USB means Universal Serial Bus. It was introduced in 1990 to make easier the procedure by which so many devices connect to computers. It worked across operational systems and platforms, it was inexpensive, and it was end-user friendly. Now, most of the existing computers have different USB ports, even including MiniUSB and MicroUSB.

What is a Micro USB?

The smaller version of USB is referred to as Micro USB. It serves as a connector for portable, small gadgets such as photo printers, MP3 players, smartphones, GPS units, and digital cameras. Micro-USB comes in three varieties: MicroA, B, and USB3. The USB3 is akin to MicroB but features an additional pin on its face, doubling the number of wires, which enables USB 3. Like standard USB, the micro versions are designed to be plug-and-play.

The creation of USB accessories was a collaborative effort among companies like IBM, Compaq, DEC, Northern Telecom, Microsoft, NEC, Intel, etc. This technology is freely available for all devices and computers.

The USB standards are established and updated by an organization called the USB-IF (USB Implementers Forum). In its basic definition, USB recognizes only two types of connectors: A & B. However, changes to the specifications and instructions for manufacturers have broadened the connector widths used in USB devices, although the majority of USB-based products still use the A & B connector interfaces.

Pin Configuration of Micro USB

A common connector, such as Micro-USB, is often employed for recharging portable gadgets using a micro-USB charging cable, or by linking mobile devices to a computer.

The setup of the Micro-USB pins is outlined below:

Pin Diagram of micro USB

• Pin 1 (VCC): This pin supplies +5 VDC, and the wire color associated with it is red.
• Pin 2 (D-): This pin is for data, and its wire color is white.
• Pin 3 (D+): This pin is for data, and its wire color is green.
• Pin 4 (ID): This pin is for identification, and its wire color is blue.
• Pin 5 (GND): This pin is for ground, and its wire color is black.

The Micro-USB cable features four shielded cables, with two cables carrying power signals such as +5 VDC and ground, and the other two cables carrying data signals such as D+ and D-.

Non-Return to Zero Invert or NRZI is a method primarily used to transmit data across a sync field, which helps in aligning the clocks of both the receiver and the host. In the USB data cable, signals like Data+ and Data- are sent over a twisted pair cable.

Specifications

Here are the details of MicroUSB:

• MicroUSB is categorized as a Type B or SMT
• It comes in three versions: drop-in, reverse mount, and standard
• It is designated as Female
• The resistance to contact is 30mΩ at 100mA
• It features 5 pins
• The highest voltage it can handle is 30V
• It can withstand more than 5,000 mating cycles
• It is rated for 1A of current

History of the Micro USB

The universal standard interface bus was developed by business collaboration from Compaq, IBM, Digital Equipment Corp., Intel, Microsoft, NEC, and Northern Telecom. It is licensed without fees to those who produce computers and devices.

The Micro-USB was developed to allow the production of the smaller size devices that were more portable. It was introduced in 2007, which brought massive popularity due to the flexibility and user-friendly nature of the device.

Due to minute size, micro USBs can easily be connected to very small devices like smartphones, tablets, digital cameras, smart watches, etc.

Working of Micro-USB

Micro-USB, while much compatible for charging ever more devices, include smartphones, tablets, cameras, and others.

However, when the USB is connected to a power source, it allows the current to run through the micro-USB cable, hence recharging the smartphone.

This feature is also present on laptops, PCs, connecting your device to a computer, so that it executes many things on your device from the computer. That can be used not only to charge but also for accessing files, photos, etc.

Types of Micro USB

Micro USBs are primarily utilized for connecting various electronic gadgets such as smartphones, GPS units, and digital cameras. These USBs enable manufacturers to create compact devices. Their primary role is to function like standard USBs. MicroUSBs come in several varieties, including Micro-A USB, Micro-B USB, and Micro-B USB 3.0.

Micro-A USB

Micro-A USB is compatible with modern devices like smartphones, GPS units, and digital cameras. It is smaller than Mini-B USB but offers high-speed data transfer at 480 Mbps. The design features a white casing and a five-pin structure, with a female connector that is only available in this design. It is shaped like a rectangle.

Micro-B USB

Micro-B USB is similar to its Micro-A counterpart, suitable for use in current gadgets and small electronic devices. It is smaller than Micro-A USB but provides similar functionalities. Devices such as USB 1.1 & 2.0 support Micro-B ports that appear identical.

This USB type has both male and female connectors, allowing for compatibility with various devices through either connection type. It is housed in a black container and features a five-pin design.

