There are many different applications for switch-mode power supplies, also known as SMPS systems. They are designed for DC-DC power conversion and require the use of SMPS inductor.
Choosing the right SMPS and the correct SMPS inductor for the circuit is always important. With their versatility, they are typically used for any types of motors, LEDs and even for microprocessors, which means they are found in most of the electronics and devices used around the home or workplace.
The benefits of choosing the right SMPS inductor means that voltage can be delivered evenly without any drops or variations that may be problematic for the system or device. Depending on the system it can be used to invert, step up, or step down the input voltage.
The Role of the SMPS Inductor
The inductor has a very important role to allow a continual output. This component is actually used as an energy storage device, which is essential in the SMPS. As the system comes on, or the semiconductor switch turns on, the current levels within the inductor also increase or ramp up. This is the point where the inductor stores the energy.
When the semiconductor switch is in the off position, the energy stored in the inductor is released back into the system. This on to off position change or the ramping up, storage and release of the system is known as the switching cycle. The changes that occur in the current, or the variation in the switching cycle, are known as the ripple current.
In many applications, the key component to consider is the ripple current. It will have to match both the output voltage ripple as well as the size of the output capacitor. If the capacitor and the inductor are not correctly matched, it will result in ongoing failures of the capacitor with use.
Options to Consider
To determine the correct size of the SMPS inductor, the specific use has to be considered. For example, with a buck converter you will need to know the top or maximum input voltage, output voltage, switching frequency, ripple current as well as the duty cycle.
In choosing an SMPS inductor, you also need to consider if it will be used in discontinuous or continuous mode. Typically most devices will use the inductor in continuous mode as it is more effective and prevents the fall to zero in the current seen in the discontinuous mode.
