A switched-mode power supply, also known as a switching power supply or SMPS, is an electronic power supply which uses a switching regulator to efficiently convert electrical power.
The reason behind its popularity is that most electronic DC loads are supplied from standard sources, and the standard voltages do not match the levels needed by motors, microprocessors, LEDs or other loads. Hence there’s the need for a switching regulator to efficiently convert the electrical power.
So just like other types of power supplies, an SMPS switches the power from a DC or AC source to DC loads, for example a PC. While doing so, it converts the voltage and some specific characteristics.
Contrary to the linear type of power supply, the switching power supply mode constantly shifts between low-dissipation, full-off and full-on conditions. It spends less time in the high dissipation state. As a result it helps in minimizing the energy wasted.
The switched-mode type of power supply does not dissipate any power. Let us know first what Is a switching power supply and what are the benefits of using it.
One of the reasons that make SMPS such an obvious choice for powering machines is versatility. Given the fact that these types of power supplies are so versatile, they help in changing any standard energy source into a usable output voltage to meet the requirements of your appliances. There are different types of SMPS topologies that can be easily grouped into fundamental categories such as invert, step up, step down,step up and down. So, you get the option to choose any category to fit the required level of output voltage.
Contemporary SMPS ICs are designed with different levels of integration which enable professionals to choose from the topologies. This helps the manufacturers ease the burden of designing their commonly used applications. They provide engineers with standard SMPS ICs to use in their custom projects.
Switching power supplies are much more efficient than linear regulated ones because in a switching transistor, very little power is wasted. SMPS are physically much smaller in size than their linear counterparts because the components used in making the switching type are much more compact and smaller in size than the non-switching supply.
As a result, SMPS provide a better option when you need efficiency, compactness, and accuracy rolled into one. The one downside of these types of switching power supplies is that they can be noisy unless they use a fan with a specific noiseless operation. Sometimes they are considered unfit for powering the devices that are sensitive to electrical noise unless the circuits are well protected and shielded against noise.
The frequencies for switching power supplies are on the rise as there are several benefits associated with higher frequencies. Some of the benefits are lower ripple voltage, reduced component size,quiet operation, and higher power per unit volume.
The standard or mostly commonly used frequency today is 20 to 30 kHz, however there are cases where 100 to 500 kHz are also used. There are some specific PWM-type ICs that can handle switching frequencies to 1 MHz and above.
According to the manufacturers of switching power supplies, consumer demands and choices are changing at a dynamic rate.
The features that are considered options today will soon become standard features as customers seek better products. As the systems become more sophisticated, the standard features don’t take long to convert into basic necessities.
Features like adjustable voltage, overvoltage protection and active soft-start that were once considered as options a few years ago are now basic features of these products. Some of the extra options that are soon expected to become standards in the years to come are power valid indicators, current balance circuits, specialized EMI filters and power failure indicators.
While switching power supplies are not without their drawbacks, the benefits outnumber the downsides. They are definitely a better and more energy efficient option over linear regulatory systems.
The modern types of SMPSs are rising in popularity and they are widely used in a variety of applications. While there are a few disadvantages, they can be easily managed. The versatility and efficiency of these systems make them highly desirable by professionals.