How to replace potentiometers with programmable devices in analog circuit design?

ckf茉莉花

How to replace potentiometers with programmable devices in analog circuit design? [Copy link]

 

Potentiometers are often used as calibration components in analog circuits, but their mechanical characteristics and other reasons make them difficult to integrate, and subsequent maintenance will be more troublesome. Therefore, some digital potentiometers have appeared, which use internal EEPROM to store resistance information to achieve the function of adjustable resistance. However, it seems that the accuracy cannot be improved. Now if an analog quantity fine-tuning chip is launched, an analog quantity can be multiplied by a small coefficient, for example, VOUT=VIN*α, and this α can be adjusted according to demand. In this way, the function of the potentiometer can be realized by calibrating the analog voltage. It can not only abandon the stupid potentiometer, but also realize online automatic calibration during mass production.

I would like to ask all the friends in the group, does this chip meet the application requirements?

btty038

This application should be very common. Instruments are now so integrated that they are definitely digital. I guess analog cannot be omitted for high precision.

dcexpert

No similar chips have been seen yet

qwqwqw2088

It is very convenient to use in LED lamps to dim

chunyang

The key is that the problem of universality cannot be solved. The circuit fine-tuning method in integrated circuits is completely different from the potentiometer for adjusting the resistance value. Many integrated circuits have internal fine-tuning designs, but they still cannot universally replace potentiometers. This is a limitation of physical properties.

ckf茉莉花

dcexpert posted on 2019-6-24 13:30 No similar chips have been seen yet

Yes, not currently, I am considering defining such a chip.

ckf茉莉花

chunyang posted on 2019-6-24 23:12 The key is that the problem of universality cannot be solved. The circuit fine-tuning method in the integrated circuit is completely different from the potentiometer for adjusting the resistance value. Many integrated circuits have internal...

Universality is relative. It is not realistic to completely replace potentiometers right away. But I am considering replacing potentiometers in a field where demand is relatively high. Gradually, a series of products may be developed. Then, potentiometers can be gradually abandoned.

ckf茉莉花

btty038 posted on 2019-6-24 10:07 This application should be very common. The integration of instruments is so high now. It is certain that the digital part is used. The simulation is estimated in high precision...

When you say common, do you mean potentiometers are very common? My idea is to use a calibration chip to replace the potentiometer. What do you think of this idea?

dcexpert

ckf茉莉花Published on 2019-6-25 09:07 Yes, there is none at the moment. I am considering defining such a chip.

If it is really designed, it will definitely be useful, it just depends on the cost and performance.

ckf茉莉花

For example, I think a current acquisition solution can be processed in this way to calibrate the discreteness of the resistor, which can actually reduce the requirements for precision resistors.

If I sell such a chip for 1 yuan, I wonder how the market will accept it? The accuracy is 0.1%~0.5%. And the calibration can be controlled digitally via I2C.

btty038

ckf茉莉花Published on 2019-6-25 09:12 When you say common, do you mean potentiometers are very common? My idea is to use a calibration chip to replace the potentiometer. What do you think of this idea?

Is the accuracy high?

ckf茉莉花

btty038 posted on 2019-6-25 09:55 Is the accuracy very high?

The accuracy can reach 0.1%. Of course, if higher accuracy is required, there will be corresponding means. I just hope it can meet the requirements of the application. Otherwise, it will be too precise and expensive.

btty038

ckf茉莉花Published on 2019-6-25 10:10 The accuracy can reach 0.1%. Of course, if higher accuracy is required, there will be corresponding means. I just hope that it can meet the requirements of the application, otherwise it will be too precise...

Really, it's OK as long as it meets the specific application requirements

leifengfirst

It should be possible to simulate this using a current source.

chunyang

ckf茉莉花Published on 2019-6-25 09:10 Versatility is relative. It is not realistic to completely replace potentiometers. But I am considering if I can put it in a field where the demand is relatively good...

Then you can only say that it can be replaced in certain areas, just as digital potentiometers can only replace traditional potentiometers in very limited application scenarios.