The ins and outs of mobile phone chargers,,,,[Copy link]
This post was last edited by qwqwqw2088 on 2018-10-10 16:52 The charger converts high voltage into low voltage and can charge the battery in constant current, constant voltage and other modes. It is sometimes called an adapter. For mobile phone chargers, the charger is responsible for voltage conversion, power output and current limiting protection. The mobile phone is equipped with a battery management system to monitor and control the current, voltage and power of the battery.
1. Big guy The first charger I came into contact with was the big guy charger for my childhood Walkman. It has an industrial frequency transformer plus a rectifier bridge and a smoothing capacitor inside. There is no voltage regulator inside. Don't ask me how I know. At that time, I thought it was an extremely magical existence that could replace batteries. You know, the batteries at that time would be retired gloriously after a short time. It is bulky, simple in structure and reliable and durable. The early NOKIA chargers were based on this principle. The input was 220VAC 50Hz, the output was 3.7VDC, and the maximum charging current was 355mA. The output power was only 1.3W. The charging cable and charger were integrated, and the charging port was also round. Although the output power was not large, the size was large. However, it was enough for mobile phone batteries of several hundred mAh at that time.
Early Nokia data cables and charging cables were separate. USB data cables can only be used for data exchange but not charging. USB was born in the middle of the last century. It was originally used to connect many peripherals to computers. It did not have the ability to charge, but it could provide a certain power supply capacity. USB2.0, which appeared in 2000, defaulted to 100mA of current absorbed by peripherals, and could provide a maximum of 500mA of current through negotiation. Mobile phones or other manufacturers who want to use USB devices for charging can get a maximum of 500mA of current when plugged into USB2.0 devices. At the same time, the output current of the charger equipped with mobile phones fluctuated around 500mA. Of course, the specific current of charging was still controlled by the mobile phone rather than the charger.
Using USB data cables as charging cables has strong versatility. Data cables can be used interchangeably, chargers can also be used interchangeably, and even any USB port can be plugged in to charge the mobile phone; charging and data transmission can be carried out at the same time. You can transfer pictures while charging. Well, as long as you plug it in, you have to charge no matter what you do. Since the USB interface is used for charging, it must obey the command of USB IF (USB Implement Forum, the organization that proposes USB specifications). The standard USB2.0 can provide 500mA of current. Currently, most of the devices on the market are USB2.0, and there are also some USB3.0, whose maximum current is 900mA. USB BC (BC Battery Charge, hereinafter referred to as BC specification) is the charging standard proposed by USB IF. The USB2.0 specification does not have a standard for charging. The BC specification (the widely used version is BC1.2) is a supplement to the USB2.0 protocol family. All devices that use Micro-USB interface charging should meet this standard, but there are always exceptions such as Apple and Samsung. The BC specification increases the maximum charging current to 1.5A.
The core of the BC specification is the identification mechanism. In layman's terms, mobile phones no longer blindly draw current, but are determined according to the type of USB device. Power supply devices are divided into three types: USB that can provide 500mA current, USB that can provide 1.5A, and chargers that can provide 1.5A. So far, the mobile phone charger can provide a maximum power of 7.5W. The switching power supply technology used has greatly reduced the size while increasing the power.
The OP, is the FP6601Q you mentioned used in chargers? Is there a chip that is not used in chargers but used at the output end of chargers?
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Published on 2018-12-26 09:23
3. Fast Charge Era After the emergence of smart phones, people's lives have been completely changed. Mobile phone processors are becoming more and more powerful and memory is getting larger and larger, and the demand for power is also increasing. Mobile phone batteries are also getting larger and larger. When the battery capacity exceeds the 3000mAH mark, the 5V 1.5A charging time is already quite impressive. Qualcomm, which occupies a large part of the mobile phone processor industry, has called for QC1.0 (Quick Charge 1.0 Fast Charging) to break the 1.5A limit of BC 1.2 and reach 5V 2A, shortening the charging time by 40%. Now most of the thousand-yuan phones are equipped with 5V2A chargers. Micro-USB, the current limit is generally considered to have reached the limit. Increasing the current will increase the heat, and higher requirements are placed on the data line and interface. We know that power is the product of current and voltage. Increasing the charging input means increasing the charging power. Since the current has reached its limit, the voltage can be increased to continue to speed up the charging speed. QC 2.0 came into being. Through the handshake protocol, the mobile phone and the fast charger can recognize each other. The charger can output high voltages of 9V, 12V and 20V, and continue to increase the charging power under the condition of 2A current unchanged. The existing wires and interfaces can fully meet the requirements. However, too high a voltage will introduce new problems. The battery voltage is generally 4.2V. If the input voltage is too high, the mobile phone will be responsible for reducing the high voltage to a low voltage of about 4.2V before charging. The efficiency of the voltage conversion stage will not be 100%, so some of it will inevitably be dissipated in the form of heat. Moreover, the greater the voltage difference, the higher the heat generation. This is also one of the reasons why the mobile phone heats up during fast charging. Another part is the heat generation of the battery. Most mobile phone manufacturers only use 5V, 9V and 12V, and almost no 20V is used. When a mobile phone that supports QC2.0 is used with a rechargeable battery, the charging time will be greatly shortened. QC3.0 is compatible with QC2.0 and further subdivides the voltage