USB Outlets Frequently Asked Questions:

The chipmaker Qualcomm developed the Quick Charge technology to work with Snapdragon processors. What makes this different than Fast Charging technology is the power that Quick Charge dictates to be used by the devices during the charging cycle. A Quick Charge USB receptacle allows 5v, 9V, or 12V to be drawn. The maximum power output is 18W. Using Intelligent Negotiation for Optimum Voltage (INOV) the charger pushes power to the device as needed to reach the charging time. Qualcomm Quick Charge 3.0 enabled devices reach a 50 percent charge in half an hour, and full charge in one hour. Most smartphones take about 2 hours to charge when using standard USB charging.

Category: USB Outlets

Understanding fast charging and how it works requires some knowledge of electrical terms such as voltage (volts), amperage (amps), and wattage (watts). Volts are the measure of electrical pressure, amps are the measure of electrical current, and watts are a measure of electrical power that is determined by multiplying the volts and amps together.  An easy way of understanding how they work is to compare them to a garden hose. The water pressure in the hose would be equivalent to the volts; the flow rate would be the amps, and the volume of the water exiting the hose would be the watts.


A USB outlet that is capable of fast charging delivers more amperage than the standard USB output of 0.5A. For example, TOPGREENER’s TU21548A amperage power rating is 2.4 amps per USB port. It is important to note that while an outlet like TU21548A provides 2.4 amperage output, the total power

drawn from the receptacle will still depend on the device limitations. For example, if an Apple iPhone is connected to the a 2.4A outlet, but has an amperage limit of 2.1A then that unit will only draw the (2.1A) amount dictated by the phone’s software. Device makers can an also place limitations on when Fast Charging starts and ends during a charging cycle. For example, Apple has safety limitations that allow fast charging when a battery is between 0 and 79 percent, but this stops once it reaches 80 percent.

This chart shows the standard power delivered through USB 1.0, 2.0, and 3.0.

Voltage Amperage Wattage
USB 1.0 5V 0.5A 2.5W
USB 2.0 5V 0.5A 2.5W
USB 3.0 5V 0.5A/0.9A 4.5W

This chart shows the maximum power capabilities of Top Greener USB products. All units use USB 2.0 technology or higher.

Voltage Amperage Wattage
USB 1.0
USB 2.0 5V 4.8Total 24W
USB 3.0 5V 0.5A/0.9A 4.5W
Category: USB Outlets

USB Power Delivery or USB-PD is a growing industry standard for power management through USB charging.  The evolution of USB ports from 1.0 to 2.0 to 3.0 and finally 3.1 was primarily focused on achieving faster data transfer. With each new addition, power was increased to meet the data transfer goal. As more devices became dependent on USB charging rather than data transfer, specifications were needed to determine what the optimum output should be for USB powered devices. Manufacturers have typically stayed closer to low level power outputs to prevent overcharge accidents, but back in 2016 the USB Implementers Forum (USB-IF) released the Power Delivery Specifications. These new guidelines made way for manufactures to make USB ports capable of powering devices that required up to 100 watts. Small devices don’t require this amount of juice, but with USB-PD an outlet could safely charge a smartphone, and still be powerful enough to charge a laptop. But how could a laptop be charged using the same adapter, outlet, or cable as a smartphone? The answer came with the introduction of USB Type-C. The design behind USB Type-C combined all previous styles into one that would support high data and power output.


USB-Type C diagram
The Type-C connector replaces the USB Type-A, mini DisplayPort, and power connectors with a single connector. It leads to sleeker designs by eliminating the need for multiple USB ports.

In short, USB-PD is technology used in devices that support USB TYPE-C to achieve a universal way of transferring data and powering multiple devices. For example: if you have an Apple iPhone 8, but your laptop is a Google Chromebook, you could charge both these devices through a USB TYPE-C cable that supported USB power delivery.

Category: USB Outlets

The marketplace is not limited to Fast Charging and Quick Charging technology. Many manufacturers have created their own versions of these high-speed options. Here is a list of some of the most popular ones:

Apple Fast Charging

Samsung Adaptive Fast Charging

Motorola TurboPower

MediaTek Pump Express

OnePlus Dash Charge

Oppo Vooc,

Huawei SuperCharge

These alternatives work on the same concepts of Fast Charging and Quick Charging, but have different voltage, amperage, and wattage regulations. Manufacturers have developed their own proprietary charging methods too so that consumers will only purchase chargers that are compatible with their technology. This can be a downside for consumers. It is best to look for a phone or device that is universally compatible with faster charging methods. The Fast Charge technology in Top Greener’s TU21548A is accepted by virtually every small device on the market.

Category: USB Outlets