An Automotive-Grade Monolithic Masterless Fault-Tolerant Hybrid Dickson DC–DC Converter for 48-V Multi-Phase Applications Mojtaba Ashourloo , Student Member , IEEE, Venkata

Abstract

Autonomous-driving features necessitate a fault- tolerant (FT) power-management unit in 48-V automotive applications. This article presents a monolithic single-phase closed-loop masterless FT four-to-one hybrid Dickson converter IC for high-conversion-ratio 48-V automotive multi-phase appli- cations. The chip includes: 1) a mixed-signal droop-based valley- current ON-time quasi-fixed-frequency control, which enables masterless multi-phase operation capability; 2) single-point short- circuit fault and open-circuit fault detection and blocking of any power switches or flying capacitors; 3) an optimized high- voltage (HV) power stage with fully integrated flying-capacitor- sourced gate drivers without any external bootstrap capacitors; 4) a glitch-free cross-coupled bootstrapped HV level shifter; and 5) a dual-leg bidirectional closed-loop current-sensing circuit opti- mized for the hybrid Dickson topology. The design was fabricated in a 0.13- µm 90-V automotive silicon-on-insulator (SOI) bipolar- CMOS–DMOS (BCD) process. The measured results confirm the operation over 20–60-V i nput, 3.3-V nominal output, 3-A maximum load, and 320-kHz effective switching frequency within the automotive-grade −40 ◦C–+125 ◦C ambient temperature. The design achieves above 90% measured efficiency at maximum con- version ratio and load at room temperature. A three-phase system is used to evaluate and confirm the fault-blocking capability and continuous power delivery upon detection of a fault.