Selecting the right power source and the type of current in a circuit is an essential part of designing PCBs. Yet, converting the power from AC to DC or the other way round in a circuit requires some knowledge to be successful. In this guide, we explain how to convert AC to DC and DC to AC circuits, tailored for embedded applications. Read on to find out more

Why Power Conversion Matters in Embedded Systems

Most embedded systems operate on low-voltage DC power (typically 3.3V, 5V, or 12V). However, power sources are often in AC form (like wall outlets) or inconsistent DC (like solar panels or batteries). This is why you will likely need to be able to convert the current from AC to DC or vice versa.

Without proper conversion:

  • Microcontrollers may receive unstable or unsafe voltages.
  • Sensors may fail due to a lack of regulated supply.
  • Overall system performance and safety are compromised.

Therefore, understanding the conversion process (involving practical application and the ability to calculate the conversion voltages) is an absolute necessity.

How to Calculate the Conversion Rate? Formula

The conversion rate formula between alternating current and direct current is quite straightforward:

VAC = VDC x √(2)

The square root of 2 equals about 1.414 - this is the multiplier you will use or the divider if you want to convert DC into AC.

How to Convert AC into DC & DC into AC on Your Printed Circuit Board?

The conversion process is pretty simple - you use an AC or DC converter. However, there are some differences between two types of conversions and additional steps you may take, if needed.

How to Convert AC to DC Circuit?

When converting from AC to DC, you should:

  • use a step-down transformer (optional) to bring down the voltage,
  • use a rectifier, which converts AC to pulsating DC,
  • add filter capacitors, which stabilize the pulsating DC,
  • finish off with a voltage regulator to ensure a stable voltage suitable for your microcontrollers or sensors.

How to Convert DC to AC Circuit?

In this case, it is even more straightforward: you will need an inverter circuit. Such a circuit consists of:

  • oscillator circuit that generates high-frequency AC signals from DC,
  • driver/amplifier that boosts the signals to the desired level,
  • transformer (optional) to bring up the voltage.

In practice, you can choose from one of the three types of inverters:

  • Square wave inverters - the most basic ones, inexpensive to use but offering limited performance.
  • Modified sine wave inverters - the most cost-efficient ones, balancing the price and performance.
  • Pure sine wave inverter - the most expensive and accurate ones, ideal for highly sensitive electronics.

DC-DC Converters

Some PCBs may also require a different type of converter: a DC-DC one. It is used in cases where you work with multiple direct current voltage domains. In this case, you can choose between:

  • buck converters, which lower the voltage,
  • boost converters, which increase the voltage,
  • buck-boost converters, which are suitable for both roles, depending on the input/output needs.

The Takeaway

If you know how to calculate the conversion rates and understand all the steps, converting AC to DC or DC to AC is relatively easy. Nevertheless, it’s just one of the challenges you might stumble upon when designing your PCB. If you need any help with current conversion or any other step of the process, check out our printed circuit board design & manufacturing services - we’ll help you build a fault-free, efficient PCB!