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What makes the phone charge faster? Here is a quick guide to mobile phones

via:博客园     time:2017/11/22 13:33:54     readed:668

LG has done oneInvestigation report, Said that more than 90% of people would feel anxiety about losing their cell phone, 41% would miss an important phone while their phone was low, while 17% of men would be easily absent because of lack of power on the cellphone & mdash; The phenomenon is called "low battery anxiety."


(LG's Report on Low Battery Anxiety, Source:Dailymail)

With more and more important features on the phone, cell phone outage has become a big problem. In the meantime, we should try our best to speed up the charging of cell phones while alleviating the "low-power anxiety disorder" in the modern world. "Quick Charge" ("Quick Charge") has come into being.

Including the 2017 new three iPhone, mainstream smartphones more or less have both "fast charge" function. "Fast charge" in the end is how the same thing, how to make mobile phone charge faster?


What is the principle of cell phone charging?

In 1991, Sony and Asahi Kasei unveiled the first commercially available lithium-ion battery. Since then, lithium-ion batteries have been widely used in digital 3C products, and mobile phones are no exception. Love Fan children (micro signal: ifanr) in the previousarticleMentioned in the working principle of lithium batteries:

Lithium battery is divided into positive and negative, the positive is a lithium compound, the negative mainly graphite material, are immersed in the electrolyte.

Whether discharge or charge, in fact, are lithium-ion battery in the positive and negative mobile, energy and chemical energy conversion process. During charging, due to the action of the electric field, the lithium ions move from the positive electrode to the negative electrode and store energy. During discharging, the lithium ions move from the negative electrode to the positive electrode under the action of the chemical reaction to form a current supply.


Lithium battery charging speed, in fact, the rate of conversion of electrical energy to chemical energy, also known as "power" (P). A brief review of secondary physics, we all know:

P = IU

Power = current * voltage

The greater the current or voltage, the greater the power, the lithium battery charging speed should be faster. However, due to the limitations of the lithium battery itself, under the condition of under-voltage or over-voltage, the battery will be damaged. Therefore, the charging method of the lithium battery is rather special and is usually divided into three stages:

  • Constant Current Pre-charge Mode
  • Constant Current Regulation Mode
  • Constant Voltage Regulation Mode

When the phone is completely de-energized, the charger first charges the lithium battery with a constant current with a small current so that it gradually regains its activity. After a period of time, the charger increases the constant current and gradually increases the voltage, which is lithium The main battery charging stage; battery power at about 80%, the charger will be under a constant voltage slowly reduce the current input until the current below a certain threshold, then the phone is fully charged.

This charging process, usually by the phone's built-in power management chip to control, and most of the charger under the command of the power chip only to regulate it.


Therefore, if you want to improve the charging speed of lithium-ion mobile phones, you must work in the "high-current constant-current charging" stage.

In the era of the functional machine, the demand for the battery capacity of the mobile phone is not high, and the technology of the lithium battery is not so mature. In order to stabilize the charging of the lithium battery, most manufacturers at that time followed the low-rate charging standard "5V 0.2C" & mdash ; & mdash; charging voltage of 5V, charging current is 0.2C (C represents the rate of charge and discharge on behalf of the battery, when the battery is charged at 1C current, 1 hour can be fully charged. If it is a 1000mAh capacity battery, 1C is Refers to the charging current of 1A; 2000mAh capacity of the battery, 1C refers to the charging current of 2A, and so on).

However, with the advent of the smart phone era, the demand for mobile phones has greatly increased, and the low-rate charging standard has hardly met the demand for charging. At this time, lithium battery technology also has a greater development, better stability, charge and discharge tolerance has also improved, "fast charge" began to stage.


What is "fast charge"?

In essence, "fast charge" is a technology that can increase the charging power of mobile phones within a reasonable range so as to quickly replenish most of the battery power of mobile phones. Due to the power and voltage and current size, the current "fast charge" is mainly divided into the following two options:

  • High voltage and low current
  • Low voltage high current

"Fast Charger" is a complete set of charging solution that requires the phone's built-in power management chip, charging cable, charger three parts co-ordination, are indispensable.

iPhone is a classic counterexample. Although iPhone 8, iPhone X already support fast charge, but the matching charge head is "5V 1A" specifications at full load, the power is only only 5W, charging efficiency is very low.