Micro-B USB 3.0

Micro-B USB 3.0 is designed for use in devices that support USB 3.0 technology. It is primarily used for high-speed data and power transfer. This type of micro USB is also compatible with devices that use USB 1.1 & 2.0.

Like its Micro-B counterpart, Micro-B USB 3.0 is similar in design. However, it stands out by incorporating an additional group of pins on its face, which doubles the number of wires. This enhancement allows for USB 3.0 to operate at its optimal speed.

How to Use Micro USB?

• The MicroUSB power bank circuit is a versatile application of MicroUSB technology. This circuit can be assembled using a TP4056 module, a Li-ion battery, and a boost converter circuit. This homemade circuit is an effective solution for providing backup power to smartphones.
• You will have to design this USB from a 18650 Li-ion battery, a slide switch, a module of the TP4056 that already includes a protection circuit for the battery, and a 3V-5V boost converter with a current control function of 1A.
• The 18650 Li-ion battery is a cylindrical form factor, 85mm in height and diameter of 18mm. There are other sizes available and with different applications, these batteries have a rechargeable and have an output of 3.7v.
• A module such as TP4056A is a cost-effective option for charging various types of Lithium-Ion batteries.
• Therefore, this is a dependable method for charging batteries of lower capacity, thanks to its adjustable 1A output current. It can be connected to any power outlet, depending on the phone charger. The design features a PMOS IC load switch, which reduces the number of additional components needed.
• The Li battery supplies 3.7V, but the circuit requires 5V to function. To achieve this, a boost converter module with a 3v to 5v output is used. This module boasts an efficiency of up to 92% and includes built-in current protection. The circuit’s design is a step-up converter with a non-isolated structure, operating at a switching frequency of 1MHz.
• The total power output of this circuit is 5Watts, and the output voltage can be adjusted to 12V by replacing a resistor in the module, but the maximum current it can handle is 400mA. However, the module is designed to operate at a 1A 5V rating by default. It is equipped with a universal type-A USB connector at the end, which interfaces with any available USB power cable.
• The circuit comes in a temperature range of –40°C to +85°C. The charge status is indicated by an incorporated LED indicator. An LED that turns red indicates that the battery is providing power.
• After correctly wiring the circuit according to the diagram, it is ready to be used for charging smartphones.

Applications

The Applications of Micro USB are as follows.

• MicroUSB is utilized in numerous embedded projects where a power supply is needed in place of serial communication. It’s commonly found in applications such as mobile phone charging, ESP modules, and Raspberry Pi, among others.
• You’ll often see MicroUSB ports in smartphones, tablets, and various other gadgets like GPS units, video game controllers, digital cameras, etc.
• The compact version of USB is known as MicroUSB, specifically designed for connecting mobile and compact devices.

How to Choose a Micro USB Cable

• Cable Sheath/Braiding: The braiding or outer covering mainly protects the cable, reducing the likelihood of damage.
• Cable Gauge: Gauge is determined in Amperes and strengthens the cable, enabling faster charging for your device.
• Iron Ferrite Core/Ferrite Bead: This material inside the cable helps to minimize noise and improve data transfer speeds.
• Strain Relief: This function, like with braiding, protects the cable from damage and prevents fraying. A reinforced cable neck can also reduce tension and protect against cable breakage.
• Your Devices: It’s also important to think about the types of devices you’ll be using with the cable when you’re buying.

Conclusion

Therefore, this provides a summary of MicroUSB and its functionality. A USB cable is crucial for linking devices to a computer for data exchange and file sharing, as well as for charging mobile phones and tablets by connecting them to a laptop or computer. There are various types of USB interfaces, with Micro-USB being one of them; it was primarily created to replace older interfaces such as Mini USB.

Frequently Asked Questions on Micro USB – FAQs

Is Micro USB the same as C?

No, The charging port of a Type-C cable is flat and round, and you can plug it in either way. The charging port of a micro-USB cable has a stepped shape and can only be plugged in one way.

What are the components of a micro USB?

The micro USB connector is made up of four primary elements: the plug, the casing, the terminals, and the circuit board. The micro USB wire features a single twisted pair that is used to transport the electrical charges and signals required for quicker data transfer.

Which is faster Type-C or micro USB?

Type-C is generally faster than micro-USB. Type-C supports higher data transfer speeds and faster charging capabilities compared to micro-USB.

What is the difference between Type-C charging connectors and micro-USB connectors?

Now, the end connector of chargers using Type-C are oval and flat; thus, it is inserted either way. In contrast, the connector at the end of a micro-USB charger is in the shape of a ladder and cannot be inserted in the reverse direction.