There are times when you need a basic power application for your business that can efficiently convert high DC voltages to low DC voltages. So, what do you do when you need to reduce your DC voltage to a lower one, or in other words, you need to step down the voltage?
This is where you can make use of a device known as the buck converter. Buck converters are step down voltage regulators that can buck or lower the input voltage of an unregulated DC supply to a stabilised lower output voltage. Buck converter is a type of DC-DC converter that is used in many commonly used gadgets that we use daily, such as your battery chargers, communication equipment, and power audio amplifiers, among others.
What are the different elements of a buck converter?
A buck converter falls in the switch-mode power supply (SMPS) class. A basic buck converter has the following elements:
- Two semiconductors that could either be a diode and a transistor or in some cases, two transistors.
- One energy storage element that could either be a capacitor or inductor or the two in combination.
Working principle of a buck converter
Buck converter incorporates a switch, for e.g. a MOSFET, to close and open a circuit. The buck converter has two states – the on-state/switch closed and the off-state/switch open. When the switch is turned on and off it creates a square wave. If the duty cycle of the switch is set to 50%, then the average voltage will be 50% of the input.
- During the on-state, current flows from the source through the coil and towards the capacitor, charging it. As the current increases, the inductor creates an opposing voltage resulting in a ramp up in the current.
- During the off-state, the circuit is broken disconnecting the source from the rest of the circuit. The inductor creates a voltage that charges the capacitor and powers the load through the diode.
Applications of a buck converter
The buck converter is used in several common applications.
USB on the go: A USB on the go is a device used to connect your smart phone or laptop to a keyboard, mouse, or any other peripheral. Once the peripheral device is connected to the USB it draws power from the phone. The USB drive has a buck converter that can transfer power in both directions. So, when you plug your phone into a battery charger, the buck converter charges the lithium battery in the phone. On the other hand, when a peripheral is plugged in, the buck converter works as a boost converter to generate power from the lithium battery.
Solar charger: A solar charger has a buck converter that can capture the maximum amount of solar power by changing the load current to charge the battery in the shortest time possible.
Advantages of buck converters
The buck converter offers several key benefits:
- Offers a higher efficiency solution performing step-up or step-down of voltage with the smallest of components.
- A lower operating duty cycle.
- High efficiency across all voltage ranges.
- Lower output ripple voltage.
- Better transient performance
- Lower ripple-current-rating requirements for the input capacitor.
The technology of buck converter is utilised around the world to provide regulated low-voltage DC/DC power. Take a look at some of the popular buck converters on our website.