A 95.2% efficiency dual-path DC-DC step-up converter with continuous output current delivery and low voltage ripple

DC-DC boost converters are widely used to increase the supply voltage in various applications, including LED drivers, energy harvesting, etc. [1-5]. The conventional boost converter (CBC) is shown in Fig. 27.5.1, where the switches S 1 and S 2 are turned on and off alternately at φ 1 and φ 2 , respectively, and the inductor current (I L ) is built up and delivered to the output. There are some critical issues in CBC because the output delivery current (I S ) is not continuous. As a result, the I L can be much larger than the load current (I LOAD ) as φ 1 becomes longer. Since a bulky-size inductor having a low parasitic DC resistance (R dcr ) is not usable for mobile applications with a strictly limited space, this large I L results in significant conduction loss in the large R DCR of a small-size inductor. Another issue is that the discontinuous I S in φ 2 causes large voltage ripple (AV OUT ) at the output. Moreover, switching spike voltages can cause over-voltage stress on the loading block due to large di/dt of I S combined with parasitic inductances of the GND path.