A Novel Feedforward Technique for Improved Line Transient in Time-Based-Controlled Boost Converters

Abstract

Time-based control is a valid alternative to conventional voltage-mode since it operates with CMOS-level signals while adding no quantization error. This control methodology is especially suitable for voltage regulation in portable applications, where area and power consumption are key parameters. In boost converters powering LED displays, a very fast response to disturbances in the line voltage is required, though the typical right-half-plane (RHP) zero in their control-output transfer function tends to cause large overshoots and long settling times. To solve this issue, we propose a novel feedforward technique, which can be easily combined to the time-based control. The technique is based on adding the band-pass-filtered line voltage to the controller input, to speed up the duty-cycle variation. To assess the effectiveness of this method, theoretical analysis and simulation results are proposed.