A 4-to-42V Input, 95.5% Efficiency, 3.2μA-IQ, DC-DC Buck Converter Featuring a Leakage-Emulated Bootstrap Re-fresher and Anti-Deadlock Self-Bias Supply for Battery-Powered Automotive Uses

• Published in: 2023 IEEE Custom Integrated Circuits Conference (CICC) pp. 1 - 2
• Main Authors: Lee, Heejun, Han, Hyunki, Kim, Hyun-Sik
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.04.2023
• Subjects: Automobiles; Batteries; Switching frequency; System recovery; Temperature control; Temperature distribution; Voltage
• ISSN: 2152-3630
• DOI: 10.1109/CICC57935.2023.10121275

As more components of advanced automobiles become electrified, the importance of DC-DC converters, which efficiently supply reliable power from the car battery (V_{1\mathrm{N}}), is increasing. DC-DC converters for automotive use should accommodate a high V_{1\mathrm{N}} as well as have broad and large step-down ratios of V_{\mathrm{O}}lV_{1\mathrm{N}} (e.g., V_{\mathrm{O}}=3.3V), especially considering that some modern automobiles have adopted 42V battery systems [1-5]. Aside from high reliability against abnormal faults [2], the operable temperature range must comply with the AEC-O100 standard (-40\sim+125°C). Furthermore, to prevent battery drain from standby systems when the car ignition is turned off, it must consume low quiescent current (l_{\mathrm{O}}) that flows into I/_{1\mathrm{N}} at no load. However, there are several obstacles to achieve a low l_{\mathrm{O}} in high-V_{1\mathrm{N}} DC-DC converters. For instance, at an ultra-low switching frequency (f_{\mathrm{S}\mathrm{W}}) that is to reduce l_{\mathrm{O}}, the converter working in discontinuous conduction mode (DCM) and pulse-frequency modulation (PFM) is hard to securely maintain the bootstrap-capacitor voltage due to the considerable leakage current of the high-voltage (HV) diode at high temperature. in addition, while self-biasing the controller's power (V_{\mathrm{D}\mathrm{D}}) from the converter output (V_{\mathrm{O}}) may be a straightfonNard way to lower l_{\mathrm{O}} in \mathrm{h}\mathrm{i}\mathrm{g}\mathrm{h}-V_{1\mathrm{N}}8_{(}1\mathrm{o}\mathrm{w}-V_{\mathrm{O}} DC-DC converters [6], a deadlock issue is likely to arise because of the inherent positive feedback structure.