High-Voltage DC–DC Converters

This chapter presents high-voltage power converters as a solution to the design challenges at high input voltages and low output powers, identified in Chap. 2. Characteristics of state-of-the-art converter architectures and control approaches are discussed regarding their suitability for a chip-scale high-voltage low-power conversion. The following converter architectures, developed and implemented in this work, are presented: (1) A step-down converter that uses a constant-on-time control to enable a high light-load efficiency even at input voltages of up to 400 V. (2) A converter that uses a resonant approach to enable an efficient and compact power conversion at high voltage-conversion ratios. (3) A combination of the presented resonant converter and step-down converter to take advantage of both architectures. (4) An active-clamp flyback as a solution for applications requiring galvanic isolation. This chapter also compares the performance of the implemented converters to commercial products and prior-art publications. It also discusses the design of the power inductor and transformer for light-load-optimized high-voltage power converters.