A DC-DC converter is an electro-mechanical device or circuit that transforms a DC voltage from one level to another according to the needs of the circuit. The DC-DC converter, which falls under the category of electric power converters, can be used for both low voltage applications, such as batteries, and high voltage applications, such as HV power transmission.
In the absence of semiconductors, a prevalent method for converting direct current (DC) voltage into higher voltage levels for low-power projects was the utilization of vibrator circuits to transform it into alternating current (AC) voltage. Subsequently, an upscaling transformer was employed to amplify the output voltage magnitude, succeeded by a rectifier circuit to accomplish the conversion to direct current. A hybrid motor-generator system was utilized for high-power applications. The motor functions to power the generator, supplying the necessary voltage for the load. Despite their high cost and limited efficiency, these procedures were employed due to the absence of any other methods at that time.
The development of power semiconductors and integrated circuits (ICs) resulted in the emergence of cost-effective alternatives, such as the DC power supply, which involves feeding high-frequency AC into a transformer. This device is cost-effective and user-friendly. The voltage is modulated and subsequently transformed into direct current (DC) using rectifiers.
Operation of a DC-DC Converter
The toggling technique is frequently implemented in converter operation. Depending on the requirements of the application, a switched-operated DC-DC converter converts DC voltage from one level to another; the output voltage may therefore be greater or lesser than the input value. The converter reserves energy for a period of time while delivering varying levels of output. The energy is stored in the form of an electrical field in capacitors and a magnetic field in conductor transformers. In contrast to linear voltage conversion, which results in power dissipation through heat, switching voltage conversion is more energy efficient and simpler to process. To attain efficiency, high-speed semiconductor devices with rapid rise and decline times are required. High-speed switching complicates circuit design by necessitating an exact configuration. The prolonged battery life is a result of the switched-mode converter’s high efficiency, which eliminates the requirement for heat absorbers. The utilization of FETs enhances the efficacy of the converter as these components execute the switching process with reduced losses in comparison to BJTs.
Additional enhancements to the DC-DC converter consist of substituting the flyback diode in the synchronous rectifier circuitry with a power FET, which reduces switching losses and possesses a lower resistance.
The power transfer through the majority of DC-DC converters is unidirectional, from input to output. Replacing all diode-controlled active rectifier circuits, on the other hand, enables bidirectional power transfer in any direction for all switching regulator circuits. Bidirectional converters are advantageous in situations such as vehicle regenerative braking, in which power is supplied to the wheels while the vehicle is in motion and received while the vehicle is coming to a stop.
Similar to other high-frequency circuits, DC-DC converters require certain adjustments, including the selection of components, establishment of connections, and regulation of switching noise to an acceptable degree. At first, the cost of creation was greater than that of linear regulators; however, that soon diminished as a result of employing the most recent circuit creation technique.
DC-DC converters today are IC-based and a few additional components are required. A hybrid configuration of these components is also present in a number of electronic structures.
The various types of DC-DC converters are illustrated in Figure 1, including buck, boost, buck-boost, and Ňuk circuits. The circuits are designed with the input located on the left and the load receiving the output on the right. Power switches may consist of BJTs, MOSFETs, or IGBTs.
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