As early as 2013, Qualcomm realized the importance of "fast charging" to smartphones. At that time, it introduced the Quick Charge 1.0 standard, which improves the charging efficiency by increasing the input current, so that the cell phone with the Snapdragon 600 processor supports "5V 2A "charge.

However, due to the limitations of the micro USB interface, more than 2A current is likely to cause damage, then Qualcomm thought of another solution - to increase the interface voltage. In the input current limit within the case of 2A, by increasing the supply voltage, the same can be achieved to enhance the power effect.

After continuous improvement, Qualcomm Quick Charge 2.0 / 3.0 can achieve "9V 2A", which is up to 18W of power charging.


(Qualcomm Quick Charge evolution, Source:Anand Tech)

"High-voltage small current" fast charge program inspired many peers, MediaTek's Pump Express Plus 1.0 / 2.0, Samsung's Fast Charge, Meizu's mCharge 3.0 are similar solutions.

However, there will be a step-down process after the high voltage is input into the mobile phone, at this time, heat loss will be generated inside the mobile phone, resulting in serious heating. Therefore, many mobile phones using this solution will not be activated when the bright screen fast charge, to prevent the body overheating.

In addition, due to the rivalry between manufacturers, compatibility issues exist between each other due to the fact that fast charge-up is similar in principle. Therefore, in order to enhance the charging efficiency, the primary one is to select a compatible charger.

In 2014, the OPPO Find 7 with VOOC flash turned out to be a phenomenal 22W of charging power. With the popularity of OPPO handsets, the ad that "charged for five minutes and talked for two hours" has gained popularity. Consumers are beginning to realize the meaning of "quick charge."

VOOC flash charge fast charge principle is the "low voltage high current" strategy.

Since the micro USB interface limits the size of the input current, OPPO simply customizes the entire charging system. Chargers, charging lines, and the internal circuits of the handset are all modified. The method of multi-line charging allows the VOOC flash memory to Charging with "5V 4A".


(VOOC flash charger)

The advantage of VOOC flash memory is that the heating components in the charging process are basically arranged in the charger, and the mobile phone can not overheat during fast charging. But the shortcomings are also more obvious, one with the VOOC flash charger, charging cable to use, and second, the higher cost of the entire solution, equipped with VOOC flash charge mobile phone prices will not be too cheap.

In the final analysis, the crux of the fast cell phone is that little micro USB interface You may have noticed, in recent years equipped with USB-C interface (full name USB Type-C) more and more mobile phones, in fact This is a precursor to the revolutionary mobile phone interface. USB-C can be said that the future interface standard of a point of intersection, there are several important features:

  • Support positive and negative plug
  • Compatible with USB 3.1 standard, the fastest support 10Gbit / s transmission
  • Support USB Power Delivery charging protocol, the maximum can provide 100W of electricity, and can be bi-directional power supply
  • Support DisplayPort, you can output audio and video


(USB-C interface benefits, picture source:LinkedIn)

At present, the most typical application of USB-C is actually on the new host Switch released by Nintendo earlier this year. USB-C interface alone, the Switch achieved positive and negative plug, host power supply, game output and other functions, so that the Switch can switch between the handheld and the host. This is why the new MacBook and MacBook Pro only use the Thunderbolt 3 interface (the same look and feel as USB-C and functionally compatible with USB 3.1).

USB-C supports the USB Power Delivery Charging Protocol (referred to as the PD Charging Protocol for short), which enables the input current and voltage of the mobile phone to be recharged up to "20V 5A".


(The new MacBook Pro equipped with four USB-C interface)

At this stage, USB-C is still in a transitional period, and not all mobile phone functions using the USB-C interface are compatible with the USB 3.1 standard, using the PD charging protocol,But according to the news of charging head network, The new standard or will be announced in December, by then, the mobile phone market may usher in a fast new order.

