USB I/O Controller Power Input

Powering Up IOaT-U4 & IOaT-U2

One great feature about IOaT controller is the ease of getting it power up. The built-in power circuitry is specially designed to allow the electronic controller to operate from a wide variety of power source. It is very convenient to power up this I/O controller electronic device from just about every power source available to you.

Multiple power supply options to choose from. USB, DC or AC Voltage



  • Can be powered entirely from the USB port.
  • 3 power socket to choose from. (mini-B USB, DC Barrel, Pluggable)
  • Accept a wide range of power supply source.

The standard means of powering up is the USB cable from your computer. For standard alone operation (operating without the host computer), you can also choose to power up the device from external power supply.

For standalone application where you do not need to use the USB communication, there are more options for the controller to get its power supply from.

The electronic controller features two external power input. The one on the right is a pluggable connector for bare wire power input, and the one on the right is a standard barrel socket for DC power plug.

Content Summary

  1. Power Socket Type
    1. Mini-B USB
    2. DC Barrel Socket
    3. Pluggable Screw Terminal
  2. Power Supply Source
    1. USB Power
    2. AC Mains
    3. Portable Power


Power Socket Type

  • Mini-B USB
  • DC Barrel Socket
  • Pluggable Screw Terminal

There are 3 means which the controller can get its power from. It is designed to accept many types of power supply, for your convenient of deploying the controller in many different situations.


Mini-B USB

For project that requires USB as a communication channel, this mini-B USB socket will be a primary means where the controller gets its power from.

Powering up IOaT-U4 through the standard mini-B USB socket.

The power that is required to operate the controller can be supplied entirely from the USB host itself. The USB host can be the following electronic computing platform,

  • Desktop/Laptop Computer System
  • Embedded Electronic System
  • Raspberry Pi
  • Arduino boards
  • much more…

If you are using USB for communicating with the controller, you do not need an additional power supply or cable. The power and communication can be from a USB cable. The cable end to the USB host is a USB type A, and the other end is a USB mini-B connector.

Please take note: USB standard voltage is 5V. Do not attempt to supply any non-USB standard voltage/polarity to the controller through the mini-B USB socket.


DC Barrel Socket

This DC barrel socket uses the standard size (OD 5.5mm, ID 2.1mm, Length 12mm). You can easily get the power supply adapter that uses this standard plug.

DC barrel jack to IOaT-U4 (OD 5.5mm, ID 2.1mm)

The device can accept a wide range of voltage. The socket is able to take a voltage ranging from 9-24V in DC or in AC (direct current, alternate current), at max 0.5A current. The power design features an efficient power switching regulator. You do not need to look for the exact power supply.


Pluggable Screw Terminal

This is a pluggable screw terminal (2pos, 3.81mm pitch connector) is exactly the same as the DC barrel socket input. Both socket are inter-connected. You can use this terminal to tap onto the the input power that you have connected to the DC barrel socket.

Pluggable Screw Terminal power input to IOaT-U4

This terminal also allows you to get your power from bare power wire when you cannot find the fitting plug to the standard DC barrel socket. You can simply cut the plug away, strip the cable and connect to this controller using the bare wires. You can also tap from available power source to this terminal.

You need not have to worry too much about getting the connection right. The power input is protected against reverse voltage polarity. This means that even if you connect the power input wire in the wrong polarity, it will still be going to work.

Warning: Both the DC Barrel socket and pluggable screw terminal is interconnected. Do not connect two power supply source to both the DC barrel socket and pluggable screw terminal.

You can tap the power from the DC barrel socket using the pluggable screw terminal. Please DON’T connect another power source to the screw terminal when you already supply the power through the DC barrel socket.

Tapping out power from the screw terminal. Series power connection.


Power Supply Source

The controller is designed to accept a variety selection of power source, providing you with the flexibility to deploy your electronic system for a wide range of scenario.


USB Power

Power up USB I/O Controller from a computer USB portThe controller is designed especially for USB communication. You can get your power directly from the USB host computer.


