Multiphase optimal response mixed-signal current-programmed mode controller

Abstract

This paper presents a simple and practical implementation of a proximity optimal-time (OT) response controller for multiphase interleaved dc-dc switch-mode power supplies (SMPS). This novel solution enables equal current sharing between phases not only in steady state, but also during load transients. It also achieves a bump-less transition between the transient and steady state, where the interleaved operation is resumed without any delay. To minimize calculation burden and hardware complexity, a single digital voltage loop and multiple analog current loops are combined to implement a capacitor-charge balance based optimal-time recovery algorithm. The interface between the loops is provided through a structure consisting of a sample-and-hold circuit (S&H) and a relatively slow successive approximation digital-to-analog converter (DAC) providing control signals for all the current loops. The effectiveness of the controller is demonstrated on a 2-phase, 5V-to-1.8V, 20W, interleaved buck converter operating at a 1MHz switching frequency. The experimental results verify equal current sharing under all operating conditions, bump-less transition between the modes, and demonstrate that upon a transient converter reaches new steady state in the virtually fastest possible time.

Design of envelope amplifier based on interleaved multiphase buck converter with minimum time control for RF application

“…There are two parameters can be used to describe the state of converter, the inductor current and output voltage. The method of MTC is to change the buck converter from the initial state to the target state through a single on-off switching action [8]. In order to apply MTC properly, some solutions use pre-define on and off time, and the others have control loop to operate MTC.…”

Minimum Time Control for Multiphase Buck Converter: Analysis and Application

“…Using phase-plane trajectory from the geometric control surface, the length of the on-time and off-time can be obtained to achieve minimum time transition [14], [15]. However, some approximations can be done in order to get analytical expressions for minimum control in most of applications, which lead to the charge balance method [16] described by observing Fig. 1.…”

A 10 MHz mixed-signal CPM controlled DC-DC converter IC with novel gate swing circuit and instantaneous efficiency optimization

“…In the design introduced here, the CP-DAC is modified such that the high resolution is maintained throughout the whole operating range. This modification not only improves the voltage regulation but also allows implementation of fast dynamic response control laws that usually require accurate control signals [13][14][15][16].…”

“…To verify the closed loop response of the converter in CPM and fast response of CP-DAC, Fig.7 shows the results of converter operation with near time-optimal controller [13][14][15][16] to a 150mA-450mA load step. The light to heavy load transient is shown in Fig.7.a.…”