How do you select an inductor for a buck converter?

How do you select an inductor for a buck converter?

When selecting an inductor for a buck converter the following parameters need to be defined:

1. Maximum input voltage = Vin max.
2. Minimum input voltage = Vin min.
3. Maximum output current = Iout max.
4. Operating frequency = f.
5. Output voltage = Vout.
6. Minimum output current = Iout min.

What is inductor in buck converter?

Inductors in a Buck Converter The inductor and capacitor play a critical role in providing stable current to the load as the PWM signal switches. Finally, the duty cycle of the PWM signal is the primary function allowing the user to control the output voltage delivered to the load.

What is multiphase DC?

A multiphase buck regulator is a parallel set of buck power stages as shown in Figure 2-1 and Figure 2-2, each with its own inductor and set of power MOSFETs. Collectively, these components are called a phase. These phases are connected in parallel and share both input and output capacitors.

What is a multiphase converter?

Switched mode DC-DC converters, including switching regulators, switching controllers, and PMICs that have multiple outputs, provide additional benefits if they offer multiphase functionality. A multiphase converter consists of paralleled power trains which drive a common load.

How is the duty cycle of a buck boost converter calculated?

A step-down (buck) converter, as shown in Figure 1, has a duty cycle D according to D = output voltage/input voltage. For a step-up (boost) converter, the duty cycle D = 1 – (input voltage/output voltage).

What is multiphase chopper?

A multiphase DC chopper converts an input voltage of an input capacitor into an output voltage of an output capacitor. A regulation device, which in each case regulates a phase difference signal of two charge currents, which sequentially charge the output capacitor to a value of 360°/N.

What is a multiphase controller?

Digital multiphase controllers They are PMBus™-programmable and feature embedded non-volatile memory (NVM) for storing configuration data. The PMBus communication interface also allows reporting of voltage, current, power, temperature, and fault status.

What is the basic principle of inductor?

An inductor is a passive electronic component which is capable of storing electrical energy in the form of magnetic energy. Basically, it uses a conductor that is wound into a coil, and when electricity flows into the coil from the left to the right, this will generate a magnetic field in the clockwise direction.

What is the duty cycle for a buck-boost converter in buck mode?

The input voltage is 100 V DC and the duty cycle is 0.5.

How to choose the correct inductor for a buck converter?

For a buck converter, choosing the correct value of inductance is important to obtain acceptable inductor and output capacitor sizes and sufficiently low output voltage ripple. As you can see from Fig. 1, the inductor current is made up of ac and dc components.

What are the phases of a multiphase buck regulator?

A multiphase buck regulator is a parallel set of buck power stages as shown in Figure 2-1 and Figure 2-2, each with its own inductor and set of power MOSFETs. Collectively, these components are called a phase. These phases are connected in parallel and share both input and output capacitors.

Can a buck converter be operated in discontinuous mode?

You can operate buck converter inductors in continuous or discontinuous mode. This means that the inductor current can flow continuously or can fall to zero during the switching cycle (discontinuous). However, operating in discontinuous mode is not recommended as it makes for a more complex converter design.

What should be the peak current of an inductor?

To allow some margin, you should select a value of 10µH. This gives a nominal peak-to-peak ripple current of 450mA. In the finished design, this can be seen as an output ripple voltage of 0.45 × output capacitor ESR. Inductors are normally specified with two current ratings: continuous (Irms) and peak (Isat).