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.