Time-Shift Current Balance Technique in Four-Phase Voltage Regulator Module with 90% Efficiency for Cloud Computing

Abstract

Four power stages for voltage regulator module (VRM) are adopted to provide high current driving capability and low output ripple in cloud computing. Thus, the time-shift current balance (TSCB) technique is proposed to achieve high performance power supply for servers. In addition, the power request, which includes the number of active phases and voltage identification, is acknowledged by servers for high driving capability during high throughput and high efficiency during standby mode. Furthermore, to equally distribute the current in each phase, the proposed TSCB technique in either voltage-mode or peak current-mode control improves the current balance performance and solves the stability problem. In the scale-down clouding computing prototype, the efficiency can be kept higher than 90% over a wide load current range of 2 A. In addition, the performance and operating frequency of the servers in stable operation are not limited by the VRM with the TSCB technique.