DC-DC Converters

A DC-DC converter is a type of DC power supply that utilizes DC voltage as an input. The main function of DC-DC converters is to generate regulated output voltage for electric and electronic applications.

 

A DC-DC converter is a type of aerobic exercise equipment that utilizes DC voltage as an input. The main function of DC-DC converters is to generate regulated output voltage for electric and electronic applications. Unlike AC, DC cannot be changed from one voltage level to another (step up or step down) using a transformer. Instead, a DC-DC converter is used for this purpose. Hence, this type of DC power supply can be considered an equivalent of a transformer. Like transformers, DC-DC converters convert the input energy into a different impedance level. It should be noted that no energy is generated inside the converter since all the output power comes from the input power. In real applications, energy losses occur inside the converter; the energy is consumed by some components in the circuit. Due to advances in components and circuit techniques, DC-DC converters can have an efficiency as high as 90%. For the older models, the efficiency usually ranges from 80-85%.

 

Principle of operation of a DC-DC converter:

 

DC-DC converters are categorized into two types:

1.Non-Isolating Converters

A type of DC-DC converter that is used for stepping up or down the voltage by a small ratio (< 4:1).

Non-isolating converters do not use dielectric isolation between the input and output.

Some of the examples include 24V/12V voltage reducers, 5V/3V reducers, and 1.5V/5V step-up converters.

 

Non-isolating converters have five types:

â–ºBuck Converter:

For voltage step-down

â–ºBoost Converter:

For voltage step-up

â–ºBuck-Boost:

For either step-down or step-up

â–ºCuk:

For either step-down or step-up

â–ºCharge-Pump:

Also used for either voltage step-up or inversion (low power applications)

 

2. Isolating Converters

Isolating Converter is a type of DC-DC converter that completely isolates the output from the input using dielectric isolation. There are two types of isolating converters:

 

❤Flyback Converter

It has a similar operation to buck-boost converters, but instead of using a single conductor to store the energy, it utilizes a transformer.

❤Forward Converter

It utilizes the transformer in a more typical manner i.e., it directly transfers the energy between the input and output in one step.

 

DC-DC converters are useful in the following applications:

â–ºOperation of car radio, CB transceiver, or mobile phone

Stepping down of 24V DC (truck battery) to 12V DC

â–ºRunning a personal CD player

Stepping down of 12V DC (car battery) to 3V DC

â–ºEnergizing one of the latest CPU chips

Stepping down of 5V DC (personal computer motherboard) to 3V, 2V or less

â–ºPC power supply application

Stepping down of 340V DC (from rectified 240V AC power) to 5V, 12V, and other DC voltages

â–ºOperation of electronic circuitry

Stepping up of 1.5V (single-cell) to 5V or more

â–ºProviding an insulation testing voltage

Stepping up of 6V or 9V DC to 500V DC or more

â–ºRunning a car HiFi amplifier’s circuitry

Stepping up of 12V DC to +/- 40V

â–ºDC-AC sine wave inverter application

Stepping up of 12V DC to 650V DC