An Automotive-Use Battery-to-Load GaN-Based Switching Power Converter With Anti-Aliasing MR-SSM and In-Cycle Adaptive ZVS Techniques

Abstract

In modern automotive electronics, there are uprising demands on enhanced power density and reliability for power delivery systems. To achieve high power density, single-stage gallium-nitride (GaN)-based power converters at high switching frequencies ( f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SW</sub> ) are highly desirable but face formidable reliability challenges in the aspects of electromagnetic interference (EMI) suppression and consequential output voltage V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">O</sub> regulation. To address these challenges, this article presents a GaN-based switching power converter that employs an anti-aliasing multi-rate spread-spectrum modulation (MR-SSM) technique for EMI suppression and an in-cycle adaptive zero-voltage switching (ZVS) technique to minimize switching power losses. Compared with classic fixed-rate SSM (FR-SSM), the proposed MR-SSM technique spreads EMI spectra in a wider frequency range without aliasing spikes and, thus, reduces peak EMI more effectively. To improve efficiency, an elastic dead-time ( t <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dead</sub> ) control facilitates in-cycle ZVS despite of a continuously changing f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SW</sub> . An IC prototype based on this design was fabricated on a 180-nm HV BCD process, with an active die area of 0.87 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The converter can handle a variable automotive-use battery voltage from 5 to 24 V and delivers up to 1.2-W power to a regulated output V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">O</sub> at 1 V, with a peak efficiency of 90.2%. It accomplishes a 29% further peak EMI reduction compared with the FR-SSM counterpart.