BLOGS
2019-01-30
With the development of science and technology, the performance of smart phones is becoming more powerful and more popular, and its status in our daily life is rising. However, in today's battery technology has no breakthrough development, battery life has become a parameter that all mobile phones have to mention, and charging, as an indispensable part of it, is also sparing no effort to publicize by major mobile phone manufacturers.
Charging knowledge
Charging voltage and heating
At present, most cell phones are made of single lithium or polylithium. The working voltage of the cell is between 3.0v and 4.4v, and the voltage sharing platform is 3.6v-3.8v. When charging is carried out, the electric energy enters the phone and is processed by the step-down circuit inside the phone, and then outputs about 3.3-4.5v voltage to charge the battery. The process of voltage conversion and voltage drop is taken charge of by the IC module of charging management in the mobile phone.
This process of voltage conversion and voltage drop will generate heat, and the greater the voltage difference, the more heat will be generated.
The current and power of charging
The current is not constant while the phone is charging. A good charging solution is to give the charger as much power as the phone needs, instead of the phone passively accepting the same power of the charger.
When the phone is low, the phone will require the charger to be fully charged, which is called peak charging. At this time charging speed is very fast, but the loss and heat is also very big.
When charging, with the increase of the phone's power, the power of charging tends to decrease gradually. When the phone's battery charge reaches 60%~80% (depending on the setting of the phone manufacturer), the charging current will be reduced to achieve the purpose of reducing battery loss and the phone's heat output.
In the latter stage, the current is usually only a few hundred milliamps or less, and the charging power is also very small (relatively speaking), that is, trickle charging.
It should be noted that trickle charging is a product of the era of high-power charging, and there is no trickle charging for a 5V/500mA charger. (the current is already small.)
prehistory
Let's first talk about the time when function machines still ruled the earth. There are three obvious differences between early chargers and current chargers:
In the past, the charger was not separated from the data line and adapter (charging head) as it is now, but integrated, that is, the charging head is connected to the data line;
Why were the chargers so small? There are two main reasons:
mobile phone relatively less function, less power consumption, so the battery is also small (most is a few hundred mAh /mAh), do not need too much power charger;
High power charger manufacturing difficulty, high cost, obviously not cost-effective in the environment at that time.
However, with the development of mobile phones, especially the rise of android phones, the functions of mobile phones begin to increase, the power consumption also begins to increase, and the battery capacity also begins to advance by leaps and bounds, to The Times of thousands of mah. At this time, if you still use the 5V/500mA charger, it will be very slow to charge, and you will play with your phone while charging, and the power will be less and less.
At the beginning of the smart phone, USB port on the mobile phone has also become popular. And the revolution of mobile phone charging technology starts from here.
The tone-one
One of the early standards is USB BC 1.2.
The first USB specification was introduced in 1995 by the USB IF Forum, which was set up by seven companies, namely Intel, NEC, Compaq, DEC, IBM, Microsoft and Northern Telecom.
With the advent of BC 1.2, simultaneous charging and data transmission became mainstream.
The USB BC1.2 standard, issued by the USB IF association in 2010, refers to the portable device battery that can be directly charged for shutdown, and has become the key standard for establishing the correct way to charge the battery through the USB port. In plain English, BC1.2 is the official standard for charging portable devices, including mobile phones, via USB ports (including off charging).
Before the advent of BC 1.2, portable devices such as digital cameras and DV, in addition to increasingly powerful smart phones, began to gain popularity. Data exchange between these portable devices and computers also became much more frequent, so USB ports became common on these devices.
Although the purpose of USB interface is to transmit data and connect devices such as keyboard and mouse, rather than charging, at this time, it will be much more convenient to use USB interface to charge these devices, and USB BC 1.2 was born.
At present, the mainstream USB interfaces in the market can be divided into USB 2.0 and USB 3.0, in which the voltage of both is 5V, while the current of USB 2.0 is 500mA and USB 3.0 is 900mA.
Quick charge the secular
Although the USB BC 1.2 standard could meet the charging needs at that time, the development of technology is endless. With the development of smart phones, higher requirements are put forward for charging speed. At this time, the USB IF association, which released the USB BC 1.2 standard, did not provide a feasible solution, which set the stage for the later quick charging standard free-for-all.
Then, in 2013, came the qualcomm big brother. Qualcomm at that time a clap table, vibrate one shout: comrades, follow me to have meat to eat! It takes the lead in breaking through the maximum current limit of 1.5a in USB IF association's standard of USB BC 1.2 and elevates it to 2A, namely 10W power (5V/2A), which greatly improves the charging speed.
