Dual-Edge Pulse Width Modulation Scheme for Fast Transient Response of Multiple-Phase Voltage Regulators

Abstract

Transient response is a key performance for the multiphase voltage regulator, especially in microprocessor core (Vcore) applications. Conventional PWM modulation schemes have delay times which can increase the demand on the output capacitors, forcing designs to employ more capacitors for acceptable performance. A new modulation scheme is proposed to achieve very fast transient response by dramatically reducing the modulator delay time. The required output capacitors are much less with this scheme, especially in a Vcore multiphase voltage regulator. In this paper, the conventional modulator delay time is investigated and compared with the new scheme, and some experimental results are included to illustrate the impact of the new modulator on transient performance.