Improving the efficiency of DC-DC converters by selecting an appropriate inductor current
Tutor / director / evaluadorReverter Cubarsí, Ferran
Tipo de documentoProjecte Final de Màster Oficial
Condiciones de accesoAcceso abierto
[ENGLISH] The main goal of this project is to find an optimal current flowing through the DC-DC converter's inductor during the energy transfer from the voltage source to the load. To do this, it has been proposed a circuit divided into two blocks: the first one is a DC-DC converter whose main function is to convert an input voltage into a higher output voltage and the second one is a comparator whose main function is to compare two different voltages to force the DC-DC converter working in PFM mode and more particular in burst mode. To find this optimal current, first of all we have to validate performing a circuit simulation with LTspice software and later design a PCB layout to test it. All tests consist in obtaining the behaviour of the DC-DC converter if certain critical values are modified such as the programmable resistance of the circuit to change the inductor's current, the input voltage to simulate the wear that could may have the batteries, the output voltage of the circuit to emulate the circuits that require a different supply to operate and finally the output current of the circuit that emulates the current that can consume several circuits connected to the output of the DC-DC converter. As manufacturer says, in light-load conditions, this DC-DC converter has a very poor efficiency of 40% approximately working in PWM mode but if we change to PFM mode, this efficiency will double. To improve more the efficiency, burst mode is used and this efficiency will increase to 86% producing an enhancement of the efficiency between burst PFM mode and PWM of 49%.