This is qualcomm's QuickCharge 1.0 version, also known as QC 1.0.
Anyone who knows qualcomm should know that it is a giant in mobile chip and communication patents, and with its dominant position, it can quickly promote its own QC fast-charging standard. Then, can sit to collect the authorization fee of QC standard.
By 2014, however, things were a little different. Type-c cables were already available, but they weren't yet widely available. As mentioned earlier, there are only four wires inside the MicroUSB 2.0 data line, which has very limited carrying capacity for current. 2A is basically the limit, and type-c interface is superior to the design because of its numerous contacts. Therefore, there are many more wires inside the MicroUSB 2.0 data line, which can support up to 5A current. Therefore, type-c interface is inherently friendly to large current.
The battle for high and low
Let's go back to 2014.
At the moment, if charging power continues to be boosted by boosting the current, MicroUSB's frail frame can't handle the huge current. As a result, the high-voltage fast-charging scheme led by qualcomm QC and the low-voltage high-current fast-charging scheme led by OPPO VOOC parted ways, and the free-for-all of fast-charging protocol started from then on.
First let's talk about the high voltage quick charging scheme of qualcomm.
We all know that P (power) =U (voltage) *I (current), but since increasing current doesn't work then, it's a good idea to increase the voltage, which is the same thing as a quick charge with 18W power. If you need 5V, the current already exceeds 3A. At 12V, the current is only 1.5a, which drops off immediately. One of the advantages of this scheme is that the cost is relatively low, while the disadvantage is that the voltage of the charger is raised to such a high level. In the process of secondary voltage reduction, the heat generated by the charging management IC of the mobile phone is also extremely high. Therefore, one of the characteristics of high voltage quick charging is that the mobile phone generates severe heat. Unlike qualcomm, OPPO USES a different solution. If a normal MicroUSB cable can't handle that much current, reinvent the charger from start to finish. OPPO adopted what was at the time a rather unusual solution, adding two contacts to the ordinary MicroUSB data cable, turning it into seven wires inside, and making the charging head ridiculously large thanks to the integration of IC circuits.
Not only that, because from the beginning the transformation circuit, so the data line can only use the official special cable, the general cable cannot reach the effect of fast charge, and the cost of doing so is high, large current charging for battery depletion is also more obvious, many of the early use VOOC quick charge mobile phones in use for about a year later, battery life serious decline.
Unify the whole country
Of course, it is impossible for people to send money to qualcomm foolishly. Driven by interests, various manufacturers began to develop their own quick charging standards.
Here are some of the more mainstream quick chargers.
Then mediatek also launched their own Pump Express (PE) and later Pump Express Plus (PEP) quick Charge, while the meizu mCharge quick Charge is based on this, huawei launched early Fast Charge Protocol (FSP) quick Charge, the international giant samsung also have their own an AFC (Adaptive Fast Charging) quick Charge, and the use the such as millet and Nubian qualcomm SoC as its flagship phone makers of SoC is also used by qualcomm QC quick Charge. These are the high pressure quick charging schemes used.
Of course, the low-voltage high-current scheme is not without reinforcements, such as oneplus. Liu zuohu, CEO of oneplus, is a former executive of OPPO. Although oneplus USES qualcomm SoC, it still chooses the low-voltage and high-current scheme, namely oneplus Dash flash charging, when oneplus launches its own quick charging scheme.
See here is not feel that the high pressure quick charge scheme has won the victory, the low pressure scheme can only linger on the side?
Of course not! Things changed in 2016.
In 2016, type-c interface has been widely used in all android flagship phones, which provides a favorable condition for low-voltage solution turning. (although the type-c interface supports large current, its wires are still thick)
This year, huawei changed the quick charging scheme and introduced its own type of quick charging Protocol (SCP), which is called Super Charge Protocol. The models it USES include the honor Magic, Mate9 and P10/plus, and it USES the 4.5v /5A low-voltage high-current scheme.
The latest flagship Pro7 Plus released by meizu also USES the mCharge4.0 with low voltage. The earlier mCharge3.0 belongs to the high voltage quick charge scheme (24W), and the charger's output voltage is up to 12V. As for mCharge4.0 (25W), it is a low-voltage high-current solution with a 5V charger output and 5A current.
Nubia has also launched its own quick charge scheme, which is called NeoCharge. It USES A 5V/ 5.2a 26W low voltage high current quick charge scheme and is installed on the M2 released by Nubia in 2017.
Sopower USES the most professional quick charge technology to fill your mobile phone quickly and safely.
