How does the phone calculate the remaining charge?

How do you calculate mobile phone battery display? Is it accurate? Why your battery can be accurate to 1%? Such a question often make a lot of netizens have some doubts, but looking for less than you want to answer, today happens to have a net friend put forward this problem, the small make up rubbish also not much said, is simple for you answer the phone by what kind of method to calculate power and accurate display.

Mobile phone battery display on the screen, is calculated by means of what?

The mobile phone battery power there are many kinds of calculation methods, such as voltage test method, through to monitor the battery voltage, and then through the change of the voltage to determine the change of the power, but because of the battery power and voltage is not linear relationship, lead to voltage test relative accuracy will be much worse, and when power is lower than 50%, the voltage monitoring to determine more electricity method is not accurate, so use this method to measure the power of mobile power after power down to 50% fall very fast. As a result of current science and technology aspects of demand, also have improved, also causes the method gradually eliminated by the mobile phone market, although there are still some phones with this calculation method, but is not the mainstream, it aside.

Now, calculation of mobile phone use most is the coulombmeter, coulometer is the English name is coulom bcounter according to Faraday's law designed to measure circuit by electricity in the device is called "coulometer" or "electricity meter". Simple, on the battery protection circuit in series a power measurement chip, which is an integrated sampling resistor connected in series, the resistance test unit time loop through the current size, if the current is changing with time, after the current through the different and produce different pressure differential, integral by the change of current, which is in this period of time, distance etc. to accumulative total of current, the resulting user use the right power.

Obtain the present capacity of the battery to get the final accurate power surplus value, calculate the coulombmeter through two types of design to obtain the current capacity of the battery. Is A kind of A/D analog-to-digital conversion, usually 12 precision, accuracy of converts voltage to 12 hexadecimal number multiplied by the sampling time interval, the second is the integration model, use RC integral circuit for voltage on the integral value of time, will get the capacity of the battery, in the end by battery power divided by the capacity of the battery current numerical calculate the percentage of how many and to get the battery remaining on the phone software via software display to the user.

While the lithium battery over time to increase the capacity of the battery will be a loss, such as a 2000 mAh capacity of the battery in the recycling of 100 times, the capacity of the battery itself may be attenuation to 1800 mAh capacity, while the coulombmeter if has maintained the original nominal capacity will lead to power calculation is not accurate, so the coulombmeter with a capacity to use adjustment algorithm, can according to the actual rated capacity of battery cycle adjustment.

And because of the weather will affect the size of the battery rated capacity, such as the temperature at 26 ° battery can get 100% of the rated capacity, when the temperature at 0 °, the capacity of the battery is only 80%, coulombmeter to make calculation is more accurate in the chip increases in capacity of an algorithm for the temperature adjustment, according to the actual temperature to adjust the rated capacity of the battery.

The page contains the contents of the machine translation.