Various fast charging protocols for mobile phones - what is PD? What is QC?
Fast charging, referred to as fast charging, when the mobile phone battery cannot be improved quickly, the way to increase the battery life is to 1. increase the battery capacity 2. speed up the charging speed. However, increasing the battery capacity will make the mobile phone thicker, so fast charging has become one of the important functions pursued by various manufacturers/consumers. The following introduces the fast charging of various companies and their differences.
Introduction 1-Fast charging principle
Generally, the USB charging standard is 5V 0.5A, which is obviously insufficient for smartphones. In order to increase the charging speed, various manufacturers have developed fast charging. The principle of mobile phone fast charging is to increase the power (P) input into the mobile phone battery. According to the electric energy formula learned in high school
P (power) = V (voltage) x I (current)
Currently, there are several ways to increase power
1. Increase the current (I)
To increase power, the simplest way is to increase the current. Increasing the current can charge quickly, so Qualcomm Quick Charge (QC) technology appeared. After detecting the D+D- of USB, it allows a maximum output of 5V 2A, but how can 5V 2A be enough? Today’s fast charging starts at 18W. Maybe you say that it should be increased to 3A? No, after the current is increased, the requirements for the charging cable are also increased. The charging cable needs to be thicker to transmit such a large current, so the next fast charging method appears.
2. Raise the voltage (V)
In the case of limited current, raising the voltage to achieve fast charging becomes the second solution, so Qualcomm Quick Charge 2.0 (QC2) comes on the scene, and by raising the power supply to 9V 2A, it achieves a maximum charging power of 18W. However, the 9V voltage does not meet the USB specification, so D+D- is also used to determine whether the device supports QC2 fast charging. But...high voltage means more loss. The lithium battery of a mobile phone is generally 4V. In order to charge, there is a charging IC in the mobile phone to control the charging and discharging process, and reduce the 5V voltage to the operating voltage of the lithium battery (about 4). If the charging voltage is raised to 9V, it will cause more serious energy loss, causing the phone to heat up, so a new generation of fast charging technology has appeared again.
3. Dynamically increase voltage (V) and current (I)
Since there are disadvantages to unilaterally increasing voltage and current, let’s increase both! By dynamically adjusting the charging voltage, the mobile phone will not overheat when charging. This is Qualcomm Quick Charge 3.0 (QC3), but this technology is not without disadvantages - high cost.
Introduction 2-Different fast charging specifications and differences
After introducing the principle, let’s talk about the charging specifications of various manufacturers and classify them according to their principles
Pulling up current (I)
In terms of pulling up current, there are several fast charging technologies
Qualcomm Quick Charge (QC)-supports up to 5V2A (10W), which is the most common fast charging solution, but because this solution is too common, solutions that are usually less than or equal to 10W are no longer called fast charging.
OPPO VOOC/OnePlus DASH-also increases the current, but OPPO/OnePlus is more advanced. VOOC/DASH supports up to 5V4A (20W), which is twice as fast as Qualcomm’s QC. Because the voltage is not high, the heat generation is less, but this solution requires a special charger and special charging cable. Only some mobile phones of OPPO/OnePlus support it, so the support is weak.
Huawei Super Charge Protocol (SCP)-also increases the current, but the minimum voltage can reach 4.5V, supports 5V4.5A/4.5V5A (22W) modes, which is faster than VOOC/DASH.
Raise the voltage (V)
There are many solutions for raising the voltage.
Qualcomm Quick Charge 2.0 (QC2)-supports up to 9V2A (18W), the second most common solution, including Huawei Fast Charge Protocol (FCP)/Samsung Flash Charge are all extended from QC2.0, but this solution is prone to heat due to the high voltage.
MediaTek Pump Express Plus (PE+)-Supports 5/7/9/12V 3/4.5A (up to 15W), few mobile phones use this solution.
USB Power Delivery 1.0-Supports multiple solutions, 5/12/20V 1.5/2/3/5A (up to 100W), designed for a variety of devices, can charge laptops. (Requires new connectors and cables with large amperage)
Dynamic adjustment
Dynamic adjustment of voltage is when charging, the voltage can be slightly adjusted according to the status of the device/charger/charging cable, with the advantages of both high current and high voltage
Qualcomm Quick Charge 3.0 (QC3)-Up to 20V 18W Dynamic adjustment of voltage 200mV
Qualcomm Quick Charge 4.0 (QC4)/4+ (QC4+)-Compatible with USB-PD
USB Power Delivery 2.0/3.0-Supports multiple solutions up to 100W, designed for a variety of devices, can charge laptops, and the special thing is that it only supports Type-C, which is the trend of future charging protocols.
MediaTek Pump Express Plus 2.0 (PE+2) - 5~20V dynamically adjusts the voltage to 0.5V
MediaTek Pump Express Plus 3.0 (PE+3) - bypasses the charging IC for charging, which can reduce heat generation, but few devices support it.
Introduction 3-Comparison
After talking about so many fast charging solutions, which one is better?
In fact, each charging solution has its advantages and disadvantages, such as:
Although QC is common, QC2.0 is less friendly to the battery, and QC3.0 supports fewer charging heads and devices, not to mention 4.0/4+.
Although VOOC is less prone to heat generation and less damaging to the battery, it is expensive and requires special cables and connectors. The only mobile phones that support this solution are OPPO’s own. As long as the mobile power supply and charging head are not from OPPO, this solution will fail.
Because PE+ uses fewer devices, it is much more difficult to find a suitable charging head than the Qualcomm camp.
Finally, ATon believes that USB PD is the most promising. PD is set by the USB Association and supports almost all mobile devices. As long as the device/charging head permits, it can charge high-wattage devices such as laptops. However, USB-PD is more complicated. Currently, except for APPLE, few laptops support the PD protocol and only support Type-C connectors.
Conclusion-Fast Charging
There are many fast charging technologies on the market, many of which are incompatible with each other. For consumers, it is too complicated, resulting in most people using only the original charging head included in the phone box. Fortunately, the USB Association has launched the PD protocol, a charging protocol with unified specifications that supports various devices. It is hoped that more manufacturers will join the PD ranks. If you want to buy a fast charging charger at this stage, it is recommended to use the original charger of your mobile phone first. If you want to use only one charger in the future to charge all devices, you can buy a charger that supports the USB-PD protocol, which can save a lot of trouble. However, the premise is that your mobile phone must have Type-C to "possibly" support PD.
For any questions about power adapters and chargers, you can always consult BID’s sales staff. We believe that as a mature power adapter and charger manufacturer, BID will be able to provide you with professional solutions. Welcome email us via [email protected]