Power Up Your IoT Projects: Voltage Regulators and Converters

IoT hobby projects power conversion


4 min read

Power Up Your IoT Projects: Voltage Regulators and Converters

Why did the microcontroller break up with its power supply? Because it couldn't handle the voltage difference - they were just too far apart!

Incorporating insights from a helpful YouTube video Power For Your Electronics Projects - Voltage Regulators and Converters by DroneBot Workshop, this blog post dives into the world of microcontroller power supplies.

The heart of countless electronic projects, microcontrollers rely on a steady flow of power to function. Choosing the right power supply is crucial for optimal performance and project success. This blog post explores popular options like linear regulators, buck converters, boost converters, and buck-boost converters, helping you pick the perfect one for your needs.

Understanding Your Power Needs

Before diving in, it's important to understand your microcontroller's voltage and current requirements. This information is typically found in the microcontroller's datasheet. Armed with this knowledge, you can select a power supply that delivers the necessary power efficiently.

Linear Regulators: Simple and Reliable

Linear regulators are the workhorses of the power supply world. They offer a simple and reliable way to reduce a higher voltage to a lower voltage. A classic example is the 78xx series. These handy chips come in various versions, each providing a fixed output voltage (e.g., 7805 = +5V output, 7803 = +3.3V output). They're easy to use, requiring just a couple of capacitors for stable operation. However, linear regulators can be less efficient, especially with large voltage drops, and generate heat, which can be a concern in space-constrained applications.

Here are some popular linear regulators to consider:

  • 78xx Series: Fixed voltage regulators for common voltages (3.3V, 5V, etc.)

  • LM317: Adjustable voltage regulator for odd voltages (1.25V to 37V), requiring two resistors to set the output voltage.

  • PSM-165 Linear Module: Compact 3.3V regulator with a typical input range of 4.5V to 12V and up to 800mA output current, commonly used with Arduino Uno boards.

  • AMS117-5 Linear Module: Offers lower voltage drop (around 1V) compared to 78xx regulators, providing a stable 5V output with up to 1A current.

  • L4931CZ33 Regulator: This versatile option offers both 3.3V and 5V outputs with an extremely low voltage drop (0.4V) and can handle up to 250mA current. It's also budget-friendly and allows for various capacitor types (not just electrolytic).

Buck Converters: Efficiency Champions

For superior efficiency (up to 95%), buck converters are the way to go. They use inductors and transistors to step down a voltage, making them ideal for battery-powered projects where maximizing battery life is critical. A popular option is the MINI-360, known for its compact size and high efficiency (95%). It offers a wide input range (4.75V to 23V) and a variable output range from 1V to 17V, with a maximum current of 1.8A.

Boost Converters: Power Up When Needed

Boost converters take the opposite approach of buck converters, increasing a lower voltage to a higher voltage. This is useful for powering microcontrollers from low-voltage sources like single-cell batteries or solar panels. For instance, the PSM-205 features an integrated USB jack as output, with an input range of 0.9V to 5V and a boosted output of up to 600mA at 96% efficiency. The MT3608 offers even more flexibility, handling an input range of 2V to 20V and providing a boosted output up to 28V at a whopping 2 amps, with an impressive efficiency of 97%.

Buck-Boost Converters: The All-Rounders

Buck-boost converters are the ultimate power supply chameleons. They can step-up, step-down, or even invert the input voltage to provide a regulated output. This versatility makes them suitable for a wide range of applications. However, their design complexity is the highest among the options discussed here. The S9V11F5 is a popular buck-boost converter offering a fixed 5V output with a wide input range (2V to 16V, although it requires 3V for startup). It can deliver up to 1.5A continuously, with 2A peak current, but be aware that it can get quite hot during operation.

Choosing the Right Power Supply

The best power supply for your project depends on several factors:

  • Input voltage range: What voltage will your power supply be receiving?

  • **Output voltage requirement

  • Max current draw

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Disclaimer: I am an IoT hobbyist and simply sharing my notes and learnings here, and do not take credit for the content