In addition, the three new iPhones released in 2017 also support the PD charging protocol. The high-voltage and low-current fast charging scheme enables input power up to 15W, but the power consumption is reduced to about 7.5W after the power reaches 75%.


(IPhone 8 Plus fast charge measured, picture source:@ Li white nemo)

Tips: How to make cell phone charging faster?

After clarifying the principle and type of mobile phone fast charging, the way to improve the charging speed of mobile phone will also be clear at a glance:

  • Charge less when playing mobile phone
  • Turn on the "power saving mode" to charge
  • Use a suitable fast charge charger

The first two points are well understood, belong to the ability to slightly increase the charging speed.

For mobile phones with "high voltage and low current" fast charging solution, the heat loss will be generated due to the step-down process inside the mobile phone. Therefore, fast charging is not usually activated when the screen is bright, so as to prevent the body from overheating.

And turn on the "power-saving mode" (iOS called "low-power mode"), the power consumption of the phone system will be reduced, so the charging speed is faster. At present, Fast Charging and other claims that make charging faster applications, are also using a similar principle - by strictly controlling the phone's power consumption, to enhance the phone charging speed.


(IPhone's "low battery mode" switch)

In fact, the selection of suitable chargers, seemingly insignificant, but it is the most affected part of the phone charging efficiency.

Charger support for fast Android phone, the original charger charging speed is usually the fastest (but there are counter-examples exist, there is no standard Huawei P10 fast header).

For example, the HUAWEI Mate 10 uses the standard HUAWEI SuperCharge charger, which can be charged at a low voltage of "5V 4A". However, if the charger is used, the fast charging effect can not be guaranteed.

If you are not sure whether your charger on hand supports fast charging, you can also easily judge by the parameters identified on the charging head:

"Circle Lightning" logo that support Qualcomm Quick Charge technology, as long as your phone equipped with a Qualcomm processor, basically you can use this charging head to achieve fast charge.

"Output power" determines the speed of charging, the power head above 15W are fast charge head. In general, larger power head, the charging speed will be relatively faster, but also depending on the specific model support.


For example, with millet 6 standard charging head, charging the millet 6 can be 15W power to charge, but to the red rice Note 4X (Xiaolong 625 version) can only be 10W power charging, although all belong to the category of Quick Charge , But the charging speed difference is obvious.

As for the OPPO VOOC flash program used, due to the higher degree of customization, so only the use of standard VOOC charger and charging line to achieve 20W power fast charge.

It is worth mentioning that the power of mobile phone charging is controlled by the mobile phone, there is a "handshake agreement" between different standards. Charger will automatically adjust the input power according to the phone's instructions, so do not have to worry about the problem of high-power charger to burn the phone. On the contrary, high-power charger is not easy to run at full capacity, so the heat will be smaller than the smaller power charger.

As for the standard 5W slow-filled head iPhone, it is recommended to buy Apple's official 12W charger, which is cost-effective iOS device fast charge solution.


Although iPhone 8 / iPhone X support fast charge, but need to buy an extra Apple official 29W charger and Lighting to USB-C data cable, the two were 388 yuan and 188 yuan, which means you have to spend an extra 576 yuan to use 29W charging head.

If you buy a $ 149 12W charger, although the input power is not as good as 29W, but it is already much faster than the 5W slow filling head.According to AppleInsider's test, Full charge for the iPhone 8 Plus, although the 12W charger slower than the 29W for about 20 minutes, but full enough faster than the 5W head for an hour faster.


(IPhone 8 Plus charging test, Picture Source:AppleInsider)

In addition, 12W charger can give the old iPhone 6s, iPhone 7 charging, charging power up to 10W, which is also much faster than the original 5W slow filling head.

In the case of battery technology has not been greatly strided, "fast charge" is indeed a significant improvement in user experience. However, the confusion of fast charging standards, compatibility issues, but also become a constraint "fast charge" short board.

Wait until what time, Android unified fast charge standard, iPhone will be equipped with fast charge it?

Picture source:Wired

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