Co nstant on Time Controller f or Voltage Regulator with and without Adaptive Voltage Positioning

Abstract

Advancement in electronics prompted for incremental usage of power supplies in digital circuits. In devices such as Central Processing Unit (CPU), Graphic Processing Unit (GPU) a Voltage regulator (VR) is utilized for microprocessors powering application. During load transients, microprocessor input voltage losses stability. High speed devices need quick response from the converters under transient conditions. Therefore, futuristic electronic devices demand a VR with new control schemes to operate at low operating voltage with improved efficiency thereby improving light load efficiency. In this paper a comparative study about the performance of Constant on Time (COT) controller with and without Adaptive Voltage Positioning (AVP) technique is presented. . The aim of the paper is to present the idea of AVP with COT during transients. Since load transient demands large number of capacitors to maintain stable voltage but increases the cost and volume. Thus, to overcome the transient time frame problem, voltage spikes and to reduce the number of capacitors. The converters need to operate under a new control scheme i.e. COT controller with AVP. Simulation of the voltage regulator is carried out for both Non AVP and AVP compliant schematics in LTSpice software. The simulation results show Non-AVP topology with output voltage spikes for 445uF but the AVP compliant topology with 222uF shows smooth output voltage transition.