USB Power Delivery & Quick Charge

What is USB Power Delivery

Today, many devices charge in laptops, cars, airplanes and even wall sockets, charging from the USB ports. USB has become a ubiquitous power outlet for many small devices, such as mobile phones, MP3 players and other handheld devices. Users need the USB to meet their needs, not only for data, and in order to achieve the USB function, they also need to provide power supply or charging for their equipment, and these devices usually don’t need to load drivers.


USB Power Delivery(also known as USB PD) is a fast charge protocol for a wide range of devices. Because USB PD supports an output power of up to 100 watts, it can be used to charge a broad spectrum of battery-powered electronics. This benefits consumers, in particular, because they can use just one lightening-fast charger for their laptops, tablet, smartphones and other devices.

USB Power Delivery Features:

  • Increased power levels from existing USB standards up to 100W.
  • Power direction is no longer fixed. This enables the product with the power (Host or Peripheral) to provide the power.
  • Optimize power management across multiple peripherals by allowing each device to take only the power it requires, and to get more power when required for a given application.
  • Intelligent and flexible system level management of power via optional hub communication with the PC.
  • Allows low power cases such as headsets to negotiate for only the power they require.


USB Power Delivery is designed to increase the flexibility of USB, by providing enough power for many more devices, while at the same time still allowing data delivery. It is also even more flexible, due to a couple of changes. First, the direction of power delivery is no longer fixed. Imagine a tablet with a keyboard attached. The keyboard can have a battery, and the battery can be charged through the data connection, but when the tablet is unplugged from its charger, the power flow can reverse and the tablet can now be powered by the keyboard. Another example is a laptop with six USB ports. The USB ports can be used for peripherals, or, a USB charger can be connected to any port to charge the laptop. Dedicated charging connectors will no longer be required.

USB Power Standards
USB 1.x and 2.0500mA5V2.5W
USB 3.X900mA5V4.5W
USB 2.0 with Type-C500mA5V4.5W
USB 3.1(gen1) with Type-C900mA5V4.5W
USB 3.1(gen2) with Type-C1.5A5V7.5W
USB Power Delivery2A5V10W


USB Power Delivery and USB Type-C

USB has evolved from a data interface capable of supplying limited power to a primary power source with a high-speed data interface. USB Type-C and USB Power Delivery (PD) 2.0 (and the imminent 3.0 version) have accelerated this evolution. However, care is required to select the most cost-effective solution for the application as USB Type-C and USB PD offer multiple power levels. Currently, USB Power delivery is mainly implemented on USB type-c.

USB Type-C alone can support up to 5 volts at 3 amps (15 W), while USB Type-C with USB PD allows the ecosystem to support several power levels up to a maximum of 20 volts at 5 amps (100 W). The downside is that USB PD increases design complexity and the cost.









What is The Difference Between USB Power Delivery and USB Type-C?

It’s easy to understand, USB Power Delivery (USB-PD) is a specification standard which supports power delivery up to 100W while transmitting data over the same cable at same time. USB Type-C is a new reversible USB connector specification that can support a number of new standards including USB 3.1 (Gen 1 and Gen 2), Display Port and USB power delivery. The USB Type-C ports by default can support the power of 5 V up to 3A. If USB Type-C port is implemented with USB PD, it can support up to 100W as defined in the USB PD specification. So, having USB Type-C port does not mean that it supports USB PD.





What is Quick Charge?

First we should to know,for chare a phone,

Both the phone and the charger must be compatible with the same charging voltages and currents. Such as your phone may support charging at 9V/2A, but if you only have a 0.7A charger then the process will take longer. As the same,if you plugging a 2A charger into a phone that can only accept 0.7A it also won’t make it charge any faster.


Quick charge, the purpose is to optimize the initial power transmission, reduce the charge time, let the user unplug the equipment in a short time with the appropriate battery capacity. Whatever use charging technology, the battery power transmission are much lower in the late, so why quick charge battery power can be increased to 50% or higher, but still need an hours to fully charged smartphones.


QC 3.0 is a charging protocol designed by Qualcomm, it offers stepless multi-voltage charging from 3.6V to 20V; your device can receive the perfect voltage and current optimized to its exact charging state. Your device needs to support Quick Charge to receive any benefit.

Quick charge works by increasing the Voltage delivered by the charger to the phone rather than the current (Power = Volts x Amps).

So the current stays at 2 Amps (maximum) for Micro-USB but the voltage can be either 5V, 9V or 12V.

Let’s check below:

5V x 2A = 10 Watts
9V x 2A = 18 Watts

12V x 1.67A = 20 Watts (A bit less maximum current is allowed in the 12V case)

There is a negotiation protocol between the phone and the charger, the charger always starts out at 5V and only increases the voltage once the phone has signaled it is safe to do so (so that a quickcharge charger won’t destroy a phone that isn’t designed for the higher voltage).
There are some variations on this.


What is The Difference Between USB-PD and Qualcomm’s Quick Charge

Fast charging technology is a really helpful feature for most mobile user.

USB-PD 2.0 is a USB-IF defined protocol, which provides a standardized mechanism for power delivery between USB devices at up to 100 W (20 V at 5 A) while simultaneously supporting both USB and non-USB data signals on the USB Type-C port. It enables the host and peripheral to dynamically negotiate power direction.Power delivery (PD) charging is basically a fast charging protocol which is making use of the great functionality and universality.


Qualcomm Quick Charge is a Qualcomm-defined proprietary charging protocol used for charging devices that support Qualcomm Quick Charge protocol using a custom charger, which also supports the protocol. Quick Charge 3.0 delivers up to 18W but does not support simultaneous power and data transfer.


USB Power Delivery technology increases the power levels to 100W. It is also compliant with the safety standards of the USB charging. One of the most interesting things about PD is that the power direction is no longer fixed. you can use your portable power banks to charge your laptop while charging your mobile phone from your laptop. Not only that but you can also charge your Bluetooth headset from your phone.

Quick Charge 2.0 vs Quick Charge 3.0

 Quick Charge 3.0Quick Charge 2.0Quick Charge 1.0
Voltages3.6V – 20V Dynamic5V/9V/12V5V
Max Power18W18W10W


Here we can see that the quick charge provides the same amount of electricity, but increasing the charging voltage can help with faster charging times.With 3.0, the voltage range will allow for quick charging and better efficiency. Quick Charge 2.0 can increase the charge time advantage up to 75% than the normal charge.


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