Abstract
With perpetual electrification and highly dynamic operations, modern automotive ICs face unprecedented elec- tromagnetic interference (EMI) challenges. To address such, this article presents a condition-adaptive 1 f 3 EMI control for automotive power circuits, which coordinates integral spread- spectrum modulation (SSM) schemes to regulate EMI adaptively in response to drastic condition changes of input voltage VIN and load current ILOAD. Specifically, a 1 fSW,UP/DN spread control technique steers the 1 fSW spread direction according to VIN, while a 1 fSW spread range modulation scheme adjusts the 1 fSW range according to ILOAD. Meanwhile, a 1 fSW adaptive multi-rate (MR) SSM scheme prevents spectrum overlap spikes. With the three distinct 1 fSW-focused control modules working cohesively, we name the overall EMI control as the 1 f 3 EMI control in this work. In addition, to avoid high-energy EMI from entering the audible frequency range, a modulation frequency fM envelope tracking scheme is also developed. Demonstrated in an automotive-use GaN switching power converter, this work was fabricated using a 180-nm HV BCD process. It auto-extends 1 fSW from 10% to 32% and reduces EMI by 17.2 dB to counteract ILOAD elevation from 200 mA to 1 A. Meanwhile, it can down-spread fSW adaptively by the MR-SSM with a 16.3 dB reduction in response to a VIN increase from 12 V to 24 V without causing overlap spikes.