at the parameter requirements, it is enough. 60dB is 60dB, which is better than nothing.)
All right. You have completed the design.
The above is just a simple example. The analog circuit systems actually encountered are much more complicated than this small system. Market requirements are also becoming more and more abnormal. Who is calling so many smart people designing analog circuits?
So people who design analog circuits are struggling. Poor mind to meet all kinds of unreasonable requirements and reach many unreasonable standards.
But for the subject, these are all words.
If the subject wants to do the work of analog design, then according to the small example written above, can you see how many subjects need to be learned?
circuit analysis
Analog circuit design basis
Signals and Systems
Feedback theory/compensation theory
If the subject wants to do analog IC design, you also need to study the following subjects:
Semiconductor process technology
Principle of semiconductor devices
Probability and statistics
Analog IC design.
Among them, the analog IC design includes:
Small signal analysis
Linear modeling of amplifiers
Benchmark design
ESD protection
Layout design
Parasitic effect
Failure analysis
noise
Oscillator
Too many ellipsis
I hope that the answer will satisfy the subject, or help more young EEs.
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