Power up USB I/O Controller from AC wall plug adaptorYou can also get the power from USB power/charger adapter. A standard USB power adapter of 2.5W (5V, 0.5A) is enough to operate the I/O controller.


AC Mains

For power supply from the electronic main socket 230Vac or 11oVac, you will need a converter to step down the voltage. The converter is also acting as a safety barrier, isolating the dangerous high main voltage from the electronic I/O controller and the end user.

Power Adapter (AC-DC)

AC-DC power adaptor to power up USB I/O ControllerYou can use a typical AC-DC power adapter (9-24Vdc, 0.5A) as a power supply. Choose those that have the DC barrel socket, so that you can easily plug it directly to the I/O controller.


AC-DC power desktop adaptor to power up USB I/O ControllerYou can also recycle the power adapter from your power supply adapter that comes with you old laptop or electronic devices. The I/O controller can accept a wide range of input voltage. This makes it easy to get its power from almost any power supply adapter.


Industrial Power Supply (AC-DC)

Open frame power supply for USB I/O Controller

AC-DC power supply for USB I/O Controller

Open frame power supply is another common power source used in an industrial system. The I/O controller is able to accept a wide voltage range and uses very low power. This makes it easy to share the power supply with your other electronic devices in your system. You can simply share and tap from existing power supply without the need for another power adapter.

Power Transformer (AC-AC)

AC-AC transformer to power up USB I/O ControllerA transformer steps down the higher AC voltage of 230Vac or 110Vac to a lower AC voltage. The I/O controller is also designed to accept this alternating current (AC). You can simply tap it from the transformer output. The controller can accept AC voltage from 9Vac to a maximum AC voltage of 24Vac from a power transformer (minimum about 5W).


Portable Power

Portable power may be required, where AC mains may not be available or suitable for your electronic system.

There can be also a situation where an uninterruptible power supply is required. The following illustrate how the I/O controller can be set up to become portable by using the uninterrupted power supply as a supply for your system.

USB Power Bank

Power up USB I/O Controller using a portable USB power bankThe recommended portable power supply for the I/O controller will be the power bank. You can power up the controller directly from a USB power bank making your whole setup portable.

You can also use the power bank as an uninterruptible power supply (UPS) for the I/O controller. The power bank can continue to supply power to the controller even when the electrical mains power gets cut off. USB power adapter will be connected to charge the power bank when the electrical mains power is available.

Seal Lead Acid Battery

Portable Seal Lead Acid Battery to power up USB I/O ControllerFor non-USB portable power supply solution, you can use an SLA battery (seal lead acid battery). You can use a 6V, 12V or 24V SLA battery to power up the controller via the pluggable screw terminal.

The SLA battery can use as a backup power supply for the controller for UPS purpose. By default, the I/O controller will accept power from the mini-USB socket first, if there is also power supply coming in from the DC barrel or pluggable terminal. If the power source from the mini-USB fails, the controller will switch over to the SLA battery for alternative supply source. This makes the SLA as a UPS supply source.

The I/O controller can also get its power from vehicle’s cigarette lighter socket. The supply from a car, small lorry/van is typically 12Vdc. For a larger truck vehicle, the voltage is typically 24Vdc.

Standard Battery

li-ion battery to power up USB I/O ControllerRechargable battery to power up USB I/O Controller

Standard battery typically has a lower voltage and smaller current capacity. It will require a few batteries in order to make up a minimum of 9Vdc to operate the I/O controller.

You can get a battery holder and connect the supply to the controller via the screw terminal or DC socket barrel.

Some of the typical batteries are as follows,

  • Li-ion
  • UltraFire
  • NiMh
  • AA, AAA

Using standard batteries are not recommended if the I/O controller is operating for a long period of time. For temporary operation or demonstration application, it is good as your setup can be minimum and light in weight.

Other Portable Power Supplies

Portable power pack to power up USB I/O Controller

There are other forms of power source that you can use for the I/O controller too. Check out the portable battery pack, and the emergency power module