Boost converter principals

Another variation is to use synchronous switching where, instead of using diodes that simply respond to the voltage polarity across them, four synchronised by the control unit MOSFETs do all the switching. The control unit may also carry out over current and over voltage protection, as well as the normal oscillator and pulse width modulation functions to regulate the output voltage. This reduces the overall current drawn from the typically battery supply, prolonging battery life.

Buck-Boost Converter I. These range from very low power, high efficiency I. Hons All rights reserved. Revision Learn about electronics Power Supplies. Power Supply Basics 2. Regulated Power Supplies 3. Switched Mode Power Supplies. Module 3. After studying this section, you should be able to: Understand the need for a choice of DC to DC converter designs.

Understand the principles of Buck-Boost Converters. Understand the relationships between different converter designs. Recognise the limitations on the output voltage. Recognise typical commercial I.

The circuit boosts the voltage from the supply, hence named as boost converter. There are many ways to converter a lower DC voltage to a higher one.

The boost converter however does not involve the tedious method of converting DC to AC, then stepping up the voltage and then converting the stepped AC voltage to DC. This method is inefficient and involves too many steps. A boost converter also known as step-up converter is one of the simplest types of switch-mode converters. As the name suggests, the converter takes an input voltage and boosts it.

In other words, its like a step up transformer i. All it has is an inductor, a semiconductor switch, a diode and a capacitor. The boost converter is very simple and requires very few components, this is because they were originally designed and developed in the s to power electronics on aircraft. The biggest advantage of a boost converter is it offers very high efficiency.

The inductor , in general is used to store energy. In this circuit , it will be performing the same function as well. Increasing the inductance allows for greater voltage output, because greater the inductance, the more energy it can store. If you place a lower value of inductor then it will produces less voltage at output. We can play around with the inductance values to see how it affects the output voltage. Just any type of inductor which is available cannot be used to make a boost converter.

The inductor should have the required current rating. That means that, the inductor should be able to withstand the high currents and have a highly permeable core, so that the inductance for a given size is high.

It works almost as a switch. These types of diodes allow only the flow of the electrical current in one direction. So, it can be used for the conversion of DC power to DC. The pinout for the given Diode is given below. The diagram above shows the symbolic and the actual picture of the 1N The understanding of any component of an electrical circuit is vastly improved when the electrical characteristics of that device is known. The electrical characteristics of the diode 1N is tabulated below.

The diode 1N features are as follows:. Related Post: 24V Flasher Circuit. We have already mentioned in the beginning that boost converters are types of chopper circuits. In chopper circuits, we have discussed that it performs dc to dc conversion, i. Previously, we have seen another type of chopper circuit i. Buck converters generate an output voltage that is lower than the supplied input. So, we can say, boost converters are the ones that perform a reverse operation of the buck converter.

Due to the type of operation performed by boost converters, these are referred to as step-up choppers. It is to be noted here that since the product of voltage and current results in power then with the increase in the output voltage, the output current through the circuit will automatically decrease.

The circuit here is an elementary form of step-up chopper which necessarily requires a large inductor L in series connection with the voltage source. The whole circuit arrangement operates in a way that it helps in maintaining a regulated dc signal at the output. Let us understand how the given circuit operates in order to provide an increased dc signal at the load. Initially, when the chopper CH is in on state, then in the presence of supply dc input current begins to flow through the closed path of the circuit i.