One of the most critical components of reliable wireless communication is reliable power. At RFWEL Engineering, our expertise spans the entire solutions space starting from remote data acquisition (DAQ), wireless sensor, remote terminal unit (RTU), cameras to the wireless aggregation & backhaul networks. These allow us to leverage heavily our in-house expertise as well as our strategic partnerships with top equipment vendors to offer the most optimal TOTAL solution for your radio backup power needs.

AC-DC Power supplies converts power from the mains to a stable DC power for proper operation of loads such as motor or electronic devices. A power supply can be external such as laptops and phone chargers, or internal for larger devices such as in desktop system units. They can be categorized into two types:

Linear AC/DC Power Supply

In this design, AC voltage is step-down by a transformer. The reduced AC voltage is then rectified into a direct voltage and further filtered to a more stable output. Due to transformers at the input and at low frequencies (e.g. 50Hz), miniaturization of these devices is impossible.

Switching AC/DC Power Supply

These switch power supplies employs high-power MOSFET transistors. Their advantage is the lower heat dissipation. Instead of using a transformer at the input, AC power is rectified and filtered at the input. The DC power produced is fed to a chopper which produces high frequency pulse. This high frequency wave goes through a another rectifier and filter to produce a stable DC.  

Due to amount of noise generated in the system from its design, complex control circuitry composing of integrated components is used to filter out the noise.

Check out the table below for various AC-DC power supplies.

DC-AC Inverters are devices that change DC power supply to AC power supply which is used with most electronics. Power inverters are generally used in applications where high voltage and currents are involved.

AC voltage from power inverters is usually regulated to be same as grid voltage which is normally 120 or 240 VAC allowing them to power various devices designed for these voltages.

Power inverters often have an overall power rating expressed in watts or kilowatts. Since the runtime of an inverter powered by batteries is dependent on the battery power and the active load connected to the inverter output, see below formulae to calculate inverter battery capacity:

Battery Capacity (Ah) = Total Load (In Watts) X Usage Time (in hours) / Input Voltage (V)

Once we have the battery capacity required for a project, we can connect batteries either is a series configuration or parallel configuration.

In large paralleled batteries connection, they may be connected via diodes or intelligent monitoring with automatic switching to isolate an under-voltage battery from the others to avoid the risk of fire in case a single battery has a too low charge and other batteries discharge through it.

Applications for these inverters are in automotive-usually with 12 VDC source, photovoltaic cells used in homes or WAN solar sites, uninterrupted power supply systems, and power backup sites with battery banks.

See the comparison table below for high-efficiency power inverters (DC/AC converters)

A DC to DC converter is designed to take the voltage from a DC source (usually a battery) and converts the voltage of the supply into another DC voltage level. They can increase or decrease the voltage level. For example, it might be necessary to step down the power of a large battery of 24V to 12V to run a radio.

DC-DC conversion can either be electronic or magnetic. Electronic conversion uses switching technology. DC voltage level is converted by storing the input energy temporarily and then releases that energy at different voltage output. The storage is done either in magnetic field components like an inductor, transformers, or electric field components like capacitors. Magnetic conversion is done by storing energy in magnetic field periodically and releasing it in a frequency range. By adjusting duty circle of charging voltage, control of power to the load becomes easy.

Depending on the circuitry used, DC-DC converters can either be Non-isolated or Isolated converters. Non-isolated converters are generally used for small voltage conversions. The input and output terminals share a common ground in this circuit. 

They include Step-Down (Buck) converter. This generates a lower voltage than the input.

Step-up (Boost) Converter on the other produces higher voltage than the input.

Buck-boost converter works by either increasing or decreasing the input voltage.

Isolated converters have the input and output terminals separated unlike in the non-isolated converters. They are of two types. Flyback converter acts like the buck-boost but uses a transformer to store energy instead of an inductor.

See table below for DC/DC regulators.