Detailed explanation of OTP technology for mobile phone HD cameras

As 5Meg, 8Meg, 12Meg and other high-pixel cameras are increasingly used in mobile phones, end customers have higher and higher requirements for camera imaging effects and quality. How to improve the consistency and performance of camera modules has become particularly important. Today, we will introduce OTP technology, which is increasingly widely used in high-pixel modules.

1. What is OTP?

Full name: OTP (One Time Programmable) is a type of memory in MCU, which means one-time programming. Most of them adopt fuse structure, and the programming process is an irreversible destructive activity.

2. Advantages and Disadvantages

Compared with the eeprom used by traditional companies, OTP has the advantage of low price, which is very important in the increasingly competitive mobile phone market. The disadvantage is self-evident. Once an error occurs in the data burned in OTP, the entire mobile phone module will be scrapped, increasing the production cost. In order to overcome this disadvantage, each module manufacturer has its own core technology, which is currently to maximize the overall yield. In addition, the method of storing checksums is also a way to avoid burning errors. Its disadvantage is that it increases the complexity of calculations, but the advantage is that regardless of whether the data is burned correctly, customers can eventually get the correct data, greatly improving the production yield.

Mobile HD Camera

3. Application of OTP technology in our modules

(1) Storing Lens shading parameters

Due to various factors, camera modules have certain differences in shading. If the same set of parameters is used to calibrate lens shading, the effect is often unsatisfactory. If the module is calibrated for lens shading separately when it leaves the factory, and these calibration parameters are burned into the OTP, then when the client displays the image, it only needs to read these parameters from the OTP and apply them to the image, and they will get a very consistent imaging effect.

(2) Storing AWB parameters

Like lens shading, the quality of white balance setting is also an important factor in evaluating the quality of camera imaging. When the module leaves the factory, the R/G, B/G ratios of each module are calculated and burned into the OTP. When the client displays the image, it only needs to read these ratios from the OTP and calculate the final gain value, and set them in the image, so that color cast is not likely to occur.

(3) Storing AF position

Storing the AF position of each module in OTP can quickly improve the speed and accuracy of module AF focusing.

(4) Others

Storing the Module ID in OTP can effectively manage the version control of the product. When a problem occurs, effective information can be obtained in a timely manner to analyze the background and cause of the problem. Similarly, storing the Lens ID in OTP can also make it easier for customers to distinguish between different module manufacturers and different lenses used, so as to facilitate their control of the product.

In summary, OTP has been increasingly used in high-pixel cameras due to its low price and convenient and fast use. It is like a behind-the-scenes hero. Although it is inconspicuous, it plays a big role in the quality of high-pixel cameras.