Integrated Loop-Gain Measurement Circuit for DC/DC Boost Converters with Time-Based Control

Abstract

The open-loop transfer function provides valuable insights into the key dynamic characteristics of DC/DC voltage regulators, such as stability, line and load transient response. Nonetheless, the experimental measurement of the loop gain in a monolithically integrated regulator is not straightforward or not even possible by using standard techniques, especially when complex control strategies are adopted. To overcome this issue, we propose an integrated loop-gain measurement circuit specifically designed for DC/DC converters with time-based control. The measurement circuit includes a transconductor, two delay lines, and a simple logic that can be easily integrated in a small silicon area. Moreover, the circuit can be easily disabled during normal operation to minimize its impact on the regulator performance. The proposed circuit was fabricated in a 180nm CMOS technology, occupying a silicon area of $0.027\mathrm{mm}^{2}$. Experimental validation was performed by embedding the circuit into a boost converter with time-based control.