98.1%-Efficiency Hysteretic-Current-Mode Noninverting Buck–Boost DC-DC Converter With Smooth Mode Transition

Abstract

 Abstract-A non-inverting buck-boost dc-dc converter can work in buck, boost, or buck-boost mode. Hence, it provides a good solution when input voltage may be higher or lower than output voltage. However, a buck-boost converter requires four power transistors, rather than two. Therefore, its efficiency decreases, due to the conduction and switching losses of the two extra power transistors. Another issue of a buck-boost converter is how to smoothly switch its operational mode, when its input voltage approaches its output voltage. A hysteretic-current-mode non-inverting buck-boost converter with high efficiency and smooth mode transition is proposed, and it was designed and fabricated using TSMC 0.35 μm CMOS 2P4M 3.3V/5V mixed-signal polycide process. The input voltage may range from 2.5 to 5 V, the output voltage is 3.3 V, and the maximal load current is 400 mA. According to the measured results, the maximal efficiency reaches 98.1%, and the efficiencies measured in the entire input voltage and loading ranges are all above 80%.

A novel active‐clamp zero‐voltage‐switching buck‐boost converter

“…Similarly, the inductor current i L2 at t 5 can be rewritten by replacing i L2 (t 2 ) in Equation 26 into Equation 28…”

“…Numerous researchers have focused on ideas to implement non-inverting buck-boost converter. Other papers in the literature [26][27][28][29] introduce some control schemes using digital signal processors to reduce the switching losses, and hence, the efficiency is improved. On the other hand, 4-switch buck-boost converters feature a more complicated control algorithm, high number of external components.…”

“…Large circulating current and complex control strategy limit the operation of this converter in light load condition because it requires significant negative inductor current to maintain the ZVS feature. Other papers in the literature [26][27][28][29] introduce some control schemes using digital signal processors to reduce the switching losses, and hence, the efficiency is improved. However, they are not suitable for high switching frequency application due to clocking speed limitation of digital signal processors.…”

Low-frequency ripple-shaping controller for operation of non-inverting buck-boost converters near step-up step-down boundary

“…Finding a control scheme for the smooth transition between step-up and step-down operation while preserving high power processing efficiency has been a challenge [8,9]. Multiple control methods [10,11,12,13,14,15] proposed in recent years aim at avoiding the buck-boost mode while reducing the average inductor current and switching losses at the same time. These control methods will be reviewed in Chapter 2.…”

“…To address the aforementioned transition problem in non-inverting buck-boost converter, a number of control based solutions have been proposed [10,11,12,13,14,15,21,22,23]. In this chapter, prior state of the art are reviewed.…”