using the INOV algorithm, with 200mV as a step adjustment, the lowest voltage can be down to 3.6V and the highest voltage is 20V, and it is backward compatible with QC2.0. As the Type-c interface gradually replaces the original Micro-USB interface, the maximum current has also been increased to 3A; standard output scheme: 3.6V~6.5V3A, 6.5V~9V2A, 9V~12V1.5A (18W). QC4.0 technology adjusts the maximum power to 28W, the scheme is designed to be 5V/4.7A~5.6A and 9V/3A, abandoning the 12V design, and the step voltage is adjusted to 10mV. From high voltage and small current to low voltage and large current, the trend of transition from rough to refined control. Fast charging is nothing more than increasing the current or increasing the voltage. In the Micro-USB era, the current of 2A was already a bottleneck, and the solution for fast charging was high voltage and low current. In the Type-C era, the current exceeded 5A, and the solution for fast charging is more inclined to low voltage and high current. The basic solution is there, and the remaining problem is to solve when to output high voltage and when to output low voltage. In addition to Qualcomm's charging protocol, many manufacturers such as OPPO, Huawei, Meizu and MTK have also launched their own fast charging protocols. The essence of them is to charge with a standard voltage of 5V first, and then perform handshake recognition, and then the mobile phone controls the power output of the charger, or increases the output voltage or increases the output current. The typical low-voltage high-current charging technology is OPPO's VOOC. In order to meet the requirements of high-current output, VOOC first modified the standard data, increasing from the traditional 5-pin to 7-pin, and the appearance is still the same as Micro-USB. The advantage of low-voltage charging technology is that the mobile phone does not add additional voltage conversion, which greatly reduces the charging heat. For the charger, increasing and decreasing the output voltage does not change the efficiency much. In addition, the application of synchronous rectification technology in the secondary application will not generate much heat. Taking the fast charging chip FP6601Q that supports QC3.0 as an example, the recognition and control process of fast charging is simply analyzed.
The chip defaults to controlling the output of 5V. First, set D+ and D- to 2.7V to facilitate charging of Apple devices. If a QC2.0/3.0 device is connected, the D+ voltage will be pulled down to between 0.325V and 2V. At the same time, the chip will short-circuit D+ and D- inside and enter BC1.2 mode, that is, output 5V@1.5A. If D- continues to remain between 0.325V and 2V for more than 1.25 seconds, it will enter QC2.0/3.0 or FCP (Huawei's high-voltage charging protocol) mode. For QC2.0, the chip outputs 5V, 9V and 12V according to the voltage of D+ and D-. For QC3.0, it enters the continuous mode and adjusts the voltage according to the D+/D- step: on the D+ data line, the high pulse of more than 200uS will increase the voltage step by step until the voltage rises to 12V. On the D- data line, the low pulse of more than 200us will reduce the output voltage step by step until the voltage drops to 3.6V.
It can be seen that there is no technical difficulty in fast charging technology. Instead, in order to save the expensive certification fees, major manufacturers are using their own fast charging protocols. To achieve fast charging, you must use the original charger, otherwise you can only charge at 5V. The emergence of USB-PD is expected to bring about a unified situation, so wait and see.
Adapter with fast charging protocol (5V3A/9V2A/12V1.5A 18W)
While enjoying the convenience brought by fast charging, will fast charging accelerate battery aging and shorten battery life? The answer is no. There are several reasons that affect battery life, such as overcharge, over discharge, and too high or too low temperature. As for the battery, as mentioned earlier, the battery management system has been integrated into the mobile phone to monitor the battery temperature, charging current and discharge current in real time. Fast charging can provide a lot of power, but how much can enter the mobile phone battery is still controlled by the mobile phone itself. The charging speed and discharge speed are controlled within the range allowed by the battery, so you can use fast charging with confidence. Some high-end models are already equipped with wireless chargers, which will not cause the plug-in wear and tear caused by wired connections. They can be charged and used as needed. The current power of wireless charging is about 10W, which is still a gap from the speed of wired fast charging of 20W. Moreover, wireless charging is not truly wireless. The mobile phone needs to be placed on a matching charging stand. Wireless charging is still in its early stages of development. There are countless wireless charging devices on the market, but not many of them can bring convenience to consumers. Major mobile phone manufacturers have never ignored this technology and have equipped their flagship models with this function. When wireless charging technology achieves true wireless, the day of replacing wired fast charging is not far away. The charging piles used by the rapidly developing new energy vehicles are functionally equivalent to large-scale fast chargers, except that they have more complete protection mechanisms, smarter charging mechanisms, and greater charging power. The biggest disadvantage of new energy vehicles compared to traditional vehicles is that the charging time is much longer than the refueling time, while the cruising range is lower than that of traditional vehicles. Even with the support of charging piles, the charging time is not short enough, so there is no advantage in using wireless charging. If you want to save the trouble of getting out of the car and plugging in the gun to charge, just to lock the car and leave, then you can try wireless charging; but if you want to charge it as soon as possible and drive away, you'd better use the charging pile. For new energy vehicles, whether it is wired charging or wireless charging, charging speed is an urgent problem to be solved.
liushiming82 posted on 2018-12-26 09:23 OP, is the FP6601Q you mentioned used in the charger? Is there a chip that is not used in the charger but used at the output end of the charger?
I have not found a fast charging chip that is only used at the output end
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